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Questions tagged [support-vector-machines]

For questions about using support vector machines (SVMs), models that aim to separate a given data space using hyperplanes.

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5 votes
1 answer
172 views

How to train a model to classify object trajectories?

I have a tracker that outputs the trajectory $(x,y,z)$ of an object (e.g., a can). I want to use these trajectories to train a classifier (i.e., SVM) in order to infer the activity that the person ...
Gianpiero Francesca's user avatar
0 votes
1 answer
40 views

Support Vector Machines to use after Classification?

I'm a little bit about the SVM. I'm actually understanding for which purpose Support Vector Machines are used. The aim is to find the biggest (best) hyperplane between two different data clusters. The ...
user1844505's user avatar
0 votes
0 answers
67 views

approximation of nonlinear time-dependent system with history

I have two time-dependent coupled equations. One of which is several orders of magnitude more computationally demanding than the other. I am trying to use machine learning to reproduce the behavior of ...
user1984528's user avatar
0 votes
1 answer
76 views

SVM Math Question

I'm studying support vector machines and came across this paper. The following equation doesn't make sense to me, especially the part with the 0 ∀i. Any help understanding the basics of SVMs? yi * (...
Josh F's user avatar
  • 165
6 votes
1 answer
193 views

Support Vector Machines as Neural Nets?

This is more of a conceptual question. I have learned about Neural Nets, and I have some clue as to how Support Vector Machines work. I read somewhere however that given the appropriate kernel (is ...
Josh F's user avatar
  • 165
3 votes
1 answer
1k views

How to train an L2-regularized L1 Hinge Loss SVM using vowpal wabbit?

I'm trying to train an L2-regularized L1-hinge loss SVM using vowpal-wabbit. I use the following commands to train and test on the splice dataset: ...
Hugh Perkins's user avatar
10 votes
2 answers
3k views

Do RBF kernel matrices tend to be ill-conditioned?

I use RBF kernel function to implement one kernel based machine learning algorithm(KLPP), the resulting kernel matrix $K$ $$K(i,j)= \exp\left({\frac{-(x_{i}-x_{j})^2}{ \sigma_{m}^2}}\right)$$ is ...
ZeyuHu's user avatar
  • 317
2 votes
1 answer
46 views

Why do some known kernel functions manage to achieve linear separation in feature space?

I'm currently learning the maximal margin classifier with kernels, and I'm wondering - why do they work? In which cases do they work best? I'm especially interested in the RBF and polynomial kernels, ...
Michael Litvin's user avatar
1 vote
1 answer
77 views

Confusion related to svm optimization

I was reading thispaper related to kernel SVM. It states Support Vector Machine (SVM) (Cortes and Vap- nik, 1995) as the state-of-the-art classification algo- rithm has been widely applied in ...
user34790's user avatar
  • 473
7 votes
2 answers
285 views

Why is the Dual problem preferred for Maximal Margin Classification?

The primal problem is $$\min_{w,b}\frac{1}{2}w^Tw$$ $$s.t. f_i(w)=1-y_i(w\cdot x_i+b)\leq0$$ Where $y_i=\pm1$. Instead of using Gradient Descent directly, the dual is usually solved: $$\max_{\...
Michael Litvin's user avatar
0 votes
1 answer
57 views

Confusion related to convexity of a problem

I was reading this paper related to Multiclass Classification with Multi-Prototype Support Vector Machines - paper However, I am having difficulty in understanding why they have mentioned the ...
user34790's user avatar
  • 473
6 votes
1 answer
186 views

Confusion related to convexity and concavity of a function

I was reading this paper http://www.ist.temple.edu/~vucetic/documents/wang11kdd.pdf related to adaptive multi-hyperplane machine for non linear classification In that paper, they have mentioned about ...
user34790's user avatar
  • 473
10 votes
2 answers
4k views

Calculating Lagrange coefficients for SVM in Python

I'm trying to write a full SVM implementation in Python and I have a few issues computing the Lagrange coefficients. First let me rephrase what I understand from the algorithm to make sure I'm on the ...
Charles Menguy's user avatar