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<Paper uid="C96-1054">
  <Title>Semantic-based Transfer*</Title>
  <Section position="2" start_page="0" end_page="316" type="intro">
    <SectionTitle>
1 Introduction
</SectionTitle>
    <Paragraph position="0"> The work presented in this article was developed within the Verbmobil project (Kay et al., 1994; Wahlster, 1993). This is one of the largest projects dealing with Machine Translation (MT) of spoken language. Approxinmtely 100 researchers in 29 public aad industrial institutions are involved.</Paragraph>
    <Paragraph position="1"> The application domain is spontaneous spoken language in face-to-face dialogs. The current scenario is restricted to the task of appointment scheduling and the languages involved are English, German and Japanese.</Paragraph>
    <Paragraph position="2"> This article describes the realization of a transfer approach based on the proposals of (Abb and Buschbeck-Wolf, 1995; Caspari and Schmid, 1994) and (Copestake, 1995). Transfer-based MT 1, see e.g. (Vauquois and Boi~et, 1985; Nagao et al., 1985), is based on con~rastive bilingual corpus analyses from which a bilingual lexicon of transfer equivalences is derived. In contrast to a purely *This work was funded by the German Federal Ministry of Education, Science, Research and Technology (BMBF) in the framework of the Verbmobil project under grant 01 IV 101 U. We would like to thank our colleagues of the Verbmobil subproject Transfer, our IMS colleagues Ulrich Heid and C.J.</Paragraph>
    <Paragraph position="3"> Rupp and our anonymous reviewers for usefltl feed-back a~ld discussions on earlier drafts of the paper. The responsibility for the contents of this paper lies with the authors.</Paragraph>
    <Paragraph position="4"> 1For a more detailed overview of different approaches to MT, see e.g. (Hutchins and Solners, 1992). lexicalist approach which relates bags of lexical signs, as in Shake-and-Bake MT (Beaven, 1992; Whitelock, 1992), our transfer approach operates on the level of semantic representations produced by various analysis steps. The output of transfer is a semantic representation for the target language which is input to the generator and speech synthesis to produce the target language utterance. Our transfer equivalences abstract away from morphological and syntactic idiosyncracies of source and target languages. The bilingual equivalences are described on the basis of semantic representations.</Paragraph>
    <Paragraph position="5"> Since the Verbmobil domain is related to discourse rather than isolated sentences the model theoretic semantics is based on Kamp's Discourse Representation Theory, DRT (Kamp and Reyle, 1993). In order to allow for underspecification, variants of Underspecified Discourse Representation Structures (UDRS) (Reyle, 1993) are employed as semantic formalisms in the different analysis components (Bos et al., 1996; Egg and Lebeth, 1995; Copestake et al., 1995).</Paragraph>
    <Paragraph position="6"> Together with other kinds of information, such as tense, aspect, prosody and morpho-syntax, the different semantic representations are mapped into a single multi-dimensional representation called Verbmobil Interface Term (VIT) (Dorna, 1996). This single information structure serves as input to semantic evaluation and transfer. The transfer output is also a VIT which is based on the semantics of the English grammar (el.</Paragraph>
    <Paragraph position="7"> Copestake et al. (1995)) and used for generation (see Kilger and Finkler (1995) for a description of the generation component).</Paragraph>
    <Paragraph position="8"> Section 2 of this paper sketches the semantic representations we have used for transfer. In section 3 we introduce transfer rules and discuss examples. In section 4 we compare our approach with other MT approaches. In section 5 we present a summary of the implementation aspects. For a more detailed discussion of the implementation of the transfer formalism see Dorna and Emele (1996). Finally, section 6 summarizes the results.</Paragraph>
  </Section>
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