粗糙集理论在中文文本分类中的应用

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1、谣南交通大学研究生学位论文粗糙集理论在中文文本分类中的应用年姓级二oO二级名杜卫锋申请学位级别博士专业恕唯一鼬唏删指导教师多薹多教授二oo六年四月第1I页西南交通大学博士研究生学位论文AbstractAstheexplosiveincrementofdata，informationprocessinghasbecometheindispensabletoolforpeopletoacquireinformationandknowledge．Textcategorizationistheimportant

2、researchfieldofinformationprocessing．Itistheprocessofautomaticallydeterminingthecategorizationofsometextaccordingtothecontentoftext，whichisundertheestablishedcategorizationsystem．Thispaperhasmadesomeresearchanddiscussionaboutthecriticalpointoftextcategor

3、ization，includingVectorSpaceModel，thefuzzificationofrealvaluedwordfrequencyvector,knowledgeacquisitionbasedonroughset，thecomputationofrulestrengthinknowledgebase，theconflictresolutionwhendisagreementamongtheresuhsoftherelatedrulesandSOon，moreover,thecomp

4、lexitycomparisonwithothermethodofcategorizationisgiven．Inaddition，werealizeatextcategorizationsystemwiththemethod，whichacquirestheexperimentalresultofthecategorizationaccuracv．ThemaincontentiSlistedhere：PartOne：KnowledgereductionresearchbasedOnroughsetth

5、eory1．TheimprovementofSkowrondiscemibilitymatrix．TheconditionthattheelementsinSkowrondiscernibilitymatrixsatisfyisimproved．Thus，theverificationtotheconditionissimplerandtheelementssatisfyingtheconditionindiscernibilitymatrixareless．Thenthecomplexityofcom

6、putingreductswithdiscernibilityfunctiondecreaseseffectively；2．Therelationshipamongseveralknowledgereductionapproaches．AstOdecisiontable，positivedomainreduction，entropyreduction，distributivereduction，distributionreduction，approximatereductionandSOonareint

7、roducedfromdifferentviews．ItiSprovedthatthedistributivereductionandtheentropyreductionareequivalent．Furthermore，astoconsistentdecisiontable，positivedomainreduction，entropyreduction，distributivereduction，distributionreductionandapproximatereductionarealle

8、quivalent．3．Logicalcharacteristicsofknowledgereductionapproaches．Theknowledgeofdecisiontableisrepresentedwithrules，whichCallbelookedasformulaeofnon·classicallogicalsystem．Thispaperwillstudythelogicalcharacteristicsofknowle