学科分类
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500 个结果
  • 简介:Theinverserecursionoperator,threenewsetsofsymmetries,andinfinite-dimensionalLiealgebrasforthenonlineardiffusionequationaregiven.SomenonlocalsymmetriesrelatedtoeigenvectorsoftherecursionoperatorФwiththeeigenvalueλiarealsoobtainedwiththehelpoftherecursionoperatorФi=Ф-λi.Usingapartofthesesymmetrieswegettwelvetypesofnontrivialnewsimilarityreduction.

  • 标签: 相似简化 对称简化 非线性扩散方程 逆递推算符 数学物理方法
  • 简介:柔韧的差错诊断为非线性的系统的一个类基于适应观察员被学习直到输出注射。适应差错更新法律被设计保证诊断系统的稳定性。州的评价错误的上面的界限;适应观察员的差错评价错误分别地被给;在差错评价精确性上的适应更新法律的参数的效果也被讨论。模拟例子表明建议方法的有效性;分析结果。

  • 标签: 非线性系统 故障诊断 自适应观测 稳定性
  • 简介:BasedonKármán’snonlinearfundamentaldifferentialequations,thenewapproach,whichcombinesmodifiediterationmethodwithGalerkin’sone,hasbeenputforwardtosolvenonlinearbendingofshallowsphericalshellwithconcavebaseandclampededgesonthePasternakfoundationunderuniformloadsinthispaper.Mathematicalexpressionofload-deflectionhasbeengiven;furthermore,resultsobtainedareingoodagreementwithexistentones.

  • 标签: SHALLOW sphericall/pasternak FOUNDATION modified ITERATION METHOD
  • 简介:Thepile-soilsystemisregardedasavisco-elastichalf-spaceembeddedpile.Basedonthemethodofcontinuummechanics,anonlinearmathematicalmodelofpilesoilinteractionwasestablished-acouplingnonlinearboundaryvalueproblem.Underthecaseofhorizontalvibration,thenonlinearlydynamicalcharacteristicsofpileapplyingtheaxisforcewerestudiedinhorizontaldirectioninfrequencydomain.Theeffectsofparameters,especiallytheaxisforceonthestiffnesswerestudiedindetail.Thenumericalresultssuggestthatitispossiblethatthepileapplyinganaxisforcewillloseitsstability.So,theeffectoftheaxisforceonthepileisconsidered.

  • 标签: 非线性力学 水平变量 参数研究 管道-土壤界面
  • 简介:Inthispapertheconceptofabsoluteobservabilityofnonlinearcontrolsystemsisadvanced.Differentfromthelineartime-invariantversion,therearedifferentdefinitionsofabsoluteobservabilityfornonlinearcontrolsystems.Twoalgorithmsformaximalabsolutelyobservablesubsystemsaregiven.Correspondingly,therearetworelevantnormalforms.Therelationswiththelargestcontrolledinvariantdistributioncontainedinkerdh,zerodynamicsetc.,arediscussedfromtheviewpointofmaximalabsoluteobservabilities.

  • 标签: ABSOLUTE INVARIANT MAXIMAL transformed terminology NEIGHBORHOOD
  • 简介:我们在场一个新歧管的学习算法叫了保存排列(LOPA)的本地Orthogonality。我们的算法被试图用仿射的转变排列多重本地邻居进一个全球坐标系统的本地正切空间排列(LTSA)方法启发。然而,LTSA经常没能保存象距离和角度那样的原来的几何数量。尽管为保存orthogonality的一个反复的排列过程被LTSA的作者建议,既不相应初始化也不实验被给。普罗克拉斯提斯Subspaces排列(PSA)实现由与退火模仿独立估计每旋转转变保存想法的orthogonality。然而,在PSA的优化是复杂、多重的分开的本地旋转可以生产全球性倾向於矛盾的结果。探讨这些困难,我们首先使用LTSA的伪逆诡计与统一全球坐标代表每本地直角的转变。第二,orthogonality限制被放松是半明确的编程(SDP)的一个例子。最后一个二拍子的圆舞反复的过程被采用进一步在直角的限制减少错误。广泛的实验证明LOPA能忠实地保存原来的数据集的距离,角度,内部产品,和邻居。在比较,当LOPA的运行时刻比PSA,MVU和MVE的显著地快时,LOPA的嵌入的表演比PSA的好、比得上象MVU和MVE一样的最先进的算法的。

  • 标签: 正交变换 空间对准 非线性 降维 学习算法 旋转变换
  • 简介:Boththeinplaneandout-of-planetransversevibrationsofaviscoelasticcablesubjectedtoaninitialstressdistributinguniformonthecrosssectionarestudied.Theconstitutionofthecablematerialisas-sumedtobeofthehereditaryintegraltype.Thepartialdifferential-integralequationsofmotionarederivedfirst.ThenbyapplyingGalerkin’smethod,thegoverningequationsarereducedtoasetofsecond-ordernon-lineardifferential-integralequationswhicharesolvedbyfinitedifferencenumericalintegrationprocedures.Finally,theeffectsoftheviscosityparameterandtheelaslicparameteronthetransientamplitudesofthefirstmodeareinvestigatedbynumericalsimulation.

  • 标签: VISCOELASTIC cable SMALL SAG INTEGRAL CONSTITUTIVE
  • 简介:1.INTRODUCTIONG.LadasandI.P.Stavroulakis[1]Consideroscillationofthesolutionsinfirstorderlineardelaydifferentialequationsbydifferentialinequalities.L.C.LinandG.Q.Wang[2]studiedtheoscillatorybehaviorofsolutionsinfirstorderlineardifferentialequationswithretardedarguments.I.P.Stavroulakis[3]studiedtheOscillationinfirstordernonlineardelaydifferentialequationswithretardedargumentsbynonlineardelaydifferentialinequalities.

  • 标签: OSCILLATORY oscillation inequality INFINITE eventually proof
  • 简介:Forthesimulationofthenonlinearwavepropagationincoastalareaswithcomplexboundaries,anumericalmodelisdevelopedincurvilinearcoordinates.Inthemodel,theBoussinesq-typeequationsincludingthedissipationtermsareemployedasthegoverningequations.Inthepresentmodel,thedependentvariablesofthetransformedequationsarethefreesurfaceelevationandtheutilityvelocityvariables,insteadoftheusualprimitivevelocityvariables.TheintroductionofutilityvelocityvariableswhicharetheproductsofthecontravariantcomponentsofthevelocityvectorandtheJacobimatrixcanmakethetransformedequationsrelativelyconcise,thetreatmentoflateralboundaryconditionseasierandthedevelopmentoftheprogramsimpler.Thepredictor-correctormethodandfive-pointfinite-differenceschemeareemployedtodiscretizethetimederivativesandthespatialones,respectively.Thenumericalmodelistestedforthreecases.Itisfoundthatthenumericalresultsareingoodagreementwiththeanalyticalresultsandexperimentaldata.

  • 标签: 数值模型 曲线坐标 非线性波 BOUSSINESQ型方程 波传播 有限差分格式
  • 简介:Basedonthe1stordercnoidalwavetheory,thewavediffractionaroundthepiergroupinshallowwaterisstudiedinthispaper.Theformulasforcalculatingthenonlinearwaveforcesarealsopresentedhere.Inordertoverifythetheoreticalresults,modeltestsareconductedinthewaveflumeinTheStateKeyLaboratoryofCoastalandOffshoreEngineeringlocatedinDalianUniversityofTechnology.TherangeofthewaveparametersintheexperimentsischaracteristicwaveperiodTg/d1/2=8.08-22.86,characteristicwaveheightH/d=0.10.45.Theresultsobtainedfromtheexperimentsagreewiththetheoreticalresultsquitewell.Itisshownthat,inshallowwaterthenonlinearwaveforcesactingonapiergrouparegreaterthanthosecalculatedbylinearwavetheory,thevalueofincrementinwaveforceincreaseswiththeincreasesofthenonlinearityofthewave.Inthewaverangestudiedinthispaper,thenonlinearwaveforcecanreachover4timestheforcecalculatecdbylinearwavetheory.Thus,itissuggestedthat,whenTg/d1/2>8,thewaveforceonthepiersinthepiergroupinshallowwatershouldbecalculatedbyusingthecnoidalwavetheory.

  • 标签: CYLINDER PIER GROUP WAVE FORCE SHALLOW
  • 简介:Inordertoprovidethebasisforparameterselectionofvocaldiseasesclassification,anonlineardynamicmodelingmethodisproposed.Abiomechanicalmodelofvocalcordswithpolyporparalysis,whichcouplestoglottalairflowtoproducelaryngealsoundsource,isintroduced.Andthenthefundamentalfrequencyanditsperturbationparametersaresolved.Poincaresectionandbifurcationdiagramareappliedtononlinearanalysisofmodelvibration.Bychangingthepathologicalparametersorsubglottalpressure,thechangesoffundamentalfrequencyandLyapunovexponentsareanalyzed.Thesimulationresultsshowthat,vocalcordparalysisreducesthefundamentalfrequency,andthechaosoccursonlywithinacertainpressurerange;whilevocalcordwithapolypdon’treducethefundamentalfrequency,chaosdistributesthroughouttheentirerangeofpressure.Thereforethisstudyishelpfulforclassificationofpolypandparalysisbytheacousticdiagnoses.

  • 标签: 非线性动力学模型 分类 麻痹 LYAPUNOV指数 发声
  • 简介:最近,C.-.C.杨和我。Laine调查了有限顺序形式fn+L的非线性的微分差别的方程的全部答案f(z,f)=h,在此2是的n一个整数。特别地,这被知道方程f(z)2+q(z)f(z+1)=p(z)p(z),q(z)是多项式,不先验有限顺序的全部答案。假定那Q(z)也是一个多项式和c,形式f(z)n+q(z)eQ(z)f(z+c)的方程=p(z)做团队有限顺序全部答案。以生长和零分布,愿望被给的这些答案的一个分类。特别地,任何指数的多项式溶液必须归结为一种相当特定的形式,这被显示出。这个推理由于N依靠一份更早的报纸。Steinmetz。

  • 标签: 指数多项式 差分方程解 非线性 微分差分方程 欧共体 零分布
  • 简介:Errorestimatesareestablishedforthefinitedementmethodstosolveaclassofsecondordernonlinearparabolicequations.OptimalratesofconvergenceinL2-andH1-normsarederived.Meanwhile,theschenesaresecondordercorrectintime.

  • 标签:
  • 简介:Recentprogressesmadebyauthorsonmonochromaticandtunableterahertz(THz)generationbasedonnonlinearopticsarereviewed,includingTHzparametricoscillation(TPO)anddifferencefrequencygeneration(DFG).Fromthetechnicalpointofview,wedevelopextra-andintra-cavitysurface-emittedTPO,aswellasDFGwithQPM-GaAscrystal.Fromthepointofviewofmechanism,Cherenkovphase-matchingiscomprehensivelyinvestigatedinbothbulkcrystalandplanarwaveguide.AnovelschemeforcascadingenhancedCherenkovDFGinwaveguideisproposed.Fromthepointofviewofmaterial,organiccrystal4-N,N-dimethylamino-4’-N’-methyl-stibazoliumtosylate(DAST)isutilizedasthenonlinearmedium.

  • 标签: 非线性光学 太赫兹 可调谐 单色 GAAS晶体 平面波导
  • 简介:这篇论文基于inviscid和imcompressible液体和无旋的流动在液体/结构影响上论述工作的评论。焦点在和边界元素方法(BEM)的速度潜力理论上。充分非线性的边界条件在未知免费表面和动人的身体的弄湿的表面上被强加。评论包括(1)在常数或规定变化速度的身体的垂直、倾斜的水入口,以及免费秋天运动,(2)液体微滴或列影响以及波浪影响身体,(3)膨胀身体的类似答案。它盖住二维(2D),axisymmetric并且三维(3D)盒子。在数字模拟使用的关键技术被构画出,包括multivalued上的网孔产生免费表面,为扩展域的拉长的坐标系统,压力的相互的依赖和身体打手势的为去耦的辅助函数方法,并且为喷气或薄液体电影的处理在影响期间发展了。

  • 标签: 结构影响 拟流体 非线性模 自由落体运动 非线性边界条件 展望
  • 简介:Thebandwidthandthedurationofincidentpulsedbeamareprovedtoplayimportantrolesinmodifyingthenonlinearimageofamplitude-typescatterer.Itisfoundthattheinitiallypositivechirp-typebandwidthcansuppressthenonlinearimage,whilethenegativeonecanenhanceit,andthatbotheffectsareinverselyproportionaltotheincidentpulseduration.Numericalsimulationsfurtherdemonstratethatthelocationofnonlinearimageisattheconjugateplaneofthescattererandthat,fornegativelypre-chirpedpulsedbeam,thenonlinearimagepeakintensitycanbehigherthanthatinthecorrespondingmonochromaticcaseundercertainconditions.Moreovertheeffectofgroupvelocitydispersiononnonlinearimageisfoundtobesimilartothatofchirp-typebandwidth.

  • 标签: 非线性散射 预啁啾 脉冲激光束 图像 脉冲持续时间 脉冲光束