学科分类
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9 个结果
  • 简介:分发评价是很重要的以便基于这分布为参数或它的函数做统计推理。例如,在这个工作,我们与非光滑的辅助信息建议某变量的分发的一个评估者这个变量的对称的分布。一种变光滑的技术被采用处理非可辨的功能。因此,分布能基于弄平的辅助信息被估计。分发评估者的Asymptotic性质被导出并且分析。没有这些辅助信息,分发评估者基于我们的方法被发现比相应评估者显著地有效。一些模拟研究被进行说明建议评估者的有限样品表演。

  • 标签: 分布估计 辅助信息 平滑 统计推断 分布参数 对称分布
  • 简介:ThispaperextendstheSPHmethodtogassimulation.TheSPH(SmoothedParticlesHydrodynamics)methodisthemostpopularmethodofflowsimulation,whichiswidelyusedinlarge-scaleliquidsimulation.However,itisnotfoundtoapplytogassimulation,sincethosemethodsbasedonSPHcan’tbeusedinreal-timesimulationduetotheirenormousparticlesandhugecomputation.ThispaperproposesamethodforgassimulationbasedonSPHwithasmallnumberofparticles.Firstly,themethodcomputesthepositionanddensityofeachparticleineachpoint-in-time,andoutlinestheshapeofthesimulatedgasbasedonthoseparticles.Secondlythemethodusesthegridtechniquetorefinetheshapewiththediffusionofparticle’sdensityunderthecontrolofgrid,andgetmorelifelikesimulationresult.Eachgridwillbeassigneddensityaccordingtotheparticlesinit.Thedensitydeterminesthefinalappearanceofthegrid.Forensuringthenaturaltransitionofthecolorbetweenadjacentgrids,wegiveadiffuseprocessofdensitybetweenthesegridsandassignappropriatevaluestovertexesofthesegrids.Theexperimentalresultsshowthattheproposedmethodcangivebettergassimulationandmeettherequestofreal-time.

  • 标签: 光滑粒子流体力学 气体模拟 实时仿真 光滑粒子流体动力学 SPH方法 网格技术
  • 简介:Particlebasedmethodscanbeusedforboththesimulationsofsolidandfluidphasesinmultiphasemedium,suchasthediscrete-elementmethodforsolidphaseandthesmoothedparticlehydrodynamicsforfluidphase.Thispaperpresentsacomputationalmethodcombiningthesetwomethodsforsolid-liquidmedium.ThetwophasesarecoupledbyusinganimprovedmodelfromareportedLagrangian-Eulerianmethod.Thetechniqueisverifiedbysimulatingliquid-solidflowsinatwo-dimensionallid-drivencavity.

  • 标签: 光滑粒子流体力学 离散元方法 液固流动 耦合 液体培养基 平滑
  • 简介:Thepredictionaccuracyofasimulationmethodislimitedbyitstheoreticalbackground.Thisfactcanleadtodisadvantagesregardingthesimulationqualitywheninvestigatingsystemsofhighcomplexity,e.g.containingcomponentsshowingafairlydifferentbehavior.Toovercomethislimitation,co-simulationapproachesareusedmoreandmore,combiningtheadvantagesofdifferentsimulationdisciplines.Thatiswhyweproposeanewstrategyforthedynamicsimulationofcuttingprocesses.ThemethodcouplesLagrangianparticlemethods,suchasthesmoothedparticlehydrodynamics(SPH)method,andmultibodysystem(MBS)toolsusingco-simulations.Wedemonstratethecapabilityofthenewapproachbyprovidingsimulationresultsofanorthogonalcuttingprocessandcomparingthemwithexperimentaldata.

  • 标签: 光滑粒子流体力学 多体系统 仿真方法 流体动力学 加工过程 算法
  • 简介:Inthisstudy,theNorthChinaseismicregionwasselectedasthestudyarea,andevaluationofseismichazardusingthespatialsmoothingseismicitymodelwasperformed.Firstly,thestudyareaisdividedintogrids,andsomeparameters(e.g.b-value,M0,Mu,azimuthandM-Lrelationship)foreachseismotectonicmodelwereassigned.Secondly,usingellipticalsmoothingbasedonaseismotectonicbackgroundmodel,thestatisticalearthquakeincidencerateineachgridissuccessivelycalculated.Lastly,therelevantgroundmotionattenuationrelationshipischosentoassessseismichazardofgeneralsites.Themapsforthedistributionofhorizontalpeakgroundaccelerationwith10%probabilityofexceedancein50yearswereobtainedbyusingtheseismichazardanalysismethodbasedongridsource.Thisseismicitymodelsimplifiesthemethodologyofprobabilisticseismichazardanalysis,especiallyappropriateforthoseplaceswhereseismictectonicsisnotyetclearlyknown.Thismethodcanprovidevaluablereferencesforseismiczonationandseismicsafetyassessmentforsignificantengineeringprojects.

  • 标签: 地震活动性参数 空间平滑 危险性估计 概率地震危险性分析 构造背景 地震构造模型
  • 简介:Thenumericalmodellingoftheinteractionsbetweenwaterwavesandfloatingstructuresissignificantfordifferentareasofthemarinesector,especiallyseakeepingandpredictionofwave-inducedloads.SeakeepinganalysisinvolvingsevereflowfluctuationsisstillquitechallengingevenfortheconventionalRANSmethod.Particlemethodhasbeenviewedasalternativeforsuchanalysisespeciallythoseinvolvingdeformableboundary,wavebreakingandfluidfragmentationaroundhullshapes.Inthispaper,theweaklycompressiblesmoothedparticlehydrodynamics(WCSPH),afullyLagrangianparticlemethod,isappliedtosimulatethesymmetricradiationproblemforastationarybargetreatedasaflexiblebody.Thisiscarriedoutbyimposingprescribedforcedsimpleharmonicoscillationsinheave,pitchandthetwo-andthree-nodedistortionmodes.Theresultant,radiationforcepredictions,namelyaddedmassandfluiddampingcoefficients,arecomparedwithresultsfrom3-Dpotentialflowboundaryelementmethodand3-DRANSCFDpredictions,inordertoverifytheadoptedmodellingtechniquesforWCSPH.WCSPHwerefoundtobeinagreementwithmostresultsandcouldpredictthefluidactionsequallywellinmostcases.

  • 标签: WEAKLY COMPRESSIBLE Fluid structure interaction Smoothedparticlehydrodynamics
  • 简介:肝胞虫疾病是在农场和牧剧区域的普通寄生疾病,它严重影响人的健康。基于这疾病的CT成像特征,为肝分割的一条反复的途径和胞虫损害抽取同时被建议。在每次重复,我们的算法由二主要的步组成:1)根据在肝和胞虫的自定义象素种子,损害,Gaussian概率模型试穿和弄平的贝叶斯的分类被使用得到肝和损害的起始的分割;2)用priori形状力量地的参量的活跃轮廓模特儿被收养精制起始的分割。我们由不同病人的CT片的肝和胞虫损害分割的实验在建议算法有效性上做主观、客观的评估。与地面真相手册分割结果比较,试验性的结果显示我们的方法的有效性分割肝和胞虫损害。

  • 标签: 肝胞虫疾病 CT 图象分割 贝叶斯的分类 活跃轮廓模型