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1、ABSTRACTResearchonReverseSkylineQueryoverDistributedDataResearchonReverseSkylineQueryoverDistributedDataAbstractReverseskylinequery,asatypicalmethodaboutmulti-criteriaoptimization,isbeingwidelyusedindataminingandmulti-criteriadecision.However,tillnow,mo
2、stoftheworkisbasedonthecentralizeddataandthereisnoworkoverdistributeddata.Inpractice,mostofthedataisstoredoverdierentsitesconnectedbynetworkinconsiderationofthecostandperformance.Theexistingcentralizedalgorithmcan’tsimplysatisfydistributedenvi-ronment.I
3、nthisthesis,wetalkaboutreverseskylinequeryalgorithmoverdistributeddata,andourworkincludesthefollowingparts:(1)Bystudyingreverseskylinequeryovercentralizeddata,weputforwardBBDRSal-gorithmthatissuitablefordistributedstaticdatasets.Ontheremotesites,ittakes
4、useofRtreeindextopre-computethecandidateandfilterdatasetasthedatasummarywhichappar-entlyreducesnotonlythequerydelaybutalsocommunicationcostbyavoidingsendingallthedata.(2)AsRtreemethodcostssomuchtimetocreateindex,thenweproposeanoptimizedPDRSalgorithmbased
5、onthepre-sorting.PDRStakesthesamecommunicationstrategyasaboveandpre-sortsallthepointsaccordingtotheirdistancetothequerypoint.AsPDRShasnoneedtocreateindex,andalsocanreduceagreatmanytimesofdominationchecksthroughpre-sorting,alotofcomputationtimecanbesaved
6、.Overanotsobigdataset,PDRSalgorithmperformsbetterthanBBDRS.(3)Byusingcurrentreverseskylinequerymethodoversingledatastreamforref-erence,wedesignanDCDRSalgorithmtocomputereverseskylineoverdistributeddatastreams.Ontheremotesites,ittakesuseofDCtreetotimelyc
7、omputeandmaintainthedatasummaryofthecurrentwindowobjets.Whileonthecentralizedsite,centralizedalgorithmisappliedtocomputethelastresults.DCDRSalgorithmcannotonlyaccuratelybutalsoecientlycomputethereverseskylineoverdistributeddatastreams.(4)Anexperimentpl
8、atformisdesignedforreverseskylinequeryoverdistributeddata.Asforkindofcontrolfunctionofcontrolend,itmakesalltheexperimentsbeautomatedcompletedandavoidsalotofmanualoperation.Tosomeextent,itguaranteestherealnessandaccuracyoftheexper
