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<Paper uid="J82-3002">
  <Title>An Efficient Easily Adaptable System for Interpreting Natural Language Queries 1</Title>
  <Section position="2" start_page="0" end_page="0" type="abstr">
    <SectionTitle>
Artificial Intelligence Center
SRI International
</SectionTitle>
    <Paragraph position="0"> This paper gives an overall account of a prototype natural language question answering system, called Chat-80. Chat-80 has been designed to be both efficient and easily adaptable to a variety of applications. The system is implemented entirely in Prolog, a programming language based on logic. With the aid of a logic-based grammar formalism called extraposition grammars, Chat-80 translates English questions into the Prolog subset of logic. The resulting logical expression is then transformed by a planning algorithm into efficient Prolog, cf. &amp;quot;query optimisation&amp;quot; in a relational database. Finally, the Prolog form is executed to yield the answer. On a domain of world geography, most questions within the English subset are answered in well under one second, including relatively complex queries.</Paragraph>
  </Section>
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