Accession Number : ADA307955

Title :   The Impact of a Machine-Readable Lexicon on a Principle Based Parser,

Corporate Author : ROME LAB ROME NY

Personal Author(s) : McHale, Michael L.

PDF Url : ADA307955

Report Date : MAR 1996

Pagination or Media Count : 107

Abstract : The goal of this research was to provide the groundwork for an investigation of an approach to domain independent semantic processing; the combination of a principle based parser (PBP) with a semantically enhanced machine readable dictionary (MRD). The parser is an implementation of Chomsky's Government-Binding theory and therefore provides complete syntactic coverage. The coverage of a parsing system is, however, ultimately a function of the size and richness of its lexicon. To provide both size and richness, the lexicon for the system was extracted from Longman's Dictionary of Contemporary English and semantically enhanced using Roger's International Thesaurus. Increased lexical richness increases system coverage but it may decrease the efficiency of the parser. Therefore, this research investigated the impact of using an MRD as the lexicon for a PBP. The results show that an MRD can indeed be used with a PBP though the larger, more ambiguous lexicon requires controls in the parser to avoid producing a large forest of candidate parse trees. With such controls, the impact of the larger lexicon becomes no greater for a PBP than for a traditional phrase structure grammar (ex., ATN, APSG) dealing with lexical ambiguity.

Descriptors :   *COMPUTATIONAL LINGUISTICS, *PARSERS, *LEXICOGRAPHY, *MACHINE AIDED INDEXING, SEMANTICS, INTERNATIONAL, VOCABULARY, AMBIGUITY, MACHINE CODING, SYNTAX, NATURAL LANGUAGE, DICTIONARIES, GRAMMARS, THESAURI, PHRASE STRUCTURE GRAMMARS.

Subject Categories : Linguistics

Distribution Statement : APPROVED FOR PUBLIC RELEASE