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<Paper uid="P98-2142">
  <Title>Integrated Control of Chart Items for Error Repair</Title>
  <Section position="5" start_page="866" end_page="866" type="concl">
    <SectionTitle>
Conclusion
</SectionTitle>
    <Paragraph position="0"> This paper has presented a hierarchical error recovery system, CHAPTER, based on a chart parsing algorithm using an augmented context-free grammar. CHAPTER uses an integrated-agenda manager that invokes subsystems incrementally at four levels: lexical, syntactic, surface case, and semantic. A sentence has been confirmed as well-formed or repaired when it has been processed at all levels.</Paragraph>
    <Paragraph position="1"> Semantic processing performs pattern matching using a concept hierarchy and verb templates (which specify semantic selectional restrictions). In addition, procedural semantic constraints have been used to improve the efficiency of semantic processing based on a concept hierarchy. However, it increases computational cost.</Paragraph>
    <Paragraph position="2"> CHAPTER repaired 89.9% of the ill-formed sentences on which it was tested, and in 79.3% of cases suggested the correct repair (as judged by a human) as the best of its alternatives. CHAPTER's semantic processing rejected 27% of the repairs judged &amp;quot;best&amp;quot; by the syntactic system.</Paragraph>
  </Section>
class="xml-element"></Paper>