简介：Thisarticlepresentsadatamanagementsolutionbasedonthedatadistributionservice(DDS)communicationmodel.ThebasicDDScommunicationmodelconsistsofaunidirectionaldataexchangewhereapplicationsthatpublishdata'push'therelevantdata,whichisupdatedtothelocalcachesofco-locatedsubscriberstothedata[1].DDShasnospecifiedcenternodetoforwarddatapacketsandmaintainthecommunicationdata.Thistypeofpublish-subscribe(P/S)modelpresentsintegrityandconsistencychallengesindatamanagement.Unlikepeer-to-peer(P2P)distributedstorage,DDSapplicationshaveahardreal-timeenvironmentandfewerdatafeatures,andthecoreproblemisensuringtheintegrityandconsistencyofdataindistributedsystemsunderthishardreal-timeenvironment.ThisarticlebeginswithabriefintroductionofthecommunicationmodelusedbyDDS,thenanalyzespersistentdatamanagementproblemscausedbysuchmodel,andprovidesanappropriatesolutiontotheseproblems.Thissolutionhasbeenimplementedinaprototypesystemofthereal-timeservicebus(RTSB)ofTsinghuaUniversity.

简介：Acompressionalgorithmisproposedinthispaperforreducingthesizeofsensordata.Byusingadictionary-basedlosslesscompressionalgorithm,sensordatacanbecompressedefficientlyandinterpretedwithoutdecompressing.Thecorrelationbetweenredundancyofsensordataandcompressionratioisexplored.Further,aparallelcompressionalgorithmbasedonMapReduce[1]isproposed.Meanwhile,datapartitionerwhichplaysanimportantroleinperformanceofMapReduceapplicationisdiscussedalongwithperformanceevaluationcriteriaproposedinthispaper.Experimentsdemonstratethatrandomsamplerissuitableforhighlyredundantsensordataandtheproposedcompressionalgorithmscancompressthosehighlyredundantsensordataefficiently.

简介：Networktrafficclassificationaimsatidentifyingtheapplicationtypesofnetworkpackets.ItisimportantforInternetserviceproviders(ISPs)tomanagebandwidthresourcesandensurethequalityofservicefordifferentnetworkapplications.However,mostclassificationtechniquesusingmachinelearningonlyfocusonhighflowaccuracyandignorebyteaccuracy.TheclassifierwouldobtainlowclassificationperformanceforelephantflowsastheimbalancebetweenelephantflowsandmiceflowsonInternet.Theelephantflows,however,consumemuchmorebandwidththanmiceflows.Whentheclassifierisdeployedfortrafficpolicing,thenetworkmanagementsystemcannotpenalizeelephantflowsandavoidnetworkcongestioneffectively.Thisarticleexploresthefactorsrelatedtolowbyteaccuracy,andsecondly,itpresentsanewtrafficclassificationmethodtoimprovebyteaccuracyattheaidofdatacleaning.Experimentsarecarriedoutonthreegroupsofreal-worldtrafficdatasets,andthemethodiscomparedwithexistingworkontheperformanceofimprovingbyteaccuracy.Experimentshowsthatbyteaccuracyincreasedbyabout22.31%onaverage.Themethodoutperformstheexistingoneinmostcases.

简介：在无损失的压缩的地里，当他们面对集体数据时，传统的软件的大多数类型有一些缺乏。他们的压缩能力被数据窗口尺寸和压缩格式设计限制。这份报纸论述格式说出支持数据窗户尺寸直到4GB并且在集体数据压缩有一些优点的CZ格式的压缩的一个新图案。用这种格式，一个压缩共享软件说出ComZip被设计。实验结果支持那ComZip在大多数情况中比WinZip，Bzip2和WinRAR有更好的压缩比率，特别当集体数据的GB或TB被压缩时。并且ComZip有潜力当数据窗户尺寸超过128MB，在未来打败7压缩。

简介：Timelyandcost-efficientmulti-hopdatadeliveryamongvehiclesisessentialforvehicularad-hocnetworks(VANETs),andvariousroutingprotocolsareenvisionedforinfrastructure-lessvehicle-to-vehicle(V2V)communications.Generally,whenapacket(oraduplicate)isdeliveredoutoftheroutingpath,itwillbedropped.However,weobservethatthesepackets(orduplicates)mayalsobedeliveredmuchfasterthanthepacketsdeliveredalongtheoriginalroutingpath.Inthispaper,weproposeanoveltreebasedroutingscheme(TBRS)forultilizingthedroppedpacketsinVANETs.InTBRS,thepacketisdeliveredalongaroutingtreewiththedestinationasitsroot.Andwhenthepacketisdeliveredoutitsroutingtree,itwon'tbedroptimmediatelyandwillbedeliveredforawhileifitcanarriveatanotherbranchofthetree.WeconducttheextensivesimulationstoevaluatetheperformanceofTBRSbasedontheroadmapofarealcitycollectedfromGoogleEarth.ThesimulationresultsshowthatTBRScanoutperformtheexistingprotocols,especiallywhenthenetworkresourcesarelimited.

简介：AnorthogonallymultiplexedQAM(OQAM)systemallowstransmissionspeedtobeveryclosetotheNyquistratewithlittlesensitivitytodelayandsignaldistortionsoftransmissionmediumwhenalargenumberofchannelsareused.Itscircuitcomplexitycanbelargelyovercomebyintroducingdigitalsignalprocessing(DSP)technology,Inthispaper,theimplementationofgroupbanddatamodemusingOQAMtechniqueispresented,whereOQAMsystemisrealizedbymeansofcascadingadiscretecosinetransformer(DCT)andaweightingnetwork.TheproperalgorithmofevaluatingFIRfilterandDCTprovidesfurtherreductionofthecomputationcomplexitywhichdropsto35.6%ofthatofHirosaki'sscheme[5].

简介：Toimprovedatacacheperformance,optimizingprogramdatalayoutbydatareorganizationhasbecomeanimportantmethodofdecreasingtheimpactofincreasinggapofspeedbetweenprocessorandmemory.Inthisarticle,astructuresplittingframeworkwithananalysismodelnamedstructurefieldrelationgraph(SFRG)ispresentedtooptimizeprogramdatalayout.TheSFRGcanbeusedtoquantifyrelationshipbetweenfields.Ithelpstofindanoptimallayoutforstructureaswellastheoptimalprogramdatalayout.AndthedatacacheperformanceisimprovedthroughSFRG-basedstructuresplitting.Experimentsshowthatthisframeworkiseffectiveinoptimizingprogramdatalayoutandimprovingtheperformanceofdatacacheandwholeprogram.

简介：在最近的年里，与数据的快速的开发集中的应用程序，数据复制成为了一种创新技术让数据格子改进数据可获得性，和还原剂文件转移时间和带宽消费。复制品的放置被证明了是必须被解决认识到数据复制的过程的最困难的问题。这份报纸探讨服务(QoS)的质量在数据格子的知道的复制品放置问题，并且建议动态编程基于不仅让一个QoS要求保证全面复制花费了，而且能最小化的复制品放置算法，包括存储费用和通讯费用。由模拟，实验证明复制品放置算法超过存在在数据的流行复制品放置技术格子。

简介：EncryptedCommunicationtechniqueisanimportantmeasuretotheinformationsafety.BasedontheadvantagesoftwopublicencryptionalgorithmRSA&DES,anovelhighintensitypublicencryptionalgorithmChaosRandomHighIntensity(CHR)isproposedinthispaper.TheprincipleofCRHisdescribedandanalyzedindetail,andtheresultsofcomputersimulationhasproveditseffectivenessandcorrectness.

简介：Themainchallengesofdatastreamsclassificationincludeinfinitelength,concept-drifting,arrivalofnovelclassesandlackoflabeledinstances.Mostexistingtechniquesaddressonlysomeofthemandignoreothers.Soanensembleclassificationmodelbasedondecision-feedback(ECM-BDF)ispresentedinthispapertoaddressallthesechallenges.Firstly,adatastreamisdividedintosequentialchunksandaclassificationmodelistrainedfromeachlabeleddatachunk.Toaddresstheinfinitelengthandconcept-driftingproblem,afixednumberofsuchmodelsconstituteanensemblemodelEandsubsequentlabeledchunksareusedtoupdateE.Todealwiththeappearanceofnovelclassesandlimitedlabeledinstancesproblem,themodelincorporatesanovelclassdetectionmechanismtodetectthearrivalofanovelclasswithouttrainingEwithlabeledinstancesofthatclass.Meanwhile,unsupervisedmodelsaretrainedfromunlabeledinstancestoprovideusefulconstraintsforE.AnextendedensemblemodelExcanbeacquiredwiththeconstraintsasfeedbackinformation,andthenunlabeledinstancescanbeclassifiedmoreaccuratelybysatisfyingthemaximumconsensusofEx.ExperimentalresultsdemonstratethattheproposedECM-BDFoutperformstraditionaltechniquesinclassifyingdatastreamswithlimitedlabeleddata.

简介：在挑战性的环境，感觉数据必须在水池失败的情况下在网络内被存储，我们需要与可得到的存储空间和剩余精力从弄空的存储来源节点再分配溢出的数据项目到传感器节点。我们设计有效数据存储算法与优先级说出分布式的数据保藏的一个分布式的精力(D2P2)。这个算法考虑两数据再分配费用和数据检索费用并且把这二个问题合为一个单个问题。D2P2能有效地由在传感器节点之中使用合作通讯认识到数据再分配。以便解决再分配竞争问题，我们介绍数据优先级的概念，它能避免在来源节点和还原剂精力消费之间的竞争咨询。最后，我们由理论和模拟验证建议算法的表演。我们表明那D2P2s性能以数据保藏时间以精力消费和表演优势接近最佳的集中的算法。

简介：数据仓库DBMS市场正发生转变，大大小小的数据仓库解决方案已经进入竞争激烈的市场，其中不乏传统的数据仓库大鳄，更有不少新兴的创业公司。以AsterData为代表的大规模并行处理数据仓库市场中的新生力量，目前正呈现出惊人的成长速度。就连MySpace也对其作出这样高度的评价：“如果没有AsterData,我想我们将会陷入一个没有光的时代。”新一轮的深度较量正在全面铺开，就这一比拼中，谁会造就数据仓库市场的“阿凡达”？

简介：Withthewideapplicationofvirtualizationtechnologyinclouddatacenters,howtoeffectivelyplacevirtualmachine(VM)isbecomingamajorissueforcloudproviders.Theexistingvirtualmachineplacement(VMP)solutionsaremainlytooptimizeserverresources.However,theypaylittleconsiderationonnetworkresourcesoptimization,andtheydonotconcerntheimpactofthenetworktopologyandthecurrentnetworktraffic.Amulti-resourceconstraintsVMPschemeisproposed.Firstly,theauthorsattempttoreducethetotalcommunicationtrafficinthedatacenternetwork,whichisabstractedasaquadraticassignmentproblem;andthenaimatoptimizingnetworkmaximumlinkutilization(MLU).Ontheconditionofslightvariationofthetotaltraffic,minimizingMLUcanbalancenetworktrafficdistributionandreducenetworkcongestionhotspots,aclassiccombinatorialoptimizationproblemaswellasNP-hardproblem.Antcolonyoptimizationand2-optlocalsearcharecombinedtosolvetheproblem.SimulationshowsthatMLUisdecreasedby20%,andthenumberofhotlinksisdecreasedby37%.

简介：在现代数据中心，网络消费的电源是全部的精力预算并且这样的看得见的部分改进数据中心网络(DCN)的精力效率真正有关系。为这精力效率的一个有效方法是由流动巩固与交通要求一起使DCN的尺寸有弹性，关掉减少电源消费的不必要的网络部件并且安排的带宽，即。同时，为数据中心管理有本能支持，软件定义联网(SDN)提供一个范例有弹性地控制DCN的资源。完成如此的电源积蓄，大多数优先的努力就采用简单贪婪对还原剂启发式计算复杂性。由于贪婪算法的固有的问题，然而，好足够的优化不能总是被保证。处理这个问题，一个修改混合基因算法(MHGA)被采用改善答案精确性，和SDN的有细密纹理的路由功能充分被利用。模拟结果证明更有效的电源管理能比以前的研究被完成，由增加大约5%网络精力积蓄。

简介：最大的挑战在之一极端宽带(UWB)无线电是为接收装置的精确预定获得。在这篇文章，我们为脉搏振幅调整(PAM)开发一个新奇帮助数据的同步算法UWB系统。飞行员和信息符号被直角的代码部门multiplexing(民防国防动员署)同时播送计划。在接收装置，一个算法基于协调察觉者的最小的平均误差概率(MAEP)被使用估计预定偏移量。多，为预定偏移量评价的路径干扰(MI)问题被考虑。mean-square-error(MSE)和bit-error-rate(BER)我们的建议计划的表演被模仿。结果证明我们的算法基于最大的相关因子产量(MCO)超过算法在多路径隧道。

简介：Theonlinesocialnetworks(OSNs)offerattractivemeansforsocialinteractionsanddatasharing,aswellasraiseanumberofsecurityandprivacyissues.Althoughcurrentsolutionsproposetoencryptdatabeforesharing,theaccesscontrolofencrypteddatahasbecomeachallengingtask.Moreover,multipleownersmayenforcedifferentaccesspolicytothesamedatabecauseoftheirdifferentprivacyconcerns.Adigitalrightsmanagement(DRM)schemeisproposedforencrypteddatainOSNs.Inordertoprotectusers'sensitivedata,theschemeallowsusersoutsourceencrypteddatatotheOSNsserviceproviderforsharingandcustomizetheaccesspolicyoftheirdatabasedonciphertext-policyattribute-basedencryption.Furthermore,theschemepresentsamultipartyaccesscontrolmodelbasedonidentity-basedbroadcastencryptionandciphertext-policyattribute-basedproxyre-encryption,whichenablesmultipleowners,suchastaggeduserswhoappearinasingledata,customizetheaccesspolicycollaboratively,andalsoallowsthedisseminatorsupdatetheaccesspolicyiftheirattributessatisfytheexistingaccesspolicy.Securityanalysisandcomparisonindicatethattheproposedschemeissecureandefficient.

简介：本文结合G．983规范的建议，介绍了EPON协议参考模型，并重点描述了协议参考模型中的基于帧的仿真子层，以及点到点仿真子层和共享仿真子层的工作过程。

简介：Recently,alotofdigitalsubscriberloopsystems(DSL)andhighratedigitalsubscriberloopsystems(HDSL)havebeendeployedindigitalsubscriberaccessnetworks.DataechocancellerisextensivelyusedintheDSLandHDSLsystemstorealizefullduplextransmissionontwistedcable.Insuchsystems,2B1Qlinecodeisadopted.Therefore,symbolrateisdecreasedanddigitaltransmissionsystemsgetlongerreach.Inthispaper,aperformanceevaluationmethodoftheechocancellerisproposedbasedonanautocorrelationmatrixof2B1Qlinecode.Usingthismethod,theformulaofratioofdatasignaltoechoresidualsignalisobtained.Accordingtotheformula,theratioofdatasignaltoechonoisedependsonFIRfiltertap,convergencefactor,adaptivealgorithmandthecorrelationmatrixofthelinecode.Computersimulationiscarriedouttoverifytheoreticalanalysis.Thesimulationresultscoincidedwiththetheoreticalformulaintheprocessestimatingtheratioofsignaltonoise.

简介：以某地市电信企业的客户为目标用户群，结合电信行业的业务规则，利用SPSS公司的数据挖掘工具Clementine，运用数据挖掘中的CRISP—DM模型方法建立了客户流失预测模型，为电信企业对流失客户采取更有效的营销策略提供一些建议。

简介：关于万物互联这一宏大的目标,如何架构及通过何种途径实现,业界还没有达成共识,特别是关于在万物互联的环境下如何保证信息安全,保障参与互联的各方隐私权,这些都制约了中国在物联网方面取得更大的发展。文章根据笔者以前参与西欧智能计量网项目时的体会和感悟,提出一些设想和思路,抛砖引玉,供各界专家进一步研究中国的物联网发展大计。