简介:LetB(H)bethealgebraofalltheboundedlinearoperatorsonaHilbertspaceH.ForA,PandQinB(H),ifthereexistsanoperatorX∈B(H)suchthatAPXQA=A,XQAPX=X,(QAPX)*=QAPXand(XQAP)*=XQAP,thenXissaidtobetheΓ-inverseofAassociatedwithPandQ,anddenotedbyAP,Q+.Inthisnote,wepresentsomenecessaryandsu?cientconditionsforwhichA+P,Qexists,andgiveanexplicitrepresentationofAP,Q+(ifAP,Q+exists).
简介:Letp(z)=akzkbesuchthat|p(eip)|≤1forRand|p(1)|=a[0,1].AninequalityofDewanandCavilforthesum|av|+|au|,0≤u
简介:Vibrationofacircularmembraneincontactwithafluidhasextensiveapplicationsinindustry.Thenaturalvibrationfrequenciesfortheasymmetricfreevibrationofacircularmembraneincontactwithaboundedincompressiblefluidarederivedinthispaper.Consideringsmalloscillationsinducedbythemembranevibrationinanincompressibleandinviscidfluid,thevelocitypotentialfunctionisusedtodescribethefluidfield.Twoapproachesareusedtoderivethefreevibrationfrequenciesofthesystem,whichincludeavariationalformulationandanapproximatesolutionemployingtheRayleighquotientmethod.Agoodcorrelationisfoundbetweenfreevibrationfrequenciesevaluatedbythesemethods.Finally,theeffectsofthefluiddepth,themassdensity,andtheradialtensiononthefreevibrationfrequenciesofthecoupledsystemareinvestigated.
简介:SAT-basedboundedmodelchecking(BMC)hasbeenintroducedasacomplementarytechniquetoBDD-basedsymbolicmodelcheckinginrecentyears,andalotofsuccessfulworkhasbeendoneinthisdirection.TheapproachwasfirstintroducedbyA.Biereetal.incheckinglineartemporallogic(LTL)formulaeandthenalsoadaptedtocheckformulaeoftheuniversalfragmentofcomputationtreelogic(ACTL)byW.Penczeketal.Astheefficiencyofmodelcheckingisstillanimportantissue,wepresentanimprovedBMCapproachforACTLbasedonPenczek'smethod.Weconsidertwoaspectsoftheapproach.Oneisreductionofthenumberofvariablesandtransitionsinthek-modelbydistinguishingthetemporaloperatorEXfromtheothers.Theotherissimplificationofthetransformationofformulaebyusinguniformpathencodinginsteadofadisjunctionofallpathsneededinthek-model.Withtheseimprovements,foranACTLformula,thelengthofthefinalencodingoftheformulaintheworstcaseisreduced.TheimprovedapproachisimplementedinthetoolBMVandiscomparedwiththeoriginalonebyapplyingbothtotwowellknownexamples,mutualexclusionanddiningphilosophers.Thecomparisonshowstheadvantagesoftheimprovedapproachwithrespecttotheefficiencyofmodelchecking.
简介:Thescalingandsimilarityofwallboundedturbulentflowwerestudied.Thepropertiesofsuchflowsandtherelationshipbetweenapowerlawandalogarithmictypeofvelocitydistributionwereinvestigated.Basedonthephysicalmechanisminvolved,ourresultsshowthatthepowerlawandthelogarithmicdistributionareonlydifferentformswiththesamehypothesisandholdonlyintheouterflowzone.Thus,auniversalexplanationforvariousempiricalformulaeofvelocitydistributionwasobtained.Manning’sformulawasstudiedtoexplaintheoreticallytheexperientialresultthattheroughnesscoefficientisonlyacomprehensiveparameterofthewholesystemwithoutacorrespondingphysicalfactor.Thephysicalmechanismofthevelocitydistributionofparalleltowallboundedflowwasexplored,theresultsshowthattheparametersintheformulaofvelocitydistributionareindicesofthesystemrespondingtoflowingenvironmentalfactorstorepresentgeneralcaseofboundaryroughnessandtheflowingstate,correspondingphysicalmechanismisvortexmotion.
简介:Theboundedparameterestimationproblemanditssolutionleadtomoiemeaningfulresults.Itssuperiorperformanceisduetothefactthatthenewmethodguaranteesthattheeffectoftheuncertaintieswillneverbeunnecessarilyoverestimated.Wethenconsiderhowtoupdateanddowndatetheboundedparameterestimationproblem.WhenupdatinganddowndatingofSVDareusedtothenewproblem,specialtechnologiesaretakentoavoidformingUandVexplicitly,thenincreasethealgorithmperformance.BecauseofthelinkbetweentheboundedparameterestimationandTikhonovregularizationprocedure,wepointoutthatouralgorithmscanalsobeusedtomodifyregularizationproblem.
简介:Turbulencepropertiesofawall-boundedturbulentmixinglayerassociatedwithanopeningstepwereextensivelymeasuredusingI-andX-typehotwires.Theturbulentmixinglayerflowwasanalyzedintermsofwallstaticpressuredistribution,turbulenceintensity,Reynoldsstress,streamwisevelocityprofileandcontinuouswavelettransformcoefficients.Developmentofvorticalstructuresembeddedintheturbulentmixinglayerwastemporallyandspatiallyresolvedbyusingcontinuouswavelettransform.Theconstraintofthedownstreamsolidwallonthemixinglayerflowwasdelineated.
简介:ThispaperpresentsanewfamilyofsolutionstothesingularlyperturbedAllen-Cahnequationα~2Δu+u(1-u~2)=0inasmoothboundeddomainΩR~3,withNeumannboundaryconditionandα>0asmallparameter.Thesesolutionshavethepropertythatasα→0,theirlevelsetscollapseontoaboundedportionofacompleteembeddedminimalsurfacewithfinitetotalcurvatureintersecting?Ωorthogonallyandthatisnon-degeneraterespectto?Ω.Theauthorsprovideexplicitexamplesofsurfacestowhichtheresultapplies.
简介:Inthispaper,thenotionoftheboundedcompactapproximationproperty(BCAP)ofapair[Banachspaceanditssubspace]isusedtoprovethatifXisaclosedsubspaceofL∞withtheBCAP,thenL∞/XhastheBCAP.WealsoshowthatX*hastheλ-BCAPwithconjugateoperatorsifandonlyifthepair(X,Y)hastheλ-BCAPforeachfinitecodimensionalsubspaceY∈X.LetMbeaclosedsubspaceofXsuchthatM⊥iscomplementedinX*.IfXhasthe(bounded)approximationpropertyoforderp,thenMhasthe(bounded)approximationpropertyoforderp.
简介:一个概括控制器基于不可思议地使不安的系统的稳定性理论被建议,到在机器人轨道追踪处理围住的致动器输入的问题控制。有错误获得矩阵的浸透功能在转矩控制法律被使用,它在任何给定的有限范围保证转矩输入的上面的界限。通过适当地设置错误获得矩阵的条目,追踪的性能能被改进。而且,一个假信号从一个线性过滤器被产生代替实际速度错误,为速度大小消除需要。最后,验证概括控制器的有效性,有error-gain-contained弧正切功能的一个新浸透的控制器被设计。建议控制器能严格地保证转矩的界限得到的比较实验表演与非零处于状况输入起始的追踪错误,并且比另外的控制器给更好的追踪结果。
简介:LetDbeaboundedC3-domaininRdand(aij)beaboundedsymmetricmatrixdefinedonD.Considerthesymmetricform(u,v)=1/2∫Daij(x)(u(x))/(xi)(v(x))/(xj)dx,u,v∈H1(D).UndersomeassumptionsitisshownthatthediffusionprocessassociatedwiththeregularDirichletspace(,(H1(D))onL2(D)canbecharacterizedasauniquesolutionofacertainstochasticdifferentialequation.
简介:InthisarticlewestudyholomorphicisometriesofthePoincar'ediskintoboundedsymmetricdomains.EarlierwesolvedtheproblemofanalyticcontinuationofgermsofholomorphicmapsbetweenboundeddomainswhichareisometriesuptonormalizingconstantswithrespecttotheBergmanmetric,showinginparticularthatthegraphV0ofanygermofholomorphicisometryofthePoincar'ediskΔintoanirreducibleboundedsymmetricdomainΩ€CNinitsHarish-Chandrarealizationmustextendtoanaffine-algebraicsubvarietyVC×CN=CN+1,andthattheirreduciblecomponentofV∩(Δ×Ω)containingV0isthegraphofaproperholomorphicisometricembeddingF:Δ→Ω.Inthisarticlewestudyholomorphicisometricembeddingswhichareasymptoticallygeodesicatageneralboundarypointb∈Δ.Startingwiththestructuralequationforholomor-phicisometriesarisingfromtheGaussequation,weobtainbycovariantdifferentiationanidentityrelatingcertainholomorphicbisectionalcurvaturestotheboundarybehaviorofthesecondfundamentalformσoftheholomorphicisometricembedding.Usingthenonpositivityofholomorphicbisectionalcurvaturesonaboundedsymmetricdomain,weprovethatσmustvanishatageneralboundarypointeithertotheorder1ortotheorder21,calledaholomorphicisometryofthefirstresp.secondkind.Wedealwithspecialcasesofnon-standardholomorphicisometricembeddingsofsuchmaps,showingthattheymustbeasymptoticallytotallygeodesicatageneralboundarypointandinfactofthefirstkindwheneverthetargetdomainisaCartesianproductofcomplexunitballs.WealsostudytheboundarybehaviorofanexampleofholomorphicisometricembeddingfromthePoincar'ediskintoaSiegelupperhalf-planebyanexplicitdeterminationoftheboundarybehaviorofholomorphicsectionalcurvaturesinthedirectionstangenttotheembeddedPoincar'edisk,showingthatthemapisindeedasymptoticallytotallygeodesicatageneralboundarypointandofthefirstkind.Fo