外文文献及翻译.docx

外文文献及翻译.docx

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外文文献及翻译

WhatisDataMining?

Manypeopletreatdataminingasasynonymforanotherpopularlyusedterm,“KnowledgeDiscoveryinDatabases”,orKDD.Alternatively,othersviewdataminingassimplyanessentialstepintheprocessofknowledgediscoveryindatabases.Knowledgediscoveryconsistsofaniterativesequenceofthefollowingsteps:

·datacleaning:

toremovenoiseorirrelevantdata,

·dataintegration:

wheremultipledatasourcesmaybecombined,

·dataselection:

wheredatarelevanttotheanalysistaskareretrievedfromthedatabase,

·datatransformation:

wheredataaretransformedorconsolidatedintoformsappropriateforminingbyperformingsummaryoraggregationoperations,forinstance,

·datamining:

anessentialprocesswhereintelligentmethodsareappliedinordertoextractdatapatterns,

·patternevaluation:

toidentifythetrulyinterestingpatternsrepresentingknowledgebasedonsomeinterestingnessmeasures,and

·knowledgepresentation:

wherevisualizationandknowledgerepresentationtechniquesareusedtopresenttheminedknowledgetotheuser.

Thedataminingstepmayinteractwiththeuseroraknowledgebase.Theinterestingpatternsarepresentedtotheuser,andmaybestoredasnewknowledgeintheknowledgebase.Notethataccordingtothisview,dataminingisonlyonestepintheentireprocess,albeitanessentialonesinceituncovershiddenpatternsforevaluation.

Weagreethatdataminingisaknowledgediscoveryprocess.However,inindustry,inmedia,andinthedatabaseresearchmilieu,theterm“datamining”isbecomingmorepopularthanthelongertermof“knowledgediscoveryindatabases”.Therefore,inthisbook,wechoosetousetheterm“datamining”.Weadoptabroadviewofdataminingfunctionality:

dataminingistheprocessofdiscoveringinterestingknowledgefromlargeamountsofdatastoredeitherindatabases,datawarehouses,orotherinformationrepositories.

Basedonthisview,thearchitectureofatypicaldataminingsystemmayhavethefollowingmajorcomponents:

1.Database,datawarehouse,orotherinformationrepository.Thisisoneorasetofdatabases,datawarehouses,spreadsheets,orotherkindsofinformationrepositories.Datacleaninganddataintegrationtechniquesmaybeperformedonthedata.

2.Databaseordatawarehouseserver.Thedatabaseordatawarehouseserverisresponsibleforfetchingtherelevantdata,basedontheuser’sdataminingrequest.

3.Knowledgebase.Thisisthedomainknowledgethatisusedtoguidethesearch,orevaluatetheinterestingnessofresultingpatterns.Suchknowledgecanincludeconcepthierarchies,usedtoorganizeattributesorattributevaluesintodifferentlevelsofabstraction.Knowledgesuchasuserbeliefs,whichcanbeusedtoassessapattern’sinterestingnessbasedonitsunexpectedness,mayalsobeincluded.Otherexamplesofdomainknowledgeareadditionalinterestingnessconstraintsorthresholds,andmetadata（e.g.,describingdatafrommultipleheterogeneoussources）.

4.Dataminingengine.Thisisessentialtothedataminingsystemandideallyconsistsofasetoffunctionalmodulesfortaskssuchascharacterization,associationanalysis,classification,evolutionanddeviationanalysis.

5.Patternevaluationmodule.Thiscomponenttypicallyemploysinterestingnessmeasuresandinteractswiththedataminingmodulessoastofocusthesearchtowardsinterestingpatterns.Itmayaccessinterestingnessthresholdsstoredintheknowledgebase.Alternatively,thepatternevaluationmodulemaybeintegratedwiththeminingmodule,dependingontheimplementationofthedataminingmethodused.Forefficientdatamining,itishighlyrecommendedtopushtheevaluationofpatterninterestingnessasdeepaspossibleintotheminingprocesssoastoconfinethesearchtoonlytheinterestingpatterns.

6.Graphicaluserinterface.Thismodulecommunicatesbetweenusersandthedataminingsystem,allowingtheusertointeractwiththesystembyspecifyingadataminingqueryortask,providinginformationtohelpfocusthesearch,andperformingexploratorydataminingbasedontheintermediatedataminingresults.Inaddition,thiscomponentallowstheusertobrowsedatabaseanddatawarehouseschemasordatastructures,evaluateminedpatterns,andvisualizethepatternsindifferentforms.

Fromadatawarehouseperspective,dataminingcanbeviewedasanadvancedstageofon-1ineanalyticalprocessing（OLAP）.However,datamininggoesfarbeyondthenarrowscopeofsummarization-styleanalyticalprocessingofdatawarehousesystemsbyincorporatingmoreadvancedtechniquesfordataunderstanding.

Whiletheremaybemany“dataminingsystems”onthemarket,notallofthemcanperformtruedatamining.Adataanalysissystemthatdoesnothandlelargeamountsofdatacanatmostbecategorizedasamachinelearningsystem,astatis