Function of Semantic Features in Opinion Target Extraction and Its Polarity Identification

The authors bring forward seven types of semantic features related to opinion target extraction. They are evaluation-triggering words, evaluation-eliminating words, the words insulated from opinion target, the forward-orientated verbs, the backward-orientated verbs, the verbs of psychological movement and the attributive-directing verbs. Five types of semantic features related to polarity identification are also proposed. They are positive nouns, negative nouns, meaning-shifting nouns, measuring adjectives and semantic construction. The authors explain the twelve features from aspects of the necessity and their usages. The result shows that the application of semantic features improves the precision of the system.