(7.3.1)--7.3Fuzzyreasoning.ppt

《(7.3.1)--7.3Fuzzyreasoning.ppt》由会员分享，可在线阅读，更多相关《(7.3.1)--7.3Fuzzyreasoning.ppt（21页珍藏版）》请在得力文库 - 分享文档赚钱的网站上搜索。

1、Chapter7CognitiveintelligenceFuzzyreasoning内容提要 Vaguelanguage1 Fuzzyproposition2Fuzzy reasoning3VaguelanguageLanguage:symbolsystemnaturallanguageArtificiallanguageThelanguageusedbyhumanstocommunicateinformationcanrepresentvariousthings,ideas,behaviors,emotions,etc.ofthesubjectiveandobjectiveworldUnc

2、ertainty,ambiguityArtificiallanguagemainlyreferstoprogramminglanguage,suchasthefamiliarClanguage,assemblylanguage,etc.Strictformatandclearconcept（X,T(X),U,G,M)VaguelanguageNameoflanguagevariableLanguagevaluesoflanguagevariablesDiscourseGrammarrulesSemanticrulesPentad：VaguelanguageVaguelanguageAlllan

3、guageswithambiguityarecalledfuzzylanguage.Languagevariablesarewords,phrasesorsentencesinnaturallanguageasvariables.Thelinguisticvaluesoflinguisticvariablesareusuallydescribedbyfuzzysets,andthenumericalvariablescorrespondingtothefuzzysetsarecalledbasicvariables.Thevalueofalinguisticvariableiscalledal

4、inguisticvalue,andisgenerallycomposedofwords,phrases,orsentencesinnaturallanguage.VaguelanguageVaguelanguageMathematicallogicisadisciplinebasedonthestudyofconcepts,judgmentsandreasoningformsinclassicsettheory,alsoknownasclassiclogic.FuzzypropositionThebiggestfeatureofclassiclogic:Thecontentreflected

5、iseithertrueorfalse.BeijingisthecapitalofthePeoplesRepublicofChina.Themoonisthesatelliteoftheearth.FuzzypropositionPropositionsthataredifficulttomakeclearjudgments:Motorvehiclesarefasterthanbicycles.Theweatherinthesouthisveryhot.FuzzypropositionFuzzypropositionVaguepropositionreferstoadeclarativesen

6、tencewithambiguity.Fuzzylogicisatoolforcharacterizingfuzzypropositions,Itisthemostbasicmathematicalmethodtostudyfuzzyreasoning.FuzzypropositionscanbedividedintonaturepropositionsandrelationalpropositionsSuchas:P:metalobjectshavegoodconductivity;Q:100ismuchlargerthan1.Thegeneralformofasimplefuzzyprop

7、ositionis:Amongthem,theelementsxX,Xistheuniverseofdiscourse;Aisthefuzzysetcorrespondingtoafuzzyconcept.SimplefuzzypropositionSimplefuzzyproposition:ThetruthvalueofthefuzzypropositionisrepresentedbythedegreeofmembershipoftheelementxtothefuzzysetA.Infuzzypropositions,isiscalledafuzzypredicate.Simplefu

8、zzypropositionCompoundfuzzyproposition：Simplefuzzypropositionsareconnectedbytheconjunctionsand,or,not,etc.toformacompoundfuzzyproposition.Thegeneralformofcompoundfuzzypropositionis:CompoundfuzzypropositionBasicoperations：CompoundfuzzypropositionFuzzypropositionFuzzyrulesarealsocalledfuzzyconditional

9、statements,andtheirexpressionsare:WhereAandBarethelinguisticvaluesdefinedbythediscoursedomainandthefuzzysetsaboveit,respectively.Containingmultipleprerequisitesiscalledmulti-dimensionalfuzzyrules.ifxisA,thenyisBExamplesoffuzzyreasoning：FuzzypropositionTypicalfuzzyinferencemethod：FuzzypropositionMamd

10、aniFuzzyreasoningLarsenreasoningZadehreasoningTakagiSugenoFuzzyreasoningMamdaniFuzzyproposition：Fuzzyproposition Mamdanifuzzyinferencemethodisthemostcommonlyusedinferencemethod.ItsfuzzyimplicationrelationshipRM(X,Y)issimpletodefineandcanbeobtainedbytheCartesianproductoffuzzysetsAandB(whicheverissmal

11、ler).whichis:Larsenreasoning：Fuzzyproposition Larsensreasoningmethod,alsoknownasproductreasoningmethod,isanotherwidelyusedfuzzyreasoningmethod.ThereasoningprocessofLarsensreasoningmethodisverysimilartothatofMamdanismethod.Thedifferenceisthatthecalculationoftheexcitationintensityandthecombinationofre

12、asoningreplacesthesmalloperationwiththeproductoperation.Zadehreasoning：Fuzzyproposition ComparedwithMamdanisinferencemethod,Zadehsinferencemethodalsoadoptsthesmall-combinationalgorithm,butitsdefinitionoffuzzyrelationshipisdifferent.TSFuzzypropositionFuzzyproposition T-Sfuzzyreasoning:Thetypicalfuzzyrulesintheprocessare:IfxisAandyisB,thenz=f(x,y)WhereAandBarethefuzzysetsinthepreconditions,Andz=f(x,y)istheexactfunctioninthepost.