Methods and principles of building "computer systems that automatically improve with experience."

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Unsupervised feature learning from raw text as a previous step for clasification?

I have a corpus of 2500 opinions, is it posible to use scikit´s restricted boltzmann machine implementation to extract a feature vector as a previous step to a classification task?. What aproach do i ...
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20 views

Hard Case - prediction of chain stores revenue

Data about average monthly revenue from 2000 stores around whole country. Gini coeff. of reve around 20%, with 50% of observation around average, very thin tails of distribution Explanatory ...
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18 views

mob model tree algorithm

I am trying to figure out the inner workings of the mob function in the party package. I can't figure out how the splitting variable is selected when it is a categorical variable. In the publications ...
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1answer
39 views

About grid search to find the best value of C

I know when I want to find the best values of C and gamma, I should use grid-search. But in my case I want to find just the best value of C. So, this is called a line-search. Is there any function ...
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1answer
55 views

Logistic Regression, SVM or NN?

Just attended Andrew Ng’s online course on ML and although I’ve understood the methods I seem to be missing the intuition on where to apply them in terms of classification problems. What are the ...
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30 views

How to handle systematically missing values?

In my situation, one of two sources is not invoked if the confidence reported by the first source is higher than a threshold and hence it is missing in some examples. How can account for such missing ...
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1answer
17 views

Gaussian MRF/Markov Network: the zero precision = no connection?

Gaussian MRF in Gaussian information form: edge potential: $exp(\frac{-1}{2} y_s\Lambda_{st} y_t)$ node potential: $exp(\frac{-1}{2} y_t\Lambda_{t} y_t+\eta_ty_t)$ Why: precision parameter ...
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1answer
35 views

prediction of polls

Just as an example Scotland has poll to decide whether they need to be independent from UK or not. Here is BBC's summary of different polls: ...
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27 views

In Kneser-Ney smoothing, how are unseen words handled?

From what I have seen, the (second-order) Kneser-Ney smoothing formula is in some way or another given as $ \begin{align} P^2_{KN}(w_n|w_{n-1}) &= \frac{\max \left\{ C\left(w_{n-1}, w_n\right) - ...
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6 views

number of nodes in an unpruned decision tree

What is the number of nodes in an unpruned decision tree that is trained using n samples and that grows until there is only one sample in each leaf? I would like to know if there is a formula to ...
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18 views

Creating obligatory combinations of variables for drawing by random forest

Problem For my machine learning task, I create a set of predictors. Predictors come in "bundles" - multi-dimensional measurements (3 or 4 - dimensional in my case). The hole "bundle" makes sense ...
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21 views

Fusing probability scores from different independent sources

Consider a situation where two independent sources, $s_1$ and $s_2$ are giving probability estimates regarding the occurrence of a event $e$. I tried to model this as a bayesian network but that ...
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25 views

A/B split/bucket testing with three or more variants

Lets say I have three search engine e.g. search engine A, search engine B and search engine C. Each search engine is given a set of queries Q (e.g. apple,banana,carrot....), this set Q remains the ...
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18 views

choosing best value for N when using N-Gram approach

the question is quite general, but I am doing a research related to supervised machine learning to classify two set of characters into two categories. in fact, I want to compute some measures of ...
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1answer
28 views

Cluster migration visualization

I have asked a very similar question at the Latex forum here, but in order to address the part of my question where I ask if there is a better way of visualizing the data I have, I wanted to cross ...
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19 views

What book about use of machine learning in pharmacy would you recommend?

I know that machine learning is a very popular tool in pharmacy. Are there any books that describe use of machine learning in pharmacy?
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2answers
90 views

Newbie to neural networks

Just starting to play around with Neural Networks for fun after playing with some basic linear regression. I am an English teacher so don't have a math background and trying to read a book on this ...
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16 views

How to choose negative training sample for Classification problem

Choosing positives sample is a relative straightforward task, but I'm having some problem on determine what should I use for the negative example. I'm working on a SVM binary classificator, trying to ...
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26 views

Word probabilities in a Naive Bayes filter

While implementing a Naive Bayes filter, I stumbled across a problem with the calculation of the conditional probabilities $p(w|c)$ of a word $w \in \mathcal{W}$ given a class $c \in \mathcal{C}$. ...
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59 views

Random Forest proof notation

I am having a bit of difficulty understanding the notation in equation (1) on page 4 of the following paper: https://escholarship.org/uc/item/35x3v9t4#page-4 Specifically, what do $E_{X,Y}$ and ...
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52 views

What does correlated data mean and how can I visualize it with scatterplot?

I'm playing around with the Abalone dataset in R and following along with this article. The dataset has 8 variables that are taken into account to predict the number of ...
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1answer
46 views

What is meant by effective parameters in machine learning

My question might be a bit ambiguous, but I started to wonder what does the "effective parameters" mean in machine learning? I have heard few professors of machine learning in my university talk about ...
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2answers
58 views

Does the dataset size influence a machine learning algorithm?

So, imagine having access to sufficient data (millions of datapoints for training and testing) of sufficient quality. Please ignore concept drift for now and assume the data static and does not change ...
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37 views

Why PCA performed on two similar data sets result in different number of components?

I have two data sets (2048 dimensions) collected under slightly different circumstances. I am using PCA to reduce the dimension of the data before passing it further for classification. Both data sets ...
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184 views

Predicting time to finish

Out of curiosity, I want to understand how to model this problem. I've been hearing people suggest the use of linear regression but I am not sure how to encode this problem (included my attempt below) ...
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44 views

Unsupervised machine learning with numerical and text data

My dataset has numerical variables and one "Note" variable with around a paragraph of text. I'd like to classify the data with an unsupervised learning algorithm. I've done some searching and one ...
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28 views

Libraries for Online learning

I am looking for packages (either in python, R, or a standalone package) to perform online learning to predict stock data. I have found and read about Vowpal Wabbit ...
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33 views

Financial time series model

I have an interesting question that I think has not been asked yet here. I am building an AI that has as goal to predict how wrong a standard based-on-history model is. This is done based on Natural ...
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17 views

Asking tweet classification

I want to ask you the process to classify the tweet data. Now, I am working to Twitter data but i have confuse how to classify the tweet data using Mallet Tool. Example; I have 200,000 tweets. The ...
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35 views

Sample Weights for classification using Gradient-Boosted trees?

How can "weights" be given to different samples according to their relative importance while using Gradient boosted decision trees for classification? How does the ...
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20 views

Feature boosting via rescaling in logistic regression and linear SVMs

If I were expressing a problem in terms of binary features, all encoded as {0,1}, could I boost some features by encoding them as {0,2}? Would the effect change based on whether I used either of the ...
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2answers
106 views

How to choose the training, cross-validation, and test set sizes for small sample-size data?

Assume I have a small sample size, e.g. N=100, and two classes. How should I choose the training, cross-validation, and test set sizes for machine learning? I would intuitively pick Training set ...
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1answer
26 views

computing EP messages in factor graph

I'm using infer.net for implementing a dynamic Bayesian network model. every node in each layer is dependent on all nodes in previous layer (we want to train wji, the weights of edges between each ...
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1answer
67 views

what are the alternative open source tools for PredictionIO?

PredictionIO is good to be enough for content discovery and recommendation but it seems it does not support classification. Then I should use a different tool then Prediction IO for my prediction ...
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63 views

Linear regression of 0/1 response (Fig. 2.1 of The elements of statistical learning)

In chapter 2 ESL book authors write: Let's look at example of linear model in a classification context They fit a simple linear model $g = 0.3290614 -0.0226360\cdot x_1 + 0.2495983 \cdot x_2 + e$, ...
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29 views

How to compare two clusterings generated by two clustering approaches

I am currently working on a modification of a clustering algorithm to suit my problem domain. I want to know which methods are available for me to compare the centroids generated from the two ...
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19 views

The ethics of using an optimal multiclass feature set for binary classification

I'm currently trying to find the best feature set/network architecture configuration for a binary classification problem, however to approach it via the usual means of building and testing does not ...
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14 views

Is time-delay embedding/attractor reconstruction used in some machine learning algorithm?

I try to model/forecast blood glucose levels from my diabetes diary, so I have to deal with some 5-7 daily measurements of estimated carbohydrates, physical activity, insulin doses and measured blood ...
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22 views

Interpreting R results, are the data multivariate normal?

I ran "mvn" using the "mclust" package in R using the following codes: mvn("EEE", data[,18:22], prior = NULL, warn= NULL) I am having trouble figuring out how to ...
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3answers
106 views

How to Use Neural Networks to Forecast Time Series Data with Predictor Variables?

I have browsed a lot of topics here, but the ones I see were all about forecasting a single variable, depending on its historical values. Whereas I want to predict a variable, by estimating a ...
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24 views

Is it true that decision trees can handle dependent features very well?

I have once heard that decision trees can handle dependent features very well, compared to e.g. Naive Bayes classifiers. However, I can't find any scientific source for that. So my question: is it ...
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1answer
42 views

Machine learning with categorical data: Can I delete examples?

I have a machine learning project that uses a bunch of features to predict a class that has categorical values. The possible values are: 1, 2, 3, 4, and 5. I'm interested whether the class has the ...
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11 views

Which terms are more standard: precision and recall or correctness and completeness?

I am familiar with terms like precision rate and recall rate from the machine learning literature, but recently I was reviewing a thesis which used the terms correctness and completeness. A quick ...
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61 views

Calculate rating/score based on multiple criteria to rank data

I extract data related to a movie by sentiment analyzing the reviews. Hence,extracted movie data contains average sentiment values (avg_pos and avg_neg) calculated over multiple reviews, total no of ...
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27 views

Stacked Generalization Ensemble Algorithm for regression

I am using stacked generalization(Rupert 1992) for combining multiple(8) heterogeneous base learners for regression. What I understand from the pseudo codes that Train the 8 learners on 8 instances ...
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16 views

Comparing densities of a feature for different classes when the feature is irrelevant to one class

Let us suppose that I have a number of features. I design pdfs for every feature and every class, some of them by smoothing some histogram of training samples, others just by introducing the prior ...
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4answers
79 views

Evaluating performance of machine learning models

I'm trying to predict when a location has enough wind to go sailing. I've built several models that look for correlations between different weather conditions and whether it ends up being windy X ...
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2answers
43 views

Instance weighing in libsvm/liblinear

I often use the instance weights with Libsvm for classification problems. http://www.csie.ntu.edu.tw/~cjlin/libsvmtools/#weights_for_data_instances Does anyone know the details of the algorithm that ...
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62 views

How can I evaluate my model when the the testing data are too few and the generated results don't match testing data

I have a bioinformatic data set includes a very large negative examples (let's say 30000 examples) and just a few positive examples (let's say 150 positive examples). Since I need to feed an enough ...
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Has anyone publicly shared an implementation of RUSBoost in R?

There's no package available on CRAN, so I was hoping someone in the community had written their own function/package. I see it's been done in MATLAB, so I may just have to start with that and write ...