1、浙江大學博士學位論文基于特征符號的程序理解研究姓名：錢劍飛申請學位級別：博士專業(yè)：計算機應用指導教師：俞瑞釗何欽銘20060501AbstractAbstractProgramUnderstanding(PU)orProgramComprehension(PC)isoftenviewedastheprocessofrecognizingandextractingsystemdesignconceptsfromthesourcecodeT

2、hisactivitytakesplacethrou曲outthewholelifecycleofsoftwaresystemsIt’swidelyacceptedthatsoftwaremaintenancespentabout35～80％costofsoftwaresystemsinsidewhichabout30～90％costisspentonPUincludingprogrammaintenance，debugging，fra

3、meworkreconstructing，SOWCCcodereusing，errorcheckinganddocumentcoordinatingPUanditsrelatedtechnologieshavebeendevelopedandresearchedactivelyTherearethreemainstrategiesinPU：Top—down，BottomupandtheirhybridapproachBottom—ups

4、仃ategyislikebuildingapyramid：itconstructsupperlevelconceptsfrombasiccomponentsstepbystepuntilthewholeconceptofselectedprogramisachievedAlmostallautomaticPUmethodsapplyBottomupstrategyandarebasedonPlanswhichisthetemplateo

5、fprogramAlthoughthisstrategyisfeasibleintheoryitreallyencounterstwoproblems：1)theconstructionandorganizationofPlanlibrary；2、theefficiencyofexhaustivematchingalgorithmsInthispaperwcfocusourresearchonCS—basedPUByapplyingch

6、aracteristicsymbols(CS)inPUdomainweconstructourCS—basedPlanmatchingframeworktosolvethetwomainproblemslistedaboveby：1)constructinghierarchyandconstraint—orientedCSPlanlibrary；2、applyinglayeredmatchingmechanismtoimprovethe

7、efficiencyofexhaustivesearching；3)applyingcomparabilityanalysisontheresultstoensuretheveracitywhileusingCSasthematchingagentOurchiefinnovationsinclude：1)Alayeredmatchingalgorithmisproposedwhichincludesstagesofroughmatchi

8、ngandrefinedmatchingRoughmatchingisusedtoreducetheresponsetimewhilesearchingontotalPlanlibraryRefinedmatchingisusedtoreducethescopeofpossiblefitPlansetbyapplyingmorecharacteristicsymbols；2)Acomparabilityanalysisalgorithm