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简介：Formanyclusteringalgorithms,itisveryimportanttodetermineanappropriatenumberofclusters,whichiscalledclustervalidityproblem.Inthispaper,anewclusteringvalidityassessmentindexisproposedbasedonanovelmethodtoselectthemarginpointbetweentwoclustersforin-ter-clustersimilaritymoreaccurately,andprovidesanimprovedscatterfunctionforintra-clustersimilarity.Simulationresultsshowtheeffectivenessoftheproposedindexonthedatasetsunderconsiderationregardlessofthechoiceofaclusteringalgorithm.

简介：Byusingfourspeciallydesignednarrowbandpassfiltersandphotodetectorsintheinstrument,theincidentandreflectedradiancesofsunlightonthevegetationareopticallysensed,attheredandnearinfraredbands,thenthenormalizeddifferencevegetationindex(NDVI)isprocessedbyamicroprocessor.ComparedwithconventionalspectrometermeasuringmethodofNDVI,theinstrumentiseasytobeused,compact,lightandlow-cost.

简介：Aimingattheproblemthatthereisn'tanystandardizedcalibrationmethodfortheperformanceindexofsurfaceplasmonresonance(SPR)sensor,thecalibrationmethodforkeyperformanceindicesofSPRsensorissummarizedandproposedbasedonthecomparisonofrelativemethodsanddefinitionofeachindex.Experimentaldataofsucrosesolutionswithvariousconcentrationsareobtainedbytheself-buildingSPRinstrument,andthenthecalibrationmethodisusedtodeterminetheperformanceindices,suchasnoise,drift,sensitivity,resolution,linearity,dynamicrangeandreproducibility.Experimentalresultsshowthatthedefinitionofindicesisreasonable,andthecalibrationmethodiscorrect,whichhasgreatsignificanceforperformanceevaluationofSPRsensor.

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简介：Aswitchingvariabilityindex(SVI)constantfalsealarmrate(CFAR)detectorisproposedforimprovingthedetectionperformanceofVI-CFARdetectorsinmultipletargetsbackgrounds.Whenthepresenceofnon-homogeneityinCFARreferencewindowsisindicatedbyaVI-CFARdetector,aswitchingCFARdetectorisintroducedtooptimizetheperformanceoftheVI-CFARdetectorinhomogeneous,multipletargetsandclutteredgebackgrounds.ThestructureandparametersselectionmethodoftheSVI-CFARdetectorispresented.ComparisonswithclassicCFARdetectorsandrecentlyproposeddetectorsarealsogiven.TheoreticalanalysisandsimulationresultsshowthatSVICFARdetectormaintainsthegoodperformanceoftheVI-CFARdetectorinhomogeneousandclutteredgebackgrounds,whilegreatlyimprovingthecapacityofanti-multitargets.

简介：Losslessdatahidingcanrestoretheoriginalstatusofcovermediaafterembeddedsecretdataareextracted.In2010,Wangetal.proposedalosslessdatahidingschemewhichhidessecretdatainvectorquantization(VQ)indices,buttheencodingstrategiesadoptedbytheirschemeexpandthefinalcodestream.ThispaperdesignsfourembeddingandencodingstrategiestoimproveWangetal.'sscheme.TheexperimentresultoftheproposedschemecomparedwiththatoftheWangetal.'sschemereducesthebitratesofthefinalcodestreamby4.6%andraisesthepayloadby1.09%onaverage.

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简介：ByuseoftheKeldyshnn-equilibriumGreen's-functionmethods,thethirdharmonicsusceptibilitiesoftwopolyanilinefamilies,PANI-HCl巨PANI－H3PO4，arccalculated[x^(3)(ω）≈10^-12esu].Itwasfoundthatthethirdharmonicsusceptibilityofpolyanilinestronglydependsonthedelocalizationoftheelectrons.Therefractiveindicesn(λ=589nm)ofPANI-HClandPANI-H3PO4arecalculatedbyuseofthreecommonmethods(theLorentz-Lorentztheoreticalmodel,theGladstone-DalegroupcontributionandtheVogelgroupcorrelation)basedongroupcontributionstomolarrefraction.Thecalculatenvaluesarevariedfrom1.31to1.42forPANI-HCland1.36to1.45forPANI-H3PO4.

简介：Thecharacteristicmodificationsarereportedonthesurfaceofpolymericwaveguidefilmintheprocessofvolume-gratingfabrication.Thelightfromamode-locked76MHzfemtosecondlaserwithpulsedurationof200fsandwavelengthof800nmisfocusednormaltothesurfaceofthesample.Thesurfacemorphologymodificationsareascribedtoafactthatsurfaceswellingoccursduringtheprocess.Periodicmicro-structureisinscribedwithincreasingincidentpower.Thelaser-inducedswellingthresholdonthegrating,whichishigherthanthatoftwo-photoninitiatedphoto-polymerization(TPIP)(8mW),isverifiedtobeabout20mW.Itisfeasibletoenhancethesurfacesmoothnessofintegratedopticsdevicesforfurtherencapsulation.Thevariationofmodulationdepthisstudiedfordifferentvaluesofincidentpowerandscanspacing.Ablationaccompaniedwithsurfaceswellingappearswhenthepowerishigher.Byoptimizingthelasercarvingparameters,highlyefficientgratingdevicescanbefabricated.

简介：Inthispaper,thephotonicbandgapofphotoniccrystalswithchiralandnegative-indexmaterialsalternatelyisinvestigated.Itisshownthatthiskindofphotoniccrystalexhibitsverywidephotonicbandgap.Thephotoniccrystalswithadefectlayerhaveanarrowdefectmodeinthebandgap,whichcanbeusedasaverygoodfilteringmaterialbychoosingtheparametersofthedefectlayerproperly.

简介：Inthispaper,aplasmonicsrefractiveindexsensorwiththesemiring-stubsystemcoupledtoabuswaveguideispro-posed.Thestructurecanachievewavelengthbandtunableandultra-sharpFanoresonance.Thecouplingmechanismbetweenthebrightmodeanddarkmodeisinvestigatedindetail,andapparentplasmoninducedtransparency(PIT)isrealizedontheresonancewavelength.Thefullwidthathalfmaximum(FWHM)oftheresonantwavelengthismodulatedbyadjustingthecoupleddistance.Thesensitivityandfigureofmerit(FOM)oftheproposedsensor'canreachupto600nm/RIUand120onthevisibleregion,respectively,andthisperformancecanbehelpfulfordesigningthephotonicintegratedcircuitandopticalcommunication,inaddition,itcanbeappliedforbio-sensing.

简介：Lightpropagationinnanoparticle-loadedencapsulantsissimulatedbasedonthemethodofMonteCarlo,referringtothemultilayergraded-refractive-indexstructureforLEDencapsulants.Andtheinfluenceofscatteringcoefficientonthetransmittanceisanalyzed.Theresultsshowthatthetransmittancedecreaseswithscatteringcoefficient.Foragivennumberoflayers,theencapsulantswillyieldmaximumtransmittanceiftherefractiveindexvalueofeachlayerisoptimized.Thenanoparticle-loadedencapsulantconsistsofmultiplelayerswithrefractive-indexvaluesthatgraduallydecrease.Thetransmittancewillbehigherthanthatoftraditionalnon-gradedencapsulants,andwillimprovelightextractionefficiencyofLED.

简介：Torealizecontent-basedretrievaloflargeimagedatabases,itisrequiredtodevelopanefficientindexandretrievalscheme.ThispaperproposesanindexalgorithmofclusteringcalledCMA,whichsupportsfastretrievaloflargeimagedatabases.CMAtakesadvantagesofk-meansandself-adaptivealgorithms.Itissimpleandworkswithoutanyuserinteractions.Therearetwomainstagesinthisalgorithm.Inthefirststage,itclassifiesimagesinadatabaseintoseveralclusters,andautomaticallygetsthenecessaryparametersforthenextstage-k-meansiteration.TheCMAalgorithmistestedonalargedatabaseofmorethantenthousandimagesandcompareitwithk-meansalgorithm.Experimentalresultsshowthatthisalgorithmiseffectiveinbothprecisionandretrievaltime.

简介：我们报导在与公司2激光制作的熊猫纤维摇长时期栅栏(PR-LPGs)的期刊。PR-LPGs很高完成与12个时期和3.5湩愠汬慩据?楷桴联合19dB的效率？

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简介：以便在量井思考类型波导解决过多的插入损失和低开／关比率光开关，新奇InGaAs/InAlAs联合了量很好结构被建议。在低应用电场(F=19kV/cm)和低吸收损失的情况中(伪鈮?1.2厘米?1)，一个大否定导致地的折射索引变化(螖n=?0.0134)在操作波长在新奇的联合的量井结构被获得(位=1550nm)。值在上述一样的工作条件上在一口矩形的量井(RQW)由与那相比的超过一～二个数量级是更大的。CLC数字TN365不到资助号码60277034和60436020由中国的国家自然科学基金会支持了

简介：Side-matchvectorquantization(SMVQ)achievesbettercompressionperformancethanvectorquantization(VQ)inimagecodingduetoitsexplorationofthedependenceofadjacentpixels.However,SMVQhasthedisadvantageofrequiringexcessivetimeduringtheprocessofcoding.Therefore,thispaperproposesafastimagecodingalgorithmusingindirect-indexcodebookbasedonSMVQ(IIC-SMVQ)toreducethecodingtime.Twocodebooks,namedindirect-indexcodebook(II-codebook)andentire-statecodebook(ES-codebook),aretrainedandutilized.TheII-codebookistrainedbyusingtheLinde-Buzo-Gray(LBG)algorithmfromside-matchinformation,whiletheES-codebookisgeneratedfromtheclusteredresidualblocksonthebasisoftheII-codebook.Accordingtotherelationshipbetweenthesetwocodebooks,thecodewordintheII-codebookcanberegardedasanindicatortoconstructafastsearchpath,whichguidesinquicklydeterminingthestatecodebookfromtheES-codebooktoencodetheto-be-encodedblock.TheexperimentalresultsconfirmthatthecodingtimeoftheproposedschemeisshorterthanthatofthepreviousSMVQ.