A Hierarchical Multi-Agent System for Natural Language Diagnosis

... this paper some aspects of a new methodology for diagnosing NLP systems. When the analysis of some input is unsuccessful that can be due to either one of the following twotypes of problems: either there is an error (lexical, semantic, syntactic, ...) on the input being analysed or some component of the system is flawed (the lexicon is incomplete, the coverage of the grammar is insufficient, ...). In our system, problems with input analysis are detected during syntactic parsing. We use a layered approach to syntactic parsing([8i with three steps: part-of-speech tagging, pre-processing and chart-parsing. The POS tagger (described in [6]) assigns a tag (a syntactic category) to eachword in the sentence being processed, the pre-processing module uses specialised grammars to pre-process proper nouns, dates and numbers. Finally,the chart-parser either completely parses the input or obtains a partial parsing. The nee