简介：TheperformancesofnonlinearWDMsystemswithdifferentdutycyclearecomparedbymeansofnumericalsimulation.Thenumericalresultsshowthattheopticalpulsewithdutycycleof0.5issuperiortotheconventionalNRZmodulationschene.Theconclusionisdifferentfromthatofsomereferences.Thereasonisthatintersymbolinterferenceisnotincludedinsomereferences.Infact,intersymbolinterferenceplaysanimportantroleinmonlinearWDMsystem.Althoughthelargerthedutycycleis,thestrongertheeffectofthecross-phasemodulationandself-phasemodulationonnonlinearWDMishowever,thelargerthedutycycleis,thestrongertheintersymbolinterferenceis.

简介：Transmissionperformanceofelectroabsorptionmodulatorin10Gb/stransmissionsystemshasbeensimulatedandanalyzedundertheconditionoftakingintoaccountthechirp,extinctionratio,transmissivityandrise/falltime.ResultsshowthatshorttransmissiondistancewithoutEDFAafterEAMcanbeusedinfuturemetropolitanareanetwork,butthetransmissivitymustbecarefullyconsidered.Thesamplingtimerangeanddecisionlevelcanbeoptimizedtoreducethebiterrorratio.

简介：Pure-Ge/Sishortperiodsuperlattice(SPS)grownbygassourceMBE(GSMBE)isstudiedbyphotoluminescencespectroscopyandRamanscatteringspectroscopy.AnabnormalbandinphotoluminescenceisfoundinanintermediaterangeofLsibetween1.9nm-2.9nmforsampleswithLgefixedat1.5ml.Incontrasttoapure-Ge/Siquantumwell,theenergyofthebandshowsred-shiftasLsiincreases.RamanscatteringshowsthatSi-SivibrationrelatedRamanshiftreachesaminimumforsampleswithstrongestPLintensityoftheabnormalband.Itisthereforeconcludedthattheabnormalbandisrelatedwithstrainrelaxationprocess.

简介：Multilayerdielectricthinfilmedgefilterhasseriouspolarizationsensitivityunderobliqueincidence.Thecutoff-bandsofthes-polarizationandp-polarizationlightinconventionaledgefilterwillseparateobviouslyunder45°obliqueincidence,whichlimitsitsapplication.BasedonthetwochosenmaterialsTiO2andSiO2,anovelstackstructureisproposedtodesignthenon-polarizationshort-wave-passthinfilmedgefilter.Byusingthe(4H4L4H)asthematchinglayers,thepolarizationseparationat3dBtransmittanceforthethinfilmedgefiltercutoff-bandislessthan1nmattheincidentangleof45°.Inthisway,thenon-polarizationshort-wave-passedgefilteriseasilydesignedandfabricated.

简介：Inthispaper,twospeechenhancementsystemswithsupergaussianspeechmodelingarepresented.ThecleanspeechcomponentsareestimatedbyMinimum-Mean-Square-Error(MMSE)es-timatorundertheassumptionthattheDCTcoefficientsofcleanspeecharemodeledbyaLaplacianoraGammadistributionandtheDCTcoefficientsofthenoiseareGaussiandistributed.Then,MMSEestimatorsunderspeechpresenceuncertaintyarederived.Furthermore,theproperestimatorsofthespeechstatisticalparametersareproposed.ThespeechLaplacianfactorisestimatedbyanewdeci-sion-directedmethod.ThesimulationresultsshowthattheproposedalgorithmyieldslessresidualnoiseandbetterspeechqualitythantheGaussianbasedspeechenhancementalgorithmsproposedinrecentyears.

简介：Thispaperstudiestheproblemofthespacestationshort-termmissionplanning,whichaimstoallocatetheexecutingtimeofmissionseffectively,schedulethecorrespondingresourcesreasonablyandarrangethetimeoftheastronautsproperly.Adomainmodelisdevelopedbyusingtheontologytheorytodescribetheconcepts,constraintsandrelationsoftheplanningdomainformally,abstractlyandnormatively.Amethodbasedontimeiterationisadoptedtosolvetheshort-termplanningproblem.Meanwhile,theresolvingstrategiesareproposedtoresolvedifferentkindsofconflictsinducedbytheconstraintsofpower,heat,resource,astronautandrelationship.Theproposedapproachisevaluatedinatestcasewithfifteenmissions,thirteenresourcesandthreeastronauts.Theresultsshowthatthedevelopeddomainontologymodelisreasonable,andthetimeiterationmethodusingtheproposedresolvingstrategiescansuccessfullyobtaintheplansatisfyingallconsideredconstraints.

简介：Anovelandsimplefibergratingsensorbasedonhigh-duty-cyclesamplefiberBragggratingisproposedanddemonstratedexperimentally.Thistypeofsensorcanmeasurestrainandtemperaturesimultaneouslywithmeritsoflowcost,highsensitivityandimmunitytoelectro-magneticinterference.Thesensorhasanaccuracyof20μεand0.8℃overastrainrangeof500～1500μεandatemperaturerangeof5～36℃underexperimentalconditions.

简介：Low-duty-cyclemechanismscanreducetheenergyconsumptionsignificantlyinwirelesssensornetworks(WSNs).Sensorsstaydormantmostofthetimetosavetheirenergyandwakeupbasedontheirneeds.However,suchatechnique,whileprolongingthenetworklifetime,setsexcessivechallengesforreducingtheend-to-end(E2E)delaywithinthenetwork.Inthispaper,thecentralizedcluster-basedlocationfinding(CCLF)algorithmisproposedtoreducethehighlatencyinlow-duty-cycleWSNsbyfindingasuitablepositionforthesink.Thealgorithmismainlycomposedofthreesteps:a)theclusterconstruction,b)thefastlook-uptable(FLU-table)construction,andc)thesinklocationdecision.ThesimulationresultsshowthattheperformanceoftheCCLFalgorithmissignificantlysimilartothatoftheoptimalalgorithm.Moreover,theCCLFalgorithmrequireslessoperationtimecomparedwiththeoptimalalgorithm.

简介：Toeliminatethealiasingthatappearedduringthemeasurementofmulti-componentsnonstationarysignals,anovelkindofanti-aliasingalgorithmbasedontheshorttimeFouriertransform(STFT)isbroughtforward.Firstthephysicalessenceofaliasingthatoccursisanalyzed;secondtheinterpolationalgorithmmodelissetupbasedontheHammingwindow;thenthefastimplementationofthealgorithmusingtheNewtoniterationmethodisgiven.Usingthenumericalsimulationthefeasibilityofalgorithmisvalidated.Finally,theelectricalcircuitexperimentshowsthepracticalityofthealgorithmintheelectricalengineering.