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<Paper uid="C92-1049">
  <Title>USING LINGUISTIC, WORLD, AND CONTEXTUAL KNOWLEDGE IN A PLAN RECOGNITION MODEL OF DIALOGUE ~</Title>
  <Section position="8" start_page="0" end_page="0" type="concl">
    <SectionTitle>
6 Conclusions and Future Work \[LC91\]
</SectionTitle>
    <Paragraph position="0"> Our plan-based model of dialogue incorporates world, linguistic, and contextual knowledge sources into the recognition of communicative actions. Lin- \[LC92\] guistic knowledge suggests certain discourse acts, a speaker's beliefs, and the strength of those beliefs; contextual knowledge suggests the most coherent continuations of the dialogue; and world knowledge provides evidence that the applicability conditions hold for those \[MT83\] discourse acts that identify the relationship of the current utterance to the discourse as a whole. By combining these different knowledge sources, we are able to recognize complex discourse acts such as express- \[Po186\] ing doubt, to identify the relationship of utterances to one another, and to capture the rich structure of task-oriented dialogue.</Paragraph>
    <Paragraph position="1"> Grosz and Sidner \[GS86\] claim that a robust model of understanding must use constraint satisfaction to interpret utterances; that is, when evidence is \[Pol90\] available from one source, less evidence is needed from other sources. We have partially included their suggestion by using world and linguistic knowledge when contextual knowledge is not sufficient to infer actions for which there must he some evidence. However, we would like to expand our notion of partial evidence \[Ram91\] to allow evidence from the three knowledge sources to be represented in terms of degree: thus, when world knowledge is overwhelmingly strong, no other knowledge is needed, but when it is very weak, knowledge from other sources will be needed to support the inferences not allowed by the weak world knowledge alone.</Paragraph>
    <Paragraph position="2"> AcrEs DE COLING-92, NANTES, 23-28 ^ot~r 1992 3 1 6 PROC. OF COLING-92, NANTES, AUG. 23-28, 1992</Paragraph>
  </Section>
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