简介：AHFreceiverfordatatransmissionbasedonKalmanfilterandchannelestimatorisproposed.Thesimulationresultsshowthattheperformanceoftheproposedschemeisabout2dBbetterthanthatofDecision-FeedbackEqualizerbasedonSquare-RootKalmanAlgorithm(SRKA/DFE)anditscomputationalcomplexityislowerthanthatofMaximumLikelihoodSequenceEstimation(MLSE).

简介：Thisresearchaimstoimprovetheforecastingprecisionofelectricquantity.ItisdiscoveredthatthetotalelectricityconsumptionconsiderablyincreasedduringtheSpringFestivalbytheanalysisoftheelectricquantitytimeseriesfrom2002to2007inShandongprovince.Thefestivalfactorisascertainedtobeoneoftheimportantseasonalfactorsaffectingtheelectricquantityfluctuations,andthemultiplicationmodelforforecastingisimprovedbyintroducingcorrespondingvariablesandparameters...

简介：Asecond-ordermixingdifferenceschemewithalimitingfactorisdeducedwiththereconstructiongradientmethodandappliedtodiscretizingtheNavier-Stokesequationinanunstructuredgrid.Thetransformofnonorthogonaldiffusionitemsgeneratedbytheschemeindiscreteequationsisprovided.TheDelaunaytriangulationmethodisimprovedtogeneratetheunstructuredgrid.ThecomputingprogrambasedontheSIMPLEalgorithminanunstructuredgridiscompiledandusedtosolvethediscreteequationsoftwotypesofincompressibleviscousflow.Thenumericalsimulationresultsofthelaminarflowdrivenbylidincavityandflowbehindacylinderarecomparedwiththetheoreticalsolutionandexperimentaldatarespectively.Intheformercase,agoodagreementisachievedinthemainvelocityanddragcoefficientcurve.Inthelattercase,thenumericalstructureanddevelopmentofvortexunderseveralReynoldsnumbersmatchwellwiththatoftheexperiment.Itisindicatedthatthefactordifferenceschemeisofhigheraccuracy,andfeasibletobeappliedtoNavier-Stokesequation.

简介：Thestressintensityfactor(SIF)isacriticalparameterassociatedwiththefracturebehaviourofmaterials.Inthispaper,weselectthedisplacementfunctionaroundacracktipastheshapefunctionofthedigitalimagecorrelation(DIC),whichmakesitpossibletodirectlycalculatetheSIFbythecorrelationscheme.Moreover,weuseanon-rectangularsubset,whichcanreducetheinfluenceofplasticdeformationandcrackwidthontheDICmeasurementaccuracy.WemeasuredtheSIFofamodeIcrackinasuper-hardaluminiumalloyspecimentoverifytheperformanceoftheproposedmethod.OurexperimentalresultsshowthataDICwithaspecificshapefunctioncanbeusedtoaccuratelyandefficientlycalculatetheSIF.Furthermore,wealsopresentapracticalapplicationofourproposedmethodfordeterminingtheSIF,crackpropagationangleandcracktipdisplacement.

简介：Single-gritgrindingofa2.5Dwovencompositewasinvestigatedbythefinite-elementmethod(FEM)usingaunit-cellmodel.Accordingtoourhypotheses,theaxisofthewarpyarnwasasinusoidalcurveandthecrosssectionoftheweftyarnwasshapedlikeabiconvexlens.AVUMATsubroutinewasusedtoconstructtheconstitutivemodelofthe2.5Dwovencomposite.ThegrindingprocessofthecompositewasanalyzedusinganFEMsimulationwiththeABAQUS/Explicitsoftware.Avalidationexperimentwasalsocarriedout.Thesimulationresultsshowedthatagrindingcrackwaswellsimulated.Furthermore,thejunctionsbetweenthewarpyarnandweftyarnwerefoundtobeseriouslydamagedandcrackswereobservedtoextendoutwardalongthewarpfiberduringgrinding,ingoodagreementwiththeexperimentalresults.Inaddition,thestrainofweftyarnswasobviouslygreaterthanthatofwarpyarnswhenthegrindingdirectionwasperpendiculartotheweftyarnsandparalleltotheaxisofthewarpyarns.Theseresultsdemonstratethatthemesostructurestronglyinfluencesthegrindingdamageinflictedonwovencomposites.

简介：Randomphasemasksplayakeyroleinopticalimageencryptionschemesbasedondoublerandomphasetechnique.Inthispaper,amixedchaoticmethodisproposed,whichcanefficientlysolvesomeweaknessesthatone-dimensional(1-D)singlechaoticmapsencountertogeneraterandomphasemasks.Basedonthechaoticrandomphasemasks,opticalimageencryptionanddecryptionarerealizedwithasingle-shotdigitalholographictechnique.Intheproposedencryptionscheme,theinitialvalueandparametersofmixedchaoticmapsserveassecretkeys,whichisconvenientforthekeymanagementandtransmission.Moreover,italsopossesseshighresistanceagainststatisticalattack,brute-forceattack,noiseattackandshearattack.Simulationresultsandsecurityanalysisverifythevalidityandsecurityoftheproposedencryptionscheme.