<?xml version="1.0" standalone="yes"?>
<Paper uid="P89-1025">
  <Title>PLANNING TEXT FOR ADVISORY DIALOGUES&amp;quot;</Title>
  <Section position="9" start_page="209" end_page="209" type="relat">
    <SectionTitle>
RELATED WORK
</SectionTitle>
    <Paragraph position="0"> Schemata (McKeown, 1985) encode standard patterns of discourse structure, but do not indude knowledge of how the various parts of a schema relate to one another or what their intended effect on the hearer is. A schema can be viewed as a compiled version of one of our text plans in which all of the non-terminal nodes have been pruned out and only the leaves (the speech acts) remain. While schemata can produce the same initial behavior as one of our text plans, all of the rationale for that behavior has been compiled out. Thus schemata cannot be used to participate in dialogues. If the user indicates that he has not understood the explanation, the system cannot know which part of the schema failed to achieve its effect on the hearer or which rhetorical strategy failed to achieve this effect. Planning a text using our approach is essentially planning a: schema from more fine-grained plan operators. From a library of such plan operators, many varied schemata can result, improving the flexibility of the system.</Paragraph>
    <Paragraph position="1"> In an approach taken by Cohen and Appelt (1979) and Appelt (1985), text is planned by reasoning about the beliefs of the hearer and speaker and the effects of surface speech aWe are also currently implementing another interface which allows users to use a mouse to point at the noun phrases or clauses in the text that were not understood {Moore, 1989b).</Paragraph>
    <Paragraph position="2"> acts on these beliefs (i.e., the intentional effect). This approach does not include rhetorical knowledge about how clausal units may be combined into larger bodies of coherent text to achieve a speaker's goals. It assumes that appropriate axioms could be added to generate large (more than one- or two-sentence) bodies of text and that the text produced will be coherent as a by-product of the planning process. However, this has not been demonstrated. null Itecently, Hovy (1988b) built a text structurer which produces a coherent text when given a set of inputs to express. Hovy uses an opportunistic planning approach that orders the inputs according to the constraints on the rhetorical relations defined in Rhetorical Structure Theory. His approach provides a description of what can be said when, but does not include information about why this information can or should be included at a particular point. Hovy's approach confiates intentional and rhetorical structure and, therefore, a system using his approach could not later reason about which rhetorical strategies were used to achieve intentional goals.</Paragraph>
  </Section>
class="xml-element"></Paper>