Searching For Sentences Expressing Opinions By Using Declaratively Subjective Clues

This paper presents a method for searching the web for sentences expressing opinions. To retrieve an appropriate number of opinions that users may want to read, declaratively subjective clues are used to judge whether a sentence expresses an opinion. We collected declaratively subjective clues in opinionexpressing sentences from Japanese web pages retrieved with opinion search queries. These clues were expanded with the semantic categories of the words in the sentences and were used as feature parameters in a Support Vector Machine to classify the sentences. Our experimental results using retrieved web pages on various topics showed that the opinion expressing sentences identified by the proposed method are congruent with sentences judged by humans to express opinions.