AQUA A Knowledge-Based Architecture for a Question Answering

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1、AQUA:AKnowledge-BasedArchitectureforaQuestionAnsweringSystemTechReportkmi-04-15MariaVargas-VeraandEnricoMottaAQUA:AKnowledge-BasedArchitectureforaQuestionAnsweringSystemMariaVargas-VeraandEnricoMottaKnowledgeMediaInstitute(KMi),TheOpenUniversity,WaltonHall,MiltonKeynesMK76AA,England{m.varg

2、as-vera}@open.ac.ukhttp://kmi.open.ac.uk/AbstractThispaperdescribesAQUA,aquestionansweringsystem.AQUAcombinesNaturalLanguageprocessing(NLP),Ontologies,Logic,andInformationRetrievaltechnologiesinauniformframework.AQUAmakesintensiveuseofanontology(whichencodeknowledge)inseveralpartsoftheques

3、tionansweringsystem.Theontologyisusedintherefinementoftheinitialquery,thereasoningprocess(ageneralization/specializationprocessusingclassesandsubclassesfromtheontology),andinthenovelsimilarityalgorithm.ThesimilarityalgorithmisakeyfeatureofAQUA.Itisusedtofindsimilaritiesbetweenrelations/con

4、ceptsinthetranslatedqueryandrelations/conceptsintheontologicalstructures.Thesimilaritiesdetectedthenallowtheinterchangeofconceptsorrelationsinalogicformulacorrespondingtotheuserquery.Inthisway,wemakethemappingbetweenuser’squeriesandontologicalspaces.TheAQUAarchitectureisflexibleenoughtoall

5、owthatAQUAcanbeusedasclosed-domainandopendomainquestionansweringsystem.1.IntroductionInrecentyears,theriseinpopularityofthewebhascreatedademandforserviceswhichhelpuserstoskipoverallirrelevantinformationquickly.Oneoftheservicesisquestionanswering(QA),thetechniqueofprovidinganswerstospecific

6、questions.Givenaquestionsuchas‘whichcountryhadthehighestinflationratein2002?’akeyword-basedsearchenginessuchasGooglemightpresenttheuserwithwebpagesfromtheFinancialTimes,whereasaQAsystemwouldattempttodirectlyanswerthequestionwiththenameof1acountry.Ontheweb,atypicalexampleofaQAsystemisJeeves

7、(Askjeeves2000)whichallowsuserstoaskquestionsinnaturallanguage.Itlooksuptheuser'squestioninitsowndatabaseandreturnsthelistofmatchingquestionswhichitknowshowtoanswer.Theuserthenselectsthemostappropriateentryinthelist.However,userswouldusuallypreferapreciseanswe