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

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Is my learnings in Machine Learning fine? [on hold]

I am a self learner in Machine Learning. I am from humanities background. My goal was to know bit of Machine Learning and to develop few applications based on few algorithms. To get feel of the ...
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1answer
55 views
+50

Estimating the time for completing a sequence of actions

In short: suppose I have observations for times taken to do some action. I want to estimate, how long will it take to complete a sequence of actions. The estimate should minimize the mean absolute ...
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25 views

Sales Forecasting using Support Vector Machine

I have sales data for last three years 2011-2013. I want to use Support Vector Machine technique in R to do the predictions. I just wanted to know that the approach that I am using is correct or not? ...
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2answers
153 views

What variable importance criterion?

A student of mine developed a heuristic supervised machine learning algorithm for highly multivariate data. It seems to work pretty well, and once the model has been derived from the training data ...
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4answers
2k views

Recall and precision in classification

I read some definitions of recall and precision, though it is every time in the context of information retrieval. I was wondering if someone could explain this a bit more in a classification context ...
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13 views

Is there deep learning,especially RBM, code that is really good to do classification [on hold]

For example, I found some code , but they didn't do wake-sleep algorithms to adjust the weights. I am especially interested in the one that google brain used for recognizing "cat" from youtube, no ...
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19 views

Hidden Markov Models relationship

I have a question regarding a small investigation that I have been conducting into the relationship between the length of observation sequence, T, on which two decoders (BCJR and classic Viterbi) ...
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0answers
29 views

The best way to solve particular classification problem?

I got training set (time series) of size approximately 2 million precedents {x,y}. Each x is a vector of size 20 and each y is a binary vector of size 10 like {1,0,0,1,1,0,1,1,1,0}. For a new input x ...
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0answers
16 views

How do you deal with different distance based features?

If I have a model where the set of features where a cosign distance measure makes sense for some of the features, and a Euclidean distance measure makes sense for the others for example using a BOW ...
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1answer
2k views

Online vs offline learning?

What is the difference between offline and online learning? Is it just a matter of learning over the entire dataset (offline) vs. learning incrementally (one instance at a time)? What are examples ...
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0answers
6 views

Hyper-parameters for pretrain and fine-tuning

When doing deep learning, in particular dnn, it's shown that pre-train each layer in a unsupervised fashion, then fine-tune the weights using the labeled data in a supervised fashion. My problem is, ...
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1answer
540 views

Decision boundaries and Gaussian density functions

This is for my hw, and if anyone can solve the first part of the question it will be great. Here is the question: Assume a two-class problem with equal a priori class probabilities and Gaussian ...
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0answers
12 views

Examine SVM result by plotting histogram of decision values of training samples

I'm working for object detection(computer vision) and have some problems in SVM training. My training configuration is as below. Balanced training set (positive 3998/ negative 3998) The dimension of ...
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2answers
2k views

Generative vs. discriminative

I know that generative means "based on $P(x,y)$" and discriminative means "based on $P(y|x)$," but I'm confused on several points: Wikipedia (+ many other hits on the web) classify things like SVMs ...
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0answers
11 views

Whats going wrong in Implementation of this gaussian bernoulli RBM?

I have a problem in finding negdata value. In particular multiplying with sigma. Could someone help in representing this equation vishid*sigma*poshidstates + visbias in matlab. ...
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3answers
80 views

What are the most popular artificial neural network algorithms for recognising the content of images?

What are the most used/popular artificial neural network algorithms for recognising the content of images in general? E.g. If the picture is of a person, dog, cat or a car. If the picture is a ...
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1answer
61 views

error increasing with no of estimators in adaboost

My error gets increased when i increase the n_estimators value in ...
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0answers
14 views

Choosing fold size for highly Imbalanced dataset + nested CV + svm

I am trying to classify a dataset with ~1000 points. 90/10 is the class ratio - super imbalanced. Here are the following steps I did: Use 20 relevant features from previous knowledge Remove highly ...
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1answer
48 views

Classification using correlation

Given two correlation matrix (each $p \times p$), where each belongs to a different group, is it possible to classify a new sample into one of the group (based on the correlation matrix only)? What ...
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1answer
160 views

Comparison of two classifiers based on precision/recall/F1 only?

For two classifiers h1 and h2 I have the precision, recall and F1 score as a percentage (along with the original labeled data set that they were tested on). If I had access to which samples each ...
2
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2answers
75 views

Weighting words based on position in text

I'm currently working on semantic analysis and had a question about text organization and structure. Are there any algorithms, or statistical / machine-learning models that weight the importance of a ...
2
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1answer
273 views

Forecasting optimization techniques in fantasy baseball

I am currently trying to build a better forecasting model for my fantasy baseball roster. I currently am using commonly accepted projected season statistics (ZiPS from Fangraphs) to determine the ...
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0answers
20 views

different feature types for classification

There has a data set with several features. One feature is of the type of continuous numerical values; another feature is of the type of categorical values, such as A, B and C. If I want to build a ...
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1answer
56 views

High Standard Deviation for Leave one out cross-validation?

I am using the leave one out cross-validation technique to evaluate my model. If the prediction on the test sample is right the output is 1 otherwise 0. So I have a array of N samples with 0's and 1's ...
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2answers
51 views

How does random Forest work for regression?

I am an absolute beginner in field of machine learning, I started doing titanic assignment in Kaggle and found(read some where) Random Forest is the best fit. I started reading about random forest and ...
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2answers
77 views

How to build a prediction model for exam score based on previous scores

I am trying to construct a formula, which will take student's previous exam results (for ex: SAT) taken at particular dates and predict his future test result. One X is previous test result 1; ...
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1answer
14 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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1answer
18 views

Is my understanding of how to calculate the reachability distance in local outlier factor correct?

Reading lof implementation at : http://www.cse.ust.hk/~leichen/courses/msc-it5210/lectures/LOF_Example.pdf the local reachability distance is given as : I don't fully understand this equation as ...
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2answers
52 views

Which property of count data make mean-variance dependency?

I have read about the fact that, there is dependency of variance on mean of count data.In most of cases they do variance stabilization transfomration as preprocessing step of data modeling. I wonder, ...
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1answer
247 views

Observation symbols for training a set of HMMs

If we are to classify 2 separate classes/actions using HMMs, we design 2 separate HMMs (one for each class). Do they share same set or a different set of observations-symbols for each of the HMM? If ...
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1answer
310 views

Variational inference for nested Chinese restaurant process

I recently read paper by Chong Wang and David M. Blei "Variational Inference for the Nested Chinese Restaurant Process". And I couldn't understand the next part (from p.5): The variational update ...
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0answers
11 views

Applying autoencoders for dimensionality reduction in audio: Why does this create a low-pass effect? [on hold]

I've been playing around with framing audio data and training a single-layer autoencoder to find a dimensionality-reduced form (say 128-sample frames to 32-dimension frames). When I test the audio ...
3
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2answers
72 views

Good machine learning algo for partial derivatives?

Does anyone know of good robust algos to estimate partial derivatives of a regression model? I am talking about a general regression model like this: $\mathbb{E}(y|x_1, x_2, ... x_n) = f(x_1, x_2, ...
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2answers
172 views

Test data generation for neural network handwriting recognition

Can someone share some Octave/Matlab code or algorithm to pre-process a photo taken from mobile camera of a handwritten digit. After pre-processing, the data should have similar characteristics to ...
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1answer
249 views

How do I calculate random baseline?

I am a bit confused as to how to calculate random baseline. If I understand correctly the random baseline is calculated by adding up the squared probabilities of all the classes. The random baseline ...
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3answers
65 views

Is it necessary to scale the target value in addition to scaling features for regression analysis?

I'm building regression models. As a preprocessing step, I scale my feature values to have mean 0 and standard deviation 1. Is it necessary to normalize the target values also?
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2answers
139 views

When to avoid Random Forest?

Random forests are well known to perform fairly well on a variety of tasks and have been referred to as the leatherman of learning methods. Are there any types of problems or specific conditions in ...
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21 views

List of widely used statistical technique or models in the financial industries [closed]

Please let me know the commonly used statistical technique in the financial industries like banking and their applications.
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1answer
62 views

Growing Self-Organizing Map for mixed-type data

I am trying to write code to build a growing SOM for mixed-type data. I came across a paper Growing Self-Organizing Map with cross insert for mixed-type data ...
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1answer
134 views

machine learning model with 50% chance to be deterministic

I am trying to predict auction prices from a self gathered data set. I have titles available, and the price it was offered for. Now I noticed that whenever there is a 3 digit string of numbers in the ...
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1answer
41 views

Post hoc selection of important features in random forest?

I want to guarantee a parsimonious random forest (few features used). What are methods to do this? It was suggested to me to get the feature importance after the model was created, and then create a ...
2
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1answer
139 views

Dirichlet process mixture model with Bayesian hierarchical clustering

I am doing Bayesian hierarchical clustering. From my understanding, there are three basic points for this algorithm. Use marginal likelihoods to decide which clusters to merge Asks what the ...
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2answers
135 views

Evaluating features and similarity measures

I am currently developing a classificator, which is supposed to classify into a number of classes. For this purpose I am designing some features and similarity measures which I might use for a later ...
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0answers
30 views

Neural Networks and Picture Recognition

I have spent a bunch of time looking at this series of videos (Neural Network Tutorial), by Ryan Harris: https://www.youtube.com/watch?v=Q_5B3GuWPCc&index=41&list=PL29C61214F2146796 I am ...
2
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1answer
23 views

How to isolate impact of event in a product's lifecycle?

I'm trying to figure out how a single event affects sales numbers of a song. For example, see what the effect of being featured in iTunes store compared to songs with comparable previous download ...
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0answers
27 views

Validation accuracy larger than training accuracy

I was performing an experiment but got a higher validation accuracy than training accuracy. I've got a 39 mice data and performed leave one out cross-validation. The validation accuracy was 100%. But ...
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1answer
82 views

How do Restricted Boltzmann Machines work?

I don't have a strong math background, so I am kind of stuck trying to understand how RBMs work. On wikipedia page about RBMs, I am able to understand the formulas in isolation, however, I'm not sure ...
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0answers
65 views

MHT: Pre-Selecting statistical tests without Bias

Summary: The last formula boxed in red (which is a modified log likelihood from logistic regression) is a special non-differentiable loss function that is adapted to contain a Bonferroni correction in ...
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1answer
142 views

Choosing correct C and g parameters for libsvm

libsvm 3.18 Features: 10 I have used following, parameter range: ...
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2answers
30 views

Accuracy of random prediction with non equal distribution

Assume that I want to predict the value of a variable that has three different states: a, b, and c. The chance that these variables have the 3 states is not equally distributed. Out of 10 trials, the ...