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dc.contributor.advisorBundy, Alanen
dc.contributor.authorMellish, Christopher Stuarten
dc.date.accessioned2013-04-03T15:02:25Z
dc.date.available2013-04-03T15:02:25Z
dc.date.issued1981
dc.identifier.urihttp://hdl.handle.net/1842/6616
dc.description.abstractA computer program which can "understand" natural language texts must have both syntactic knowledge about the language concerned and semantic knowledge of how what is written relates to its internal representation of the world. It has been a matter of some controversy how these sources of information can best be integrated to translate from an input text to a formal meaning representation. The controversy has concerned largely the question as to what degree of syntactic analysis must be performed before any semantic analysis can take place. An extreme position in this debate is that a syntactic parse tree for a complete sentence must be produced before any investigation of that sentence's meaning is appropriate. This position has been criticised by those who see understanding as a process that takes place gradually as the text is read, rather than in sudden bursts of activity at the ends of sentences. These people advocate a model where semantic analysis can operate on fragments of text before the global syntactic structure is determined - a strategy which we will call early semantic analysis. In this thesis, we investigate the implications of early semantic analysis in the interpretation of noun phrases. One possible approach is to say that a noun phrase is a self-contained unit and can be fully interpreted by the time it has been read. Thus it can always be determined what objects a noun phrase refers to without consulting much more than the structure of the phrase itself. This approach was taken in part by Winograd [Winograd 72], who saw the constraint that a noun phrase have a referent as a valuable aid in resolving local syntactic ambiguity. Unfortunately, Winograd's work has been criticised by Ritchie, because it is not always possible to determine what a noun phrase refers to purely on the basis of local information. In this thesis, we will go further than this and claim that, because the meaning of a noun phrase can be affected by so many factors outside the phrase itself, it makes no sense to talk about "the referent" as a function of -a noun phrase. Instead, the notion of "referent" is something defined by global issues of structure and consistency. Having rejected one approach to the early semantic analysis of noun phrases, we go on to develop an alternative, which we call incremental evaluation. The basic idea is that a noun phrase does provide some information about what it refers to. It should be possible to represent this partial information and gradually refine it as relevant implications of the context are followed up. Moreover, the partial information should be available to an inference system, which, amongst other things, can detect the absence of a referent and provide the advantages of Winograd's system. In our system, noun phrase interpretation does take place locally, but the point is that it does not finish there. Instead, the determination of the meaning of a noun phrase is spread over the subsequent analysis of how it contributes to the meaning of the text as a whole.en
dc.contributor.sponsorSRC Postgraduate Studentship,en
dc.contributor.sponsorSRC grants B/RG 94493 and GR/A 57954en
dc.language.isoen
dc.publisherThe University of Edinburghen
dc.relation.hasversionBundy, A., Byrd, L., Luger, G., Mellish, C. and Palmer, M. Solving Mechanics Problems using Meta-Level inference. In Procs of the Sixth International Joint Conference on Artificial Intelligence. IJCAI, 1979.en
dc.relation.hasversionMellish, C.S. Preliminary Syntactic Analysis and Interpretation of Mechanics Problems Stated in English. Working Paper 48, Dept of Artificial Intelligence, University of Edinburgh, 1978.en
dc.subjectComputational linguisticsen
dc.subjectNatural language processingen
dc.subjectSemanticsen
dc.subjectData processingen
dc.titleCoping with Uncertainty: Noun Phrase Interpretation and Early Semantic Analysisen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD Doctor of Philosophyen


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