学科分类
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35 个结果
  • 简介:Recently,Changetal.proposedaSudoku-basedsecretimagesharingscheme.TheyutilizedtheSudokugridtogeneratemeaningfulshadowimages,andtheirschemesatisfiedallessentialrequirements.BasedonChangetal.'sscheme,weproposeanovel(n,n)secretimagesharingschemebasedonSudoku.Intheproposedscheme,asecretimagecanbesharedamongndifferentcoverimagesbygeneratingnshadowimages,andthesecretimagecanbereconstructedwithoutdistortionusingonlythesenshadowimages.Also,theproposedschemecansolvetheoverflowandunderflowproblems.Theexperimentalresultsshowthatthevisualqualityoftheshadowimagesissatisfactory.Furthermore,theproposedschemeallowsforalargeembeddingcapacity.

  • 标签: 图像共享 视觉质量 阴影 不失真 子图像 大容量
  • 简介:InviewofthelimitationsofaRn-GnmodelinthelowfrequencyrangeandthedefectsofanEn-Inmodelincommonusenow,thispaperbuildsacompleteEn-Inmodelaccordingtothetheoryofrandomharmonic.Theparametersforthelow-noisedesignsuchastheequivalentinputnoisyvoltageEns,theoptimumsourceimpedanceZsoptandtheminimumnoisefigureFmincanbecalculatedaccuratelybyusingthisEn-Inmodelbecauseitconsidersthecoherencebetweenthenoisesourcesfully.Moreover,thispaperpointsoutthatitwillcausethemaximum30%miscalculationwhenneglectingtheeffectsofthecorrelationcoefficient7.Usingtheseries-seriescircuitsasanexample,thispaperdiscussesthemethodsfortheEn-InnoiseanalysisofelectroniccircuitspreliminarilyanddemonstratesitscorrectnessthroughthecomparisonbetweenthesimulatedandmeasuredresultsoftheminimumnoisefigureFminofasinglecurrentseriesnegativefeedbackcircuit.

  • 标签: En-In MODEL LOW-FREQUENCY CIRCUITS LOW-NOISE DESIGN
  • 简介:n类型的坚持的光导增益(PPC)现象轧了电影成年bymetalorganic化学药品蒸汽免职(MOCVD)被学习了。在使用一些测试和分析方法以后,例如双水晶X光检查衍射(DCXRD),光致发光(PL)系列,等等,在n类型的PPC轧了影响的问题不相对脱臼和黄乐队(YB),这被发现,并且被Si的做的水平很可能引起。

  • 标签: MOCVD GAN DCXRD 光致发光 光电导率
  • 简介:Linearcomplexityandk-errorlinearcomplexityofthestreamcipheraretwoimportantstandardstoscaletherandomicityofkeystreams.Forthe2n-periodicperiodicbinarysequencewithlinearcomplexity2n1andk=2,3,thenumberofsequenceswithgivenk-errorlinearcomplexityandtheexpectedk-errorlinearcomplexityareprovided.Moreover,theproportionofthesequenceswhosek-errorlinearcomplexityisbiggerthantheexpectedvalueisanalyzed.

  • 标签: 2-误差线性复杂性 周期二进制序列 k-误差线性复杂性 线性反馈移位寄存器 流密码
  • 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.

  • 标签: 发光二极管 GA 厚度 光学性质 P型 光输出功率
  • 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。

  • 标签: 固态功率放大器 功率合成 失效分析
  • 简介:文章对0.5μm/40V高压工艺中形成的N阱电阻的SPICE模型进行研究。因为高压电路的实际应用,N阱电阻的寄生效应不可忽略,所以精确反应其电学特性的SPICE模型也显得尤为重要。从N阱电阻的测量结果反映其IV曲线的非线性特性和结型栅场效应管JFET输出特性曲线具有相似性,并通过对高压阱电阻与JFET的结构分析认为可以采用JFET的电压电流关系来建立合理的数学模型反映高压阱电阻的这种非线性特性。因此在文中借用JFET的SPICE模型作为基础,用宏模型的方法为高压N阱电阻建立了一套精确的SPICE模型、此模型适用于各类仿真器,具有一定的通用性.

  • 标签: 高压N阱电阻 SPICE模型 结型栅场效应管JFET
  • 简介:最高的接触n类型有低操作电压的器官的地效果晶体管被采用Ta2O5/PMMA作为双绝缘体和PTCDI-C12作为半导体活跃的层。Ta2O5层被使用简单节俭的阳极化技术准备,PMMA层被使用纺纱涂层方法准备。与有单个Ta2O5绝缘体,有两倍绝缘体的设备显示出显然更好的电的性能。它有0.063厘米2/Vs,的地效果电子活动性1.7×1的开/关比率04和2.3V的阀值电压。

  • 标签: 场效应器件 电压 双绝缘体 半导体
  • 简介:Photoluminescenceevaluationofpandntype6H-SiCsampleshasbeendone.Resultsshowthatatlowtemperaturethephotoluminescenceof6H-SiCisclearlydominatedbydonor-acceptorpairtransitions,insomecase,free-to-donortransitioncouldbeobservedathighertemperature.Thethermalquenchingprocessesofthephotoluminescencehavebeeninvestigatedtodeterminethepossibleionizationnenergiesoftheimpurities.

  • 标签: 光致发光 估算 碳化硅
  • 简介:Intheopennetworkenvironment,maliciousattackstothetrustmodelhavebecomeincreasinglyserious.Comparedwithsinglenodeattacks,collusionattacksdomoreharmtothetrustmodel.Tosolvethisproblem,acollusiondetectorbasedontheGNalgorithmforthetrustevaluationmodelisproposedintheopenInternetenvironment.Byanalyzingthebehavioralcharacteristicsofcollusiongroups,theconceptofflattingisdefinedandtheG-Ncommunityminingalgorithmisusedtodividesuspiciouscommunities.Onthisbasis,acollusioncommunitydetectormethodisproposedbasedonthebreakingstrengthofsuspiciouscommunities.Simulationresultsshowthatthemodelhashighrecognitionaccuracyinidentifyingcollusionnodes,soastoeffectivelydefendagainstmaliciousattacksofcollusionnodes.

  • 标签: 信任模型 挖掘算法 探测器 恶意攻击 网络环境 识别精度
  • 简介:Animprovedgeneticalgorithmforsearchingoptimalparametersinn-dimensionalspaceispresented,whichencodesmovementdirectionanddistanceandsearchesfromcoarsetoprecise.Thealgorithmcanrealizeglobaloptimizationandimprovethesearchefficiency,andcanbeappliedeffectivelyinindustrialoptimization,dataminingandpatternrecognition.

  • 标签: 遗传算法 数据收集 计算机集成制造系统
  • 简介:ThisletterpresentsanewchunkingmethodbasedonMaximumEntropy(ME)modelwithN-foldtemplatecorrectionmodel.Firsttwotypesofmachinelearningmodelsaredescribed.Basedontheanalysisofthetwomodels,thenthechunkingmodelwhichcombinestheprofitsofconditionalprobabilitymodelandrulebasedmodelisproposed.Theselectionoffeaturesandruletemplatesinthechunkingmodelisdiscussed.ExperimentalresultsfortheCoNLL-2000corpusshowthatthisapproachachievesimpressiveaccuracyintermsoftheF-score:92.93%.ComparedwiththeMEmodelandMEMarkovmodel,thenewchunkingmodelachievesbetterperformance.

  • 标签: 程序分块 最大熵模型 模板修正 确认系统
  • 简介:Blindrecognitionofconvolutionalcodesisnotonlyessentialforcognitiveradio,butalsofornon-cooperativecontext.Thispaperisdedicatedtotheblindidentificationofratek/nconvolutionalencodersinanoisycontextbasedonWalsh-Hadamardtransformationandblockmatrix(WHT-BM).Theproposedalgorithmconstructsasystemofnoisylinearequationsandutilizesallitscoefficientstorecoverparitycheckmatrix.Itisabletomakeuseoffault-tolerantfeatureofWHT,thusprovidingmoreaccurateresultsandachievingbettererrorperformanceinhighrawbiterrorrate(BER)regions.Moreover,itismorecomputationallyefficientwiththeuseoftheblockmatrix(BM)method.

  • 标签: BLIND RECOGNITION convolutional code Walsh-Hadamard TRANSFORMATION
  • 简介:AgeneralizedspectralGreen’sfunctionformulationofN-layersubstratestructureisgivenwiththreedimensionsources,whichisasetofclosedformformulas.Afull-waveanalysismodelforrectangularmicrostripantennascoveredwithN-dielectriclayershasbeenestablishedbyusingtheabovespectralGreen’sfunction.Theunknownsurfacecurrentdensityontheniicrostrippatchforsuchstructureisfoundasasolutionofanintegralequation.TheinputVSWRandradiationpatternsoftheantennaarealsoobtained.Thenumericalresultshavebeenverifiedbytheexperimentalresults.

  • 标签: MICROSTRIP ANTENNA N-layer dielectric cover Full-wave
  • 简介:Coexistenceandinteroperabilitybetween20MHzand40MHzdeviceandmodesofop-erationsarestressedinstandardIEEE802.11nsystem.Itismandatetoreportthebothsub-channelsstatestoMediumAccessControl(MAC)atreceiver,sincefor40MHzdevice,itshouldservenotonly20MHzbutalso40MHzsignalsreceiving.Bothenergydetectionandcarriersenseareemployedtodetectchannelstate.Inthecaseof20/40Mmode,thepowerdifferencebetweenthetwosub-channelsisalsodetectedinordertoreportthechannelstateaccurately.Thesimulationresultsdemonstratethattheperformanceoftheproposedmethodsaremuchbetterthanthemethodswhichjustemployenergydetection.Besides,thesimulationresultsshowthattheproposedmethodsensurethatthechannelsensingisnotaroadblockofIEEE802.11nsystemdesign.

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  • 简介:TheanalysisofsolarcellperformancehasbeendonebysimulatingtheexternalI-Vcharacteristicsofn^+/p/p^+singlecrystalsiliconsolarcellunderhighlightintensityand1.5airmass(AM).Thismethodallowsthemaximizationofsolarcellefficiency.Tofabricatelow-costn^+/p/p^+singlecrystalsiliconsolarcells,solidsourceofdopedphosphorousandboronwasused.

  • 标签: 单晶硅 太阳能电池 效率 伏安特性曲线
  • 简介:<正>Diodes公司推出同步MOSFET控制器ZXGD3104N8,其额定电压为25V,适用于90W及以上的笔记本和便携式电脑的电源设计。这款新品能取代返驰式转换器内效率较低的肖特基二极管,并通过减少多达70%的整流器损耗,有效提升最高达3.5%的电源效率。因此,该器件有助电源供应系统更容易达到能源之星V2.0所规定的电源平均效率需达到87%的评级要求。

  • 标签: DIODES ZXGD3104N 肖特基二极管 电源设计 电源供应 电源效率
  • 简介:ThispaperinvestigatesthedesignofdigitalSigma-DeltaModulator(SDM)forfractional-Nfrequencysynthesizer.CharacteristicsofSDMsarecomparedthroughtheoryanalysisandsimulation.Thecurveofmaximum-loop-bandwidthvs.maximum-phase-noiseissuggestedtobeanewcriteriontotheperformanceofSDM,whichgreatlyhelpsdesignerstoselectanappropriateSDMstructuretomeettheirrealapplicationrequirementsandtoreducethecostaslowaspossible.Alow-spur3-orderMul-tistageNoiseShaping(MASH)-1-1-1SDMusingthree2-bitfirst-ordercascadedmodulatorsisproposed,whichbalancestherequirementsoftone-freeandmaximumoperationfrequency.

  • 标签: 频率合成器 非整数锁相回路 Σ-Δ调制器 比较研究