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<Paper uid="P89-1001">
  <Title>A TRANSFER MODEL USING A TYPED FEATURE STRUCTURE REWRITING SYSTEM WITH INHERITANCE</Title>
  <Section position="9" start_page="2" end_page="2" type="concl">
    <SectionTitle>
CONCLUSION
</SectionTitle>
    <Paragraph position="0"> The rewriting formalism has been implemented in LISP by Martin Emele and the author at ATR in order to develop transfer and generation models of dialogues for a machine translation prototype \[Emele and Zajac 89\]. The two main characteristics of the formalism are (1) type inheritance which provides a clean way of defining classes and sub-classes of objects, (2) the rewriting mechanism based on typed unification of feature structures which provide a powerful and semantically clear means of specifying (and computing) relations between classes of objects. This latex behavior is somehow similar to the PROLOG mechanism, and grammars can be written to be reversible, which is the case for our transfer grammar. We hope this feature will be useful in the future development of the grammar, allowing for a precise constrastive analysis of Japanese and English.</Paragraph>
    <Paragraph position="1"> At present, the transfer grammar is in a very early stage of development but nevertheless, capable of translating a few elementary sentences. It covers basic sentence patterns; compound noun phrases and coordination of noun phrases; verb phrases including auxiliaries, medals and adverbs; sentence adverbials; conditionals.</Paragraph>
    <Paragraph position="2"> The transfer module and the generation module \[Emele 89\] use the same formalism and integration is thus simple to achieve. As for efficiency considerations, the transfer and generation of the sentence in Figure 2 takes approximately 5 seconds on a Symbolics with our current implementation.</Paragraph>
    <Paragraph position="3"> However, this figure is not very meaningful because our dictionaries and grammars are still very small, and the implementution of the interpreter itself is still evolving.</Paragraph>
    <Paragraph position="4"> Full integration with the analysis module (a unification-based parser which produces a set of feature structures) remains to be worked out, but should not cause major problems. In this respect, the closest related works are a transfer model proposed by \['Isabelle and Macklovitch 86\] and a model in the LFG framework proposed by \[Kudo and Nomura 86\] (see also \[Beaven and Whitelock 88).</Paragraph>
    <Paragraph position="5"> There are two major topics for further research: I) the extension of the formalism to include full logical expressions, as described for example in \[Smolka 88\], and some kind of control mechanism in order to treat default values and prune some solutions (when an idiomatic expression is found for example); (2) the development of a transfer grammar for a larger language fragment, using outputs of the parser already available described in \[Yoshimoto and Kogure 1988\].</Paragraph>
  </Section>
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