Long Sentence Analysis by Domain-Specific Pattern Grammar

We propose a method for analyzing long complex and compound sentences that utilizes global struc-ture analysis with domain-specific pattern grammar. Previously, long sentence analysis with global in-formation used the following methods: two-level analysis--global structure analysis of long sentences with domain-independent function words and pars-ing of their constituents[Doi et al., 1991], and pat-tern matching--adaptation of domain-specific fixed pattern to input sentences. By utilizing domain-dependent information the latter method could an-alyze long sentences of that domain. But since the matching is made only on the surface the sentence isn't analyzed well when patterns appear recursively. 2 Domain-Specific Pattern Grammar Our method analyzes the global structure of long sentences by using three knowledge-bases: domain-specific patterns that can be described as a phrase structure grammar, a list of keywords that denote constituents of the patterns, and a pure basic gram-mar. An input sentence is initially parsed and di-vided into its constituents with these knowledge-bases, and then each constituent is parsed with a general grammar. Each constituent must be guaran-teed uniformity by parsing with pure basic grammar. To obtain a pattern grammar of Japanese long sentences we analyzed the structures of about 750 long sentences from the leads of news articles in a Japanese newspaper, Asahi Shinbun, and identified several fixed global patterns. An example of pat