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<Paper uid="P87-1005">
  <Title>AN ENVIRONMENT FOR ACQUIRING SEMANTIC INFORMATION</Title>
  <Section position="3" start_page="0" end_page="0" type="intro">
    <SectionTitle>
1 Introduction
</SectionTitle>
    <Paragraph position="0"> The existence of commercial natural language interfaces (NLI's), such as INTELLECT from Artificial Intelligence Corporation and Q&amp;A from Symantec, shows that NLI technology provides utility as an interface to computer systems. The success of all NLI technology is predicated upon the availability of substantial knowledge bases containing information about the syntax and semantics of words, phrases, and idioms, as well as knowledge of the domain and of discourse context. A number of systems demonstrate a high degree of transportability, in the sense that software modules do not have to be changed when moving the technology to a new domain area; only the declarative, domain specific knowledge need be changed. However, creating the knowledge bases requires substantial effort, and therefore substantial cost. It is this assessment of the state of the art that causes us to conclude that know~edge acquisition is one of the most fundamenta/ prob/ems to widespread applicability of NLI techno/ogy.</Paragraph>
    <Paragraph position="1"> This paper describes our contribution to the acquisition of semantic knowledge as evidenced in IRACQ (for Interpretation Rule ACQuisition), within the context of our overall approach to representation of domain knowledge and its use in the IRUS natural language system \[5, 6,271. An initial version of IRACQ was reported in \[19\]. Using IRACQ, mappings 1The work presented here was supported under DARPA contract #N00014-85-C-0016. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessenly representing the officual policies, either expressed or implied, of the Defense Advanced Research Projects Agency or of the United States Government.</Paragraph>
    <Paragraph position="2"> between valid English constructs and predicates of the domain may be defined by entering sample phrases. The mappings, or interpretation rules (IRules), may be defined for nouns, verbs, adjectives, and prepositions. IRules are used by the semantic interpreter in enforcing selectional restrictions and producing a logical form as the meaning representation of the input sentence.</Paragraph>
    <Paragraph position="3"> IRACQ makes extensive use of information present in a model of the domain, which is represented using NIKL \[18, 21\], the terminological reasoning component of KL-TWO \[26\]. Information from the domain model is used in guiding the IRACQ/user interaction, assuring that acquisition and editing yield IRules consistent with the model. Further support exists for the IRule developer through a flexible editing and debugging environment. IRACQ has been in use by non-AI experts at the Naval Ocean Systems Center for the expansion of the database of semantic rules in use by IRUS.</Paragraph>
    <Paragraph position="4"> This paper first surveys the kinds of domain specific knowledge necessary for an NLI as well as approaches to their acquisition (section 2). Section 3 discusses dimensions in the design of a semantic acquisition facility, describing our approach. In section 4 we describe IRules and how they are used. An example of a clause IRule definition using IRACQ is presented. Section 5 describes initial work on an IRule paraphraser. Conclusions are in section 6.</Paragraph>
  </Section>
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