简介:摘要:本文改进了一种基于Newton-Raphson的数字图像相关算法。首先,介绍了应用广泛的相关函数及采用了标准化协方差相关函数来分析整数像素的位移,并以此作为初值;其次,介绍了Newton—Raphson方法在亚像素分析中的应用,对优化函数的一阶偏导和二阶偏导(Hessian矩阵)进行了优化,建立了亚像素分析的迭代公式;最后,为了提高分析效率,对数字图像的离散灰度值进行了全场插值。仿真测试表明本文提出算法的合理性和正确性,该算法能够有效用于位移和应变的分析,对算法的优化处理能够显著提高计算速度。
简介:InthispaperwediscusstheconvergenceofamodifiedNewton’smethodpresentedbyA.Ostrowski[1]andJ.F.Traub[2],whichhasquadraticconvergenceorderbutreducesoneevaluationofthederivativeateverytwostepscomparedwithNewton’smethod.Aconvergencetheoremisestablishedbyusingaweakconditiona≤3-2(21/2)andasharperrorestimateisgivenabouttheiterativesequence.
简介:AconicNewtonmethodisattractivebecauseitconvergestoalocalminimizzerrapidlyfromanysufficientlygoodinitialguess.However,itmaybeexpensivetosolvetheconicNewtonequationateachiterate.InthispaperweconsideraninexactconicNewtonmethod,whichsolvesthecouicNewtonequationoldyapproximatelyandinsonmunspecifiedmanner.Furthermore,weshowthatsuchmethodislocallyconvergentandcharacterizestheorderofconvergenceintermsoftherateofconvergenceoftherelativeresiduals.
简介:Recentexperiencehasshownthatinterior-pointmethodsusingalogbarrierapproacharefarsuperiortoclassicalsimplexmethodsforcomputingsolutionstolargeparametricquantileregressionproblems.Inmanylargeempiricalapplications,thedesignmatrixhasaverysparsestructure.Atypicalexampleistheclassicalfixed-effectmodelforpaneldatawheretheparametricdimensionofthemodelcanbequitelarge,butthenumberofnon-zeroelementsisquitesmall.AdoptingrecentdevelopmentsinsparselinearalgebraweintroduceamodifiedversionoftheFrisch-NewtonalgorithmforquantileregressiondescribedinPortnoyandKoenker[28].Thenewalgorithmsubstantiallyreducesthestorage(memory)requirementsandincreasescomputationalspeed.Themodifiedalgorithmalsofacilitatesthedevelopmentofnonparametricquantileregressionmethods.Thepseudodesignmatricesemployedinnonparametricquantileregressionsmoothingareinherentlysparseinboththefidelityandroughnesspenaltycomponents.ExploitingthesparsestructureoftheseproblemsopensupawholerangeofnewpossibilitiesformultivariatesmoothingonlargedatasetsviaANOVA-typedecompositionandpartiallinearmodels.
简介:Thegeneralizedcomplementarityproblemincludesthewell-knownnonlinearcomplementarityproblemandlinearcomplementarityproblemasspecialcases.Inthispaper,basedonaclassofsmoothingfunctions,asmoothingNewton-typealgorithmisproposedforsolvingthegeneralizedcomplementarityproblem.Undersuitableassumptions,theproposedalgorithmiswell-definedandglobalconvergent.
简介:Analgorithmforsolvingaclassofsmoothconvexprogrammingisgiven.Usingsmoothexactmultiplierpenaltyfunction,asmoothconvexprogrammingisminimizedtoaminimizingstronglyconvexfunctiononthecompactsetwasreduced.ThenthestronglyconvexfunctionwithaNewtonmethodonthegivencompactsetwasminimized.
简介:Inthispaper,aswitchingmethodforunconstrainedminimizationisproposed.ThemethodisbasedonthemodifiedBFGSmethodandthemodifiedSR1method.Theeigenvaluesandconditionnumbersofboththemodifiedupdatesareevaluatedandusedintheswitchingrule.WhentheconditionnumberofthemodifiedSR1updateissuperiortothemodifiedBFGSupdate,thestepintheproposedquasi-NewtonmethodisthemodifiedSR1step.OtherwisethestepisthemodifiedBFGSstep.Theefficiencyoftheproposedmethodistestedbynumericalexperimentsonsmall,mediumandlargescaleoptimization.Thenumericalresultsarereportedandanalyzedtoshowthesuperiorityoftheproposedmethod.
简介:Thispaperconsiderstheexistenceandasymptoticestimatesofglobalsolutionsandfinitetimeblowupoflocalsolutionofnon-Newtonfiltrationequationwithspecialmediumvoidofthefollowingform:{ut/|x|^2-△pu=u^q,(x,t)∈Ω×(0,T),u(x,t)=0,(x,t)∈ЭΩ×(0,T),u(x,0)=u0(x),u0(x)≥0,u0(x)全不等于0,where△pu=div(|△↓u|^p-2△↓u),ΩisasmoothboundeddomaininR^N(N≥3),0∈Ω,2
简介:ThebasicprincipleofintervalarithmeticandthebasicalgorithmoftheintervalNewtonmethodsareintroduced.Theprototypealgorithmcannotfindanyzeroinanintervalthathaszerosometimes,thatis,itisinstable.Sotheprototyperelaxationprocedureisimprovedinthispaper.Additionally,animmediatetestoftheexistenceofasolutionfollowingbranch-and-boundisproposed,whichavoidsunwantedcomputationsinthoseintervalsthathavenosolution.ThenumericalresultsdemonstratthattheimprovedintervalNewtonmethodissuperiortoprototypealgorithmintermsofsolutionquality,stabilityandconvergentspeed.
简介:Withtheemergenceoflocation-basedapplicationsinvariousfields,thehigheraccuracyofpositioningisdemanded.Byutilizingthetimedifferencesofarrival(TDOAs)andgainratiosofarrival(GROAs),anefficientalgorithmforestimatingthepositionisproposed,whichexploitstheBroyden-Fletcher-Goldfarb-Shanno(BFGS)quasi-Newtonmethodtosolvenonlinearequationsatthesourcelocationundertheadditivemeasurementerror.Althoughtheaccuracyoftwo-stepweighted-least-square(WLS)methodbasedonTDOAsandGROAsisveryhigh,thismethodhasahighcomputationalcomplexity.Whiletheproposedapproachcanachievethesameaccuracyandbiaswiththelowercomputationalcomplexitywhenthesignal-to-noiseratio(SNR)ishigh,especiallyitcanachievebetteraccuracyandsmallerbiasatalowerSNR.Theproposedalgorithmcanbeappliedtotheactualenvironmentduetoitsreal-timepropertyandgoodrobustperformance.Simulationresultsshowthatwithagoodinitialguesstobeginwith,theproposedestimatorconvergestothetruesolutionandachievestheCramer-Raolowerbound(CRLB)accuracyforbothnear-fieldandfar-fieldsources.
简介:WeprovideconvergenceresultsanderrorestimatesforNewton-likemethodsingeneralizedBanachspaces.TheideaofageneralizednormisusedwhichisdefinedtobeamapfromalinearspaceintoapartiallyorderedBanachspace.Convergenceresultsanderrorestimatesareimprovedcomparedwiththerealnormtheory.