大規(guī)模信息過濾技術研究及其在Web問答系統(tǒng)中的應用.pdf

1、中國科學院研究生院博士學位論文大規(guī)模信息過濾技術研究及其在Web問答系統(tǒng)中的應用姓名：許洪波申請學位級別：博士專業(yè)：計算機軟件與理論指導教師：白碩20030701人規(guī)模信息過濾技術研究及其經Web問答系統(tǒng)中的應用：AbstractResearchonTechniquesofLarge—scaleInformationFilteringanditsApplicationinWebQuestionAnsweringSystemXuHongb

2、o(ComputerApplicationTechnology)DirectedByProfessorBaiShuoThisdissertationaddressesthetechniquesofInformationFilteringinknowledgediscoveryanddatamining，makesathoroughanalysisonsomekeyproblemsinInformationFiltering，especi

3、allyinAdaptiveFiltering，andproposedalarge—scaleandhighcapableintegratedinformationfilteringmethodThismethodproducedthebestresultsamongcurrentinformationfilteringsystemsUserrequirementanduserinterestprofilearethebasisofIn

4、formationFilteringThedissertationintroducesdifferentuserrequirementexpandingmethodsusingtraditionalthesaurus—basedandpseudo—relevancefeedbacktechniques，thenproposedatwolayerprofileinitializationmethodbasingonanunbiasedse

5、lectingtechniqueforpseudorelevantdocumentsTosolvetheproblemthat“smalltopic”ishardtofiltering，thedissertationproposeda‘‘smalltopic”automaticidentificationandoptimizationmethodThismethodeffectivelyimprovesthefilteringperfo

6、rmanceon“smalltopic”Aftersummarizingandanalyzingtraditionalmethodsoffeatureselection，thisdissertationproposedaflexiblefeatureselectionmethodaimingattopicgranularityThismethodautomaticallydividesoriginaluserrequirementsin

7、tudetopic(requirementwithbiggranularity)anddetailedtopic(requirementwithsmallgranularity)，andthenselfdeteminesthebestfeatureselectionmethodaccordingtodifferenttopicgranularityThisdissertationalsoinvestigatesthesmoothingt

8、echniquesintermweightingThisdissertationdiscussestheproblemlearningfromuncertaintyinformationinAdaptiveFiltering，andproposedanadaptivelearningmethodusinguncertaintyinformationItthoroughlyexplorestheeffecttoperformancebya

9、pplyingdifferentmethodsdealingwiththeunjudgeddocumentsforprofileupdating，andfinallyachievesthemostrobustandeffectiveprofileupdatingmethodThresholdoptimizationisoneofthemostimportantanddifficultproblemsinAdaptiveFiltering

10、Thisdissertationpointsoutgeneraldrawbacksofcurrentthresholdoptimizationmethods，andthenproposedatarget—orientedthresholdoptimizationmethod，takingtheevaluationmeasureitselfasthetargetfunctionforoptimizingMeanwhile，thedisse

11、rtationalsoaddressesholisticandlocaltargetfimctionoptimizationstrategies，summarizestheiradvantagesanddisadvantages，andthencomparesintheroundthedifferentperformanceswiththemethodsthatholisticorlocaltargetoptimizationcontr