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

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Batch Gradient Descent - Parallelization

Here is the scenario that I have been thinking for sometime: You have a large dataset over which you want to run a regression analysis, using the classic gradient descent method to minimize the error ...
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10 views

how to improve linear regression model [on hold]

i am working on a simple linear regression model for practicing in order to learn machine learning . my model runs correctly however it get a bad score which means it is a bad model so any advice for ...
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33 views

Feature engineering

I recently realized, that feature engineering (designing input vectors for machine-learning algorithm) is one of the most complicated tasks when applying known algorithms (for example kernel ...
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1answer
24 views

Adding observations by aggregating existing data

Question I'm aware that generating features from existing data can be a valid method for adding new features for a regression/ML algorithm*, but can you add observations generated from existing data? ...
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24 views

Generalization error of PCA and kernel PCA

I've been recently reading Shawe-Taylor et al. 2005, On the Eigenspectrum of the Gram Matrix and the Generalization Error of Kernel PCA, where the authors analyze the squared residual of kernel ...
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How can I calculate the AUC for softmax classifier (e.g., logistic regression)?

At the end of a convolutional neural network(CNN) , there are usually a softmax classifier attached to it. How can I calculate the AUC for the CNN (that is, for the softmax classifier)? Thanks!
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2answers
54 views

Representative elements of a set

I'm looking for the technical name of the following problem. It sounds like a standard machine learning technique, but I'm not familiar with the field, and can't seem to find it. Let's say that we ...
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1answer
30 views

Neural Network Forward Propagation

I'm trying to solve this neural network problem found here: How do I go ahead and calculate the forward propogate in this example? I've see examples of how to calculate the expected output but ...
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1answer
33 views

How to to find and evaluate optimal discretization for continuous variable with $\chi^2$ criterion?

I have a data set with continuous variable and a binary target variable (0 and 1). I need to discretize the continuous variables (for logistic regression) with respect to the target variable and ...
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19 views

The effect on learning [on hold]

What is the effect of providing the learning system with more data of some kind than the other? Will it become more effective at recognizing the first one than the other? For example, consider any ...
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19 views

How to stack a convolutional autoencoder?

I am trying to figure out as to how to stack a convolutional autoencoder (CAE)? Consider a convolutional autoencoder (CAE) (using MNIST data, 28x28 input dimensions): ...
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7 views

Heuristics for streaming data matching [duplicate]

I have an index composed by thousands of documents. Slightly modified copies of those documents are sent to my application in small chunks, and I need to check, from those chunks, which document has ...
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24 views

Heuristics streaming data matching

I have an index composed by thousands of documents. Slightly modified copies of those documents are sent to my application in small chunks, and I need to check, from those chunks, which document has ...
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1answer
44 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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5 views

Guarded Discrete Stochastic network to solve CSP

There is a lot about NPL and vision systems but not a lot about constraint satisfaction problems (CSP). I have been digging around but I could use some guidance on how to use neutral network to solve ...
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1answer
41 views

What if high validation accuracy but low test accuracy in research?

I have a specific question about validation in machine learning research. As we know, the machine learning regime asks researchers to train their models on the training data, choose from candidate ...
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1answer
36 views

What is pretraining and how do you pretrain a neural network?

I understand that pretraining is used to avoid some of the issues with conventional training. If I use backpropagation with, say an autoencoder, I know I'm going to run into time issues because ...
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17 views

How to learn data fusion functions?

TL;DR: I have multiple datasets that say different/similar things (properties) about a bunch of entities (people, places etc.). I want to combine these into a single dataset that's closest to the ...
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28 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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9 views

How to perform pattern identification using ML?

I have the following problem: An event, takes place at a determined day of the week, hour, and with a pre-defined format (movie, music concert, lecture (3 items). Based on exit polls we determine 3 ...
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21 views

Overfitting in the validation set

When running an algorithm for training a system it is common to consider a lot of models and using the validation set for selecting one of them. In my case I am running a mini-batch gradient descent ...
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21 views

What will be the simple interpretation for the coefficients for features obtained in any Machine learning models?

I am working with a data that consists of two classes. I have used scikit learn, to craete models using SVM, Randomforest etc.I used to r2_score and I sorted the scores for features I am having and I ...
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1answer
17 views

Extracting Standard Errors Caret Model

I have tuned a glm net model with caret using the train function. I am trying to extract the coefficients and standard errors of those coefficients for the best tuned model. Following this CV post I ...
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1answer
20 views

Will normalizing training and testing data separately cause under/overfitting?

Suppose I have training and testing data and I want to train a classifier (e.g. SVM). Typically, features are normalized before classification to ensure some features aren't weighted more heavily than ...
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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. ...
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Interpreting crfsuite output model for numerical features

I am using crfsuite-python to implement a linear chain CRF in which I would like to use numerical features rather than strings as is the case with the standard CRF application parts of speech tagging. ...
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52 views

Ideal statistical or machine learning technique to model highly cross-correlated data

I'm trying to build a model that can predict streamflow for an alpine (snowmelt-fed) watershed using snow albedo (roughly, the energy reflectance of the snow) data. Albedo controls the melt of the ...
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1answer
23 views

Need a little help understanding K-means++ seeding

I have been working on a project that involves using K-means clustering for generating adaptive palettes from images. I understand the general process of K-means clustering, and I understand the ...
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1answer
54 views

R: Finding relationships between 2 variables to determine any patterns in data

I am working on finding relationships/patterns between 2 variables (Type_A, Type_B). ...
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1answer
29 views

Generative algorithms

If I understand slide 4 correctly, the idea here is that in order to compute $p(y|x)$ we can use the fact that $$p(y|x) = \frac{p(x|y)p(y)}{p(x)}.$$ Then $p(x|y)$ and $p(y)$ are calculated using our ...
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1answer
84 views

Do CART trees capture interactions among predictors?

This paper claims that in CART, because a binary split is performed on a single covariate at each step, all splits are orthogonal and therefore interactions among covariates are not considered. ...
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2answers
43 views

Are Random Forests and Boosting parametric or non-parametric?

From this excellent paper by Breiman, we can seize all the difference between traditional statistical models (e.g., linear regression) and machine learning algorithms (e.g., Bagging, Random Forests, ...
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9 views

Variable representations for faster learning convergence

My notes on machine learning state that transforming a classification problem from 2 classes, class A = 0, and class B = 1, to class A = $(1,0)$, and class B = $(0,1)$ leads to faster convergence in ...
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15 views

How could these two simple Bayesian algorithms be explained, simply? [on hold]

count(this token in class) + 1 / count(all tokens in class) + count( all tokens ) and ...
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0answers
34 views

How to make use of less data of a particular class for better modeling?

I have a dataset, say 9000 rows, with some features. Around 8000 belong to class 1 and 1000 to class 0. So, if I am creating a model with any method say SVM, LR, Random forest the model has a tendency ...
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31 views

In machine learning, may I train correctly a neural network with input real data and output validation Boolean data?

I have a matrix made of ~ 100 rows and 12 columns. Each entry contains a real value. The first 6 columns refer to a particular concept (firstClass), the following 6 to another one (secondClass), and ...
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42 views
+50

What is the honesty condition for regression trees?

I have a question pertaining to Stefan Wager's "Asymptotic Theory for Random Forests": http://arxiv.org/pdf/1405.0352v1.pdf Wager first states that trees are "fully grown in the sense given training ...
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11 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
24 views

What are the benefits for semi-supervised learning over unsupervised clustering? Or any limitations?

I have another question about semi-supervised learning vs unsupervised clustering, what are the benefits and limitations? I have got some data with labels and some without labels. I performed ...
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Semi-supervised learning vs supervised learning, what are the benefits and limitations?

Just wondering if any previous work compared semi-supervised learning vs supervised learning? Currently, I have got both datasets with and without labeling. And therefore, it is intuitive for me to ...
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1answer
18 views

Determine confidence in a CART model with factor (2 levels) response variable (using rpart)

I use the package rpartto model a classification/regression tree. I have the variables $x,y,s$ where $x$ is in $\{-1,1\}$, y is continuous in $[0,1]$ and $s$ is a ...
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26 views

Reinforcement Learning in Industry [on hold]

This is my first post here I would like to start with a rather general topic of discussion. I have studied Reinforcement Learning during the university years and although I find it rather fascinating ...
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1answer
25 views

Expectation of squared error

In machine learning, we let $X$ be a real-valued input vector and $Y$ be a real number output, with joint distribution $P(X,Y)$. We are looking for a function $f(X)$ for predicting $Y$ given the ...
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21 views
0
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1answer
26 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
32 views

How is the confusion matrix reported from K-fold cross-validation?

Suppose I do K-fold cross-validation with K=10 folds. There will be one confusion matrix for each fold. When reporting the results, should I calculate what is the average confusion matrix, or just sum ...
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7 views

Gaussian classifier: if two gaussians have equal variance is it possible for them to produce a non-linear decision boundary?

I have been playing with this a bit and I don't believe they can. However, I am very new to machine learning and my maths isn't strong enough to be certain.
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1answer
30 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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1answer
34 views

Neural Network System Identification

I am trying to implement a Neural Network to identify a Nonlinear System. I have implemented a very simple system in simulink and on the basis of examples of its input and output I would like to have ...
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31 views

Gaussian Mixture and K-Means ?! a big challenge?

This is taken from Tom. Mitche Material as Old-Exam. I think the (2) is true and not (3). Who can verify me?