Detecting Opinions and their Opinion Targets in NTCIR-8

Identifying an opinion target, a primary object of the opinion expression (e.g., the real-world object, event, and abstract entity), is helpful for extracting target-related opinions and detecting user interests. This paper presents a novel framework for target-based opinion analysis, which extracts opinionated sentences and identifies their opinion targets from news articles. To determine whether a sentence includes opinions, we utilize opinion lexicons (i.e., predefined clue words) and linguistic patterns. In identifying the opinion target, candidates are generated and examined for existence of four different features. We attempt to capture the relationship between an object target and opinion clues and utilize a document theme. For evaluation, we used English news articles from New York Times, provided by NTCIR-8 MOAT and annotated opinionated sentences and theirs opinion targets. Experimental results show that our proposed method is promising although many additional issues remain to be studied in the future.