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89 个结果
  • 简介:Severalquadrilateralshaperegularmeshconditionscommonlyusedinthefiniteelementmethodareproventobeequivalent.Theirinfluenceonthefiniteelementinterpolationerrorandtheconsistencyerrorcommittedbynonconformingfiniteelementsareinvestigated.TheeffectoftheBi-SectionConditionanditsextendedversion(1+α)-SectionConditiononthedegeneratemeshconditionsisalsochecked.ThenecessityoftheBi-SectionConditioninfiniteelementsisunderpinnedbymeansofcounterexamples.

  • 标签: 四边形网格 有限元法 四节点等参数元 正则性条件 退化网格条件 非一致性四边性元
  • 简介:InCAD/CAM,meshratherthansmoothsurfaceisonlyneededsometimes.Amesh-generatingmethodfrompermanenceprincipleofCoonspatchisdeveloped.Anewmeshpointisdefinedthroughlocalsmallsubpatchandallmeshpointsarecomputedbyalinearsystemwithspecialsymmetricblocktridiagonalcoefficientmatrix.Bysimplification,thedeterminantofcoefficientmatrixisdeterminedbydeterminantsofsubmatrices.Conditionofexistenceofsolutionisgiven.Whethercoefficientmatrixissingularcanbejudgedbyasimplepolynomialfunctionwiththeeigenvalueofsubmatrixasvariable.Numericalexamplesdemonstratetheeffectsofshapeparameters.

  • 标签: 形状参数 生成网格 系数矩阵 多项式函数 表面光滑 线性系统
  • 简介:我们在场突然地重建的削尖的途径展示从的一个柔韧的网孔相配或chamfered特征,甚至与噪音和aliasing错误。特征区域首先根据用户的输入经由正常变化被认出,然后过滤的正常被用于特征区域的脸。最后,特征区域的顶点逐渐地用一个最少平方的错误标准基于新面孔正常被更新。试验性的结果证明方法在削尖有效、柔韧网孔。

  • 标签: 锐化 滤波 网通 特征区域 功能区域 误差标准
  • 简介:2.社区网络互连 采用无线mesh网技术,可在家庭互连网络中采用无线mesh网技术,无线Mesh网络的关键技术因素 无线mesh网作为一种新的无线接入网络技术

  • 标签: 网络技术
  • 简介:Thissurveyreviewstherecentdevelopmentofgradientdomainmeshdeformationmethod.Differenttootherdeformationmethods,thegradientdomaindeformationmethodisasurface-based,variationaloptimizationmethod.Itdirectlyencodesthegeometricdetailsindifferentialcoordinates,whicharealsocalledLaplaciancoordinatesinliterature.BypreservingtheLaplaciancoordinates,themeshdetailscanbewellpreservedduringdeformation.DuetothelocalityoftheLaplaciancoordinates,thevariationaloptimizationproblemcanbecastedintoasparselinearsystem.Fastsparselinearsolvercanbeadoptedtogeneratedeformationresultinteractively,oreveninreal-time.Thenonlinearnatureofgradientdomainmeshdeformationleadstothedevelopmentoftwocategoriesofdeformationmethods:linearizationmethodsandnonlinearoptimizationmethods.Basically,thelinearizationmethodsonlyneedtosolvethelinearleast-squaressystemonce.Theyarefast,easytounderstandandcontrol,whilethedeformationresultmightbesuboptimal.Nonlinearoptimizationmethodscanreachoptimalsolutionofdeformationenergyfunctionbyiterativeupdating.Sincethecomputationofnonlinearmethodsisexpensive,reduceddeformablemodelsshouldbeadoptedtoachieveinteractiveperformance.Thenonlinearoptimizationmethodsavoidtheuserburdentoinputtransformationatdeformationhandles,andtheycanbeextendedtoincorporatevariousnonlinearconstraints,likevolumeconstraint,skeletonconstraint,andsoon.Wereviewrepresentativemethodsandrelatedapproachesofeachcategorycomparativelyandhopetohelptheuserunderstandthemotivationbehindthealgorithms.Finally,wediscusstherelationbetweenphysicalsimulationandgradientdomainmeshdeformationtorevealwhyitcanachievephysicallyplausibledeformationresult.

  • 标签: 梯度 网孔变化 测量 变形方法
  • 简介:Itisachallengingproblemofsurface-baseddeformationtoavoidapparentvolumetricdistortionsaroundlargelydeformedareas.Inthispaper,weproposeanewrigidityconstraintforgradientdomainmeshdeformationtoaddressthisproblem.Intuitivelytheproposedconstraintcanberegardedasseveralsmallcubesdefinedbythemeshverticesthroughmeanvaluecoordinates.Theuserinteractivelyspecifiesthecubesintheregionswhicharepronetovolumetricdistortions,andtherigidityconstraintscouldmakethemeshbehavelikeasolidobjectduringdeformation.Theexperimentalresultsdemonstratethatourconstraintisintuitive,easytouseandveryeffective.

  • 标签: 网眼变形 刚性约束 平均值 拉普拉斯算子 能量最小化
  • 简介:不同液体的混乱混合生产旋绕的结构到分开这些液体的接口。为能溶合的液体(是这里考虑了),这个接口被定义为50%集体集中isosurface。为导致的冲击波(Richtmyer-Meshkov)不稳定性,我们发现接口当计算网孔被精制,逐渐地复杂。如果Kolmogorov规模相对网孔是小的,这界面的混乱被粘性,或由计算网孔割掉。在集成的接口统计的政体,我们然后检验混合,即集中统计,由质量调整了散开。为比统一显著地大的Schmidt数字,典型地代表液体或稠密的血浆,另外的网孔精炼通常被需要克服数字集体散开并且完成混合问题的一个集成的答案。然而,与前面追踪的利益并且与一个算法,那允许有限接口散开,我们能在Schmidt数字一致地保证集中。我们证明不同答案源于Schmidt数字的变化。我们建议潜水艇格子粘性和可能在现实主义的格子层次允许集成的答案的集体散开parameterizations。

  • 标签: 混沌理论 数学 湍流 多相流
  • 简介:众所周知,蓝牙是一项全球通用的无线标准,可以在广泛的互联设备之间建立连接,并有力驱动创新,带来简便安全的无线连接,蓝牙技术联盟携手全球三万两千多家成员公司,借助集体的智慧和共享的技术标准为用户带来简便、安全、充实的技术体验.在今年7月19日,蓝牙技术联盟正式宣布蓝牙技术全面支持mesh网状网络,适用于物联网解决方案,将极大程度地推动新兴市场的快速增长.

  • 标签: 蓝牙技术 MESH 物联网 定制 技术联盟 无线连接
  • 简介:Solution-drivenmeshadaptationisbecomingquitepopularforspatialerrorcontrolinthenumericalsimulationofcomplexcomputationalphysicsapplications,suchasclimatemodeling.Typically,spatialadaptationisachievedbyelementsubdivision(hadaptation)withaprimarygoalofresolvingthelocallengthscalesofinterest.Asec-ond,less-popularmethodofspatialadaptivityiscalled'meshmotion'(radaptation);thesmoothrepositioningofmeshnodepointsaimedatresizingexistingelementstocapturethelocallengthscales.Thispaperproposesanadaptationmethodbasedonacombinationofbothelementsubdivisionandnodepointrepositioning(rhadaptation).Bycombiningthesetwomethodsusingthenotionofamobilityfunction,theproposedapproachseekstoincreasetheflexibilityandextensibilityofmeshmotionalgorithmswhileprovidingasomewhatsmoothertransitionbetweenrefinedregionsthanispro-ducedbyelementsubdivisionalone.Further,inanattempttosupporttherequirementsofaverygeneralclassofclimatesimulationapplications,theproposedmethodisde-signedtoaccommodateunstructured,polygonalmeshtopologiesinadditiontothemostpopularmeshtypes.

  • 标签: 表面网孔产生 网孔适应 网孔优化 气候模型
  • 简介:Freesurfaceflowproblemsinvolvinglargefreemotionsareanalysedusingfiniteelementtechniques.InsolvingtheseproblemsanArbitraryLagrangian-Eulerian(ALE)kinematicaldescriptionofthefluiddomainisadopted,inwhichthenodalpointscanbedisplacedindependentlyofthefluidmotion.Anewmeshtracingmethodisproposedinthispaper.Toconfirmtheeffectivenessofthenewmethod,solitarywavepropagationisanalysedandthenumericalresultsarecomparedwiththeanalyticalresults.ThebehaviouroftheviscousfluidflowwithafreesurfaceisexpressedbytheunsteadyNavier-Stokesequation.Fornumericalintegrationintimethevelocitycorrectionfractionalstepmethodisused.

  • 标签: 自由表面 筛孔追踪 有限元法 孤立波 水力学
  • 简介:无线网状网(WirelessMeshNetwork,WMN)技术是一种具有良好市场应用前景的新型宽带无线网络技术。本文首先讨论了无线网状网的研究背景,并针对其结构特点、与其他通信网络的区别以及关键技术,进行了初步的探讨和总结。

  • 标签: 无线网状网 宽带无线接入 关键技术 分布式网络
  • 简介:Anewmeshfreemethodproposedbytheauthorswaspresented,inwhichthederivativesateachnodewereconstructedusingwholederivativeformulasthroughthenodesselectedaroundthenodeusinglocalCartesianframeinanautonomousmanner,sothatwithoutanyelementitcouldbeconsideredasacompletelymeshfreemethod.Themethodwastestedwithanumericalexample,andreliablesolutionwasobtainedwithhighaccuracyandefficiency.

  • 标签: 笛卡儿标架 高精确性 高效率 数学分析
  • 简介:Amethodforfairingasurfacecomposedofasetofdiscretedatapointsdistributedinanonrectangulartopologicalmeshispresented.AllcurvesareexpressedbynonuniformcubicB-splinecurves.Thefairingmethodisminimizingtheelasticstrainenergyofmeshcurvesandofspringsat-tachedtothedatapoints.Thefairingsurfacecanbegeneratedbyinterpolatingthroughthemeshcurves.Thegenerationandfairingofashiphullsurfaceisgivenasanexample.

  • 标签: CAD Ship-hull surface FAIRING method ELASTIC
  • 简介:Thispaperpresentsanapproachwhichenablessurfacemodelling,meshgenerationandtheFiniteElement(FE)analysistobeintegratedtogethertosimulatesuperplasticformingprocessforcomplexshapedcomponents.TechniqueshavebeendevelopedtogenerateanFEmeshovernon-four-sidedsurfaceareas,theboundariesofwhichareBeziercurvesofarbitrarydegree,usingaconsistentexpression.TheoreticalevidenceisgiventodeterminethenumberofBeziertriangularpatchesrequiredforaccuratelyre-constructingdiesurfaceswithinacommercialFEsolver.Thedevelopedtechniqueshavebeensuccessfullyusedindeterminingtheprocessparametersforforminga3Drectangularbox.

  • 标签: 塑料成形 曲面模型化 网格制作 CAD
  • 简介:Wepresentanovelalgorithmforadaptivetriangularmeshcoarsening.Thealgorithmhastwostages.First,theinputtriangularmeshisrefinedbyiterativelyapplyingtheadaptivesubdivisionoperatorthatperformsaso-calledred-greensplit.Second,therefinedmeshissimplifiedbyaclusteringalgorithmbasedoncentroidalVoronoitessellations(CVTs).TheaccuracyandgoodqualityoftheoutputtriangularmeshareachievedbycombiningadaptivesubdivisionandtheCVTstechnique.Testresultsshowedthemeshcoarseningschemetoberobustandeffective.Examplesareshownthatvalidatethemethod.

  • 标签: Voronoi图 自适应细分 三角网格 形心 CVT变速器 聚类算法
  • 简介:AnovelconstructionalgorithmispresentedtogenerateaconformingVoronoimeshforanyplanarstraightlinegraph(PSLG).Itisalsoextendedtotesselatemultiple-intersectedPSLGs.Allthealgorithmsareguaranteedtoconverge.Examplesaregiventoillustrateitsefficiency.

  • 标签: VORONOI DIAGRAM DELAUNAY TRIANGULATION conforming VORONOI
  • 简介:Withthedevelopmentofadvancedimagingtechnology,digitalimagesarewidelyused.Thispaperproposesanautomaticquadrilateralmeshgenerationalgorithmformulti-colourimagedstructures.Ittakesanoriginalarbitrarydigitalimageasaninputforautomaticquadrilateralmeshgeneration,thisincludesremovingthenoise,extractingandsmoothingtheboundarygeometriesbetweendifferentcolours,andautomaticall-quadmeshgenerationwiththeaboveboundariesasconstraints.Anapplicationexampleis...

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