简介：Avirtuallabsystemisthesimulationofrealdevicesandexperimentsusingcomputerandnetworktech-nology.Itcanmakeusersdoexperimentseasily,observeexperimentphenomenaandresultsthroughtheremotetermi-nal.Consequently,userscangetfinalresultstoverifyrelativetheory.Thearticleanalysesthefeaturesofvirtuallabsystems.Arealvirtuallabsystemnamed'MultimediaVirtualLabforDigitalCircuitLogicDesign(MVLDCLD)'whichhasbeendevelopedbytheauthorsandtheirgroupisalsopresented.

简介：DiscreteFourierTransform(DFT)basedmultiple-inputmultiple-outputOrthogonalFrequencyDivisionMultiplexing(MIMO-OFDM)isthefocusofwirelesscommunication,whichusescyclicprefixestoreducetheISI.Toimprovethespectrumefficiencyandsystemperformance,ComplexWaveletPacketTransform(CWPT)basedOFDMisusedtorealizetheMIMO-OFDMsystem.Forthegoodpropertyofcomplexwaveletpacketfunction,theCWPTbasedMIMO-OFDMsystemisbetterthantheDFTbasedMIMO-OFDMsystem,buttheCWPTbasedMIMO-OFDMschemehassomeadditionalcomplexity,andsimulationresultsshowthatthenewsystemcanimprovethesystemperformance.

简介：ThehardwarestructureandsoftwarefunctionofintelligencedoormonitoringcontrolsystemsonInternetisexpounded.Theremotemanagingfunction,databasefunction,andtherealizationofdialingusersareintroduced.Theresetcardisinstalledtoimprovereliability.Thedesignofthesystemisreasonableandreliable.Resultsshowedthat10percentofthelineinvestmenthavebeencutoff.

简介：Theperformanceofmassivemultiple-inputmultiple-output(MIMO)systemislimitedbypilotcontamination.Toreducethepilotcontamination,uplinkanddownlinkprecodingalgorithmsareputforwardbasedoninterferencealignmentcriterion.Intheuplinkreceivingprocessing,thetargetfunctionalignsthepilotcontaminationandtheinterferencesignalstothesamenullspaceandacquiresthemaximalspacedegreeofthedesiredsignals.Theuplinkreceivingprecodingmatrixissolvedonmaximalsignaltointerferenceplusnoiseratio(SINR)criterionconsideringtheimpactofthepilotcontaminationonchannelestimations.Theuplinkreceivingprecodingmatrixisusedasthedownlinktransmittingprecodingmatrix.Exploitingthechannelreciprocity,itisprovedthat,iftheuplinkreceivingprecodingmatrixachievesmaximalSINR,theidenticalprecodingmatrixcanbeusedinthedownlinktransmissionandacquiresmaximalsignaltoleakageplusnoiseratio(SLNR).Simulationsshowthatthespectrumefficiencyoftheproposedalgorithmcanreachabout1.5timeshigherthanthatofpopularmatchedfiltering(MF)precodingalgorithm,andabout1.1timeshigherthanmulti-cellminimummeansquareerror(MMSE)precodingalgorithm.Theperformanceoftheproposedalgorithmcanbeimprovedapproximatelylinearlywiththeincreasingofthenumberofantennas.

简介：Adynamicalsystemforcomputingtheellipticboundaryproblemispresented.Itisshownthattheproposedsystemisgloballyasymptoticallystable.Thesystemcanbesimulatedbyaneuralnetwork.Simulationresultsarevalidandsatisfactory.

简介：PlentyofworkhavebeendoneonSpace-Timeprocessinginwhichmultipletransmit/receiveantennasareusedinconjunctionwithcodingtoexploitbothspatialdiversityandtimediversity.ConstantModeAlgorithm(CMA)isanefficientblindadaptiveMulti-UserDetection(MUD)algorithmforCDMAsystems.Inthispaper,weputforwardanovelreceiver,whichcombinesCMAblindadaptiveMulti-userDetectionwithSTBCtechnique,andcomparetheperformancesofthesystemusingdifferentCMalgorithmsincludingSDCMA(Steepest-DescentCMA),StandardLinearityConfineCMA(SLCCMA)andLeastSquaresCMA(LSCMA).Simulationshavebeendonewithmulti-pathRayleighchannel.

简介：录像加速器在分享象YouTube那样的网站的录像为更好的用户经验被开发。PPLive录像加速器(PPVA)在中国有用户的最大的数字，基于对等(P2P)系统。在PPVA的录像和同伴的数字由比哪个多次大的数量级在需求(VoD)上的传统的P2P录像系统。作为结果，尽管资源是足够的，由于不公平赋值，服务的质量几乎不能满足所有用户。在这份报纸，我们在PPVA专注于基本资源的任务：存储和带宽。存储赋值的问题作为一个随机的变量关于请求的数字作为一个非线性的程序(NLP)被提出。当平均数比变化大得多时，请求的变化的影响不是可以忽略、比例的途径的结果表演仅仅是适当的。关于怎么定位录像到适当同伴的标准也被介绍，考虑抑制例如全部的带宽，带宽竞争的概率和在录像之间的公平的利用。而且，分配的启发式的算法以集中、分布式的时尚上载带宽被建议并且在录像之中关于平衡与广泛地使用的策略(相等的分配)作比较。模拟结果证明两个算法能导致重要表演改进。

简介：Asanimportantcomponentofinternetofthings,electronicproductcode(EPC)systemiswidelyusedinmanyareas.However,themassdeploymentofEPCsystemisfrequentlydegradedbysecurityandprivacyproblems.Therefore,themajorresearchesfocusonthedesignofasecureEPCsystemwithhighefficiency.ThispaperdiscussesthesecurityrequirementsofEPCsystemandpresentsauniversalcomposable(UC)modelforEPCsystem,theidealfunctionalityofEPCsystemisalsoformallydefinedwiththeUCframework.ThenasecureprotocolforEPCsystemunderUCframeworkisproposedandtheanalysisofsecurityandperformanceoftheproposedprotocolisgiven,incomparisonwithotherprotocols,theresultsshowthattheproposedprotocolisUCsecureandcanprovideprivacyprotection,untraceability,authorizedaccess,anonymityandconcurrentsecurityforEPCsystem.Furthermore,lesscomputationandstorageresourcearerequiredbytheproposedprotocol.

简介：Offlinenetworktrafficanalysisisveryimportantforanin-depthstudyupontheunderstandingofnetworkconditionsandcharacteristics,suchasuserbehaviorandabnormaltraffic.WiththerapidgrowthoftheamountofinformationontheInternet,thetraditionalstand-aloneanalysistoolsfacegreatchallengesinstoragecapacityandcomputingefficiency,butwhichistheadvantagesforHadoopcluster.Inthispaper,wedesignedanofflinetrafficanalysissystembasedonHadoop(OTASH),andproposedaMapReduce-basedalgorithmforTopNuserstatistics.Inaddition,westudiedthecomputingperformanceandfailuretoleranceinOTASH.FromtheexperimentswedrewtheconclusionthatOTASHissuitableforhandlinglargeamountsofflowdata,andarecompetenttocalculateinthecaseofsinglenodefailure.

简介：Inthispaper,thecapabilityofIEEE802.11bDistributedCoordinationFunction(DCF)modesupportingofConstantBitRate(CBR)andVariableBitRate(VBR)VoiceoverIP(VoIP)trafficisinvestigated.Then,thecapacityof802.11bWirelessLocalAreaNetwork(WLAN)systemcarryingvoicecallsinawiderangeofscenarios,includingvaryingdelayandpacketlossrateconstraintsisanalyzedandevaluated.BothG.711andG.729voiceencodingschemesandarangeofvoiceinter-arrivaltimeareconsidered.Theanalysesandsimulationresultsshowthatcapacityishighlysensitivetothedelaybudgetallocatedtothesumofpacketizationandwirelessnetworkdelays.Foragivenpacketlossrateconstrained,G.729isshowntohaveacapacitygreaterthanthatwhenG.711isused.ThesimulationresultsshowthatbysupportingVBRunderDCFmodethenetworkhastheapproximatelytwicemuchcapacityassupportingCBRhas,regardlessoftheencodingschemesandtheinter-arrivaltime.

简介：从4月1日起，中国移动在北京、上海、天津、沈阳、广州、深圳、厦门和秦皇岛8个城市正式启动国产3G技术TD-SCDMA（国产3G）的社会化测试和试商用，试商用的号段为157号段，首批放号总计6万个。

简介：在知识管理系统(KMS)解决这些问题例如信息分享，扩大的能力和re-engineer，和在分布式、异构的环境的遗产系统的可重用的能力。这篇文章基于设计KMS的代理人和本体论介绍一个方法。这个方法由二个机构组成。一个人是有支持知识管理过程的三个代理人的知识机构。其它是有支持知识申请的三个代理人的申请机构。在这个方法，本体论被用来在在代理人之中交换的消息在知识库和内容代表知识。表明这个方法的优点，实验被执行了，结果暗示这个方法为小、中等尺寸的企业有效、有效设计KMS。

简介：稀少的代码多重存取(SCMA)是为下一活动通讯的一个竞争nonorthogonal存取计划。作为分享系统的一个多用户，SCMA采用为在接收装置译码计划传递算法(MPA)的消息，但是它的反复的方法导致高计算的复杂性。因此，基于可变节点(VMPA)传递算法的一条连续消息在这份报纸被建议。在原来的MPA使一些成为微妙的改变到消息更改，VMPA能极大地减少译码计划的全面计算复杂性。而且，考虑那连续结构可以增加译码延期，一个新奇组织计划基于稀少的矩阵被用于VMPA。模拟结果证实新算法，作为组织VMPA(G-VMPA)称为，能比MPA完成在小点错误率(BER)和计算复杂性之间的更好的折衷。

简介：为解决传统的地质灾害分类方法中效率低下的现状，本文将模式分类中的相应方法引入到基于雷达数据分析的地质灾害分类算法中。利用PCA降维算法和KNN分类算法构建分类模型，之后利用现有雷达数据进行训练得出模型参数，最后将需要测试的数据集放入模型进行实验，经过测试发现模型处理速度明显提高，精度符合要求。

简介：我院在邮电部〔1994〕《关于通信设施建设若干政策规定》(简称3号文件)下达后,多次召开院长办公会议和院科技委员会进行研究落实,并列入1994年工作要点来贯彻。主要抓了三方面。

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简介：Theimpactofmutualcouplingontheperformanceofmultiple-inputmultiple-output(MIMO)systemswithcompactantennaarraysisanalyzed.ThisarticleaimstousetheS-parametermodelingapproachtoexaminetheimpactofmutualcouplingonthreesystem-relatedperformancemeasures:antennacorrelation,efficiencyandbandwidth.Itisshownthatimplementingagoodmatchingnetworkcandrasticallyimprovethesystemperformanceinthepresenceofstrongmutualcoupling.Experimentresultsindicatethesuperiorityofcross-shapedantennatodipoleantenna.

简介：Indownlinkcoordinatedmulti-point(CoMP)system,fullcooperationisalwaysnotapplicableinrealworldbecauseofitshighrequestinthebackhaul.Todealwiththisproblem,clusteringdecisionismadetoprocesstransmission.Inthispaperclusteringmethodsbasedonthemetricsignal-to-leakage-plus-noise(SLNR)isproposed.Inaddition,userschedulingschemesbasedonSLNRisalsoputuptomaketheschedulingsetaslargeaspossible.Simulationresultsshowthattheproposedclusteringmethodsnotonlyreducethedatasharingamongthecooperatingbasestations(BSs),butalsoimprovethesystemthroughputcomparedwiththetraditionalclusteringmethodsbasedonchannelstrength.

简介：Inthispaper,thefeedbackloadreductionprobleminwirelesssystemsbasedonorthogonalfrequencydivisionmultiplexing(OFDM)isinvestigatedandanopportunisticfeedbackscheme(OFS)isproposed.ThekeyideabehindOFSisthatonlythekeychannelgainswhichcansignificantlyaffectthesystemthroughputarefedbacktotheBS.Firstly,thekeychannelgainsareprovedtobelongtoachannelgaininterval.Secondly,astatisticalmethodisproposedtoestimatethechannelgaininterval.Thirdly,theopportunisticfeedbackschemeisformulatedandthefeedbackloadofOFSisanalyzed.TheadvantageofOFSisthreefold:thefirstisOFScanworkinbothOFDM-basedmulticastsystemandOFDM-basedunicastsystem.ThesecondisthechannelfadingtypeoftheBS-userlinkisnotrequired,whichismorerealistic.ThethirdisOFScangetbetterfeedbackloadperformancecomparedwithotherschemes,whileachievingalmostthesamethroughputperformancecomparedwiththatoffullfeedbackscheme.

简介：ThispaperstudiesthepowercontrolprobleminfemtocellsystembasedonNashnon-cooperativegametheory.Itdesignsanutilityfunctiontakingfemstations'transmitpowerasvariableandrelatesittotherequirementsofmacrousers'andfemusers'signaltointerferenceplusnoiseratio(SINR).Theutilityalsotakestheimpactoffemstations'locationintoaccountandimprovesthefairnessofnon-cooperativegame.Onthisbasis,thispaperproposesadistributedpowercontrolalgorithmandprovestheexistenceanduniquenessofParetooptimalpoint.Thesimulationresultsshowthatthealgorithmimprovestheconvergencespeedandsystemperformancethroughimprovingusers'SINR.