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<Paper uid="C92-4193">
  <Title>ON THE ACQUISITION OF CONCEPTUAL DEFINITIONS VIA TEXTUAL MODELLING OF MEANING PARAPHRASES</Title>
  <Section position="2" start_page="0" end_page="0" type="intro">
    <SectionTitle>
1 INTRODUCTION
</SectionTitle>
    <Paragraph position="0"> Conceptual knowledge bases are core components of curlgnt natural language semantic information processing systems. Their coment, structure and size crucially determines the applicability of these systems, and still their development and maintenance is a serious bottleneck. Taking into account the enormous amount of entries required for practical purposes, manual modelling procedures are hardly practicable.</Paragraph>
    <Paragraph position="1"> Much effort is therefore devoted to achieving a controlled automatic handling of these tasks.</Paragraph>
    <Paragraph position="2"> In tiffs paper a proposal is made to use a meaning dictionary as a source of conceptual knowledge, and to apply text understanding methods for processing this information. These methods include the automatic acquisition of conceptual definitions from meaning paraphrases, their transformation into a suitable representation for automatic processing, and the automatic update of conceptual definitions by means of text analysis.</Paragraph>
    <Paragraph position="3"> A meaning dictionary explains the use of natural language expressions with respect to tile access they provide to world knowledge. In principle, the kzlowledge accessed and thus represented in a meaning dictionary includes many of the different kinds of knowledge which are required for semantic information processing (i.e. &amp;quot;how nature works, practices, institutions, facts of nature, regularities, ways of doing&amp;quot; \[Searle 80:227\]).</Paragraph>
    <Paragraph position="4"> Current research work on extracting inlbrmation from machine-readable dictionaries (cf. e.g. \[Briscoe/Copestake/Boguraev 90\], \[Walker/ Zampolli/ Calzolari 88\], \[Alshawi 87\], \[Nakamura/Nagao 88\]) has mainly concentrated on semantic relationships of the vocabulary and has proposed methods for semi-automatic or partial extraction of this information. These methods basically rely on syntactic structures of meaning paraphrases or database-like coded leatures and values (see also \[Briscoe/Copestake/Boguraev 90\]). The task of acquiring conceptual information, however, laces the problem that this information in traditional meaning dictionaries is itself conveyed in terms of the means natural language provides for communicating conceptual information, namely natural language texts (meaning paraphrases, definitions, even longer explanatory texts or abbreviated textual lorms). Thus understanding conceptual definitions of meaning dictionaries requires textual mechanisms to be recognized and handled in order to analyse the information provided and to construct a semantic representation.</Paragraph>
    <Paragraph position="5"> In this paper a new method of textually modelling meaning paraplwases is proposed for the acquisition of a formal representation of tfie conceptual information conveyed in the meaning paraphrase. It is described how these paraphrases are subjected to a manual text analysis process in accordance with the KONTEXT model \[Haenelt/K0nyves-T6th 91 \]. The principles shown are general principles of text analysis and are also applied in the KONTEXT system to textual analysis of corpora (provided a basic set of dictionary entries is available). The conceptual modelling is based on the model of Semantic Emphasis \[Kunze 91\], which so far has been worked out for verbs. In order to be able to cover the meaning paraphrase as a whole, and thus to provide a basis for automatic bootstrapping, this approach has to be exteuded to modelling other word classes. A proposal for tiffs is made in this paper.</Paragraph>
    <Paragraph position="6"> First of all this paper introduces the approach to textually modelling meaning paraphrases, then an example is given. The concept and text structure related information in the system dictionary which is used as a basis of acquisition as well as for representing the newly acquired entries is presented in detail. The application of the dictionary to the analysis of a meaning paraphrase is explained.</Paragraph>
    <Paragraph position="7"> Act~.s DE COL1NG-92, NANTES, 23-28 AO~r 1992 l 2 0 9 PROC. Ol: COLING-92, NANTES, AUO. 23-28, 1992</Paragraph>
  </Section>
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