Improving the Generalization Performance of Multi-class SVM via Angular Regularization

Improving the Generalization Performance of Multi-class SVM via Angular Regularization

Jianxin Li, Haoyi Zhou, Pengtao Xie, Yingchun Zhang

Proceedings of the Twenty-Sixth International Joint Conference on Artificial Intelligence
Main track. Pages 2131-2137. https://doi.org/10.24963/ijcai.2017/296

In multi-class support vector machine (MSVM) for classification, one core issue is to regularize the coefficient vectors to reduce overfitting. Various regularizers have been proposed such as L2, L1, and trace norm. In this paper, we introduce a new type of regularization approach -- angular regularization, that encourages the coefficient vectors to have larger angles such that class regions can be widen to flexibly accommodate unseen samples. We propose a novel angular regularizer based on the singular values of the coefficient matrix, where the uniformity of singular values reduces the correlation among different classes and drives the angles between coefficient vectors to increase. In generalization error analysis, we show that decreasing this regularizer effectively reduces generalization error bound. On various datasets, we demonstrate the efficacy of the regularizer in reducing overfitting.
Keywords:
Machine Learning: Classification
Machine Learning: Learning Theory
Machine Learning: Machine Learning