简介：

简介：

简介：Thebettercompressionratecanbeachievedbythetraditionalvectorquantization(VQ)method,andthequalityoftherecoveredimagecanalsobeaccepted.Butthedecompressedimagequalitycannotbepromotedefficiently,sohowtobalancetheimagecompressionrateandimagerecoveringqualityisanimportantissue.Inthispaper,animageistransformedbydiscretewavelettransform(DWT)togenerateitsDWTtransformedimagewhichcanbecompressedbytheVQmethodfurther.Besides,wecomputethevaluesbetweentheDWTtransformedimageanddecompressedDWTtransformedimageasthedifferencematrixwhichistheadjustablebasisofthedecompressedimagequality.Bycontrollingthedeviationofthedifferencematrix,therecanbenearlylosslesscompressionfortheVQmethod.ExperimentalresultsshowthatwhenthenumberofcompressedbitsbyourmethodisequaltothenumberofthosebitscompressedbytheVQmethod,thequalityofourrecoveredimageisbetter.Moreover,theproposedmethodhasmorecompressioncapabilitycomparingwiththeVQscheme.

简介：Acrucialsystemfortheoperationofhigh-speedtrainsisthepantographcatenaryinterfaceasitisthesoleresponsibletodeliverelectricalpowertothetrain.Beingthecatenaryastationarysystemwithalonglifespanitisalsolesslikelytoberedesignedandupgradedthanthepantographsthatfitthetrainvehicles.Thisletterproposesanoptimizationprocedurefortheimprovementofthecontactqualitybetweenthepantographandthecatenarysolelybasedontheredesignofthepantographheadsuspensioncharacteristics.Apantographmodelisdefinedandvalidatedagainstexperimentaldynamiccharacteristicsofexistingpantographs.Anoptimizationstrategybasedontheuseofaglobaloptimizationmethod,tofindthevicinityoftheoptimalsolution,followedbytheuseofadeterministicoptimizationalgorithm,tofinetunetheoptimalsolution,isappliedhere.Thespringstiffness,dampingcharacteristicsandbowmassarethedesignvariablesusedforthepantographoptimization.Theobjectiveoftheoptimalproblemistheminimizationofthestandarddeviationofthecontactforcehistory,whichisthemostimportantquantitytodefinethecontactquality.Thepantographheadsuspensioncharacteristicsareallowedtovarywithintechnologicalrealisticlimits.Itisfoundthatcurrenthigh-speedrailwaypantographshavealimitedpotentialformechanicalimprovements,notexceeding10%-15%onthedecreaseofthestandarddeviationofthecontactforce.

简介：Inthiscontribution,insideturningofathin-walledcylinderisinvestigatedinsimulation.Self-excitedvibrationscanariseduetorepeatedcuttingofthesamesurface,thatleadtoinstability.Aflexiblemultibodysystemmodelofthesystemisthebasisforasubsequentanalysisofthestabilityoftheprocess.Stabilityanalysisisdoneusinganapproximationasatime-discretesystemviathesemi-discretizationmethod.Anadaptronicturningchiselcomprisingapiezoactuatorandsensorsisthenusedincombinationwithdifferentcontrolconceptstoimprovethestabilityoftheprocess.Theeffectivenessofthedifferentstrategiesiscomparedbasedontheinfluenceonthestabilitycharts.AclassicH∞controllerbasedonamodelofthecoupledsystemofworkpieceandtoolcanonlyyieldsomeimprovements,whenanadditionalmeasurementoftheworkpiecedisplacementisadded.IncorporatingknowledgeonthecuttingprocesscouplingworkpieceandtoolusingagainscheduledH∞controllerallowsfurtherimprovements.However,robustnesswithrespecttomodeluncertainties,notablyconcerningtheforcelaw,remainsanissue.

简介：为了调查autoclaved的地震行为，给忍受负担的石工技术墙(AACLMW)，没有构造上的措施的一面控制块墙和五块与不同构造上的措施围的水泥充气了被测试在下面低颠倒的周期的装载它模仿了对中等地震力量低。有不同构造上的措施的AACLMW的地震行为以失败模式，hysteretic曲线，变丑能力和排水量韧性被学习并且与那相比没有构造上的措施。试验性的结果显示包括构造上的柱和水平具体脱衣的构造上的措施为改进AACLMW的地震行为是有效的。在这份报纸的学习以后能为进一步的分析和AACLMW的工程申请提供一个可靠试验性的基础。