简介:CommunicationsecurityisacriticalaspectofQoSprovisioninginwirelessmeshnetwork(WMN).BecauseoftheinherentcharacteristicsofWMN,conventionalsecuritymechanismscannotbeapplied.Inordertoguaranteethecommunicationsecurity,anovelcommunicationsecuritymechanismisproposed.Themechanismusesacommunicationencryptionschemetoencryptdatapacketsandemploysariskavoidanceschemetoavoidthemaliciousnodesduringcommunications.Simulationresultsindicatethatthemechanismisabletoprovidesecurecommunicationeffectivelyandreducethedamageofattacksthroughmultiplepaths.
简介:BymeansofdirectanalysisoftheconnectionbetweenLoopsubdivisionsurfaceanditscontrolmeshandthecomputationofthebasisfunctions,weobtainaboundonthedistancebetweenLoopsubdivisionsurfacepatchanditscontrolmesh.Theboundcanbeusedtocomputethenumbersofsubdivisionforagiventolerance.Finally,twoexamplesarelistedinthispapertodemonstratetheapplicationsofthebound.
简介:这篇文章描述在一个无线网孔网络分享系统的一个合作文件的一个新模型。作者的途径是开发基于机会主义的随机的线性网络编码分享机制的一个有效、合作的文件。在这机制以内,每个节点根据合作优先级播送它的包的随机的线性联合,它根据对它的邻居节点的节点可能的贡献以一种分布式的方式被计算。与这机制,一个节点越贡献其它,节点越有机会首先恢复全部文件。这里的兴趣的表演度量标准是:延期被送到直到在一个文件的所有包所有节点,和一种理想的包尺寸,由作者能得到最小的传播延期的使用。没有随机的线性网络编码,通过广泛的模拟,作者在一个无线网孔网络把他们的机制与当前的传播进程作比较。作者发现用他们的机制,节点能合作地与更少的传播时间分享全部文件并且没有随机的线性网络,比当前的传播进程推迟。
简介:TheFilteringGridScale(FGS)ofsub-gridscalemodelsdoesnotmatchwiththetheoreticalProperFGS(PFGS)becauseoftheimpropermesh.Therefore,properLargeEddySimulation(LES)Meshisverydecisiveforbetterresultsandmoreeconomicalcost.Inthiswork,thepurposeistoprovideanadaptivecontrolstrategyforproperLESmeshwithturbulencetheoryandCFDmethods.AnewexpressionofPFGSisproposedonthebasisof-5/3lawofinertialsub-rangeandthepropermeshofLEScanbebuiltdirectlyfromtheadjustmentofRANSmesh.Abenchmarkofthebackwardfacingstepflowatisprovidedforapplicationandverification.Therearethreekindsofmeshsizes,includingtheRANSmesh,LAM(LESofadaptive-controlmesh),LFM(LESoffinemesh),employedhere.ThegridnumberofLAMissmallerthanthoseofLFMevidently,andtheresultsofLAMareinagoodagreementwiththoseofDNSandexperiments.ItisrevealedthattheresultsofLAMareveryclosetothoseofLFM.Theconclusionsprovidepositiveevidencesforthenovelstrategy.
简介:Thispaperpresentsanefficientmovingmeshmethodtosolveanonlinearsingularproblemwithanoptimalcontrolconstrainedcondition.ThephysicalproblemisgovernedbyanewmodelofturbulentflowincirculartubesproposedbyLuoetal.usingPrandtl'smixing-lengththeory.Ouralgorithmisformedbyanouteriterativealgorithmforhandlingtheoptimalcontrolconditionandaninneradaptivemeshredistributionalgorithmforsolvingthesingulargoverningequations.Wediscretizethenonlinearproblembyusingaupwindingapproach,andtheresultingnonlinearequationsaresolvedbyusingtheNewton-Raphsonmethod.Themeshisgeneratedandthegridpointsaremovedbyusingthearc-lengthequidistributionprinciple.Thenumericalresultsdemonstratethatproposedalgorithmiseffectiveincapturingtheboundarylayersassociatedwiththeturbulentmodel.