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I've always been interested in machine learning, but I can't figure out one thing about starting out with a simple "Hello World" example - how can I avoid hard-coding behavior?
For example, if I wanted to "teach" a bot how to avoid randomly placed obstacles, I couldn't just use relative motion, because the obstacles... |
How can I do simple machine learning without hard-coding behavior? |
What open-source books (or other materials) provide a relatively thorough overview of data science? |
I am sure data science as will be discussed in this forum has several synonyms or at least related fields where large data is analyzed.
My particular question is in regards to Data Mining. I took a graduate class in Data Mining a few years back. What are the differences between Data Science and Data Mining and in ... |
Is Data Science the Same as Data Mining? |
In which situations would one system be preferred over the other? What are the relative advantages and disadvantages of relational databases versus non-relational databases? |
What are the advantages and disadvantages of SQL versus NoSQL in data science? |
I use [Libsvm][1] to training data and predict classification on **semantic analysis**.
But it has **performance** issue on large-scale data because semantic analysis concern ***n-dimension*** issue.
Last year, [Liblinear][2] was release and it can solve performance issue.
But it cost too much **memory**.
Is... |
I use [Libsvm][1] to training data and predict classification on **semantic analysis** issue.
But it has **performance** issue on large-scale data because semantic analysis concern ***n-dimension*** issue.
Last year, [Liblinear][2] was release and it can solve performance issue.
But it cost too much **memory**. ... |
I use [Libsvm][1] to training data and predict classification on **semantic analysis** problem.
But it has **performance** issue on large-scale data because semantic analysis concern ***n-dimension*** problem.
Last year, [Liblinear][2] was release and it can solve performance bottleneck.
But it cost too much **m... |
Lots of people use the term *big data* in a rather *comercial* way, as a means of pointing that large datasets are involved in the computation, and therefore upcoming solutions must have nice performance. Of course, *big data* always carry associated terms, like scalability and efficiency, but what exactly defines a pr... |
How big is big data? |
I use [Libsvm][1] to training data and predict classification on **semantic analysis** problem.
But it has **performance** issue on large-scale data because semantic analysis concern ***n-dimension*** problem.
Last year, [Liblinear][2] was release and it can solve performance bottleneck.
But it cost too much **m... |
we created this social network application for eLearning purposes, it's an experimental thing we are researching on in our lab. it has been used by some case studies for a while and the data on our relational DBMS (SQL Server 2008) is getting big, it's a few gigabytes now and the tables are highly connected to each oth... |
the data on our relational DBMS is getting big, is it the time to move to NoSQL? |
My set of data contains a set of numeric attributes and one categorical.
Say, `NumericAttr1, NumericAttr2, ..., NumericAttrN, CategoricalAttr`,
where `CategoricalAttr` takes one of three possible values: `CategoricalAttrValue1`, `CategoricalAttrValue2` or `CategoricalAttrValue3`.
I'm using default k-means clu... |
[@statsRus][statsRus] starts to lay the groundwork for your answer in another question http://datascience.stackexchange.com/questions/1/what-characterises-the-difference-between-data-science-and-statistics:
> - **Data collection**: web scraping and online surveys
> - **Data manipulation**: recoding messy data and... |
I have a bunch of customer profiles stroed in [tag:elasticsearch] cluster. These profiles are now used for creatinon of target groups for our email subscriptions.
Target groups are now formed manually using elasticsearch faceted search capabilities (like get all male customers of age 23 with one car and 3 children... |
I have a bunch of customer profiles stroed in [tag:elasticsearch] cluster. These profiles are now used for creatinon of target groups for our email subscriptions.
Target groups are now formed manually using elasticsearch faceted search capabilities (like get all male customers of age 23 with one car and 3 children... |
Depends on 2 things: the nature/structure of your data; and your performance.
SQL databases excel when your data is well structured (e.g. when it can be modeled as a table or Excel spreadsheet). A set of rows with a fixed # of columns. Also, when you need to do a lot of table joins (which it sounds like you do).
... |
In working on exploratory data analysis, and developing algorithms, I find that most of my time is spent in a cycle of visualize, write some code, run on small dataset, repeat. The data I have tends to be computer vision/sensor fusion type stuff, and algorithms are vision-heavy (for example object detection and track... |
How to scale up algorithm development? |
I heard about many tools / frameworks for helping people to process their data (big data environment).
One is called Hadoop and the other is the noSQL concept. What is the difference in point of processing?
Are they complementary?
|
My data set contains a number of numeric attributes and one categorical.
Say, `NumericAttr1, NumericAttr2, ..., NumericAttrN, CategoricalAttr`,
where `CategoricalAttr` takes one of three possible values: `CategoricalAttrValue1`, `CategoricalAttrValue2` or `CategoricalAttrValue3`.
I'm using default k-means clu... |
R has many libraries which are aimed at Data Analysis (e.g. JAGS, BUGS, ARULES etc..), and is mentioned in popular textbooks such as: J.Krusche, Doing Bayesian Data Analysis; B.Lantz, "Machine Learning with R".
I've seen a guideline of 5TB for a dataset to be considered as Big Data.
My question is: Is R suitable ... |
I have an R script that generates a report based on the current contents of a database. This database is constantly in flux with records being added/deleted many times each day. How can I ask my computer to run this every night at 4 am so that I have an up to date report waiting for me in the morning? Or perhaps I want... |
> How can I ask my computer to run this every night at 4 am so that I have an up to date report waiting for me in the morning?
You can set up a cronjob on a Linux system. These are run at the set time, if the computer is on. To do so, open a terminal and type:
crontab -e
And add:
00 4 * * * /your/co... |
> How can I ask my computer to run this every night at 4 am so that I have an up to date report waiting for me in the morning?
You can set up a cronjob on a Linux system. These are run at the set time, if the computer is on. To do so, open a terminal and type:
crontab -e
And add:
00 4 * * * r source... |
From my limited dabbling with data science using R, I realized that cleaning bad data is a very important part of preparing data for analysis.
Are there any best practices or processes for cleaning data before processing it? If so, are there any automated or semi-automated tools which implement some of these best p... |
From my point of view, this question is suitable for a two-step answer. The first part, let us call it *soft preprocessing*, could be taken as the usage of different data mining algorithms to preprocess data in such a way that makes it suitable for further analyses. Notice that this could be the analysis itself, in cas... |
In reviewing “[Applied Predictive Modeling][1]" a [reviewer states][2]:
> One critique I have of statistical learning (SL) pedagogy is the
> absence of computation performance considerations in the evaluation of
> different modeling techniques. With its emphases on bootstrapping and
> cross-validation to tune/tes... |
What are R's memory constraints? |
Logic often states that by overfitting a model, it's capacity to generalize is limited, though this might only mean that overfitting stops a model from improving after a certain complexity. Does overfitting cause models to become worse regardless of the complexity of data, and if so, why? |
Why Is Overfitting Bad? |
Putting aside how easy it might be to replicate a given build, especially an ad-hoc one, to me replication always possible if it's planned for and worth doing. That said, it is unclear to me is how to execute a data science workflow that allows for reproducibility without it just being a replication of what has already... |
What is a reproducibile data science workflow? |
Putting aside how easy it might be to replicate a given build, especially an ad-hoc one, to me replication always possible if it's planned for and worth doing. That said, it is unclear to me is how to execute a data science workflow that allows for reproducibility without it just being a replication of what has already... |
What are the data conditions that we should watch out for, where p-values may not be the best way of deciding statistical significance? Are there specific problem types that fall into this category? |
When are p-values deceptive? |
Is it possible to automate generating reproducibility documentation? |
What is a reproducibile data science workflow? |
If small p-values are plentiful in big data, what is a comparable replacement for p-values in data with million of samples? |
Is there a replacement for small p-values in big data? |
*(Note: Pulled this question from the [list of questions in Area51](http://area51.stackexchange.com/proposals/55053/data-science/57398#57398), but believe the question is self explanatory. That said, believe I get the general intent of the question, and as a result likely able to field any questions on the question tha... |
Which Big Data technology stack is most suitable for processing tweets, extracting/expanding URLs and pushing (only) new links into 3rd party system? |
**Background:** Following is from the book [Graph Databases][1], which covers a performance test mentioned in the book [Neo4j in Action][2]:
> Relationships in a graph naturally form paths. Querying, or
> traversing, the graph involves following paths. Because of the
> fundamentally path-oriented nature of the dat... |
Is this Neo4j comparison to RDBMS execution time correct? |
Is it possible to automate generating reproducibility documentation? |
First, think it's worth me stating what I mean by replication & reproducibility:
- Replication of analysis A results in an exact copy of all inputs and processes that are supply and result in incidental outputs in analysis B.
- Reproducibility of analysis A results in inputs, processes, and outputs that are semanti... |
What is(are) the difference(s) between parallel and distributed computing? When it comes to scalability and efficiency, it is very common to see solutions dealing with computations in clusters of machines, and sometimes it is referred to as a parallel processing, or as distributed processing.
In a certain way, the c... |
I have a bunch of customer profiles stored in a [tag:elasticsearch] cluster. These profiles are now used for creation of target groups for our email subscriptions.
Target groups are now formed manually using elasticsearch faceted search capabilities (like get all male customers of age 23 with one car and 3 childre... |
Given website access data in the form `session_id, ip, user_agent`, and optionally timestamp, following the conditions below, how would you best cluster the sessions into unique visitors?
`session_id`: is an id given to every new visitor. It does not expire, however if the user doesn't accept cookies/clears cookies/... |
Given website access data in the form `session_id, ip, user_agent`, and optionally timestamp, following the conditions below, how would you best cluster the sessions into unique visitors?
`session_id`: is an id given to every new visitor. It does not expire, however if the user doesn't accept cookies/clears cookies/... |
For example, when searching something in Google, results return nigh-instantly.
I understand that Google sorts and indexes pages with algorithms etc., but I imagine it infeasible for the results of every single possible query to be indexed (and results are personalized, which renders this even more infeasible)?
M... |
How do querys into huge database return with negligible latency? |
For example, when searching something in Google, results return nigh-instantly.
I understand that Google sorts and indexes pages with algorithms etc., but I imagine it infeasible for the results of every single possible query to be indexed (and results are personalized, which renders this even more infeasible)?
M... |
Well, I'm not sure if it is MapReduce that solves the problem, but it surely wouldn't be MapReduce alone to solve all these questions you raised. But here are important things to take into account, and that make it *feasible* to have such low latency on queries from all these TBs of data in different machines:
1. di... |
Well, I'm not sure if it is MapReduce that solves the problem, but it surely wouldn't be MapReduce alone to solve all these questions you raised. But here are important things to take into account, and that make it *feasible* to have such low latency on queries from all these TBs of data in different machines:
1. di... |
Well, I'm not sure if it is MapReduce that solves the problem, but it surely wouldn't be MapReduce alone to solve all these questions you raised. But here are important things to take into account, and that make it *feasible* to have such low latency on queries from all these TBs of data in different machines:
1. di... |
While building a rank, say for a search engine, or a recommendation system, is it valid to rely on click frequency to determine the relevance of an entry? |
Does click frequency account for relevance? |
Is it valid to *use* click frequency, then **yes**. Is it valid to use **only** the click frequency, then probably **no**.
Search relevance is much more complicated than just one metric. [There are entire books on the subject][1]. Extending this answer beyond a simple yes/no would likely make the answer far too broa... |
Users normally only view the first set of links, which means that unless the link is viewable, it's not getting clicks; meaning you'd have to be positive those are the best links, otherwise the clicks are most likely going to reflect placement, not relevance. Further, using click frequency to account for relevance is n... |
[Depends on the users intent](http://research.microsoft.com/pubs/169639/cikm-clickpatterns.pdf), for starters.
[Users normally only view the first set of links](http://www.seoresearcher.com/distribution-of-clicks-on-googles-serps-and-eye-tracking-analysis.htm), which means that unless the link is viewable, it's not... |
[Depends on the users intent](http://research.microsoft.com/pubs/169639/cikm-clickpatterns.pdf), for starters.
[Users normally only view the first set of links](http://www.seoresearcher.com/distribution-of-clicks-on-googles-serps-and-eye-tracking-analysis.htm), which means that unless the link is viewable, it's not... |
[Depends on the users intent](http://research.microsoft.com/pubs/169639/cikm-clickpatterns.pdf), for starters.
[Users normally only view the first set of links](http://www.seoresearcher.com/distribution-of-clicks-on-googles-serps-and-eye-tracking-analysis.htm), which means that unless the link is viewable, it's not... |
[Depends on the user's intent](http://research.microsoft.com/pubs/169639/cikm-clickpatterns.pdf), for starters.
[Users normally only view the first set of links](http://www.seoresearcher.com/distribution-of-clicks-on-googles-serps-and-eye-tracking-analysis.htm), which means that unless the link is viewable, it's no... |
[Depends on the user's intent](http://research.microsoft.com/pubs/169639/cikm-clickpatterns.pdf), for starters.
[Users normally only view the first set of links](http://www.seoresearcher.com/distribution-of-clicks-on-googles-serps-and-eye-tracking-analysis.htm), which means that unless the link is viewable, it's no... |
Overfitting, in a nutshell, means take into account **too much** information from your data and/or prior knowledge, and use it in a model. To make it more straightforward, consider the following example: you're hired by some scientists to provide them with a model to predict the growth of some kind of plants. The scien... |
How does a query into a huge database return with negligible latency? |
For example, when searching something in Google, results return nigh-instantly.
I understand that Google sorts and indexes pages with algorithms etc., but I imagine it infeasible for the results of every single possible query to be indexed (and results are personalized, which renders this even more infeasible)?
M... |
Well, I'm not sure if it is MapReduce that solves the problem, but it surely wouldn't be MapReduce alone to solve all these questions you raised. But here are important things to take into account, and that make it *feasible* to have such low latency on queries from all these TBs of data in different machines:
1. di... |
Well, I'm not sure if it is MapReduce that solves the problem, but it surely wouldn't be MapReduce alone to solve all these questions you raised. But here are important things to take into account, and that make it *feasible* to have such low latency on queries from all these TBs of data in different machines:
1. di... |
What is the best noSQL backend to use for a mobile game? Users can make a lot of servers requests, it needs also to retrieve users history (like in app purchase) and analytics of use behavior. |
Assume that we have a set of elements *E* and a similarity (**not distance**) function *sim(ei, ej)* between two elements *ei,ej ∈ E*.
How could we (efficiently) cluster the elements of *E*, using *sim*?
*k*-means, for example, requires a given *k*, Canopy Clustering requires two threshold values. What if we don... |
Consider a stream containing tuples `(user, new_score)` representing users score in an online game. The stream could have 100-1,000 new elements per second. The game has 200K to 300K unique players.
I would like to have some standing queries like:
1. Which players posted more than x scores in a sliding window o... |
Some factors you might consider:
Developer familiarity: go with whatever you or your developers are familiar with. Mongo, Couch, Riak, DynamoDB etc all have their strengths but all should do ok here, so rather than going for an unfamiliar solution that might be slughtly better go for familiar and save a bunch of de... |
When a relational database like mySQL has better performance than a no relational, like mongo?
I saw a question on Quora other day, about why Quora still uses mySQL as their backend. And how their performance is still good. |
Consider a stream containing [tuples][tuples] `(user, new_score)` representing users' scores in an online game. The stream could have 100-1,000 new elements per second. The game has 200K to 300K unique players.
I would like to have some standing queries like:
1. Which players posted more than x scores in a slid... |
If I have a very long list of paper names, how could I get abstract of these papers from internet or any database?
The paper names are like "Assessment of Utility in Web Mining for the Domain of Public Health".
Does any one know any API that can give me a solution? I tried to crawl google scholar, however, google... |
Is there any APIs for crawling abstract of paper? |
I have a database from my Facebook application and I am trying to use machine learning to estimate users' age based on what Facebook sites they like.
There are two crucial characteristics of my database:
- the age distribution in my training set (12k of users in sum) is skewed towards younger users (i.e. I have ... |
I use [Libsvm][1] to train data and predict classification on **semantic analysis** problem. But it has a **performance** issue on large-scale data, because semantic analysis concerns ***n-dimension*** problem.
Last year, [Liblinear][2] was release, and it can solve performance bottleneck.
But it cost too much **me... |
I have a database from my Facebook application and I am trying to use machine learning to estimate users' age based on what Facebook sites they like.
There are three crucial characteristics of my database:
- the age distribution in my training set (12k of users in sum) is skewed towards younger users (i.e. I hav... |
Latent Dirichlet Allocation (LDA) is a topic modeling process (http://en.wikipedia.org/wiki/Latent_Dirichlet_allocation).
And Hierarchical Dirichlet Process (HDP) is also a topic modeling process (http://en.wikipedia.org/wiki/Hierarchical_Dirichlet_process).
**The major difference is LDA requires the specificat... |
This question asked about generative vs discriminative algorithm, http://stackoverflow.com/questions/879432/what-is-the-difference-between-a-generative-and-discriminative-algorithm but **can someone give an example of the difference when applied to Natural Language Processing?**
**How are generative and discriminat... |
What is generative and discriminative model? How are they used in Natural Language Processing? |
From wikipedia,
> dimensionality reduction or dimension reduction is the process of
> reducing the number of random variables under consideration, and
> can be divided into feature selection and feature extraction.
**What is the difference between feature selection and feature extraction?**
**What is an e... |
What is dimensionality reduction? What is the difference between feature selection and extraction? |
Some factors you might consider:
Developer familiarity: go with whatever you or your developers are familiar with. Mongo, Couch, Riak, DynamoDB etc all have their strengths but all should do ok here, so rather than going for an unfamiliar solution that might be slightly better go for familiar and save a bunch of de... |
Look it up on:
* Google Scholar [link][1]
* Citeseer [link][2]
If you get a single exact title match then you have probably found the right article, and can fill in the rest of the info from there. Both give you download links and bibtex-style output. What you would likely want to do though to get perfect meta... |
1. I think a number of clustering algorithms that normally use a metric, do not actually rely on the metric properties (other than commutativity, but I think you'd have that here). For example, DBSCAN uses epsilon-neighborhoods around a point; there is nothing in there that specifically says the triangle inequality ma... |
1. I think a number of clustering algorithms that normally use a metric, do not actually rely on the metric properties (other than commutativity, but I think you'd have that here). For example, DBSCAN uses epsilon-neighborhoods around a point; there is nothing in there that specifically says the triangle inequality ma... |
In our company, we have a MongoDB database containing a lot of unstructured data, on which we need to run map-reduce algorithms to generate reports and other analyses. We have two approaches to select from for implementing the required analyses:
1. One approach is to extract the data from MongoDB to a Hadoop cluste... |
Can map-reduce algorithms written for MongoDB be ported to Hadoop later? |
Considering another criteria, I think that in some cases using Python may be much superior to R for Big Data. I know the wide-spread use of R in data science educational materials and the good data analysis libraries available for it, but sometimes it just depend on the team.
In my experience, for people already fam... |
Any small database processing can be easily tackled by Python/Perl/... scripts, that uses libraries and/or even utilities from the language itself. However, when it comes to performance, everyone reaches out for C/C++. The possibility of tailoring the code to the needs seems to be what makes these languages so appealin... |
As All we know There are some data indexing techniques using by well-known indexing apps like Lucene (for java) or Lucene.NET (for .NET), MurMurHash, B+Tree etc.
For a No-Sql / OO Database (which i try to write/play a little around with C#) which technique you suggest ?
I read about MurMurhash-2 and specially v3... |
As we all know, there are some data indexing techniques, using by well-known indexing apps, like Lucene (for java) or Lucene.NET (for .NET), MurMurHash, B+Tree etc. For a No-Sql/OO Database (which I try to write/play a little around with C#), which technique you suggest?
I read about MurMurhash-2 and specially v3 co... |
As we all know, there are some data indexing techniques, using by well-known indexing apps, like Lucene (for java) or Lucene.NET (for .NET), MurMurHash, B+Tree etc. For a No-Sql / Object Oriented Database (which I try to write/play a little around with C#), which technique you suggest?
I read about MurMurhash-2 and ... |
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