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

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23 views

Classification Accuracy

I am classifying text based on news headlines and I am achieving accuracy up to approx 80%. I want to improve it more. But issue is that when I calculate the same with synonyms using the code below: ...
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13 views

Tutorial on Radial Basis Function Networks?

I want to learn about Radial Basis Function Neural Networks, can you please suggest a good introduction or tutorial? All the introductions I found are rather short or incomplete or so.
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7 views

Feature Selection for look alike modeling using k-NN

I have a list of items(around 7000) and various parameters for each items. For each item on my list i need to identify 10 items which are similar to the item from my whole population (17 million). I ...
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1answer
21 views

Decision boundary equation of the perceptron

As I know the standard linear equation has the following form in $R^2$: $w_1 x_1 + w_2 x_2 = b$ where $b$ is the intercept with $x_2$ Also I know that a decision boundary in $R^2$ for a perceptron ...
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1answer
28 views

algorithms to pick best collection of classifiers

I have a bunch of methods that classify a binary outcome. I'm trying to figure out if some combination of those classifiers is better than any others. I'm hoping to run a bunch of methods. I've ...
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6 views

How to validate classifier (built by using MLN method)?

I have developed a method (let's call it Method X) that has a classifier function. The classifier function was built by using MLN (Markov logic network). I need to ...
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1answer
35 views

Does using a kernel function make the data linearly separable?

I'm reading about SVM and I learned that we use a kernel function so the data become linearly separable in the high dimensional (vector?) space. But then I also learned that they use the soft-margin ...
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29 views

Technologies behind Siri and Google Now?

I'm interested to know how Siri and Google Now works. What are the technologies behind them? I don't mean voice recognition (which is obvious) but the other stuff. Like interpreting the input and ...
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1answer
36 views

How to make stochastic gradient descent algorithm converge to the optimum?

(Background info taken from my blog) In logistic regression, the hypothesis function, which models the relationshiop between the dependent variable $P(y = 1)$ and the independent variable $X$, is : ...
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1answer
30 views

How can I evaluate the performance of a system that generates word clusters?

The word2vec tool uses deep learning to compute vector representations of words. They've mentioned that - "The word vectors can be also used for deriving word classes from huge data sets. This is ...
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1answer
30 views

Performing hierarchical clustering on a large data set

I have been applying complete linkage on about 5,000 points using matlab with no problem. I want to extend this method to much more elements. It would take me a long time to process my data to test ...
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20 views

Are these descriptions of batch gradient descent algorithm conflicting each other?

The first one is from Andrew Ng The second one is from Francis Bach I might be a little confused, but why is there a summation of partial derivatives in the second description and none in the ...
2
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1answer
38 views

Gradient decay in neural networks

I read that in traditional feed-forward neural nets the gradients in the early layers decay very quickly and that this is 'a bad thing'. But I don't understand why. Can someone please explain what ...
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22 views

What is multi run lasso regression?

I have problem in understanding of multi-run lasso regression. Basically, I know what is lasso regression, but don't know what is multi-run lasso regression, which sometimes I see literatures. Does ...
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2answers
22 views

Latent Dirichlet Allocation as input for WEKA

I am using the Weka API for my research about document classification. I wish to apply Latent Dirichelet Allocation on my dataset followed by using a classifier in Weka. However, it is not so clear to ...
6
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2answers
557 views

Meaning of a neural network as a black-box?

I often hear people talking about neural networks as something as a black-box that you don't understand what it does or what they mean. I actually I can't understand what they mean by that! If you ...
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30 views

Rough estimates for training time of deep belief networks

I'm still learning about deep learning. However I'm currently interested to know if deep learning architectures scale well or not. Suppose I have a dataset with 1 million training examples, can you ...
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0answers
10 views

Why feature maps are indexed by two indices?

I'm reading about convolutional neural networks. As I understood a feature map is a set of neurons (i.e like a single hidden layer in traditional ANN). So why feature maps are indexed by (i,j)? ...
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1answer
19 views

Updating set of probabilities for sampling with features importance

I'm currently working on some algorithm and I'm kinda out of idea for a problem I'm trying to tacle. Basically I'm trying to subsample the features of a dataset. I want to subsample that given this ...
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19 views

Compare averaged GLM with boosted regression trees using cross validation : d2 and RMSE calculation

I want to compare BRT and averaged glm models on test sets by calculating the explained deviance and RMSE. How can I calculate d2 and RMSE from predictions? I use the following functions: gbm1 ...
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22 views

Response surface of a particular discontinuous function

I have a function IR that depends on several (maybe 100) input random variables. I know ...
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35 views

A new piece of clue for document classification?

I am working on a document classification problem. I am using the typical vector space model to represent a document as doc-term vector. If document has some term, the vector entry for that term is ...
2
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0answers
37 views

Conceptual issues in training neural network and learning curve

I have a 4 Input and 3 Output Neural network trained by particle swarm optimization (PSO) with Mean square error (MSE) as the fitness function using the IRIS Database provided by MATLAB. The fitness ...
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1answer
30 views

How to implement a hold-out validation in R

Let's say I'm using the Sonar data and I'd like to make a hold-out validation in R. I partitioned the data using the createFolds ...
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0answers
20 views

Fisher's Exact Test to assess the significance of a difference between false positive rates

I have trained two binary classification models on the same data and evaluated them using the same test set. For each model I have calculated a false positive rate (and a count of false positives) at ...
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13 views

sub-questions with likert scales choices

I want to determine compliance to a certain standard in ISMS and to determine that, I have the standards started and it has sub-questions (say 2,3,4 questions), with each having a 5 point likert type ...
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98 views

Random forest on multi-level/hierarchical-structured data

I am quite new to machine learning, CART-techniques and the like, and I hope my naivete isn't too obvious. How does Random Forest handle multi-level/hierarchical data structures (for example when ...
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14 views

Help about a perceptron question

while studying for my Machine Learning exam, I encountered a problem that I cannot understand. In the problem, we have this perceptron, which 3 binary inputs (0 or 1) a,b,c with respective weights of ...
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1answer
45 views

Why can we use entropy to measure the quality of a language model?

I am reading the < Foundations of Statistical Natural Language Processing >. It has the following statement about the relationship between information entropy and language model: ...The ...
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32 views

Why is the default cost function choice of a neuron quadratic loss?

I'm studying neural networks, and I'm trying to decide why the default choice of cost function for a single neuron seems to be quadratic loss: $$\sum_i(y_i-f_i)^2,$$ instead of: ...
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28 views

Estimating training values in machine learning

I've started to learn machine learning using the book 'Machine Learning' by Tom Mitchell. The first chapter introduces the reader to machine learning and to the first problem: learning to play ...
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1answer
22 views

ML for specific classification problem

I have a training dataset for classification problem $X \rightarrow y$. Where $X$ is an $n$th dimensional real vector, $y$ is an integer number in $\{0, 1\}$. I want to solve the next problem: ...
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2answers
97 views

Not very known but effective data mining algorithms?

I recently came a cross Matrix Factorization for classification or recommendations. I was very shocked that it was one of the most effective techniques in the Netflix competition. But actually I think ...
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1answer
34 views

Why features compression is good?

I'm reading about deep learning and that in principles it's a features compression technique and that is why it works. Now my question is why compressing features from 200 or so into 4 is better? How ...
8
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1answer
82 views

Would there be a model selection problem if we had access to an oracle that gave us the exact generalization error?

Let $\mathcal{E(h)}$ a function that given some hypothesis $h$ returns the generalization error for that fixed $h$. I was reading some notes about model selection and generalization error and it ...
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2answers
43 views

Ensemble of models with different feature spaces

BACKGROUND I have data in which the dependent variable is binary with a highly-skewed distribution: <1% records are 1 (doers), >99% records are 0 (non-doers). I'm using logistic regression to ...
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24 views

Handwriting Recognition - Percentage Match

I'm currently working on a senior project and we've chosen handwriting recognition. Initially I thought that using machine learning algorithms were a good idea for this, but after the thought below ...
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2answers
101 views

How to calculate p values in logistic regression with gradient descent algorithm

In logistic regression, the gradient descent algorithm for calculating coefficients can be described this way: Until convergence, do $$ \beta := \beta + \alpha \frac{\partial L}{\partial \beta} ...
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1answer
20 views

how to compute minimum required vc dimension for a classifer to classify a specific data

Suppose we're given an N dimensional data to classify. To cope with this task we may choose a classifier that suits our desires more. However obviously not every classifier is capable of classifying ...
0
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1answer
21 views

Evaluation indexes hypothesis for clustering

I read on the cluster analysis page of wikipedia: For example, k-means clustering can only find convex clusters, and many evaluation indexes assume convex clusters. On a data set with non-convex ...
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0answers
10 views

k-way MinMax spectral clustering

Is there a k-way MinMax Cut Spectral Clustering which can be easily implemented? In the spectral clustering tutorial I found only 2-way MinMax cut.
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0answers
11 views

Record linkage when sources have different fields

I have read a little about record linkage, but it seems to me that a requirement is that all fields in both sources can be compared. For example, with sources A and B, an assumption is that we can ...
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0answers
27 views

What is the best algorithm for finding attacks from log file [on hold]

I m working on forensic analysis of web logs. I have generated the DoS attack dataset and i m having the attack dataset of log files (unlabeled dataset) taken from Dr. Anton Chuvakin. I need to look ...
1
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1answer
45 views

Cascade Combination of Kernel Functions

I have a question regarding machine learning and specifically kernel functions. Suppose we have a Kernel function, say $K(x)$, and also another distinct one, say $K'(x)$. I want to know is $K(K'(x))$ ...
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1answer
25 views

SVM decision boundary conditions : derivation problem

I was trying to understand the derivation of SVM decision boundary. Suppose my decision boundary is y-x-1=0. Now in the book it was written that ...
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0answers
19 views

Comparison of cophenetic correlation coefficients on different data sets

I applied the same hierarchical clustering (weighted) on two data sets: The first is a 'raw' data set, on which I didn't do anything, and the second on the same data set after I filtered it by ...
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1answer
49 views

How can I perform 10-fold cross validation by manually constructing datasets?

I am working in text classification in RapidMiner where, because of the nature of my problem, I cannot use the built-in k-fold cross validation strategy, so I decided to create 10 copies of my dataset ...
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18 views

processing a sound file for analysis of different spoken languages

So i have sound files for 5 languages by 2 person, thus my input data has 10 sound files. Now i want to cluster them based on the languages (thus 5 clusters) and not based on the speaker/voice ( ...
1
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1answer
32 views

Linearly dependent features

I have a matrix A of 1000 observations (rows) and 100 features (cols). I would like to find: Linearly dependent features so that I can remove them and simplify the problem. rank(A) gives me 88, ...
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31 views

HIstogram of oriented gradients (HOG) features descriptor theoretical problems

I'm going to implement HOG as my features descriptor. But there are some things that make me confused: For example: If we have an image with size of 10 x 20 If we want to compute the HOG of that ...