简介:Humanimmunodeficiencyvirus(HIV)hashadaninsightfulimpactaboutthestateofhealthinessofhumanimmunesystem.Duetogreatimprovementindrugtherapy,HIVinfectionshavebeenreducedby17%overthepasteightyears.IthasbeenprovedthatmosteffectivetreatmentHAART(HighlyActiveAntiRetroviralTherapy)mainlycontrolsthediseasesprogressionbutitdoesnoteradicatethediseasescompletely.ReverseTranscriptaseInhibitordrugsspeciallyassociatedwithvirusspecificCytotoxicT-Lymphocyte(CTL)thatdeclineswithdiseaseprogression.CTLresponsesagainstAIDSpathogenesiscouldbepotentialinthedynamicsofvirusreplication,recognitionandclearanceofinfectedcells.InthisresearcharticleamathematicalmodelhasbeenproposedonthebasisofCTLresponsesuppressioninthechronicphaseofinfectionduetopresenceofvirus.WealsoconsiderthegrowthoftheviruspopulationfromtheinfectedCD4~+Tcellsbuddingprocessandfromtheotherinfectedcellslikemacrophagesandthymocytes.Ouranalyticalandnumericalstudiesareconsistentwithexistingobservationsfromalliedareas.
简介:Two-phase,immiscible,incompressibleflowinporousmediaisgovernedbyasystemofnonlinearpartialdifferentialequations.Inmostpracticalapplicationsconvectionphysicallydominatesdiffusion,andtheobjectofthispaperistodevelopafinitedifferencemethodcombinedwiththemethodofcharacteristicsandthelumpedmassmethodtotreattheparabolicequationofthedifferentialsystem.Thismethodisshownsatisfythemaximumprincipleanditserroranalysisispresented.
简介:Inthispaperweshallgivethecharacteristicdifferencemethodsfortwophasedisplacemeatprobleminnaturallyfracturedreservoirs.Weshallprovetheexistence,uniquenessoftheapproximatesolutionandaprioridiscreteL2-errorestimates.
简介:Twophase,miscible,incompressibleflowinporousmediaisgovernedbyasystemofnonlinearpartialdifferentialequations.Manynumericalmethodshavebeengivenbydidierentauthorstothissystem,hutthesemethodsneedveryhighregularityconditions.Actualty,inmostpracticalapplicationstheseregularityconditionscouldn'tbesatisfied.Inthispaper,theproblemofdiscontinuouscoefficientswithlowerregularityconditionsisconsideredandtheerrorestimatesaredemonstrated.
简介:Thispaperconsidersaperturbedrenewalriskprocessinwhichtheinter-claimtimeshaveaphase-typedistributionunderathresholddividendstrategy.Integro-differentialequationswithcertainboundaryconditionsforthemoment-generatingfunctionandthemthmomentofthepresentvalueofalldividendsuntilruinarederived.Explicitexpressionsfortheexpectationofthepresentvalueofalldividendsuntilruinareobtainedwhentheclaimamountdistributionisfromtherationalfamily.Finally,wepresentanexample.
简介:Themiscibledisplacementofoneincompressiblefluidbyanotherinaporousmediumisconsideredinthispaper.Theconcentrationissplitinafirst-orderhyberbolicequationandahomogeneousparabolicequationwithineachlimestep.ThepressureandUsvelocityfieldiscomputedbyamixedfiniteelementmethod.Optimalorderestimatesarederivedforthenodiffusioncaseandthediffusioncase.
简介:Tow-phaseflowmixedvariationalformulationsofevolutionfiltrationproblemswithseawaterintrusionareanalyzed.Adualmixedfractionalflowvelocity-pressuremodelisconsideredwithanair-freshwaterandafreshwater-seawatercharacterization.Foranalysisandcomputationalpurposes,spatialdecompositionsbasedonnonoverlappingmultidomains,aboveandbelowthesealevel,arevariationallyintroducedwithinternalboundaryfluxesdualizedasweaktransmissionconstraints.Further,parallelaugmentedandexactlypenalizeddualityalgorithms,andproximationsemi-implicittimemarchingschemes,areestablishedandanalyzed.
简介:Forcompressibletwo-phasedisplacementproblem,themodifiedupwindfinitedifferencefractionalstepsschemesareputforward.Sometechniques,suchascalculusofvariations,commutativelawofmultiplicationofdifferenceoperators,decompositionofhighorderdifferenceoperators,thetheoryofpriorestimatesandtechniquesareused.OptimalorderestimatesinL2normarederivedfortheerrorintheapproximatesolution.Thismethodhasalreadybeenappliedtothenumericalsimulationofseawaterintrusionandmigration-accumulationofoilresources.
简介:EQrot1nonconformingfiniteelementapproximationtoaclassofnonlineardualphaselaggingheatconductionequationsisdiscussedforsemi-discreteandfully-discreteschemes.Byuseofaspecialproperty,thatis,theconsistencyerrorofthiselementisoforderO(h2)oneorderhigherthanitsinterpolationerrorO(h),thesupercloseresultsoforderO(h2)inbrokenH1-normareobtained.Atthesametime,theglobalsuperconvergenceinbrokenH1-normisdeducedbyinterpolationpostprocessingtechnique.Moreover,theextrapolationresultwithorderO(h4)isderivedbyconstructinganewinterpolationpostprocessingoperatorandextrapolationschemebasedontheknownasymptoticexpansionformulasofEQrot1element.Finally,optimalerrorestimateisgainedforaproposedfully-discreteschemebydifferentapproachesfromthepreviousliterature.
简介:TheembeddedboundarymethodforsolvingellipticandparabolicproblemsingeometricallycomplexdomainsusingCartesianmeshesbyJohansenandColella(1998,J.Comput.Phys.147,60)hasbeenextendedforellipticandparabolicproblemswithinteriorboundariesorinterfacesofdiscontinuitiesofmaterialpropertiesorsolutions.Secondorderaccuracyisachievedinspaceandtimeforbothstationaryandmovinginterfaceproblems.Themethodisconservativeforellipticandparabolicproblemswithfixedinterfaces.Basedonthismethod,afronttrackingalgorithmfortheStefanproblemhasbeendeveloped.Theaccuracyofthemethodismeasuredthroughcomparisonwithexactsolutiontoatwo-dimensionalStefanproblem.Thealgorithmhasbeenusedforthestudyofmeltingandsolidificationproblems.