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

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Model Perplexity explanation

Not sure if this is the place to ask about model perplexity. I have googled some explanations but it does not seem to yield much results besides the wikipedia explanation. Can someone explain to ...
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10 views

How do i convert 30 categories into numbers for scikit [migrated]

I am new to statistics, Python, machine learning and Scikit-learn. However, I am trying this project where I have a CSV with 35 columns of student data. The first column is an ID which I think I can ...
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9 views

How to design a classifier to classify Product Reviews left by consumers in a set of predetermined labels? [on hold]

I want to build a classifier which has the ability to classify freetext into a set of pre-selected labels. Let's say I have access to all the feedback (Product Reviews) left by consumers on a ...
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9 views

Anomaly/Outlier Detection based on User Profile

I am working with time series data. These time series data basically are user login/logout session and task carried out during these session (like what are the process created and its duration). I am ...
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1answer
23 views

Linear regression to minimize the Cost Function

I am new started machine learning program. I find it difficult to understand gradient descent algorithm. I am going through machine learning from coursera by Andrew Ng.All of his lecturer in second ...
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1answer
25 views

Classification with partially “unknown” data

Suppose I want to learn a classifier that takes a vector of numbers as input, and gives a class label as output. My training data consists of a large number of input-output pairs. However, when I ...
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1answer
23 views

Do you merge your validation and training sets?

I'm currently implementing a K-Nearest Neighbours model and I'm at the stage of splitting up the datasets for cross-validation. I understand the need for the Training, Validation and Test sets, ...
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10 views

MATLAB Approach to learn XOR

In the MATLAB Example the two class exclusive or (XOR) is trained this way: inputs = [ 0 1 0 1 ; 0 0 1 1 ]; targets = [ 0 1 0 1 ; 1 0 1 0 ]; Which I read as: ...
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20 views

Methods for supervised regression learning

What ML methods should I try for a data set of around 1000 samples? The output variable is dependent on say 10 regressors of which 8 are real numbers and the other 2 are categorical. Or they might ...
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12 views

How to represent predictions in stacking (machine learning)?

I was wondering the following, suppose I have an algorithm A, B and C and they generate the following predictions: ...
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6 views

Using linear learning to rank algorithm in a mixture language model

How do I tune the parameter alpha automatically?In this formula S(Q|D) = alpha * P(t|D) + (1-alpha) P(T|D) Friend advice me to use linear learning to rank algorithm ( any example?) The formula is ...
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how to get attribute importance in a dataset in r?

I have a data set with almost 1/5th of data is NA. Out of all the columns, few are categorical and rest are numerical.My target variable is categorical variable. I want to find the most important ...
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25 views

Using gradient information in minimizing error function, in Bishop's Pattern Recognition

In Bishop's book Pattern Recognition, there appears the following paragraph on page 239, where I included the equation he refers to In the quadratic approximation to the error function, ...
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1answer
38 views

What is the best algorithm for predicting rare events? [on hold]

I heard somewhere that logistic regression is a good candidate for this, but it doesn't work really well for me. Instead, Random Forests proved to be very efficient in my observed population. The ...
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15 views

Detect multiple classes in an image?

I have a deep neural network trained with data of different kinds of fruits (apples, oranges, guava, pear, etc.). In my testing data, I have multiple fruits in the same image. For example, an image ...
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20 views

Forecasting at Customer (Household) level

I am in the process of building a model in which i need to predict total deposit balance of customers in next 3 years. Data are available at customer level. For example, I have data for 0.1 million ...
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1answer
59 views

Feature that is numeric if true, or single value if false

In regards to feature engineering for machine learning models. I would like to engineer a feature that encodes the following: value can be true and if so it will measure a numeric (maybe ...
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1answer
60 views

What are the key steps in solving Machine Learning Problem [on hold]

I am trying to make a summary to myself, what are the key steps for solving a Machine Learning problem. I tried to read good books, talked with peer, discussed many issues here, checked many web based ...
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17 views

Gaussian Process: How to use GPML toolbox for multi-dimensional input?

I am using MATLAB 2014_a student version I have 198 x 9 training data x (X1,X2,...,X9) and 198 x 1 target data y For now, I got linear equation among training data and target data ,for example, ...
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5 views

How can get F-measure, precision and re call and also Cluster labels in R [on hold]

I am new to R. I want to use hierarchical clustering of R to cluster following distance matrix. ...
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35 views

How would you modify your model according to that confusion matrix?

How would you proceed with your model, if the confusion matrix looks like on the picture below? Classes 2, 3 and 4 get misclassified a lot among each other. EDIT: The Confusion Matrix was created ...
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Why my Convolutional Neural Network always produces the same outputs?

I used MatConvNet to build a CNN model for regression. The input size is 20×20×1×32, the output size is 4×1×32, the convolutional filter size is 3×3×1. Now I found after training the training error ...
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1answer
17 views

Correct definition of classes in classification tasks

I have to predict the values of a continuous target variable $Y$ using a bunch of $X$ features. Unfortunately, the regression approach does not provide satisfying results. Thus, I was thinking to ...
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14 views

Is cross entropy only applied on the last layer of an ANN?

I was reading about L1 regularization and from what I understand, we compute the cost of the last layer like: $\ w_{new} = w−\eta\frac{\partial C_{0}}{∂w}−\frac{\eta\lambda}{n}w $ However when using ...
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Compute all paths in graph that has multiple inputs and one output

I want to compute all the paths in directed acyclic graph from multiple inputs (x1, .., xn) to one output. The graph has the same depth which d and the inputs come to the graph at the same time (the ...
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8 views

Can Naive Bayes be used with feature hashing and one hot encoding?

I was wondering if a naive bayes implementation can be used with data that has been feature hashes and one hot encoded. The data I am looking at is mobile ad click data from the avazu kaggle ...
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Classify streaming, partially complete data into groups defined by prior clustering

Suppose I have M observation vectors, offline, $y_t$, $ t =1 ... M$, and each observation is $n$ dimensional. I then cluster these observations into $k$ clusters. For computing the clustering ...
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SVM - high number of support vectors leads to a high variance SVM?

I've tuned a SVM with radial kernel that has training error about 10%, but test error is about 38%, which surprise me. I tried to understand what may cause this and noticed the number of support ...
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21 views

Merging observations in Gaussian Process

I am using Gaussian process (GP) for regression. In my problem it is quite common for two or more data points $\vec{x}^{(1)},\vec{x}^{(2)},\ldots$ to be close to each other, relatively to the length ...
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3answers
49 views

A good description of the random forests method

Can anyone suggest a good book or article describing the random forests method of classification? I'm not satisfied with the way the subject is treated in "An Introduction to Statistical Learning with ...
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1answer
21 views

Heteroscedasticity in machine learning predictions

I am using a machine learning method (PLS) to predict a continuous variable, which currently does a pretty good job, with reasonable RMSE etc. However, the residuals exhibit heteroscedasticity, where ...
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2answers
14 views

Prediction for non-negative data using PLS/alternative

I am currently using PLS (the set of predictors are quite highly-dimensional) to predict a particular variable, $age$, and I am using Caret's train implementation using the pls method: ...
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7 views

How ksvd algorithm is considered generalized kmean?

I am trying to understand more details of this paper "KSVD: An Algorithm for Designing Overcomplete Dictionaries for Sparse Representation" proposed a new algorithm called Ksvd and claims it's a ...
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What are some good datasets to learn basic machine learning algorithms and why?

I am new to machine learning and looking for some datasets through which i can compare and contrasts the differences between different machine learning algorithms (Decision Trees, Boosting, SVM and ...
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Data complexity measure which affect classifier performance

As we strive to explain accuracy of machine learning algorithms, many authors suggest to start by degree of complexity in data. I am working in data complexity measure like: class ...
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1answer
18 views

Advice on a model or approach to layered dataset

I am attempting to develop a model to estimate the number of people in a space based on the Wi-Fi Traffic. At present, I have a dataset (in xml) which is structured like the following: ...
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13 views

Improving my knn prediction

I am still somewhat new to R and machine learning. I am trying to predict the cases of diabetes in the PimaIndiansDiabetes data set. My results were not the best- and I am wondering what I could do to ...
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13 views

Problem on Clustering Discrete Input using GMM

I want to do clustering using Gaussian Mixture modeling (GMM) on a set of data which is a 5-dimension vector of real values $(x_1,x_2,x_3,x_4,x_5)$. However the clustering result were pretty bad, ...
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24 views

Bias inputs in an RNN

As far as I'm aware, the bias inputs for a feed forward neural network are typically connected as follows: How are they connected in a recurrent neural network? (My guess is below)
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2answers
93 views

X-means algorithm and BIC

I want to simulate X-means algorithm based on [1] in MATLAB. I have some questions about this algorithm. X-means Algorithm Steps: (1) Initialize K = Kmin. (2) Run K-means algorithm. (3) FOR k = ...
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What neural network architecture and weights can approximate the following functions?

I learned how to represent all the boolean functions such as AND, OR, XOR etc. If a multilayer (recurrent) neural network can approximate any function arbitrarily close, what kind of architecture and ...
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Flag Random or Nonsensical Entries in a data set using R

This is a variation on my question Machine learning to catch fraud I have a data set with about 5 million rows The data set contains names and addresses of companies The name of the company is free ...
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1answer
18 views

what is “Minimum Length Least Square”

I am in the process of implementing Bayesian Lasso with Normal-Gamma prior; In section 3.3 mention The prior for the scale parameter $\gamma$ conditional on $\lambda$ is given by $v_\beta = 2 \lambda ...
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2answers
45 views

cross-validation: what is the standard deviation if the same value is obtained for each fold?

Here is a detailed imaginary example: I am using 5-fold cross-validation to estimate the generalization MSE of my predictive model. When I hold-out fold number 1, which contains 10 observations, say ...
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23 views

Cost function spiking upon using dropout on neural network

Upon using the dropout technique, my cost function is spiking arbitrarily. Is this normal? If not, how do I avoid it? I'm using a salt-and-pepper mask to drop out neurons at a dropout rate of 5%. ...
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28 views

Lagrangian multiplier: role of the constraint sign

I am beginner learning Lagrange multipliers with wiki article. Consider: maximize $f(x,y)$ subject to $g(x,y) = 0$ I understand that to maximize I must follow the gradient $\nabla {_{x, y}}^{}f$. I ...
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22 views

How do I use MatLab or R data model in an machine learning application [closed]

I want to use matlab or R to create a prediction model, once this is complete how would I use that model in a an application?
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1answer
41 views

Classification problem where one attribute is a vector

Hello I am a layman trying to analyze game data from League of Legends, specifically looking at predicting the win rate for a given champion given an item build. Outline A player can own up to 6 ...
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Is there a classification model with possibility to set transition probabilities for each sample?

There are models where we can to set initial transition probabilities between classes like Markov models. But what if we need to change the probabilities dynamically depends on all previous ...
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8 views

Suggest suitable time series like ML model

We have data (1901 to 2002) in this schema: Fotrnight, Temp, Precipitation, WetDayFreq, (and other env variables), Cholera_cases we have one such table for each ...