Semantic interpretation of a Japanese complex sentence in an advisory dialogue-focused on the postpositional word “KEDO”, which works as a conjunction between clauses

We are developing a Japanese spoken dialogue system that helps a computer user perform his tasks through question-answering. In this paper, we propose a method for the semantic interpretation of a complex sentence connected by a conjunction, “KEDO”. “KEDO” is a postpositional word and it forms an adverbial clause. First, complex sentences containing “KEDO” are extracted from an advisory dialogue database and the semantic role of “KEDO” in each sentence is analyzed. Next, each sentence is decomposed into the part before “KEDO” and the part after “KEDO”, and each part is expressed in a semantic structure that we have developed. Finally, the relationship between the semantic structure and the semantic role is formalized into rules for semantic interpretation. Our method interprets a complex sentence semantically by applying the rules to the two semantic structures generated from the sentence. As a result, the semantic structures are modified or transformed into others, if necessary