An algorithm is a a set of one or more computations that will produce a calculated result. All statistics methods are algorithms. Algorithms can be simple, such as calculating a percentage, or can be very complex and require a computer for fast and accurate results.

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Algorithm to find common sequence

Assume that "1,2,3" are the ids of users, active means that person visited the stackoverflow in last one month (0=passive, 1=active), and there are positive and negative votes. ...
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17 views

An Algorithm for Maximal Correlation

Given a pair of random variables $(X,Y)$ over a product space $\mathcal{X}\times \mathcal{Y}$, the maximal correlation coefficient is defined as ...
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27 views

Comparing two algorithms by time series analysis

I have two algorithms. There is one vector of accuracy measurements for each algorithm. Each accuracy result in a vector corresponds to a moving average over a sliding time window and the vectors are ...
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24 views

Find meaningful next comparison for total ranking on the fly

I want to obtain a total ranking from pairwise binary comparisons. For this, I can use algorithms like Balanced Rank Estimation or Bradley-Terry Model. However, I wonder if you need fewer comparisons, ...
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40 views

data mining methods/algorithms for fraud case

I recently got into a topic regarding fraudulent transactions. I am relatively new to data mining and just looking for some input for my case here. I started with a cluster analysis / anomaly ...
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22 views

EM algorithm: With prior vs. not prior

I have a working EM algorithm without prior. I am asking for some advice on how to add prior on latent variables. Define: $t_i \in \{ +1, -1 \} $: variables of interest to be predicted $p_j \in ...
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34 views

Normalized gradients in Steepest descent algorithm

In general setting of steepest descent algorithm we have, \begin{equation} x_{n+1}=x_n-\alpha G_n, \end{equation} where $\alpha$ is the step size and $G_n$ is the gradient evaluated at the point ...
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13 views

Testing of the Grassberger-Procaccia algorithm

I've wrote the implementation of Grassberger-Procaccia algorithm in python. It is a method of reconstruction of properties of dynamical system by analysis of single realization. I would like to test ...
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57 views

Choosing an algorithm for classification

What determines what classification algorithm you should use for a certain classification problem? e.g. If there is >5 features or you only have 1000 training examples, or there is multiple class's or ...
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20 views

What machine learning algorithm should I choose to fill in blanks from context?

I have a project where I need to be able to fill in a missing word given a few words of context. In other words, suppose I have a sentence: I went ____ the store. I want to be able to deduce ...
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27 views

Recommendation system and baseline predictors

I'm participating in programming contest, where I have a data, and where the first number is a user, second number is a movie, and the third is a number in then-points rating. ...
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22 views

Algorithm to identify a correct input for only one number [closed]

Hello I'm hoping that you good folks here at CrossValidated can help me with this. I'm looking for an algorithm that takes an integer as an input and returns two types of values. One type of value ...
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11 views

What is the same or similar alogrithm in Weka for scikit-learn GradientBoostingRegressor?

I'm trying to move a GradientBoostingRegressor model to Weka. I have tried AdditiveRegression with different BaseLearners but the performance is very poor ( in terms of model quality and speed). I ...
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1answer
48 views

Computational complexity for linear discriminant analysis

The linear discriminant analysis algorithm is as follows: I want to conduct a computational complexity for it. For each step, the complexity is as follows: For each $c$, there are $N_cd$ ...
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1answer
46 views

Comparing classification algorithms using cross validation and caret's train

I am having issues understanding some concepts of algorithm comparison/parameter optimization/cross-validation in R Let's say I want to compare two classification algorithms, such as Random Forests ...
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8 views

Explanations about the parallel tempering

I am reading this paper on parallel tempering but there are a few things I do not really understand. If I'm not mistaken, parallel tempering is a MCMC method which is quite convenient to sample from ...
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26 views

Operations research problem to solve for out of stocks [closed]

I have a mathematical problem that I'm trying to solve and am wondering what kind of algorithm I should be looking at. I thought the revised simplex method would work but then I get stuck on knowing ...
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7 views

How to compute non-neighboring correlations using belief propagation?

Belief propagation is an algorithm to approximate the marginals of an arbitrary probability distribution. In principle, it allows you to compute the joint marginals at each factor node, which would ...
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2answers
219 views

Can humans cluster data sets manually? [closed]

Can human cluster data sets manually? For example, consider the Iris data set, depicted below: Instead of using clustering algorithms like connectivity-based clustering (hierarchical clustering), ...
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1answer
19 views

How to compute the $\chi^2$-table values?

How one can compute the values of $\chi^2$-tables? I saw two tables where was given for example that if degree of freedom is $1$ and $p=0.001$ then table value is in one table $10.827$ but in the ...
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1answer
80 views

Optimizing parameter estimates by minimizing chi^2 in iterative procedure

I need to minimize my Chi^2 (bottom-left in figure 1) by adjusting parameter-values in a MLE-procedure (or something alike). The chi^2 (red) is a goodness-of-fit measure. It expresses how well the ...
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36 views

Are there differences between Delta TF-IDF and TF-IDF?

Are there differences between both algorithm or not ? i mean if i implement for ex Delta TF-IDF in a project instead of ...
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67 views

Sentiment Analysis - How should I handle negatively biased word list length?

I'm implementing a simple sentiment analysis algorithm where the authors of the paper have a word list for positive and negative words and simply count the number of occurrences of each in the ...
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1answer
24 views

Best Clustering Algorithm for Protein data

I have 400 virus genomes. In each virus, there are 100 genes (these are rough estimates). The genes in these viruses are transferred between each other very frequently. So Gene5 of Virus1 could be ...
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14 views

Method or Algorithm to produce near-accurate probability selection

Are there any known algorithms or methods to accurately identify, using random occurrences, the most probable next occurrence(s) as a pre-determined length of number set, by providing an already ...
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39 views

Different behaviors for different Ridge implementations in R

I am having trouble reconciling the different behavior of different Ridge implementations in R. As the following code demonstrates it seems that MASS:lm.ridge ...
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1answer
48 views

Transform sample to achieve target mean, skewness, etc

I have a sample of data with N values from which I calculate basic moments such as mean, standard deviation and skewness. I will then change these moments to different values according to my own ...
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24 views

Minimize difference between adjacent elements in an array [closed]

How can I calculate the minimum possible difference between adjacent integer elements of an array. For example: We have the array: 11 14 14 9 16 Adjacent ...
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1answer
188 views

Is there an optimal way to find the best division of an interval of some positive integers?

I am struggling with a conceptual problem. I have positive integers from an interval [1800, 1850]. For every integer from that interval, let's say (without loss of generality) 1820, I have about 3000 ...
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1answer
103 views

One-Max fitness function (Java)

Whilst searching on Google about Genetic Algorithms, I came across OneMax Problem, my search showed that this is one of the very first problem that the Genetic Algorithm was applied to. However, I am ...
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1answer
104 views

What is a good model for revenue managment / price optimization problem

I am trying to create a dynamic pricing model to optimize revenue for a hypothetical business. Lets say I have an application that connects dog walkers to people who want to pay for their dog to get ...
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1answer
25 views

clustering verifying two basic invariance properties

disclaimer: I already asked something similar on stack overflow, but it seems to be a better place for that question here. I recently became interested in axiomatic definitions of clustering, cf. ...
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57 views

Decision tree with adaboost

Helllo! I'm currently learning the AdaBoost algorithm to use it with Decision Tree. I want to implement everything myself (that's the way I learn - implement everything from scratch and later use ...
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0answers
10 views

Training a function that maps n-dim to n-dim

As an example, say the input is an array of numbers representing an audio snippet and the output is a transformed/filtered version of it. What would be the proper term for that? Which are examples of ...
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18 views

Expected number of replacements during weighted reservoir sampling?

Consider the problem of taking a weighted sample of size $K$ from a stream of unknown but finite size $N$ in a single pass. Reservoir sampling solves this by assigning each item from the stream with ...
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28 views

adaboost with multiple classification algorithms

Up to now I saw that all adaboost implementations use single classification algorithm and a training dataset as input and then creates multiple classification models by re-sampling dataset and uses ...
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100 views

On accept-reject method for unknown function

My problem is this I have a posterior as $Gamma(\alpha, \beta) \times exp(\lambda)$. $$Y_{1}^{n} \sim Gamma(\alpha, \beta)$$ $$\alpha \sim Exp(\lambda)$$ $$\beta \sim Exp(\lambda)$$ Now $n=50, ...
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21 views

How to implement Exponential Histograms

I am having trouble in understanding the concept of exponential histograms. They are known to be much efficient for maintaining statistics. I have read it in this article but cant understand how they ...
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23 views

Algorithms for invariant image recognition

I am interested in the current state of affairs when it comes to image recognition. I am particularly interested in algorithms that can handle a high degree of invariance. Except for Artificial ...
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1answer
104 views

Types of artificial intelligence with good results [closed]

I have been looking into artificial intelligence for some time now. I am wondering what branches are still in active research and have some good/interesting results. The two that I have looked in so ...
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1answer
88 views

Low Rank Matrix Factorization Collaborative Filtering - given a sparse set of feature data

I'm playing with a "minor" variation on an otherwise typical low rank matrix factorization collaborative filtering algorithm. I'm mostly following Andrew Ng's description in Coursera's online ML ...
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1answer
199 views

Clustering data into bins of variable sizes

I'd like to build a model (in R or excel) that takes in large amount of linear data and segments it into "bins". The linear data is an attribute that reflects what condition that section/record is at. ...
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99 views

what is the algorithm of getting maximum $D$ value in ks.test?

When I was writing R code to plot two empirical cumulative density curves, I came across ks.test in R. I looked into the code of ...
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33 views

Convergence Time of the EM Algorithm Depending on the Inital Parameter Values

I try to get an intuitive understanding of the convergence properties of the EM-Algorithm. I wrote a code that does the following experiment. We are given three coins: $H$, $A$ and $B$; with ...
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42 views

HMM walk through for backward algorithm with given example

This pdf file is a resource that walk through a simple HMM algorithm of two states http://www.indiana.edu/~iulg/moss/hmmcalculations.pdf, I have question in step 4.1 of the algorithm Specifically ...
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44 views

Is There A Machine Learning Algorithm For Textual Data With Thousands Of Classifiers?

I've been asked to migrate this from StackOverflow to CrossValidated. I have a problem that I think Machine Learning can solve but am having a very hard time determining which ML Algorithm to use and ...
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47 views

Basic questions about stochastic gradient descent / Robbins and Monro algorithm

I have a LOT of time series observations and I would like to estimate a simple AR(1) model $$ y_t =c+ \phi y_{t-1}+ \varepsilon_t \qquad \varepsilon_t \sim \text{N}(0, \sigma^{2}) $$ with parameters ...
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31 views

Fast way to compute central moments of a Poisson random variable?

I am looking for a way to quickly compute the central moments of a Poisson random variable. I've found a couple of resources on how to compute the central moments, but I'm still trying to figure out ...
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2answers
302 views

Why Adaboost with Decision Trees?

I've been reading a bit on boosting algorithms for classification tasks and Adaboost in particular. I understand that the purpose of Adaboost is to take several "weak learners" and, through a set of ...
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48 views

Algorithm to Rank “Risk Factors” on Individual Level from Logit Regression Scoring

I have a logit regression which predicts the probability of attrition. The equation is roughly: ...