!495 An Analysis of Radicals-based Features in Subjectivity Classification on Simplified Chinese Sentences First Author Affiliation / Address line 1 Affiliation / Address line 2

Chinese radicals are linguistic elements smaller than Chinese characters1. Normally, a radical is a semantic category and almost all characters contain radicals or are radicals themselves. In subjectivity classification on sentences, we can use radicals to represent characters, which reduce the scale of word space while keep the subjectivity information. In this paper, we manually labeled a charac-ter set to build a high-quality radical-character mapping, and then the mapping is used to gen-eralize character-based features with radicals. In experiments, we at first evaluated the per-formance when directly generalizing charac-ters with radicals, and then offer a hypothesis that can reduce noises. Experiments show that this approach based on our hypothesis can reduce feature space while keep or improve the performance, which is es-pecially useful when the training samples are scarce