# Questions tagged [data-mining]

This tag is for questions about data mining, which is an interdisciplinary subfield of computer science. It is the computational process of discovering patterns in large data sets.

48 questions
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### Factor Analysis in Text Mining task

I was faced with the task of determining the topics of big text massive. For example you have 1 million any text phrases or sentences. I want factorize the main topic from this massive. The ordinary ...
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### How to find almost periodic lattices in a set of high-dimensional points?

sorry for lame question, but I just have no maturity in this direction. Let's say I have very large set ( millions ) of high-dimensional vectors ( typical dimensionality is 64). These vectors ...
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### Clustering elements according to covariance matrix

I'm doing a little bit of topic modelling (which is not really my area) with twitter tweets. The situation is the following: I have a (sort of) covariance matrix where the entrie $C_{ij}$ corresponds ...
291 views

### Does Gini index considers only a binary split for each attribute or can it have multi way spliting?

Does Gini-index based classification split values for any attribute always as a binary split or can it split into more than $2$ branches (multi-way split)? For more clarification, if a split on $A$ ...
45 views

### What is the meant by node role in Graph Theory?

Suppose that I have a graph with some numbers of nodes, and each node connected to other node with a relation, My question what is the node roles here ? Is the role = the relation type, weighted ...
18 views

### Different order of insertion - different Bayesian network ? how to prove formally?

I have some Bayesian network which i constructed from some data, say it consists of nodes A, B, C and D and that was the initial order of insertion. If i ...
29 views

### Which similarity formula should I use?

I was studying Cosine Similarity and I have just seen this article. https://medium.com/@rahulkuntala9/cosine-similarity-and-handling-categorical-variables-29f907951b5 The author uses Cosine ...
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### What are correlation coefficients used for in PCA?

What are correlation coefficients used for in PCA? One can discover them through the PCA formulation, but what are they useful for?
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### Why approximate pairwise distances only over lower triangle of distance matrix?

In the context of dimensionality reduction. Why approximate pairwise distances only over lower triangle of distance matrix? $$\min_{\{\hat{x_i}\}} I = \sum_{i <j} ({ \hat{ d_{ij} } - d_{ij} })^2$$...
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### How to interpret maximizing “separability and reciprocal of scattering” in Fisher's LDA?

How to interpret maximizing "separability and reciprocal of scattering" in Fisher's LDA? That is, if $s_1$ is minimized scattering inside (projected) class 1 and $s_2$ is the same for class 2. Then ...
43 views

### Elementary reference on Support Vector Machines

I am having difficulties in reading the book Support vector mathine by Ingo Steinwart with some notations and mathematical terms . Can you please recommend a prerequisite book or online course by ...
42 views

### Can't understanding information entropy and data compression, for beginners

I watched a very well done video about information entropy, and I thought I got the concept in my mind but then I asked my self a question that denied every certainty I had. The video if you are ...
17 views

### Analyze mixture of data attributes

When I have a list of persons (nodes) with the attributes: REVENUE | LINKS I can search for the people with most links and the people with most revenue. But when I want to know who has the ...
26 views

### Looking for a ranking method to produce a list of products from best to worst given some features

I am pretty new to data mining and I am trying to help a friend of mine who is working on his graduate thesis in economics. The main purpose of his work is to rank a number of items (smart home ...
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### Number of rules (Data Mining)

This is a paraphrasing of a statement from Data Mining by Witten et al., 4th edition, on section 1.6. Consider the set $S = \{1, \dots, 288\}$. A rule is defined as a one-element singleton set ...
212 views

### Does there exist closed-form solutions for calculations in the EM-algorithm for Gaussian Mixtures?

Our data can be represented as $X_{n\times d}$ matrix, where we have $n$ data points lying in $\mathbb{R}^d$. We assume that there are $k$ underlying Gaussian models, $\mathcal{N}_d(\mu_j, \Sigma_j)$, ...
355 views

### Gini coefficient vs Gini impurity - decision trees

The problem refers to decision trees building. According to Wikipedia 'Gini coefficient' should not be confused with 'Gini impurity'. However both measures can be used when building a decision tree - ...
426 views

### Spectral relaxation of k-means clustering

I am working on a presentation on Spectral relaxation of k-means clustering (http://papers.nips.cc/paper/1992-spectral-relaxation-for-k-means-clustering.pdf) and I am a bit stuck. I understand ...
278 views

### Optimization of English Braille: Using the fewest dots

Background: The English Braille system is laid out in such a way so that the letters can be referenced by their position in the alphabet. Of the six dots available for each character, the top four ...
56 views

### How can I infer order from partially ordered discrete sequences?

A really interesting problem that I can't stop thinking about! Have run in to this a couple of times but yet to find a smart approach to either solve or frame this problem. This is my try at ...
750 views

### How do I measure the goodness of cosine similarity scores across different vector spaces?

I am a computer scientist working on a problem that requires some statistical measures, though (not being very well versed in statistics) I am not quite sure what statistics to use. Overview: I ...
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### Finding statistically increasing and decreasing sub-sequences in a (noisy) vector

I have a vector of real non-negative values of length ~60. The values represent a geometric property (can be area, circumference, etc.) of an object extracted from a movie of a biological sample, and ...
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### How do I calculate the upper bound probability using Hoeffding's Ineqaulity?

The image below show mathematical expressions for the meanings of training and testing. I can understand the meaning of testing but the meaning of training is not so clear because of $M$ there. I took ...
34 views

### Can someone show me a simple example of finding simple squared error in k-means?

I'm working on some homework and one of our assignments asks us to find the final mean of each cluster and the SSE (sum of squared error). I haven't been able to find anything online and was wondering ...
37 views

### Regression of 6 input parameters

I have a set of data that contains 6 inputs and 1 output (about 500 rows). Basically, I'm trying to figure out the complex relationship between the 6 inputs (say different component of concrete mix, i....
61 views

### Odd Ratio and Logistic Regression

Windy and Play Tennis = 9 Windy and Not Playing Tennis = 8 Not Windy and Play Tennis = 14 Not Windy and Not Playing Tennis = 8 I performed logistic regression in Weka and got odd ratio as 0.3448 for ...
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### How can I get the covariance just given the variance?

This is a fairly straight forward problem but I don't know how to calculate the covariance given just the variance of X and Y. Suppose X and Y are independent random variables such that Var(X)=1 and ...
29 views

### mutual information for power low distributed data?

I have a dataset with power-low distribution, I would like to measure some kind of correlation/mutual information between the data to its class,(for feature selection task), Can I use mutual-...
16 views

### looking for a simple example in machine learning with step-by-step procedure

I am looking for a simple example in the area of machine learning as well as a step-by-step procedure. For example, if I have 3 measurement devices and each one reports 5 data hourly how can I ...
52 views

### Predict a subset from sequence of sets

I want to solve this data mining problem: There is a sequence $S(t) = [A_1,...,A_{t-1}]$ . Each $A_i \subset U$ are set. Current time is $t \in \mathbb{N}$. $B$ is a subset of $A_t$. ($B \subset A_t$)...
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### In the context of PCA and random projection, what does $\tilde{X} \sim XR$ mean?

In the context of PCA and random projection, what does $\tilde{X} \sim XR$ mean? The projection seems to generally be defined as $\tilde{X} = XR$, but what does the tilde do there?
21 views

### Does “more points” necessarily imply “smoother boundary”?

So in the context of Naive Bayes I encountered a postulate that the more "nearest neighbours" one includes (i.e. the larger the $k$ in $k$-NN), the smoother the boundaries of classes become. Is this ...
29 views

### Extrapolation of measurement data

I would like to extrapolate the results of a measurement. Following picture shows the measurements results. The best I can do is that to calculate the average values for 10 measurement and I use it ...
32 views

### Can I use independence for bayesian network?

I'm struggling trying to understand bayesian network. Having trouble finding P(F&G) I know independence and conditional independence are different things. Conditional independence is when A ...
42 views

### Difference between Data Mining and a model?

I am pretty much confused with the terms between pattern mining and a model in data mining. For example, I have a number of sequential patterns like below: No. 1: A->B->C->A = 0.5 No. 2: B->C->D = 0....
38 views

### Things between Maximum Likelihood Estimation and Ordinary Least Squares?

What are the similarities and differences between Ordinary Least Squares and Maximum Likelihood Estimation? Are they both parametric methods? If we have Ordinary Least Squares, why do we need ...
25 views

### Build the conclusion with confidence

(if this question doesn't fit here, please point me to right direction. Thanks.) We need to check a sales data S’s accuracy to determine if it can be used in downstream calculations. Currently, it's ...
269 views

### Markov chain modelling?

I am working on a personal loan dataset. For each loan, we recorded its credit status monthly after it was drawn by the borrower. Let's say there were 6 status coded by A-F. My project is to use ...
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### Number of clusters in $k$-means clustering for higher-dimensional data.

I've read the Wikipedia article and a lot of posts on stackexchange (like this really thorough one) on determining the number of clusters in a data set. Based on that, I am currently using the ...
348 views

### How to calculate conditional probability for real data

I have my data in the form as: ...
I have objects $o_1,...,o_k$where every object has a set of properties $p_1,...,p_j$. I'm looking for property patterns that are repeated among these objects. It could be perhaps called correlation of ...
I have $n$ elements, each of them have two unsigned int attributes $x$ and $y$. Now I'd like to find out all the groups that fit the following condition: $A.x \geq B.y$ and $B.x \geq A.y$. The ...