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

learn more… | top users | synonyms (1)

1
vote
0answers
22 views

How do I check or validate the RBM (Restricted Boltzmann Machine) Model?

I'm trying to implement RBM, then i used play tennis case to test the rbm. I've tried autoencoder before, and the result was good. Actually, I confuse with the function of RBM it self, i think it ...
1
vote
1answer
33 views

Neural network to tag multiple textual topics in a single document

I want to use a neural network to do some topic analysis in a textual corpus. I have used neural networks before where there is a clear decision boundary between the category to which some observation ...
0
votes
0answers
23 views

What is a good non cryptographic Hash for string feature translation?

What would be a good non cryptographic Hash function to use for converting string features to a numerical representation for feeding into machine learning algorithms? To explain the scenario my ...
0
votes
1answer
23 views

2d basis functions which are smooth and localized and sum up to unity?

We are looking for a set of basis functions for representing image-data which consists of local ‘blobs’ which tile the space and which sum up to 1 at each point in space. For 1-dimensional data, ...
0
votes
1answer
28 views

Representing signals as feature vectors for deviation detection

I want to monitor (automatic-)gearbox failures on some vehicles. For each vehicle I have a captured signal representing the selected gear at each one millisecond (the values are discrete between 0 and ...
2
votes
1answer
36 views

“One sided” classifier

Below was tried in R, but any general solution would be highly appreciated: I have 2 class samples (both classes are balanced). I want to create a classifier, where I only care about 1 class (So, if ...
1
vote
1answer
44 views

How do I implement missing value patterns?

I have a training data set and I was able to find some interesting patterns in the missing values, and I used binary variables in order to represent the missingness. I am going to train a model, say a ...
3
votes
0answers
39 views

Concept of fitting cubic splines

i am reading the elements of statistical learning, and the following diagram is included on page 262. i interpret the text (potentially incorrectly) that the fitted line $\mu(x)$ is a linear ...
1
vote
1answer
28 views

spike and slab models

Kevin Murphy discusses in this book (http://www.cs.ubc.ca/~murphyk/MLbook/index.html) the spike-and-slab model. I am struggling to understand the prior linked to this model. Why, if $\gamma$=0, and we ...
1
vote
1answer
28 views

Training lstm a sequence one item at a time

I am trying to train an lstm with a sequence and get the sequence classification for the whole sequence. I have sequences of varying length so I have one input neuron and I am feeding one item at a ...
1
vote
0answers
44 views

How does one extend radial basis function (RBF) networks formally from regularization but with vector valued outputs?

I was reading the following paper on hyper & radial basis function (HBFs & RBFs) networks and also this one that kind of summarizes the first one and was trying to understand how to extend ...
0
votes
1answer
52 views

Random Forest, dependent measurements

I have a following quiz: A random forest is used for classifying the disease state of patients based on measuring multiple genes. The dataset consists of 100 genes and 50 patients. However, ...
0
votes
0answers
16 views

Tree not predicting all factors

I'm using the "tree" function to fit a model to predict a factor "Output" based on A, B, C, D and E ...
3
votes
1answer
72 views

naming convention: what does GLM stand for?

I encountered the term "Global Linear Model" which has the same abbreviation as "Generalized Linear Model". Since I couldn't find useful information on the former, my question is whether the two ...
1
vote
2answers
131 views

What measure of training error to report for Random Forests?

I'm currently fitting random forests for a classification problem using the randomForest package in R, and am unsure about how to report training error for these ...
2
votes
0answers
21 views

Problems with classification in imbalanced datasets

I often read about the problematic of doing classification in imbalanced datasets and methods to address it. Namely, off-the-shelf classifiers learn to minimize some form of total miss-clasffication ...
0
votes
0answers
13 views

Interpolation of Data Value using Optimized Weighting of Its Features

I have a question regarding "Interpolation" / "Prediction" of a value. Assuming we have a data set $ { \left\{ \left( {x}_{i}, {y}_{i} \right) \right\}}_{i = 1}^{N} $ where $ {x}_{i} \in ...
0
votes
0answers
6 views

How to classify different skeleton poses into a predefined pose or other poses using Kinect?

I'm using Kinect for windows and the input is the skeleton frame joints locations. As a result, I can track different joints locations in time. I need to detect this pose: With hands straight ...
0
votes
1answer
90 views

Class weights in caret

I'm using the R package caret to generate classifiers using a variety of different models on an imbalanced dataset. To overcome the class imbalance problem, I am using the "weights" parameter in the ...
0
votes
1answer
34 views

Feature selection in a “Noisy” environment

My first question - This might be a basic question but I have yet to find an answer; when choosing the features for my model, I have encountered certain features which are vectors themselves. (e.g. ...
0
votes
0answers
36 views

What's the difference between logistic regression and perceptron?

I'm going through Andrew Ng's lecture notes on Machine Learning. The notes introduce us to logistic regression and then to perceptron. While describing Perceptron, the notes say that we just change ...
0
votes
1answer
23 views

What are the different frameworks for solving regression problems in Machine Learning (like GLMs)?

I'm going through Andrew Ng's lecture notes on Machine Learning. The notes start with introducing linear regression and intuitively explaining what the cost function for the problem should be and how ...
0
votes
1answer
58 views

Is my understanding of Generalized Linear Models correct?

I'm going through Andrew Ng's lecture notes on Machine Learning & I just learnt about Generalized Linear Models there. I want to check if I know correctly what Generalized Linear Models are. ...
1
vote
0answers
13 views

Deriving Linear Regression update rule: Why do we set the derivative of cost funtion to 0 to minimize it?

(This question may be more about Math in general but I have a specific context in mind and hence am asking this here as opposed to math.stackexchange) I'm going through Andrew Ng's lecture notes on ...
0
votes
0answers
21 views

Model for irregular time series

I recently started working with regularly sampled time series, i.e. evenly spaced time series. However, I would like to move to irregular time series, i.e. unevenly sampled time series. I have looked ...
1
vote
0answers
58 views

How should one learn the centers for an hyper basis function network (HBF)?

I was reading the following paper on hyper basis function (HBF) (similar to radial basis function RBF network) and was trying to figure out how one learns the movable centers of the hyper basis ...
1
vote
1answer
48 views

Binary Classification vs Multi-class Classification

In the scenario that I have a binary classification problem, and use a binary classifier to train and test my model, assuming everything else is constant, would using a multi-class classifier with 2 ...
0
votes
1answer
38 views

Regression model for edge-sensitive data set

I have data sets in which important information is allocated in the edges, which are also very sensitive to inaccuracies. I would like to find a regression model based on edge recognition that brings ...
0
votes
0answers
222 views

Learning algorithm to define prediciton region to maximize score

The title may not too fitting but here is the problem. You have a sample of data with each data point being an x,y coordinate and a score. The goal is to create a loop which encloses the values as to ...
0
votes
0answers
15 views

What does “task-dependent clustering” mean?

I was reading the following paper on hyper basis function (HBF). Its about how one can use moving centers instead of data points as the centers of radial basis functions (RBFS). In the abstract they ...
4
votes
1answer
125 views

Relative variable importance for Boosting

I'm looking for an explanation of how relative variable importance is computed in Gradient Boosted Trees that is not overly general/simplistic like: The measures are based on the number of times a ...
0
votes
0answers
18 views

Mixtures of experts

I am trying to self-study and understand "mixture of expert" models, as desribed per below: . Is my intuition here correct that the $\rho(z_i|x_i,\theta)$ is a probability vector of length k, with ...
0
votes
1answer
31 views

How to find a Information Gain for Numerical Values

I have 4 class and four sets of features extracted from the huge data extracted from Real Time data acquisition system. . In above table, there are 4 sets of the features for each class. (C1, C2, C3 ...
1
vote
3answers
44 views

Is setting lambda equal to zero the same thing as not applying regularization at all?

If I set the regularization parameter to 0, does it essentially mean I'm not applying regularization (I've boxed the regularization bits in red)? Also, what is this type of regularization called?
0
votes
1answer
33 views

Traffic Analytics using k-means

I'm going to provide some (near)real time analytics (classification) of the network traffic inside of my cluster. All traffic is aggregated into "session" and consists of some number of features. I've ...
0
votes
1answer
32 views

Classification trees: favor one classification over other

We're using classification trees (c50 package) for a BUY/WAIT advice. However, the advice in our training set is not well balanced. That is, we advice to buy 3/4 times more than to wait. Probably as ...
1
vote
0answers
47 views

Bayesian neural networks: very multimodal posterior?

Question: How do Bayesian treatments of neural networks address the fact that the posterior has an exponentially large number of modes? Background: There seems to be a lot of interest in Bayesian ...
2
votes
2answers
70 views

Why should validation error be higher than training error?

I was reading about learning curve and in a page, this curve is shown: But I think something is wrong with it. If an estimator tunes it parameters on validation set, then validation error should ...
0
votes
0answers
39 views

When does it make sense to fit a distribution to data?

More in general, if a fitted generative model is at best a biased approximation, and let's say we're interested in the predictive distribution, there is always an information loss associated with the ...
0
votes
1answer
81 views

Gradient descend algorithm ascending for learning rate

This is not an Homework assignment. I am trying to implement the gradient descend explained in the link (Page 5) [http://cs229.stanford.edu/notes/cs229-notes1.pdf][1].I am able to successfully run the ...
0
votes
0answers
16 views

validation set with ranking variables

i'm working on an approach of feature selection with SVM model and i have some questions about validation , training and test sets. the idea is to rank variables in decreasing order of relevance ...
1
vote
1answer
21 views

Quadratic error for multi-class classification

I'm trying to train a neural network to classify handwritten inputs into 10 categories, each for one digit (1,...,9,0). I represent the output of an example using a 10-dimensional vector. Digit 5, for ...
0
votes
0answers
38 views

Problem with backpropagation algorithm for Feedforward Neural Networks

The objective When trying to exercise my knowledge of Feedforward Neural Networks, I started implementing one. The result is here. The final goal is to predict some handwritten digits data I have. ...
3
votes
1answer
69 views

Understanding the use of logarithms in the TF-IDF logarithm

I was reading: https://en.wikipedia.org/wiki/Tf%E2%80%93idf#Definition But I cannot seem to understand exactly why the formula was constructed the way it is. What I do Understand: iDF should at ...
1
vote
1answer
35 views

Need guidance in image classification

I'm new to machine learning and need some help. I need image classification to tell if an image is a car or not. Is there any working example or guidance or a book for this particular question? ...
0
votes
2answers
39 views

Multi-label classification

I am working on a project and I need some suggestions. I have a data set with 600 songs and for each song we have 60 numerical features (linked to the rhythm and the timbre of the sound). Moreover ...
1
vote
0answers
27 views

What is a compact vector equation expression the back-propagation algorithm for convolution neural networks?

I was reading the lecture notes for sparse auto-encoders from Andrew Ng and was saw that it had very nice compact way of expressing back propagation for neural networks: The really nice thing about ...
0
votes
0answers
39 views

Application of probability-inequalities in machine learning. Hoeffding's inequality

I would like to know a illustrative example of Hoeffding's inequality in machine learning? Does it have something to do with confidence intervals? Thanks in advance!
0
votes
0answers
6 views

Which regression model to use for order-sensitive sequences of symbols / apps?

I have a list of sequences of symbols, representing apps used by a smartphone user within a certain time frame. For example (Whatsapp, Facebook, Calender) might be one such sequence. To each list ...
2
votes
1answer
57 views

Predicting the winner of a contest, given history

In one of the online games I play, there's a daily contest where users can make bets. I'm hoping I can place more profitable bets by analyzing the contest's history :) (Though really I just wanna ...