Questions tagged [machine-learning]

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

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5
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1answer
415 views

Comparing accuracy of models in ordinal regression / classification

I am looking into creating a model to predict whether an item is "Very Good", "Good", "Bad" or "Very Bad". After I fit the training data to the models, comparing the accuracy of the models during ...
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0answers
469 views

Where can I download a tagged dataset of text related to finance, programming, analytics etc.? [closed]

I want to create and train a model which classifies a new text content into finance, programming, analytics, design etc. Where can I get a relevant dataset to train my models? TIA.
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1answer
3k views

How do I calculate the delta term of a Convolutional Layer, given the delta terms and weights of the previous Convolutional Layer?

I am trying to train an artificial neural network with two convolutional layers (c1, c2) and two hidden layers (c1, c2). I am using the standard backpropagation approach. In the backward pass I ...
2
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1answer
622 views

Random Forest, Type - Regression, Calculation of Importance Example

I am trying to use a Random Forest Model (Regression Type) as a substitute of logistic regression model. I am using R - randomForest Package. I want to understand the meaning of Importance of ...
6
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1answer
653 views

Choosing best methods for estimating the unknown parameters in a linear regression model

Given some dataset for prediction, for eg say I have different housing price prediction dataset: dataset 1 : 100 training and 100 testing sample, 50 feature dataset 2 : 100 training and 100 ...
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4answers
3k views

How to learn spam email detection?

I want to learn how a spam email detector is done. I'm not trying to build a commercial product, it'll be a serious learning exercise for me. Therefore, I'm looking for resources, such as existing ...
2
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1answer
2k views

Package for SMOTEBoost in R

I am solving a rare event cum classification problem. I have come across a package called SMOTEBoost which oversamples the rare event and boost the results. But I'm not sure is that supported in R. ...
8
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1answer
423 views

Theano in deep learning research

How widely is Theano used in deep learning research? Is Theano a good start to learn the implementation of machine learning algorithms? Will learning the implementation of something like a feed ...
3
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4answers
132 views

Algorithm for deriving mutiple clusters

Suppose I have a set of data(with 2 diemensional feature space), and I want to obtain clusters from them. But I do not know how many clusters will be formed. Yet I want separate clusters(The number ...
5
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3answers
2k views

Need help with LDA for selecting features

I am currently selecting features of products by using LDA to group 6000 keywords of product into topics. Here is the sample of my dataset after being organized into list of keywords for each product ...
2
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3answers
159 views

What possible data products can be built using this dataset [closed]

I have a dataset which contains information about when do people enter and leave a premise. I have the following information in the dataset : Person Id Time of Entry Time of Leaving The dataset has ...
1
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1answer
314 views

Wordnet Lemmatization

I tried finding about exception lists in wordnet lemmatizers. "Morphy() uses inflectional ending rules and exception lists to handle different possibilities" which I read from http://www.nltk.org/...
5
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2answers
139 views

How to cluster a link traversal dataset

I'm using Google Analytics on my mobile app to see how different users use the app. I draw a path based on the pages they move to. Given a list of paths for say a 100 users, how do I go about ...
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0answers
65 views

Do I need to apply a Ranking Algorithm for this?

I have data of the form : ...
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1answer
219 views

Different methods for clustering skills in text

Consider a talent pool in which each member has some set of skills. Some of these talent are submitted to orders as potential candidates of which one is selected. It is reasonable to assume that the ...
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4answers
28k views

How to scale an array of signed integers to range from 0 to 1?

I'm using Brain to train a neural network on a feature set that includes both positive and negative values. But Brain requires input values between 0 and 1. What's the best way to normalize my data?
3
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2answers
3k views

Where does the sum of squared errors function in neural networks come from?

Training a basic multilayer perceptron neural network boils down to minimizing some kind of error function. Often the sum of squared errors is chosen as a this error function, but where does this ...
7
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4answers
3k views

How is Data Science related to Machine learning?

I went through this comparison of analytic disciplines and this perspective of machine learning, but I am not finding any answers on the following: How is Data Science related to Machine learning? ...
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1answer
146 views

Ideas for next step of Machine Learning [closed]

I have completely followed the machine learning course on coursera Machine Learning by professor Andrew Ng Now I want to put my knowledge to action. Some ideas that I have include : -Voice ...
12
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2answers
9k views

Using attributes to classify/cluster user profiles

I have a dataset of users purchasing products from a website. The attributes I have are user id, region(state) of the user, the categories id of product, keywords id of product, keywords id of ...
4
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1answer
143 views

What is the best technique/algorithm to compare trees changes?

I have a problem I would like to solve using machine learning. I would like to use some sort of classification to know if a just added change in a tree data structure is "good" or is "bad". Let's say ...
5
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1answer
2k views

Learning time of arrival (ETA) from historical location data of vehicle

I have location data of taxis moving around the city sourced from: Microsoft Research Overall it has around 17million data points. I have converted the data to JSON and filled up mongo. A sample ...
3
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0answers
73 views

Various algorithms performance in a problem and what can be deduced about data and problem?

HI I am currently trying to apply various algorithms to a classification problem to assess which could be better and then try to fine tune the bests of the first approach. I am a beginner so I use ...
4
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1answer
145 views

Why are HMMs called linear-chain?

I found in many sources that Hidden Markov Models are linear-chain networks(e.g. in Predicting Structured Data book by MIT). However, as I understand it, HMMs can have any edges in its graph. Even ...
2
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1answer
95 views

What kind of machine learning algorithm can I use?

I have a data set of tweets regarding vaccines. They have been collected from an API because they have keywords like "flu, measles, MMR, vaccine" etc. I need to find tweets specifically about ...
3
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1answer
243 views

Ranking Bias in Learning to Rank

Users tend to click on results ranked highly by search engines much more often than those ranked lower. How do you train a search engine using click data / search logs without this bias? I.e. you don'...
3
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1answer
68 views

When to Perform non-linear dimension reduction

When do we feel need to go through non-linear transformation like kernel PCA ? Please share an example
3
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1answer
418 views

Finding user similarities within informal data sets

I'm new to all this and am putting together a learning project. I've decided on finding similarities between users in a data set such as http://en.wikipedia.org/wiki/Enron_Corpus. After doing a bit of ...
3
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3answers
166 views

Datasource for regression model prediction : Machine Learning

I am trying to work using Amazon machine learning, but the data set that I have is small. The model I want to build is for regression based predictions and the domain I am aiming for the data set to ...
3
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1answer
2k views

In Weka, how to draw learning curve evaluated on both test and training set?

This is just for finding overfitting gap. After initial research, I can only find method to draw learning curve using evaluation of test set. However, I could not evaluate on training set and over ...
4
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1answer
4k views

Where is the cost parameter C in the RBF kernel in SVM?

RBF kernel using SVM depends on two parameters C and gamma. If the equation of the kernel RBF as the following: $K(X,X')= \exp(\gamma||X-X'||^2)$ In the equation I can see where can I use gamma, but ...
7
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1answer
3k views

Why does logistic regression in Spark and R return different models for the same data?

I've compared the logistic regression models on R (glm) and on Spark (LogisticRegressionWithLBFGS) on a dataset of 390 obs. of ...
8
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1answer
3k views

Which classification algorithms to try for classifying text data into 300 categories

I have 40000 rows of text data of health care domain. Data has one column for text (2-5 sentences) and one column for its category. I want to classify that into 300 categories. Some categories are ...
113
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5answers
61k views

What is the “dying ReLU” problem in neural networks?

Referring to the Stanford course notes on Convolutional Neural Networks for Visual Recognition, a paragraph says: "Unfortunately, ReLU units can be fragile during training and can "die". For ...
7
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3answers
6k views

Dimensionality and Manifold

A commonly heard sentence in unsupervised Machine learning is High dimensional inputs typically live on or near a low dimensional manifold What is a dimension? What is a manifold? What is the ...
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1answer
802 views

Why is the Naive Bayes classifier of sklearn faster than sklearns SVM?

I've used scikit-learn in Python to compare results of naive Bayes and SVM. I've found that naive Bayes is quicker than SVM. Could anyone shed some light on reasons ...
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2answers
4k views

How Mllib in Spark select variables in logistic regression

I have a question about MLlib in Spark.(with Scala) I'm trying to understand how LogisticRegressionWithLBFGS and LogisticRegressionWithSGD work. I usually use SAS or R to do logistic regressions but ...
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2answers
504 views

Understanding text conversion into SVM input [closed]

In Support Vector Machines, when used for sentiment analysis, text gets converted into a set of data points. How does this happen, usually?
4
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1answer
859 views

What types of features are used in a large-scale click-through rate prediction problem?

Something that I often see in papers (example) about large-scale learning is that click-through rate (CTR) problems can have up to a billion of features for each example. In this Google paper the ...
2
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2answers
55 views

Pound notation in Summation

I was going through a paper comparing glove and word2vec. I came across the pound notation shown below. What does it mean when used like this? The link for paper is here
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1answer
57 views

Which classifier is efficient in dealing with test query which belongs to no trained class?

Suppose classifier trained with 5 class, and input query content does not belong to any of the trained class data. Naive bayes provides and random class as a result here. Which classifier deals best ...
1
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1answer
180 views

What are Hybrid Classifiers used in Sentiment Analysis?

What are Hybrid classifiers used for sentiment analysis? How are they built? Please suggest good tutorial/book/link for reference. Also how are they different from other classifiers like SVM and Naive ...
3
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2answers
453 views

Using clustering and Lasso with cv

I used clustering on my dataset. Now when I'm trying to use a LASSO with cv to predict a response, one of the variables it takes into consideration is which cluster a new point is classified into.(I ...
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0answers
221 views

non-linear optimization for a linear classifier? (scikit-learn)

Using scikit-learn, why would you use bfgs optimization which is non-linear for a linear classifier as logistic regression? I am confused. Does the optimization method finds the optimum of the chosen ...
2
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1answer
948 views

Optimizing Weka for large data sets

First of all, I hope I'm in the right StackExchange here. If not, apologies! I'm currently working with huge amounts of feature-value vectors. There are millions of these vectors (up to 20 million ...
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0answers
78 views

Prove Reccurrent Neural Network can exhibit oscillatory behavior

I understand how recurrent neural networks work, however I'm trying to build a deep intuitive understanding of their behavior which is difficult for me because they exhibit such complex behaviors. ...
3
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1answer
1k views

Using EM (Expectation Maximization) algorithm for Training Logistic Regression

Is it possible to learn the weights for a logistic regression classifier using EM (Expectation Maximization)algorithm? Is there any instance reference?
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1answer
106 views

Finding frequencies in a noisy, “uneven” dataset

I'm working on a problem where frequency analysis applies (decomposition of a signal into frequencies, that is), but it's noisy and the samples are unevenly spaced. Specifically: given a list of ...
0
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1answer
32 views

percentage of confidance on desion trees results

I am looking towards a solution where classification algorithms produce output with some confidence value. but I am confused whether classification algorithms are able to produce results with ...
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1answer
552 views

Difference between OLS(statsmodel) and Scikit Linear Regression

I have a question about two different methods from different libraries which seems doing same job. I am trying to make linear regression model. Here is the code which I using statsmodel library with ...