tailieunhanh - Báo cáo khoa học: "COMPUTER AIDED INTERPRETATION OF LEXICAL COOCCURRENCES"

This paper addresses the problem of developing a large semantic lexicon for natural language processing. The increas~g availability of machine readable documents offers an opportunity to the field of lexieal semantics, by providing experimental evidence of word uses (on-line texts) and word definitions (on-line dictionaries). The system presented hereafter, PETRARCA, detects word from a large sample of press agency releases on finance and economics, and uses these associations to build a ease-based semantic lexicon. . | COMPUTER AIDED INTERPRET A TION OF LEXICAL COOCCURRENCES Paola Velardi Maria Teresa Pazienza Ợ Urùversity of Ancona Istituto di Informatica via Brecce Blanche Ancona f University of Roma Dip. di Informatica e Sistemistica via Buonarroti 12 Roma ABSTRACT This paper addresses the problem of developing a large semantic lexicon for natural language processing. The increasing availability of machine readable documents offers an opportunity to the field of lexical semantics by providing experimental evidence of word uses on-line texts and word definitions on-line dictionaries . The system presented hereafter PETRARCA detects word cooccurrences from a large sample of press agency releases on finance and economics and uses these associations to build a case-based semantic lexicon. Syntactically valid cooccurences including a new word w are detected by a high-coverage morphosyntactic analyzer. Syntactic relations are interpreted . replaced by case relations using a a catalogue of pattems interpretation pairs a concept type hierarchy and a set of selectional restriction rules on semantic interpretation types. Introduction Semantic knowledge codification for language processing requữes two important issues to be considered 1. Meaning representation. Each word is a world how can we conveniently circumscribe the semantic information associated to a lexical entry 2. Acquisition. For a language processor to implement a useful application several thousands of terms must have an entry in the semantic lexicon how do we cope with one such a prohibitive task The problem of meaning representation is one which preoccupied scientists of different disciplines since the early history of human culture. We will not attempt an overall survey of the field of semantics that provided material for many fascinating books rather we will concentrate ón the computer science perspective . how do we go about representing language expressions on a computer in a way that can be useful for natural .