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<Paper uid="W97-0611">
  <Title>I I DISTANCE ZONE I \ %alce=-=ource takeo-de=tinatPSon I I SOURCE DESTINATION I TOTAL-COST / I / I</Title>
  <Section position="5" start_page="55" end_page="56" type="concl">
    <SectionTitle>
5 Conclusion
</SectionTitle>
    <Paragraph position="0"> In naturally occuring dialogue, the structure of the surface interaction differs from the underlying dialogue history insofar as certain communicative goals  are jointly expressed in one utterance, others may even be omitted. We modelled this behaviour for mixed initiative dialogue. In particular, we focused on the system behaviour, and how the system can respond to the user's cooperation, i.e., to newly introduced goals from the user in an equally cooperative manner. We have shown that in order to achieve this behaviour, one has to define constellations of dialogue acts and given a certain state of the task model, which give rise to specific communciative goals. Several of these can be realized within a single utterance.</Paragraph>
    <Paragraph position="1"> The next step will be to take a set of communicative goals chosen for aggregation and the content selected by them and pass this to a natural language generation system. For NLG purposes, we will have to investigate how the communicative goals to be realized within one utterance are ranked, how the speech act of an utterance is determined, how the abstraction step alters the content to be expressed, and how different kinds of aggregation rules are realized linguistically.</Paragraph>
    <Paragraph position="2"> Finally, we will have to build a much more powerful task model in order to support the disambiguation and abstraction procedures, and the generation process.</Paragraph>
  </Section>
class="xml-element"></Paper>