Generalization Bounds for Learning Kernels

Proceedings of the 27th Annual International Conference on Machine Learning (ICML 2010)

Abstract

This paper presents several novel generalization
bounds for the problem of learning kernels based
on a combinatorial analysis of the Rademacher
complexity of the corresponding hypothesis sets.
Our bound for learning kernels with a convex
combination of p base kernels using L1 regularization
admits only a √log p dependency on the
number of kernels, which is tight and considerably
more favorable than the previous best bound
given for the same problem. We also give a novel
bound for learning with a non-negative combination
of p base kernels with an L2 regularization
whose dependency on p is also tight and only in
p^(1/4). We present similar results for Lq regularization
with other values of q, and outline the relevance
of our proof techniques to the analysis of
the complexity of the class of linear functions.
Experiments with a large number of kernels further
validate the behavior of the generalization
error as a function of p predicted by our bounds.

Research Areas