The University of Edinburgh -
Division of Informatics
Forrest Hill & 80 South Bridge

MSc Thesis #9572

Title:A Customisable Hpsg-Based Natural Language Front-End
Date: 1995
Abstract:As an alternative to transformationally derived approaches, Head-driven Phrase Structure Grammar (HPSG) has emerged as one of the leading frameworks in modern computational linguistics. This thesis documents the design and implementation of a natural language query interface for databases based around the HPSG formalism. The back-end database employed is derived from an existing query-answering interface called MASQUE. The implemented system, called HPSG-QAL generates HPSG feature structures for a range of English questions, transforms them into appropriate logical queries and generates answers by evaluating the queries against the MASQUE database. HPSQ-QAS provides knowledge-domain portability by specifying the lexicon as a well-formed set of commands in an input file. This aims to allow a grammar writer to easily and efficiently define a new grammar, and could be used as an intermediate form by an interactive editing tool. The system was tested with a world-geography knowledge-base, answering questions with an efficiency comparable to MASQUE but with a smaller linguistic coverage. the grammar-editing facility provided by the input file specification of the lexicon was thoroughly tested with ill-formed definitions and the system generated appropriate informative error reporting in all test cases.

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