Tagged Questions

0
votes
0answers
44 views

trouble in prediction in neural network classifier

I am training a 4-class neural network classifier. The details of my data are: featurelength = 280 ...
2
votes
1answer
32 views

Difference Between Matlabs classify and ClassificationDiscriminant functions

I recently came upon a discrepancy between Matlab's classify and ClassificationDiscriminant functions. By default, they should both be doing Linear DiscriminantAnalysis, but when given unbalanced ...
1
vote
1answer
96 views

What data from MATLAB's svmstruct are needed for classification in a different language?

As the title already states Iam wondering what data exactly are needed from the MATLAB svmstruct to be able to classify a new instance outside of MATLAB, e.g. in ...
1
vote
0answers
106 views

Least angle regression packages for R or MATLAB

I am looking for a Least Angle Regression (LAR) packages in R or MATLAB which can be used for classification problems. The only package that I currently know which fits this description is glmpath. ...
0
votes
1answer
225 views

Classification and regression trees (cart)

In matlab, classregtree can be used to implement classification and regression trees (CART) you can find this in the documentation however it's not clear what ...
2
votes
1answer
239 views

How can I classify images as “normal” or “lesions” using SVM?

I want to classify images as "normal" or "lesions", and then rate the images in the lesions category from mild and severe. This classification would be based on edge, color and texture features. For ...
3
votes
1answer
748 views

Nested Cross-Validation for Classification in Matlab

I am trying to tackle a classification problem with Support Vector Machine in Matlab using SVM. Using sample codes in Bioinformatics Toolbox documentation (SVM Classification with Cross Validation) ...
1
vote
0answers
176 views

Matlab TreeBagger Cost argument not working as it works with similar function fitensemble

The cost function of my TreeBagger class and fitensemble (Bag method) are both [0 8;1 0] for binary classification. The confusion matrix on fitensemble shows that the classfication tends to turn in ...
0
votes
1answer
361 views

Accuracy of each path in a decision tree in Matlab

I would like to know the accuracy of each path in a decision tree in Matlab. I can build a decision tree in Matlab by: ctree = ClassificationTree.fit(X,Y) ...
4
votes
2answers
610 views

Dimensionality reduction for classifying textures with MATLAB

I am trying to apply dimensionality reduction on an a set of images (~3000 pixels) using Matlab's Dimensionality Reduction toolbox. However, I know very little about dimension reduction. So I tried ...
0
votes
1answer
291 views

Using GPML in Matlab for MultiClass Classification

I am using Rasmussen's GPML code in Matlab R2011a_student. I have training data (2560x29707) w/ labels (6 classes), and test data (640x29707). To prep the data I have 1. converted from sparse to full, ...
1
vote
1answer
391 views

How to find classifier success performance?

EDIT I am playing with pattern recognition techniques and just to get a grip of it for simplicity I have tried to develop a classifier which categorizes strings into 3 classes based on the ...
1
vote
1answer
369 views

Problem in understanding hidden Markov model EM training and log-lik computation result

i'm using Kevin Murphy's HMM Toolbox. But i have a problem in understanding the results. My problem is to classify some sequences with Hidden Markov Model. I'm using a (test) dataset build with ...
1
vote
1answer
299 views

Voting in Multi-Class SVM

I am currently trying to classify 6 class of facial expression using SVM. I am using MATLAB and LIBSVM to do my classification. The problem i face is the pred label below produces 0 and 1. It treats ...
2
votes
2answers
279 views

How to deal with label switching issues with Matlab's classification trees?

I have a situation that seems trivial but I can't figure it out. I have a dataset in Matlab that has categorical values. For example: ...
2
votes
1answer
301 views

GMM with Bayes decision model

Given two classes of training data (A and B), I want to fit each class' distribution using a GMM with k components, and then use Bayes Decision Model for the classification. The first step was to ...
5
votes
1answer
992 views

Calibrated boosted decision trees in R or MATLAB

In An Empirical Comparison of Supervised Learning Algorithms (ICML 2006) the authors (Rich Caruana and Alexandru Niculescu-Mizil) evaluated several classification algorithms (SVMs, ANN, KNN, Random ...
2
votes
1answer
2k views

Bayes classifier of two normal distributions in MATLAB

Probability distribution of two classes is given by $N(5,1)$ and $N(6,1)$ where $N(\mu,\sigma^2)$: $$f(x) = \frac{1}{\sqrt{2\pi \sigma^2}} e^{-\frac{(x-\mu)^2}{2\sigma^2}} $$ How to classify ...