Questions tagged [machine-learning]

Machine learning algorithms build a model of the training data. The term "machine learning" is vaguely defined; it includes what is also called statistical learning, reinforcement learning, unsupervised learning, etc. ALWAYS ADD A MORE SPECIFIC TAG.

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53 views

A small help in understanding basic SVM

I am on the course of learning SVM. So, I am having a doubt. Suppose in the case of 2D, a point needs to be classified. So, let say I am having a point x(2,3). So according to the equation wx+b >= 1 ...
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1answer
101 views

How to setup for really deep convolution model

I'm rather new to deep learning and convolution network and got some basic models to run. However, when I tried to build a deep CNN model (i.e., more than 14, 15 layers) the error rate does not seem ...
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1answer
52 views

learning ranked instance similarity by machine learning

Here there are many vectors with rank. a = c(1, 2, 3, 5, 10,...) b = c(4,2,3,2,8,...) ... please note, here it's the rank of value but not the value itself in these vectors. There are a few ...
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39 views

How to make the right CV test?

I am going to indicate a really confused question for me in my project, I didn't learn machine learning before but I am hardworking on it, the question might be long and naive, and thanks for reading ...
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1answer
102 views

Evaluating significance of predictors in Machine Learning using R

I've bee using R for predictive analytics and here is the issue: I'm trying to predict the species (E1, E2, E3 and E4) of an animal using as predictors a set of categorical (factors) (NO1, NO2, NO3, ...
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861 views

Feature extraction based on correlations

I have a small problem regarding feature extraction with correlation. I have divided my question in four parts hoping that somebody can help me. I have a dataset consisting of fMRI images. Each image ...
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34 views

Describing the distribution of N points in D-dimensional space?

I want to tackle a classification problem by describing the samples as its descriptors' distributions. So let's say each sample has a label, and $N$ vectors of dimension $D$, (N and D are fixed) and ...
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103 views

Pairwise Learning to Rank - detecting detrimental changes

The idea behind Pairwise Learning to Rank is that if you have a set of search results then a clicked on result can be used as training example to indicate that it should rank more highly that the ...
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1answer
63 views

MANOVA application

Need to check whether it is mandatory to have at least one continuous DVs in MANOVA, also does sample size of 2 groups matters much, i am planning to check whether recruits from campus or off-campus ...
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566 views

My Cross-validation error is always increasing with increasing regularisation parameter

I am not sure what is happening, but my cross-validaton error is always increasing with increasing alpha in ridge regression. It should technically go down and then increase. Here is what I am doing ...
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159 views

k-fold on dataset

I have been doing a specific check of k-fold technique to see the difference using different number of folds and the corresponding result on the score obtained. To perform this test I have made ...
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1answer
90 views

Which machine learning model is applicable to the following case

I want to build a model that recognizes the species based on multiple indicators. The problem is, neural networks (usually) receive vectors, and my indicators are not always easily expressed in ...
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409 views

Huge overfitting with Random Forests and Boosted Trees?

In the following picture, the boxplots represent a performance metric (the closer to 1, the better) recorded for 50 runs of cross-validation, and the black filled circles are the training values of ...
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178 views

RBM hidden units becoming correlated

I am trying to train an RBM with 8 hidden binary units and 40 visible ReLUs. At first, I had issues with binary units becoming stuck due to the weight saturating, but I got rid of that problem by ...
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1answer
384 views

Online gradient descent for strongly convex function

Given that our loss function is $\alpha$ strongly convex function which means $\mbox(\nabla f(\mathbf{x})-\nabla f(\mathbf{y}))^{T}(\mathbf{x}-\mathbf{y})\geq \alpha||\mathbf{x}-\mathbf{y}||_{2}^{2} ...
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1answer
53 views

Is this feature redundant?

Say I have a data set, and there's one feature that divides the set into roughly two halves, labeling one half A, and the other half B. Now I have another feature, it labels all instances that were ...
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86 views

SVM output to probabilistic affiliation

How can I convert the svm output for multiple class classification(one vs one approach) to probabilistic values? Meaning that I want to have a probability for a tested element to be in each available ...
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24 views

Estimating class probabilities given discriminative functions per class

What is the effective way to estimating class probabilities per class, if I know discriminative functions for each class (I have trained ML models giving some scores). My naive implementation is to ...
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2answers
162 views

graph classification task - multi label?

I have a data set in graph format representing semantic connection between terms. The data set is divided into clusters, each with several labels (not unique, or mutually exclusive, no set number of ...
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2answers
60 views

Prediction of features given predictor

I am working on a problem where my objective is to predict y given some features x1,x2,x3,...x8,x9 I solved this problem using some statistical and machine learning techniques like regression, trees, ...
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361 views

Find repetitive patterns in matrices below

How can I identify the repetitive patterns from the matrices below? My problem is that the patterns in the matrix are different from matrix to matrix (dependent on the input data). I need some machine ...
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881 views

Generating a good training dataset for decision tree building

I am building a decision tree predicting the accuracy score of an image processing algorithm, based on a number of image parameters. I have identified 6 uncorrelated parameters that impact the ...
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55 views

Query re. how to set up an SVM, which SVM variation … and how to define a metric

I’d like to learn how best set up a Support Vector Machine for my particular problem (or if indeed there is a more appropriate algorithm). My goal is to receive a weighting of how well an input set ...
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215 views

Good baseline algorithm for text-related machine learning project

I'm working on a machine learning project aimed at predicting the quality/helpfulness of a review. For each review in the dataset, I have the review text, a number 'm' for the number of people who ...
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62 views

Document classification with very few documents

I wanted to know if there is any method in state of art that deals with document classification methods with very few training samples in R. I have just 20 documents and need to classify them into 3 ...
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510 views

Gaussian Mixture Model with Custom Distance Metric

I have some 1D data that I want to cluster using Mixture of Gaussian. However, the data "wraps around" at two extremes. Specifically, I have a list of angles from $-\pi$ to $\pi$ and the data near two ...
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1answer
430 views

Automatic feature building/extraction

I have a large time stamped data set (several millions of rows), with known measured inputs xi, where i is a large number to the order of magnitude of 20. The goal is to predict a response yi given ...
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566 views

implementating the bayesian linear prediction with NIG prior

In Bayesian linear regression when the covariance of weights is unknown; one can set Normal-Inverse-Gamma prior. Based on "Machine Learning: a Probabilistic Perspective", Page 235, \begin{equation} ...
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284 views

Is precision in recommender system related to mean average error (MAE)?

A recommender system is being evaluated while increasing the neighborhood size. The highest precision was achieved between 10-15 neighbors(users) while the lowest MAE was in the range from 30-40 users....
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1answer
231 views

How to optimize Gaussian-process parameters for multiple tasks with GPML?

I have a lot of test curves and I want to optimize the length and scale parameters simultaneously for all curves. Is this possible?
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312 views

Handling sparse document term matrix

I am working with a corpus of several thousand documents (41,732) however the documents tend to be short (the median number of terms per document is 3) resulting in a sparse document term matrix. ...
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1k views

Any machine Learning models to predict dates?

I have a general question regarding machine learning models. The idea is to predict what DATE the customer is likely to make transactions or purchases. Variables present in the data set are item, ...
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92 views

Obtain Precision and Recall from Click through data

I am trying to build a graph of precision and recall using click data. I have two data sources. First data source has all the user clicked item_ids based on a given query_id. Second data source has ...
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2answers
33 views

Inferring on an unknown number of function approximation

I want to ask whether a procedure to do the following job exists (or whether it makes sense for it to exist). First, assume we have $k$ functions $f_1,...f_k$ that have the same domain and range. ...
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125 views

Are these three different ways of expressing the optimal value function $V^*$ the same? (reinforcement learning)

My question didn't really fit on the title but its the following are the three following equations actually the same: $$V^*(s) = \max\limits_\pi V^{\pi}(s)$$ and $$V^*(s)=R(s)+ \max\limits_{a \in ...
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1answer
115 views

Plot that shows which attribute has the most effect on class?

I'm playing around with two datasets: Mushrooms and Breast Cancer. I'm trying to form a hypothesis of which attribute would have the most effect on the class when making predictions about the class. ...
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66 views

Profiling high-scoring clusters in a multi-dimensional feature space

I have a large amount of samples, which have a multi-imensional feature vector associated with them. Each sample has a "score", and the length of the feature vector is substantial (n>100, and in ...
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1answer
66 views

Association rules or classifier for product modeling for queries

I have a set of products P {1...n} which are rated on a goodness scale G ={1...100} (G10 is more good than G5). Each product has a set of features F {1....m}, now I want to learn a model for ...
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1answer
78 views

Analysis of Feature Importances when features are dependent on one another

I can use random forests to determine which features are important when doing a prediction problem; for example. < height, weight, IQ measure> -> Is considered obese? Applying random forests ...
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1answer
143 views

Pattern recognition in state sequences

I have a sequence of states of a system. Each state is defined by an abstract identifier e.g "Eating", "Sleeping" etc... and a duration. So a state is basically ...
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230 views

(binary) Matrix completion with less known data

Recently, I meet such problems, I call it matrix completion problem. For example, the row denotes the users and the column denotes items. And If one user like the ...
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1answer
42 views

Why is it necessary to assume that examples and labels are drawn from a joint distribution in empirical loss minimization?

Multiple sources have indicated that when trying to minimize empirical loss, $1/N \sum_i L(f(x_i, w), y_i)$, where $L$ is some loss function, $y_i$ is the true label, and $f(x_i, w)$ is the predicted ...
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93 views

Is there “infinite” universal model selection ? and Structural Risk Minimization

I ask these because I come up with an idea : If I have infinite and universal model set, then there must exist model that totally fits my data and no parameter for the model so the complexity is ...
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2answers
296 views

What's the best algorithm type for low-dimensional grouping

I'm looking for some advice on directions to head in a project I'm working on. Basically what I want to do is identify general (of varying size) groups in a 2-D grid of points belonging to one of ...
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1answer
88 views

Statistical Commute Analysis in Java

I have a rather large commute every day - it ranges between about an hour and about an hour and half of driving. I have been tracking my driving times, and want to continue to do so. I am capturing ...
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1answer
67 views

How to improve the performance of K-nn algorithm in R?

I am having a digit recognizer data set which has column names as label, pixel0, pixel1...pixel783. pixel values vary from 0 to 255 indicating the lightness or darkness of that pixel, with higher ...
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170 views

A non-negative definate matrix has a non-negative generalized inverse

I'm having trouble proving a N.N.D matrix has a N.N.D G-Inverse. So far I have: If we assume x = Az where x >= 0 and A is a nnd matrix. So if Y is a G-inverse than: x = Az = YAz = Yx >= 0 . Thus ...
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1answer
36 views

How to use a set attributes of an entity at different time snaps to make predictive analysis?

The problem is to come up with a classifier for any task based on a set of attributes of an entity having different values at different times. For instance think about football players and their match ...
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43 views

Removing labelling noise

I have a big data set with unlabelled observations (several million) and about 20 thousand properly labelled ones. There are only two classes and all correctly labelled samples belong to the same ...
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1answer
109 views

Approach for mapping consumer preferences

I have this web application where I need to map consumer preferences based on some input information and individual choices. My goal is to create a list of product recommendations and evaluate the ...