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I've had these two explained multiple times. They continue to cook my brain. Missing Not at Random makes sense to be, and Missing Completely at Random makes sense...it's the Missing at Random that doesn't as much.
What gives rise to data that would be MAR but not MCAR?
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Possible Duplicate:
Steps to figure out a posterior distribution when it might be simple enough to have an analytic form?
I must admit this is an embarrassing question. I do a lot of programming for statistics work, but rarely do I ever deal with analytical formulas for things (it's usually all just based on algorit... |
The question is
Let $X_1,...,X_n$ be drawn iid from $Beta(0.1,0.5)$. Let $\bar{X} = \frac{1}{n}\sum^n_{i=1} X_i$.
a) Derive $\mathbb{E}(\bar{X})$ and $\mathbb{V}(\bar{X})$
I know how to get the expectation and variance of a random variable from a given distribution. But I'm not how to get the expectation and variance... |
How does standardized mean decomposition differ from the simpler dummy variable regression? How does the average in mean outcomes or interpretation of results attributable to a particular treatment or dummy differ when standard decomposition is used, as opposed to dummy variable regression?
|
I couldn't find any information in the documentation of rapidminer. I have a data set with the following attributes:
a,b,c,d,e.
The types are: numerical, binomial, binomial, binomial, binomial.
Binomial values are given as {true, false}.
The last one is the label I want to be able to predict. So the value to predict is... |
Can anyone explain to me the benefits of the genetic algorithm compared to other traditional search and optimization methods?
|
In my project, I am looking at the relationship between X and Y by the grouping factor "gender".
This is at two stages. The first is to see how XY correlate in each subgroup (Pearsons r) and the second is to see if there is a gender difference in the XY correlation (general linear model).
I am using SPSS and the scat... |
I have a data set that's 200k rows X 50 columns. I'm trying to use a knn model on it but there is huge variance in performance depending on which variables are used (i.e., rsqd ranges from .01 (using all variables) to .98 (using only 5 variables)).
This kind of compounds my problem as now I need to determine k and whi... |
So we have arithmetic mean (AM), geometric mean (GM) and harmonic mean (HM). Their mathematical formulation is also well known along with their associated stereotypical examples (e.g., Harmonic mean and it's application to 'speed' related problems).
However, a question that has always intrigued me is "how do I decide w... |
A. Determine the restrictions needed on the $a$'s so that $z=\sum_{i=1}^{n}a_iX_i$ will be an unbiased estimator $E\left[X\right]$, where $X_1,X_2,\dotsc,X_n$ represents a random sample of $X$.
Answer: The $a$'s must sum to one.
B. What is the best set of $a$'s to choose from A if $z=\sum_{i=1}^{n}a_iX_i$ is to be an u... |
In Andrew Ng's machine learning course, he introduces linear regression and logistic regression, and shows how to fit the model parameters using gradient descent and Newton's method.
I know gradient descent can be useful in some applications of machine learning (e.g., backpropogation), but in the more general case is t... |
I am doing a study on the effects of bad blood sugar control on patients. BMI, age, type of diabetes (Type 1 and 2 or gestational diabetes) are all variables. Outcomes include C section, early labour etc. A reviewer told me
Comparisons should be adjusted to maternal age and baseline BMI.
How does one do this with a... |
I am looking for datasets of 2 dimensional datapoints (each datapoint is a vector of two values (x,y)) following different distributions and forms. Code to generate such data would also be helpful. I want to use them to plot / visualise how some clustering algorithms perform. Here are some examples:
star like cloud da... |
There are words from the The Elements of Statistical Learning on page 119:
It is not hard to show that the following basis represents a cubic spline with knots at $\xi_1$ and $\xi_2$:
$h_1(X)=1$
$h_2(X)=X$
$h_3(X)=X^2$
$h_4(X)=X^3$
$h_5(X)=(X-\xi_1)_+^3$
$h_6(X)=(X-\xi_2)_+^3$
Then my question is that, accordi... |
I've been reading a lot lately about the differences between Fisher's method of hypothesis testing and the Neyman-Pearson school of thought.
My question is, ignoring philosophical objections, when should we use Fisher's approach to data testing and when should we use the Neyman-Pearson method? Is there a practical way ... |
Let us say I have a bunch of rows for a classification problem:
$$X_1, ... X_N, Y$$
Where $X_1, ..., X_N$ are the features/predictors and $Y$ is the class the row’s feature combination belongs to.
Many feature combination and their classes are repeated in the dataset, which I am using to fit a classifier. I am just wo... |
I have a variable Net Promoter Score (NPS) which is an item on a survey, the answer format is ordinal, 0 to 10.
Then, there are sub-questions on the same survey, some are ordinal, some are categorical.
I would like to determine which sub-question or which group of sub-questions are the best predictors of NPS. The goal ... |
a) For a given significance-level $\alpha$, if we find $\mathop{\mathbb E}(b-a)$ such that $\mathbb P(a \leq X \leq b) \geq 1−\alpha$ for all possible values of $a$ and $b$, from the point of view of interpretability, what extra interpretability does the expected length buy us?
Say, if I had observed proportions $ p_{1... |
Related to Analysing ratios of variables and How to parameterize the ratio of two normally distributed variables, or the inverse of one?.
Suppose I have a number of samples from four different continous random distributions, all of which we can assume to be roughly normal. In my case, these correspond to some performan... |
Question:
This is a bit of an abstract question, but bear with me. I am averaging images, to try and deduce what the average image of a specific subject looks like (just out of curiosity, it might produce some interesting results).
In order to know what kind of averaging method is permitted, i am trying to determine as... |
When building a decision tree, suppose that there are two attributes that have the same maximum information gain.
Will there be any difference between choosing any of the two attributes to be a tree node? Or are there any other factors that I have to consider in order to decide which attribute should I choose?
|
I have a time series where I need to detect gross anomalies due to coding errors, not small shifts in the structure of the series. I am interested in the most recent data points, not historical data so I don't need to filter everything. What is the best way to use moving means and averages in combination with spread ... |
I have lots of problem with one data set to which I am trying to apply SEM.
We suppose the existence of 5 latent factors A, B, C, D, E, with indicators resp. A1 to A5 (ordered factors), B1 to B3 (quantitative), C1, D1, E1 (all last three ordered factors, with only 2 levels for E1. We are interested in covariances betwe... |
As far as I know you can do a F-test ($F = s_1^2/s_2^2$) or a chi-squared test ($\chi^2 = (n-1)(s_1^2/s_2^2$) for testing if the standard deviations of two independent samples are different. But does this also hold for dependent samples?
|
I want to interpret an interaction. Usually a conditional regression analysis is done with 1 SD below/above the mean (see Aiken & West, 1993, p. 18). My result is a contrast with $p=.068$ if I take 1.5 SDs $p=.044$. with 2 SDs $p=.033$.
It seems that contrasts get stronger by increasing values the number of SDs. Thus,... |
I understand how EM is used in the sense of estimating the Gaussian model that underlies a set of data, but its unclear how this is applicable.
I am trying to understand how EM might be used to perform data mining on any sort of computer vision/image processing task. This is the domain I am most familiar with, so it ... |
Here is the head of my data set (tjornres):
Fish.1 Fish.2 MORPHO DIET
1 1 2 0.03768 0.1559250
2 1 3 0.05609 0.7897060
3 1 4 0.03934 0.4638010
4 1 5 0.03363 0.1200480
5 1 6 0.056... |
I am doing a project work in sentiment analysis (on Twitter data) using machine learning approach. In order to find the 'best' way to this I have experimented with naive Bayesian and maximum entropy classifier by using unigrams, bigrams and unigram and bigrams together. I'm using the SharpEntropy library for ME, and an... |
How to get the marginal pdf of $p(y)$? Do you just integrate out $p({\sigma}^{2})$?
Say, the following joint distribution for $y \in {{R}^{d}}$ and ${{\sigma }^{2}}\in {{R}^{d}}$
IG: means inverse Gamma
$${{\sigma }^{2}}\sim IG(\alpha ,\beta )\propto {{({{\sigma }^{2}})}^{-(\alpha +1)}}{{e}^{-\beta /{{\sigma }^{2}}}}$$... |
(apologies in advance if I abuse any terminology)
I have a series of XY data points that I fit with a simple regression and I would like to be able to use this regression to obtain a p-value for the new data point. I have found a couple of sources describing how to calculate a Prediction Interval for Responses to a Par... |
A very basic question about cross validation for Neural Networks.
Do I have to create a new network for each fold or do I have to keep the network and incrementally train it with the k-th training set?
http://www.faqs.org/faqs/ai-faq/neural-nets/part3/section-12.html says "You train the net k-times..." which let's me ... |
I want to see if it is possible to analyse openly available images (from google, flickr, etc.), and conclude something from them (the same way one might do this from census data but with images as data).
In my opinion online sources offer a wealth of data, and can easily be grouped by subject (for example: by searching... |
I have the vague recollection of a result that states something along the lines of
Joint parameter estimates always lead to smaller variance than
independent parameter estimates even when the
parameters are uncorrelated.
Does this ring a bell for anyone? What is the more accurate statement of the result, and whe... |
I'm analyzing data from an unbalanced factorial experiment both with SAS and R. Both SAS and R provide similar Type I sum of squares but their Type III sum of squares are different from each other. Below are SAS and R codes and outputs.
DATA ASD;
INPUT Y T B;
DATALINES;
20 1 1
25 1 2
26 1 2
22 1 3
25 1 3
25 1 3
... |
I'm trying to design a statistics package in .NET, and I'd like to apply object-oriented design principles to some of the data structures that I'm developing.
As I look through sample data sets for simple classifiers, even though there exist other types of attributes (ordinal being the only other one I've seen, with di... |
I have a task that is specific to inventory management that is currently driving me crazy. To summarize the problem: We regularly must monitor inventory settings to ensure that they represent true demand, to ensure that we are not overstocking nor understocking. The standard procedure is to schedule reviews, where high... |
Is drawing a scatter plot, with fitted regression lines for subgroups, the way to graph a possible interaction in SPSS?
I may be missing something but I could not find a specific way to do it. I have only just migrated to SPSS from Excel!
My IV and DV are interval scale measures and the factor is a categorical variable... |
Let $\{W_t,t \geq 0\}$ be a standard Brownian motion under $\mathbb P$. Let $T_a$ be the hitting time of level $a$, that is:
$$T_a= \text{inf}\{t \geq 0:W_t=a\}.$$
From a proposition, we know that
$$\mathbb E[\exp(-\theta T_a)] = \exp(-a \sqrt{2\theta}).$$
How do we make use of the above preposition to calculate $\mat... |
Lets' $p$ and $q$ are probability mass functions of two discrete random variables. I need examples of functions $F(p,q)$ that $r = F(p,q)$ and $r$ is a probability mass function for some random variable. Thank you.
Edit: I mean that $r$ should be probability mass function for arbitrary distributions $p$ and $q$.
|
Is it valid to train a neural network over and over again with new arriving data (including pruning after each new training)?
I plan to collect data for a period of time, train/cv/test the networ, then again collect new data and train the existing and already trained network with the new data.
The time series predicti... |
In my system I have users rating objects (e.g. films) from 1 to 5 stars.
The mean rating clearly tells something about the overall opinion on an object, but I'd like to use a more precise measure of variability.
For example, if the stars are set randomly, if half of the users give 1 and the other half is 5, the average... |
I have a significant 2x2 interaction in a between-subjects design. I would normally report omega-squared as my effect-size measure, but I've been asked to provide Cohen's d instead? Can Cohen's d be computed for an interaction? If so, how?
|
I have written a computer program that can detect coins in a static image (.jpeg, .png, etc.) using some standard techniques for computer vision (Gaussian Blur, thresholding, Hough-Transform etc.). Using the ratios of the coins picked up from a given image, I can establish with good certainty which coins are which. How... |
I've got a problem. I need to create network graph where avatars are nodes (different sizes). Similar to this one:
Furthermore on this image every avatar has the same size, what I need to do is different size of avatar depending on a chosen statistic (e.g. in-degree). I cannot find any tutorial in R, which explains ho... |
I'm considering using R for my master thesis in order to do some analyses with the mvpart package. The problem is that I only have limited time to learn the program and to do the analyses. I already read through some information concerning R and I'm starting to get the feeling that it is impossible to get the know the ... |
In my system I ask $n$ people to rate [1,5] $m$ objects (e.g. films).
I'd like to get a measure of the inter-subject concordance, i.e. how much the users agreed overall, not just on a particular object but on all of the objects.
I know that Kendall's W is a well-established measure of concordance on rankings, but in my... |
I am interested in a measurement or index that will tell me if a curve is more convex or concave versus a straight line.
This curve is sampled in n points and I know the x and y coordinates of these points.
The straight line I am comparing this curve with is a line that goes through the first and last point of the cu... |
I’m working on a data set in order to evaluate the impact of drying on sediment microbial activities. The objective is to determine if the impact of drying varies among sediment types and/or depth within the sediment.
The experimental design is as follows:
The first factor Sediment corresponds to three types of sedime... |
I'm using the neuralnet in R to build a NN with 14 inputs and one output. I build/train the network several times using the same input training data and the same network architecture/settings.
After each network is produced I use it on a stand alone set of test data to calculate some predicted values. I'm finding t... |
I am trying to understand cross-validation for ordinal logistic regression. The aim of the game is to validate the model used in an analysis...
I first construct a toy data set:
set.seed(1)
N <- 10000
# predictors
x1 <- runif(N)
x2 <- runif(N)
x3 <- runif(N)
# coeffs in the model
a <- c(-2,-1)
x <- -x1+2*x2+x3
# P( y... |
In single label learning, we have a single label that we need to predict. Most training tasks are single label, like the most common example where we need to predict if a customer is going to be good or bad.
In multi label learning there are more than one labels. For example if we want to tag a photo, we put more than ... |
As a side hobby, I have been exploring forecasting time series (in particular, using R).
For my data, I have the number of visits per day, for every day going back almost 4 years. In this data there are some distinct patterns:
Monday-Fri has a lot of visits (highest on Mon/Tue), but drastically less on Sat-Sun.
Certai... |
I have a problem of the form "what is the probability that a user will 'like' a certain movie?" For a bunch of users, I know the movies each has watched historically, and the movies each has liked. Additionally, for each movie I know the name of the director.
I calibrated a logistic regression for each user of the form... |
I am solving a classification problem using pairwise-learning training set.
We have 2 classes: bad and good.
We also have pairs of objects $(a_i,b_i)_{i=1}^n$, meaning that object $a_i$ is better than $b_i$.
Each object is described through its real coordinates: $a_i = x_i^1, x_i^2, \dots x_i^k$.
My aim is to build suc... |
A friend of mine was telling me today about the need to mean adjust input variables to zero in order to "get rid of implicit intercept" or scale terms in the slope coefficients and to make their interpretation easier. He was stressing its use and even standardization by the weighted mean in a weighted regression. Both ... |
I'm running a benchmark to find the efficiency of a my computer. There are $p$ control variables say, $x_1,x_2,...,x_p$ and one output variable $Y$. For example, every time I run an experiment I change the control variables and see the output (computer efficiency). So basically, for this problem I used regression to mo... |
I need to compare the ability of two methods to predict an event with a binary response. Each method produces a score, where the higher score indicates 1 and a lower score indicates 0. I am looking to calculate the odds ratio (in univariable and multivariable analysis) to compare these methods. Here is the break down ... |
I am modeling some data where I think I have two crossed random effects. But the data set is not balanced, and I'm not sure what needs to be done to account for it.
My data is a set of events. An event occurs when a client meets with a provider to perform a task, which is either successful or not. There are thousand... |
Can you / how do you calculate the effect of a one-sample Wilcoxon signed-rank test?
Is there a way to perform the calculation in SPSS or another software package?
|
We know that a paired t-test is just a special case of one-way repeated-measures (or within-subject) ANOVA as well as linear mixed-effect model, which can be demonstrated with lme() function the nlme package in R as shown below.
#response data from 10 subjects under two conditions
x1<-rnorm(10)
x2<-1+rnorm(10)
# Now c... |
Hi all,
Could anybody please help me?
I am trying to learn if there is any good approach in modern statistics that can fit this data well, without over-fitting.
Ok, here is another plot that I used "pch=".""... thanks for pointing that out to me!
Here is a 3D one: again, I want to be able to classify the {positive, n... |
I have some problems in understanding the results of two linear regressions on the same data.
I have 2 variables and I want to know if there is a linear correlation between the two. Let's say velocity of a car and perceived velocity of the conductor.
Let's say I have 4 velocities and 2 evaluations of the perceived velo... |
Recently, I have compared two correlated AUC with the method of Delong. Someone said that since the CI’s overlap, we cannot state the two models were different.
I know that the method of Delong calculated correlated AUC, but I don't know how to answer his question in a formal way. Could someone give some help?
|
As far as I know, LARS solves the following problem (using the same notation as Efron et al. Least angle regression):
Given a vector y, and a matrix X. Pick some column vectors from X, and express y as a linear combination of these column vectors.
In my problem, I have a set of vectors, which can form a matrix Y. I w... |
I have an object:
noise.lm
it's just a simple linear model with an X and Y.
when I type in
resid(noise.lm)
it produces the residuals like this:
1 2 3 4 5 6
-0.40501681 -1.16960373 -0.66636219 -0.41798296 1.37942381 0.84336242
I would like to access the r... |
I have been exposed to R before but after being away from the language for 10 years I find my self having to start from the start.
I have a large data set with over 1 million rows and 20 variables. I know there are quicker and faster ways of mining that data but my customer insists on using hypothesis testing to identi... |
I understand that for the individual trees, a least squares measure is used to measure node impurity, given candidate splits of the data at that split, and the best split is selected.
What I don't understand yet (since I couldn't find an answer in the documentation) is how candidate splits are found in the first place,... |
I used to think my time-serie was seasonal, but then I realized it simply needed some calendar-effect adjustment. I tried that and I'm now in doubt there might still be some seasonality left. I tried adding a 12 month differencing, and it seemed to work, but then I thought: why not just try 12 month differencing in the... |
I'm trying to fit linear models to my data in R. I need to use a generalised least squares method as I have heterogeneity of variance in one of my variables. I was planning to use varIdent, as the variable is nominal.
But - I also want to have a random term as my data have a nested structure, and my data need to be mod... |
My question originated from Xi'an's suggestion to check integrability against the posterior in my nonlinear hierarchical model. I did not check it, but had possible infinity in mind and found out that one of my conditionals (which is inverse gamma distribution) have infinite variance. So that sampling resulted in chain... |
I am trying to do learn how to do a repeated measure in R using ezANOVA and I have used the following command:
> ezANOVA(data=NL2, dv=.(ln.conc.), wid=.(sample), within=.(time),
> between=.(pH), type=1, detailed=TRUE)
This is my output and my question is why Mauchuly's test is not appering? I believe I have 9 levels i... |
What is the difference between Cross Correlation and Mutual Information. What kind of problems can be solved using these measures and when is it appropriate to use one over the other.
Thanks for the comments. To clarify, the question is prompted by an interest in image analysis rather than time series analysis although... |
In the Estimates of Fixed Effects SPSS-table, I don't understand why certain parameters are set to zero an just a dotted line appears (because they are redundant according to SPSS). Moreover, I don't get what the t-tests in this table mean. What is being tested here?
Parameter Estimate Std. Error df t Sig. ... |
Given a covariance matrix, it's simple to draw a venn diagram representing the independent and shared variance of two variables. How might one go about the same (at least, computing all pertinent areas; actual visualization not necessary) for the 3-variable case? Is this even possible?
|
I coded a variable as 0/1 (species 1 vs. species 2). I assumed that a dichotomous independent variable can be put in the SPSS mixed model as either a "factor" (two levels) ("by") or, if coded 0/1 also as a covariate (predictor) ("with") and that it would not make a difference. But I was wrong. The statistics do change ... |
Let's say I have 3 variables, A, B, and C and I want to generate data where A and B are correlated at r=x, A and C are correlated at r=y, and B and C are correlated at r=z.
Is there any algorithm that will tell me, given specified values for x, y, and z, if any set of variances for A, B and C will yield a positive de... |
I am new to Matlab and data visualization in general.
I am plotting an A vs. B relation based on 100 values of (A,B) using plot(A,B) which gives me a nice 2-D line plot. Now I want to run 1,000 trials of this and see how the A vs. B relation varies across the trials. (A has a random component and B is dependent on A so... |
The background: I'm analysing survival data using a Poisson model. I've splitted the data on 2 time-scales (attained age and calendar year). Attained age is modelled using flexible parametric functions, calendar year is a categorical variable and I've also included the interaction terms between attained age and calenda... |
Say you have survival data like this:
obs <- data.frame(
time = c(floor(runif(100) * 30), floor((runif(100)^2) * 30)),
status = c(rbinom(100, 1, 0.2), rbinom(100, 1, 0.7)),
group = gl(2,100)
)
To perform a standard log rank test, one can use
survdiff(Surv(time, status) ~ group, data = obs, rho = 0)
right?
But... |
It is well-known, especially in natural language processing, that machine learning should proceed in two steps, a training step and an evaluation step, and they should use different data. Why is this? Intuitively, this process helps avoid overfitting the data, but I fail to see a (information-theoretic) reason this is... |
I need to train a linear classifier on my laptop with hundreds of thousands of data points and about ten thousand features. What are my options? What is the state of the art for this type of problem?
It seems like stochastic gradient descent is promising direction, and my sense is that this is state of the art:
"Pegaso... |
I was wondering if there under some circumstances is possible for ANN's to perform better if you prune away some connections on them as for example:
Constructing one ANN by taking two multi-layered ANN's A and B in parallel (same input and output nodes) adding a few "communication" connections between the hidden layers... |
I am looking for a good and modern Kernel Regression package in R, which has the following features:
It has cross-validation
It can automatically choose the "optimal" bandwidth
It doesn't have random effect - i.e. if I run the function at different times on the same data-set, the results should be exactly the same...... |
I'm designing a multi class classifier (for 4 classes) using Discrete HMMs with States N and Symbols M for each of the HMM.
However, I found that recognition performance(i.e highest log likelihood) of a specific class depends upon the N and M with which it was trained.
Most of the literature I found on the web suggests... |
Looking at the Heritage Health Prize, the data is structured as follows:
Each of the Data Sets will be comprised of tables as follows:
a. Members Table, which will include:
i. MemberID (a unique member ID)
ii. AgeAtFirstClaim (member's age when first claim was made in the Data Set period)
iii. Sex
b. Cla... |
Typically analysis of learning algorithms is in the worst-case setting, for example regret bounds in online learning, or generalisation error bounds in classification. Whilst worst case performance is clearly an important question, it seems that average case analysis would be much more indicative of an algorithm's real... |
I'm using a multi-layered neural network for feature extraction (similar to deep belief network).
I test the performance of my model with cross-validation.
When I'm using back-propagation to train my network, I get a very large variance in the performance.
Seems like it is really crucial which samples (and maybe in wha... |
How are PCA, LDA, CCA, and PLS related? They all seem "spectral" and linear algebraic and very well understood (say 50+ years of theory built around them). They are used for very different things (PCA for dimensionality reduction, LDA for classification, PLS for regression) but still they feel very closely related.
|
What are good strategies for performing Gaussian process regression when the function I am trying to approximate changes over time? The naive approach that springs to my mind is to only use the N most recent data points to perform the regression. What are better strategies?
|
I have a multilabel MRF MAP inference problem (a labeling problem). The graph has relatively few nodes, about a thousand or so. The pairwise term is (very) not submodular (it does not satisfy the triangle inequality). GraphCut with truncation does not work as about 40% of the entries are not submodular. What is the sta... |
I recently read this simple introduction to Adaboost as a review after learning about it a few years ago. This is in preparation for actually using it to solve a problem I am working on which is slightly different than anything addressed in this paper or that I have found online. Now in the problem I am trying to sol... |
I have a list of articles, a domain of words/stems and a calculated tf-idf matrix for them.
What distance metric should I use when I try to calculate the similarity of two documents?
|
I'm trying to build a K-means clustering system with 'online learing', that is, there are existing K clusters and data points in them, and periodically there is a new data point that is sent to an appropriate cluster.
The problem is occuring when I try to reclusterize/redistribute, as it becomes increasingly expensive... |
I remember a paper from 1999 (13 years ago!) called Probabilistic Outputs for Support Vector Machines and Comparisons to Regularized Likelihood Methods (1999) by John Platt that outlined a method for getting probabilistic outputs out of an SVM. From the abstract:
Instead, we train an SVM, then train the parameters of ... |
Are there any large, freely available (but not necessarily labeled) face datasets out there?
The ones I have seen usually range in the hundreds, but for unsupervised feature learning it would be desirable to have thousands if not tens or hundreds of thousands of images.
If the answer is no, what would be a good way of ... |
I'd like to be able to design a classifier that can distinguish between different types of conversations (not necessarily tell anything about mood, sincerity, or outcome, that's a bit too far fetched).
To know, for example, that among 50 samples of conversations, 10 involve both parties seeking information about a futu... |
I have access to a very large dataset. The data is from MEG recordings of people listening to musical excerpts, from one of four genres. The data is as follows:
6 Subjects
3 Experimental repetitions (epochs)
120 Trials per epoch
8 seconds of data per trial at 500Hz (=4000 samples) from 275 MEG channels
So each "examp... |
For a while, it seemed like Fisher Kernels might become popular, as they seemed to be a way to construct kernels from probabilistic models. However, I've rarely seen them used in practice, and I have it on good authority that they tend not to work very well. They rely on the computation of the Fisher Information - quot... |
I'm reading "The Role of Chess in Artificial Intelligence Research" (pdf) and interestingly, it says:
Experience [...] suggests that inputs from chess experts, while generally useful, cannot be trusted completely.
A good example of this is Deep Thought's evaluation function. Several changes by capable human chess ex... |
In the mid 1960s, researchers have famously referred to chess as the "Drosophila of AI": like the fruit fly, the game of chess was accessible and relatively simple problem to experiment on, which yet produced important knowledge more complex problems.
Now, people seem to say "chess is just a search problem" and "chess ... |
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