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1、ARTICLEINPRESSComputersandMathematicswithApplications()ContentslistsavailableatScienceDirectComputersandMathematicswithApplicationsjournalhomepage:www.elsevier.com/locate/camwaApplicationofthevariationaliterationmethodtoinverseheatsourceproblemsFazhanGenga,b,,YingzhenLinaaDepartmentofMathematics,H
2、arbinInstituteofTechnology,Weihai,Shandong264209,ChinabDepartmentofMathematics,ChangshuInstituteofTechnology,Changshu,Jiangsu215500,ChinaarticleinfoabstractKeywords:ThispaperinvestigatestheinverseproblemofdeterminingaheatsourceintheparabolicInverseproblemheatequationusingtheusualconditions.Thenumeri
3、calsolutionisdevelopedbyusingtheUnknownsourcetermvariationaliterationmethod.ThismethodisbasedontheuseofLagrangemultipliersforHeatequationtheidentificationofoptimalvaluesofparametersinafunctional.UsingthismethodarapidVariationaliterationmethodconvergentsequencecanbeobtainedwhichtendstotheexactsolutio
4、noftheproblem.Furthermore,thevariationaliterationmethoddoesnotrequirethediscretizationoftheproblem.Thusthevariationaliterationmethodissuitableforfindingtheapproximationofthesolutionwithoutdiscretizationoftheproblem.Twonumericalexamplesarepresentedtoillustratethestrengthofthemethod.'2009ElsevierLtd.A
5、llrightsreserved.1.IntroductionIntheprocessoftransportation,diffusionandconductionofnaturalmaterials,thefollowingheatequationisinduced:2ut auDf.x;tIu/;.x;t/2.0;T/;(1.1)whereurepresentsthestatevariable,aisthediffusioncoefficient,isaboundeddomaininRdandfdenotesphysicallaws,whichmeansasourcetermhere.
6、Therearemanyresearchesonsuchaninverseproblemofdeterminingthesourcetermfrom1970s,sincethecharacteristicofsourceinthepracticalproblemisalwaysunknown.However,thesolutionofthisproblemisunstable,hencetheinverseproblemisill-posed.Themajordifficultyinestablishinganynumericalalgorithmforapproximatingthesolu
7、tionistheill-posednessoftheproblemandtheill-conditioningoftheresultantdiscretizedmatrix.Theinverseproblemofdetermininganunknownheatsourcefunctionintheheatconductionequationhasbeenconsideredinmanypaper