文档介绍：—IF———些丝丝一㈣螋—iiii萱宣iiiiiiii萱iiiiii置iiiiiiiiiiiiiiiiiiiii宣iiiiiiii宣宣萱一Ⅲ川叫川川圳洲Ⅲ,worksformstheunprecedented‘‘BigBang'’.Theextractionofnecessaryinformationandknowledgefromlarge--tazksofinformationextraction,namedentityrecognition(NER)aimstoidentifyphraseswithinsentencesanddocumentsthatexpresspersonnames,anizationnames,dataandtime,,,andthusincorporatesentity-internalstructuralfeatures、7l,itllcontextualinformationundertheframeworkofmachinelearningtoidentifypersonnames,anizationnamesinChinesetexts,,fourtwo-layermodelsaleconstructedforChineseNERbasedonmaximumentropyandconditionalrandomfields(CRFs).ThecontrastiveexperimentsondifferentdatasetsshowedthattheCRF··basedtwo·-,apost-processingmethodbasedonmutualinformationistol'eVisesomepossibleerrorsyieldedbytheCRF—-,,afive-layersequencelabelingschemeis————一——·一proposedtohandlelexicalfeaturesandphraseSUUeUIreunder。theCRF-layermodel+to。一——’。。—。一flH',,asetofmulti·levelprefixesandsuffixesareextracted-Ⅱ.Abstractfromthetrainingdatausingalogistictransformmethodoflogisticregressionmodels·Basedonentitymorphemes,:Namedentityrecognition,nestednamedentity,maximumentropy,: 。IAbstract .... ...... .