PASCAL - Pattern Analysis, Statistical Modelling and Computational Learning

The Projectron: a bounded kernel-based Perceptron
Francesco Orabona, Joseph Keshet and Barbara Caputo
In: 5th International Conference On Machine Learning, 5-9 July 2008, Helsinki, Finland.

Abstract

We present a discriminative online algorithm with a bounded memory growth, which is based on the kernel-based Perceptron. Generally, the required memory of the kernel-based Perceptron for storing the online hypothesis is not bounded. Previous work has been focused on discarding part of the instances in order to keep the memory bounded. In the proposed algorithm the instances are not discarded, but projected onto the space spanned by the previous online hypothesis. We derive a relative mistake bound and compare our algorithm both analytically and empirically to the state-of-the-art Forgetron algorithm (Dekel et al, 2007). The first variant of our algorithm, called Projectron, outperforms the Forgetron. The second variant, called Projectron++, outperforms even the Perceptron.

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EPrint Type:Conference or Workshop Item (Paper)
Project Keyword:Project Keyword UNSPECIFIED
Subjects:Learning/Statistics & Optimisation
Theory & Algorithms
ID Code:4472
Deposited By:Francesco Orabona
Deposited On:13 March 2009