简介：Withthedevelopmentofcommunicationsystems,computernetworks,andotherinformationandcommunicationtechnology(ICT)infrastructures,challengesincommunicationsandefficientcommunicationsforgreentechnologiesarerisinginrecentyears.Inordertoreducetheenvironmentalproblems

简介：Signalsarriveoutofphaseattheintendedreceiverfromcollaborativebeamforming（CB）nodesduetotheinstabilityintheoutputfrequencysignalsoftheuniversalsoftwareradioperipheral’s（USRP）localoscillator（LO）.Thesenodesincludingthetargetmustsynchronizetheiroscillatorfrequenciesforcoherentsignalreception.Inordertodothis,frequenciesandphasesofthesignalsshouldbeestimatedinsoftwaredefinedradio（SDR）andsmoothenwithnonlinearfilterssuchastheextendedKalmanfilter（EKF）.TheprocessnoiseparametersoftheNIUSRP-2920nodeswillhavetobecalculatedandusedwiththeEKFprocessnoisecovariancematrix.Thesenodesaregreencommunicationhardwaredeviceswheremostofthehardwareunitsarenowsoftwaredefined.ThisarticleusesthedirectspectrummethodtoobtainthephasenoisevaluesatvariousfrequencyoffsetsoftheNIUSRP-2920inordertocalculatethepowerspectraldensityoffractionalfrequencyfluctuation.Byapplyingthepower-lawnoisemodeltothisobtainedvalue,thegeneratedwhitefrequencynoiseandrandomwalkfrequencynoisevaluesareq1=1.93×10-21andq2=5.86×10-18,respectively.

简介：Orthogonalfrequencydivisionmultipleaccess(OFDMA)isapopularandwidelyacceptedmultipleaccesstechniquetoprovidehighdatarateservicesinamobileenvironmentintheareaofwirelesscommunications.OFDMAcanprovidebetterflexibilityinallocatingtheradiospectrabyutilizingsubcarrierallocations,scheduling,andenergycontroltoobtainmulti-dimensiondiversitygains.Duetoitsresourceallocationflexibility,OFDMAhasbeenwidelyusedasagreenairinterfacetechnologyfortheemergingbroadbandwirelessaccessnetworks.ThispaperextensivelyaddressestheintegrationofgreenOFDMAtothefutureairinterfacetechnologies,forinstance:two-tiercellular,multiradioaccesstechnologies(RATs),FemtoCell,andrelaynetworks.ThemainfocusofthepaperistoreviewandanalyzethecurrentOFDMAtechniquestoaddressthegreenresourceallocationinmultiuserdiversity,wherethecriticalconstraintsarethecomputationalcomplexity,energyefficiency,andthesub-channelassignment.ThefuturetrendofOFDMAbasednetworkswillaimtomaximizetheenergyefficiencyoftheexclusivechannelassignmentthroughajointsub-channelandpowerallocationtoaccommodatehighdatatrafficnetworksspeciallytherelaybased5Gcellularnetworks.

简介：Energyconsumptionofsensornodesisoneofthecrucialissuesinprolongingthelifetimeofwirelesssensornetworks.Oneofthemethodsthatcanimprovetheutilizationofsensornodesbatteriesistheclusteringmethod.Inthispaper,weproposeagreenclusteringprotocolformobilesensornetworksusingparticleswarmoptimization(PSO)algorithm.Wedefineanewfitnessfunctionthatcanoptimizetheenergyconsumptionofthewholenetworkandminimizetherelativedistancebetweenclusterheadsandtheirrespectivemembernodes.Wealsotakeintoaccountthemobilityfactorwhendefiningtheclustermembership,sothatthesensornodescanjointheclusterthathasthesimilarmobilitypattern.Theperformanceoftheproposedprotocoliscomparedwithwell-knownclusteringprotocolsdevelopedforwirelesssensornetworkssuchasLEACH(low-energyadaptiveclusteringhierarchy)andprotocolsdesignedforsensornetworkswithmobilenodescalledCM-IR(clusteringmobility-invalidround).Inaddition,wealsomodifytheimprovedversionofLEACHcalledMLEACH-C,sothatitisapplicabletothemobilesensornodesenvironment.SimulationresultsdemonstratethattheproposedprotocolusingPSOalgorithmcanimprovetheenergyconsumptionofthenetwork,achievebetternetworklifetime,andincreasethedatadeliveredatthebasestation.

简介：Inrecentyears,thepotentialofrenewablegreenenergysourceshasbeenextensivelystudied.Theproventechnologywhichisphotovoltaicsolarcellsstrictlydependsondaylightandproduceslow-efficiently.Toovercometherestrictions,onetechnologystudiedisthroughharvestingthethermalradiationenergywhichcanprovidea24-hourenergysource.Thecontinuityofenergysourcespromisesverygoodenergyconversionespeciallyformilitaryapplications.Thisarticlepresentsanewstructurethatcanharvesttheabundantthermalradiationenergyintousableenergyatthewavelengthof10μm.Arectangularstructurewithaperturbationslitwasdesignedtointegratewitharectifiercircuitforgreenenergyconversion.Theslittunneljunctionguidedtheelectromagneticfieldintoajunctionwheretheenergycouldbecollectedandconverted.Anenhancementfactorofapproximately110.6canbeachievedbyaperturbationslitlengthof1.0μm.Theresultsextractedfromtheproposeddesignpromiseabettercandidatetoovercomethedisadvantagesofphotovoltaicsolarcellsforenergyharvestingdevices.

简介：Theabsenceofnetworkinfrastructureandopportunisticspectrumaccessincognitiveradioadhocnetworks(CRAHNs)resultsinconnectivityandstabilityproblems.Clusteringisknownasaneffectivetechniquetoovercomethisproblem.Clusteringimprovesnetworkperformancebyimplementingalogicalnetworkbackbone.Therefore,howtoefficientlyconstructthisbackboneamongCRAHNsisofinterest.Inthispaper,weproposeanewclusteringalgorithmforCRAHNs.Moreover,wemodelanovelclusterheadselectionfunctionbasedonthechannelheterogeneityintermoftransmissionranges.Tothebestofourknowledge,thisisthefirstattempttomodelthechannelheterogeneityintotheclusteringformationincognitiveradionetworks.Simulationresultsshowthattheperformanceofclusteringissignificantlyimprovedbythechannelheterogeneityconsiderations.

简介：Parameterestimationofsignalsofuniversalsoftwareradioperipheral(USRP)devicesiscrucialtosolvetheproblemofphaseoffsetsofreceivedsignalsindistributedbeamforming.Forsystemsthatwillutilizetheclosedloopfeedbackalgorithmwherethereceiverneedstosendthereceivedsignalstrength(RSS)valuesperiodicallytothebeamformingnodesoastotakeadvantageofenergyconservation,thefrequencyandphaseofthesesignalsshouldbeestimatedbeforesmootheningbynonlinearfilters.ThisarticlepresentstheestimationofthefrequencyoffsetsofaGaussianminimumshiftkeying(GMSK)signalfromN210USRPdevicesinrealtimebyusingtheRadix-2fastFouriertransform(FFT)algorithminGNURadio.Forthesegreencommunicationsdevices,mostoftheneededhardwarepartshavebeensoftwaredefined,therebyreducingthesupposedenergyconsumption.Thefrequencyoffsetsfromreferencecarrierfrequenciesof900MHzand2.4GHzarelessthan3kHzeachbeforetheestimation,buttheaverageoffsetsare45Hzand100Hzaftertheestimation,respectively.Thehighoffsetvalueexperiencedwiththe2.4GHzcarrierwasduetoconsistentinterferencefromdevicesonthatsamefrequency.

简介：AnovelLD-pumpedsingle-frequencymicro-chipgreenlaserispresented.ByusingthecombinationofshortcavityandLoytfilterformedbyRochonprismandKTPcrystal,astablesinglefrequencygreenlaserisobtainedwith60mWoutputat500mWLD-pump.Theoptical-to-opticalconversionefficiencyisabout12%.Theopticalcontactbetweencomponentsofthelaserisadopted.Thislaserhastheadvantagesofacompactstructureandalowcost.

简介：有铟听氧化物(ITO)的结构的蓝、绿的器官的轻射出的设备/N，N鈥?二度--(1-naphthyl)-N,N鈥?diphenyl-1,1鈥?biphenyl-4,4鈥?diamine(NPB)/aluminum(III)二度(2-methyl-8-quinolinato)4-phenylphenolato(BAlq)/tris(8-hydroxyquinolate)铝(Alq3)/Mg:Ag被制作了。到绿轻排放的蓝色与器官的电影厚度的变化被完成了。基于精力乐队图和费用搬运人通道理论，当调节颜色的层和颜色变量electroluminescence(EL)在费用搬运人再结合地区以内被归功于到调整功能，不同厚度的电影起一个作用，这被结束当调节颜色的层和颜色变量electroluminescence(EL)在费用搬运人再结合地区以内被归功于到调整功能。在有高效的heterostructure设备的情况中，观察EL系列与器官的电影的厚度显著地变化，它从再结合的移动被结果区域地点。设备相同部件创作，这迄今没被显示能被实现由改变功能的层的电影厚度认识到不同颜色排放。CLC数字TN383这个工作被中国(资助号码60425101)的国家科学基金支持了，为大学里的新世纪优秀才能的节目(资助没有。NCET-06-0812)并且UESTC(资助No.060206)的年轻优秀工程。

简介：Thewirelesssensornetwork(WSN)consistsofsensornodesthatinteractwitheachothertocollectivelymonitorenvironmentalorphysicalconditionsatdifferentlocationsfortheintendedusers.Oneofitspotentialdeploymentsisintheformofsmarthomeandambientassistedliving(SHAAL)tomeasurepatientsorelderlyphysiologicalsignals,controlhomeappliances,andmonitorhome.ThispaperfocusesonthedevelopmentofawirelesssensornodeplatformforSHAALapplicationoverWSNwhichcomplieswiththeIEEE802.15.4standardandoperatesin2.4GHzISM(industrial,scientific,andmedical)band.TheinitialstageofSHAALapplicationdevelopmentisthedesignofthewirelesssensornodenamedTelGmote.ThemainfeaturesofTelGmotecontributingtothegreencommunicationsincludelowpowerconsumption,wearable,flexible,user-friendly,andsmallsizes.Itisthenembeddedwithaself-builtoperatingsystemnamedWiseOStosupportcustomizedoperation.Thenodecanachieveapacketreceptionrate(PRR)above80%foradistanceofupto8m.ThedesignedTelGmoteisalsocomparablewiththeexistingwirelesssensornodesavailableinthemarket.

简介：

简介：Thispaperpresentsacollaborativebeamforming(CB)techniquetoorganizethesensornode'slocationinalineararrayforgreenwirelesssensornetwork(WSN)applications.Inthismethod,onlyselectedclustersandactiveCBnodesareneededeachtimetoperformCBinWSNs.Theproposedleast-squarelineararray(LSLA)managestoselectnodestoperformasalinearantennaarray(LAA),whichissimilartoandasoutstandingastheconventionaluniformlineararray(ULA).TheLSLAtechniqueisalsoabletosolvepositioningerrorproblemsthatexistintherandomnodesdeployment.Thebeampatternfluctuationshavebeenanalyzedduetotherandompositionsofsensornodes.Performancesintermsofnormalizedpowergainsaregiven.ItisdemonstratedbyasimulationthattheproposedtechniquegivessimilarperformancestotheconventionalULAandatthesametimeexhibitslowercomplexity.

简介：Thehigh-densitypopulationleadstocrowdedcities.Thefuturecityisenvisagedtoencompassalarge-scalenetworkwithdiverseapplicationsandamassivenumberofinterconnectedheterogeneouswireless-enableddevices.Hence,greentechnologyelementsarecrucialtodesignsustainableandfuture-proofnetworkarchitectures.Theyarethesolutionsforspectrumscarcity,highlatency,interference,energyefficiency,andscalabilitythatoccurindenseandheterogeneouswirelessnetworksespeciallyinthehomeareanetwork(HAN).Radio-over-fiber(ROF)isatechnologycandidatetoprovideaglobalviewofHAN’sactivitiesthatcanbeleveragedtoallocateorthogonalchannelcommunicationsforenablingwireless-enabledHANdevicestransmission,withconsideringtheclustered-frequency-reuseapproach.Ourproposednetworkarchitecturedesignismainlyfocusedonenhancingthenetworkthroughputandreducingtheaveragenetworkcommunicationslatencybyproposingadataaggregationunit(DAU).TheperformanceshowsthatwiththeDAU,theaveragenetworkcommunicationslatencyreducessignificantlywhilethenetworkthroughputisenhanced,comparedwiththeexistingROFarchitecturewithouttheDAU.

简介：Theimplementationofwirelesstechnologiesbasedonthevehicularadhocsensornetwork(VASNET)mayprovidesupportforthesearchandrescue(SAR)teamtooperateeffectivelyinnaturaldisasterevents,suchaslandslide,earthquake,flooding,andtsunami.TheoperationsofSARteamareverychallenginginsucheventsduetothepossibledamagesoftheexistingtelecommunicationinfrastructures.Theexistingdeploymentofthecellularcommunicationsinfrastructuremaybepartiallyorcompletelydestroyedaftertheoccurrenceofthesenaturaldisasters.Thus,thecurrentVASNETinfrastructuremustbeabletosupporttheinfrastructure-lessnetworkbyintegratingothergreenwirelesstechnologiesthatcanbenefittheSARteam,whichcanindirectlysavemorehumanlivesandreducethenumberofcasualties.Therefore,theintegrationofgreenInternetofthings(IoT)andVASNETisproposedtoformaheterogeneousframeworkfordatadisseminationinSARoperations.Inaddition,thispaperalsodiscussestheexistingIoTframeworkindisasterscenarioswithfutureresearchdirectionforIoTusingonanyaspect,especiallyrelatedtothenaturaldisasterscenarios.

简介：Ozoneisagreenhousegas.Ozoneabsorptioncrosssectionshavebeenreportedwithdiscrepanciesandinconsistencies.Inthispaper,simultaneouseffectsoftheopticalpathlengthandtemperaturevariationsonozonegasabsorptioncrosssectionsareinvestigatedatdifferentwavelengths.HITRAN2012,thelatestavailablelinelistonspectralcalc.comsimulator,isusedinthisstudytosimulateozonegasabsorptioncrosssectionsinrelationtothesimultaneouseffectsoftheopticalpathlengthandtemperatureatthewavelengthsof603nmand575nm.Resultsobtainedforgascellswiththeopticalpathlengthfrom10cmto120cmshowthatthedecreaseintemperaturesfrom313Kto103Kresultsintheincreaseinozonegasabsorptioncrosssections.Atwavelengthsof603nmand575nm,thepercentageincreaseofozonegasabsorptioncrosssectionsis1.22%and0.71%,respectively.Resultsobtainedinthisstudyshowthatinthevisiblespectrum,atconstantpressure,ozonegasabsorptioncrosssectionsaredependentonthetemperatureandwavelengthbutdonotdependontheopticalpathlength.Analysisinthisworkaddressesdiscrepanciesinozonegasabsorptioncrosssectionsinrelationtothetemperatureinthevisiblespectrum;thus,theresultscanbeappliedtogetoptimalconfigurationofhighaccuracyozonegassensors.

简介：FMCWSAR是一种新近被提出来的成像雷达体制，它具有体积小、重量轻、成本低、分辨率高等一系列优点。因此，人们对FMCWSAR越来越关注。首先推导了FMCWSAR的信号模型，然后讨论了方位匹配滤波函数。为了能够精确成像，同时避免计算量过大，提出将场景沿距离向分段，用不同的方位匹配滤波函数进行处理，并给出了分段标准。最后，仿真结果表明此方法可以得到理想的成像结果。

简介：蜕变测试可解决测试Oracle问题，但不是所有的蜕变关系都能有效地发现软件缺陷。提出了一种基于复合函数的蜕变关系构造方法，通过该方法构造的蜕变关系，集合了复合蜕变关系的所有特点，具有较高测试效率。试验验证表明该方法有效。

简介：Adiode-pumpedacousto-optical(A-O)Q-switchedextra-cavityfrequency-doubledNd:YVO4/KTP(KTiOPO4)greenlaserformedwithasimpleplane-planecavityhasbeendemonstrated.Withtheincidentpumppowerof12.7W,A-OQ-switchedaverageoutputpowerat1064nmwas3.81Wwithadurationof25nsatarepetitionrateof20kHz,extra-cavityfrequencydoublingwithKTPasthenonlinearcrystalyieldedthemaximumoutputpowerof1.92Wat532nm,thecorrespondingopticalconversionefficiencyfrom1064nmto532nmlightis50.4%.Thecontinuous-wave(CW)laserpropertiesofdiodepumpedNd:YVO4crystaloperatingat1064nmhavebeenstudied.Withtheincidentpumppowerof25W,themaximumCWoutputpowerof13.81Wwasobtainedwiththecorrespondingopticalconversionefficiencyof55.24%.

简介：证据间冲突程度的有效衡量是解决高冲突证据融合问题的有效途径之一。针对冲突系数无法有效衡量证据间的冲突程度问题，在分析现有冲突衡量方法基础上，提出了一种基于指数函数的证据冲突衡量方法。首先，根据证据间基本概率赋值（BPA）关系将证据分为一致证据和非一致证据2类；然后，根据证据分类结果，综合利用差异性信息和指数函数分别构造冲突衡量系数；最后，用多种冲突衡量方法进行算例分析对比，试验结果表明本文方法可有效衡量证据间冲突程度。

简介：基于在软件开发过程中有很多静态缺陷函数检测方法与工具都具有局限性,且对软件开发后期的黑盒测试关联不大,文中提出了一种在软件开发早期运用的静态缺陷函数检测框架,该框架不仅可以解决静态分析工具误报的问题,还可以为后期的安全性黑盒测试提供数据流约束,为自动生成数据流提供有效支持。