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<Paper uid="A94-1020">
  <Title>Resolving Anaphora in a Portable Natural Language Front End to Databases</Title>
  <Section position="2" start_page="0" end_page="0" type="intro">
    <SectionTitle>
1 Introduction
</SectionTitle>
    <Paragraph position="0"> The development of Natural Language (NL) systems for data retrieval has been a central issue in NL Processing research for the last three decades, motivated by the aim of helping non-expert database users.</Paragraph>
    <Paragraph position="1"> When we try to draw a line of evolution of such systems, it can be observed that growth in portability, essential for commercial viability, came at a cost in terms of broader linguistic coverage. 2 Earlier systems, mostly research motivated, were mainly developed for a single application, using domain-dependent information for treating contextual phenomena (eg, DEACON (Craig et al., 1966), SHRDLU (Winograd, 1972), LUNAR (Woods,  review on Portable NL front ends.</Paragraph>
    <Paragraph position="2"> 1973), LADDER (Hendrix et al., 1978)). In contrast, the subsequent generation of interfaces carried a higher emphasis on portability in their design (eg, INTELLECT (Harris, 1984), IRUS (Bates et al., 1986), TEAM (Grosz et al., 1987)). These systems, however, offer a reduced coverage of discourse phenomena, a central issue when continuity in the database consultation carries some priority.</Paragraph>
    <Paragraph position="3"> Thus, the ideal NL Front End (NLFE) should carry a broader linguistic coverage, in order to support a user focused query process, combined with a high degree of portability.</Paragraph>
    <Paragraph position="4"> In this light, we designed a Discourse Module, which is incorporated into a highly portable NLFE, SQUIRREL (DeRoeck et al., 1991). The system was originally conceived with a single-query based mode of consultation. By providing for anaphora and simple cases of ellipsis resolution, the Discourse Module yields continuous consultations without the use of world models (to maintain the system's general portability).</Paragraph>
  </Section>
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