欢迎来到天天文库
浏览记录
ID:22680633
大小:78.00 KB
页数:15页
时间:2018-10-30
《knowledge management》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、KnowledgeManagement----文化教育论文-->IntroductionPrincipalponentanalysisisakindofdiversestatisticsanalysismethod.Principalponentanalysisisalsoatechniqueusedtoreducemultidimensionaldatasetstoloensionsforanalysis.PCAostlyusedasatoolinexploratorydataanalysisandformakingpredictivemo
2、dels.PCAinvolvesthecalculationoftheeigenvaluedepositionofadatacovariancematrixorsingularvaluedepositionofadatamatrix,usuallyaftermeancenteringthedataforeachattribute.TheresultsofaPCAareusuallydiscussedintermsofponentscoresandloadings.Foroverallanalyzeprobleminactualtopic,pe
3、oplesusuallyputforeinformationatdissimilaritydegree.Itselectsimportantvariablethroughlinetransformationofmanyvariables.Butethodresearchthemultivariatestatisticalanalysistopic,toomanyvariablesoreinformationthroughfeationhascertaindegreeduplicationinthistopic.Principleponenta
4、nalysisestablishespossiblyfeakesteantimetheseneationintheaspectoftopicinformationreflection.Principleponentanalysisgetsaneetimeaccordingtoeffectivedemand,itcantakeoutseveraltotalvariables.Thesetotalvariablescanreflectoriginalvariables’informationpossibly.Principleponentanal
5、ysisisalsoamathematicmethodfordealathematicallydefinedasanorthogonallineartransformationthattransformsthedatatoanesuchthatthegreatestvariancebyanyprojectionofthedataestolieonthefirstcoordinate(calledthefirstprincipalponent),thesecondgreatestvarianceonthesecondcoordinate,and
6、soon.PCAistheoreticallytheoptimumtransformforagivendatainleastsquareterms.PCAcanbeusedfordimensionalityreductioninadatasetbyretainingthosecharacteristicsofthedatasetthatcontributemosttoitsvariance,bykeepingloostimportant"aspectsofthedata.HoaynotalathematicalprocessingofPCAm
7、eansusealinearitybinationoforiginalPpiecesindextodoan-->eethodisusevarianceofF1(thefirstlinearbination)todoaexpression.ItmeansbiggervariancerepresentsF1containsmoreinformation.ThereforeF1varianceselectedinalloflinearbinationsshouldbebiggest.SocalledF1isfirstprincipleponent.
8、IfthefirstprincipleponentisnotenoughforrepresentationofPpiecesofindexinformation,t
此文档下载收益归作者所有