简介:Linearcomplexityandk-errorlinearcomplexityofthestreamcipheraretwoimportantstandardstoscaletherandomicityofkeystreams.Forthe2n-periodicperiodicbinarysequencewithlinearcomplexity2n1andk=2,3,thenumberofsequenceswithgivenk-errorlinearcomplexityandtheexpectedk-errorlinearcomplexityareprovided.Moreover,theproportionofthesequenceswhosek-errorlinearcomplexityisbiggerthantheexpectedvalueisanalyzed.
简介:Inordertomeettheneedsofhigh-speeddevelopmentofopticalcommunicationsystem,aconstructionmethodofquasi-cycliclow-densityparity-check(QC-LDPC)codesbasedonmultiplicativegroupoffinitefieldisproposed.TheTannergraphofparitycheckmatrixofthecodeconstructedbythismethodhasnocycleoflength4,anditcanmakesurethattheobtainedcodecangetagooddistanceproperty.Simulationresultsshowthatwhenthebiterrorrate(BER)is10-6,inthesamesimulationenvironment,thenetcodinggain(NCG)oftheproposedQC-LDPC(3780,3540)codewiththecoderateof93.7%inthispaperisimprovedby2.18dBand1.6dBrespectivelycomparedwiththoseoftheRS(255,239)codeinITU-TG.975andtheLDPC(32640,30592)codeinITU-TG.975.1.Inaddition,theNCGoftheproposedQC-LDPC(3780,3540)codeisrespectively0.2dBand0.4dBhighercomparedwiththoseoftheSG-QC-LDPC(3780,3540)codebasedonthetwodifferentsubgroupsinfinitefieldandtheAS-QC-LDPC(3780,3540)codebasedonthetwoarbitrarysetsofafinitefield.Thus,theproposedQC-LDPC(3780,3540)codeinthispapercanbewellappliedinopticalcommunicationsystems.
简介:Amethodofminimizingrankingsinconsistencyisproposedforadecision-makingproblemwithrankingsofalternativesgivenbymultipledecisionmakersaccordingtomultiplecriteria.Foreachcriteria,atfirst,thetotalinconsistencybetweentherankingsofallalternativesforthegroupandtheonesforeverydecisionmakerisdefinedafterthedecisionmakerweightsinrespecttothecriteriaareconsidered.Similarly,thetotalinconsistencybetweentheirfinalrankingsforthegroupandtheonesundereverycriteriaisdeterminedafterthecriteriaweightsaretakenintoaccount.Thentwononlinearintegerprogrammingmodelsminimizingrespectivelythetwototalinconsistenciesabovearedevelopedandthentransformedtotwodynamicprogrammingmodelstoobtainseparatelytherankingsofallalternativesforthegroupwithrespecttoeachcriteriaandtheirfinalrankings.Asupplierselectioncaseillustratedtheproposedmethod,andsomediscussionsontheresultsverifieditseffectiveness.Thisworkdevelopsanewmeasurementofordinalpreferences’inconsistencyinmulti-criteriagroupdecision-making(MCGDM)andextendsthecook-seifordsocialselectionfunctiontoMCGDMconsideringweightsofcriteriaanddecisionmakersandcanobtainuniquerankingresult.
简介:Theinfluenceofp-typeGaN(pGaN)thicknessonthelightoutputpower(LOP)andinternalquantumefficiency(IQE)oflightemittingdiode(LED)wasstudiedbyexperimentsandsimulations.TheLOPofGaN-basedLEDincreasesasthethicknessofpGaNlayerdecreasesfrom300nmto100nm,andthendecreasesasthethicknessdecreasesto50nm.TheLOPofLEDwith100-nm-thickpGaNincreasesby30.9%comparedwiththatoftheconventionalLEDwith300-nm-thickpGaN.ThevariationtrendofIQEissimilartothatofLOPasthedecreaseofGaNthickness.ThesimulationresultsdemonstratethatthehigherlightefficiencyofLEDwith100-nm-thickpGaNisascribedtotheimprovementsofthecarrierconcentrationsandrecombinationrates.
简介:随着国内半导体工艺水平的不断提高,固态合成功率放大器也开始大量的被应用到各种微波工程之中。目前国内多种固态合成功率放大器的产品皆以多路波导合成的方式获得大功率。在使用这些多路合成结构对大量功率器件进行功率合成时,一个或者多个器件的失效将对总体的输出功率造成多大的影响便成为了大家极其关心的性能指标。文章对固态功率合成器进行了理论的分析,通过计算推导出端口失效的模式。对两路合成器进行了仿真得到了失效50%会导致功率下降6dB的结论。并通过对八路波导合成功率放大器的失效模拟试验,验证了前面的计算分析。最后对试验中取得的数据进行比较分析得出了该数据在实际工程应用的作用。
简介:Inthispaper,anextendedKendallmodelforthepriorityschedulinginput-linegroupoutputwithmulti-channelinAsynchronousTransferMode(ATM)exchangesystemisproposedandthenthemeanmethodisusedtomodelmathematicallythenon-typicalnon-anticipativePRiorityservice(PR)model.Comparedwiththetypicalandnon-anticipativePRmodel,itexpressesthecharacteristicsofthepriorityschedulinginput-linegroupoutputwithmulti-channelinATMexchangesystem.ThesimulationexperimentshowsthatthismodelcanimprovetheHOLblockandtheperfonnanceofinput-queuedATMswitchnetworkdramatically.ThismodelhasabetterdevelopingprospectinATMexchangesystem.