简介:Inthispaper,basedonastochasticmode!forinputsandweights,andinviewofthedisturbanceofcorrelativeandlargeinputandweighterrors,ageneralalgorithmtoobtaintheoutputerrorcharacteristicsofaclassofmultilayeredperceptronswiththresholdfunctionsisproposedbyusingstatisticalapproach.Furthermore,theformulatocalculatetherobustnessofthenetworksisalsogiven.Theresultofcomputersimulationindicatesthecorrectnessofthealgorithm.
简介:Ageneralizedmathematicalmodelofhumanbodycurrentthresholdforperceptionwasestablishedandthecurrentflowingthroughhumanbodycouldbearbitrarycyclicalwaveforms.Therelationshipbetweenhumanbodycurrentthresholdforperceptionandcurrentfrequency,truerootmeansquare(RMS)valueandinfluencefactorwasdescribed.Atestsystemwasestablishedbasedonelectroencephalogram(EEG)tostudytherelationshipbetweenhumanbodycurrentthresholdforperceptionandcurrentwaveform,frequency...
简介:Fordirectsequencespreadspectrum(DSSS)receivers,thecapabilityofrejectingnarrow-bandinterferencecanbesignificantlyimprovedbyaprocessoffrequency-domaininterferencesuppression(FDIS).Thekeyissueofthisprocessishowtodetermineathresholdtoeliminateinterferenceinthefrequencydomain,whichhasbeenextensivelystudied.However,thesepreviousmethodsaretediousorverycomplex.Asimpleandefficientalgorithmbasedonmediansisproposed.Theeliminationthresholdisonlyrelatedtothemedianbyascalefactor,whichcanbeobtainedbythenumericalanalysis.Simulationresultsshowthatthealgorithmprovidesexcellentnarrow-bandinterferencesuppressionwhileonlyslightlydegradingthesignal-to-noiseratio(SNR).Aone-passalgorithmusinglogarithmicsegmentationisfurtherderivedtoestimatemedianswithlowcomputationalcomplexity.Finally,theFDISisimplementedinafieldprogrammablegatearray(FPGA)ofXilinx.ExperimentsarecarriedoutbyconnectingtheFDISFPGAtoaDSSSreceiver,andtheresultsshowthatthereceiverhasaneffectivecountermeasurefora60dBinterference-to-signalratio(ISR).
简介:Inthisstudy,aMulti-LayerBPneuralnetwork(MLBP)withdynamicthresholdsisemployedtobuildaclassifiermodel.Astothedesignoftheneuralnetworkstructure,theoreticalguidanceandplentifulexperimentsarecombinedtooptimizethehiddenlayers'parameterswhichincludethenumberofhiddenlayersandtheirnodenumbers.Theclassifierwithdynamicthresholdsisusedtostandardizetheoutputforthefirsttime,anditimprovestherobustnessofthemodeltoahighlevel.Finally,theclassifierisappliedtoforecastboxofficerevenueofamoviebeforeitstheatricalrelease.ThecomparisonresultswiththeMLPmethodshowthattheMLBPclassifiermodelachievesmoresatisfactoryresults,anditismorereliableandeffectivetosolvetheproblem.
简介:摘要目的讨论超声心动图频谱分析肺动脉峰值血流加速的原因。方法选取2008.7.31—2010.5.29我院心脏超声科频谱分析有肺动脉峰值血流加速的病例156例,对其跟踪随访。根据随访结果将其按病因分为二组,A组为肺动脉器质性病变组;B组为肺动脉无器质性病变组,并对其进行组内结果分析,组内自身对照分析,以及组间差异性比较分析。结果1.A组肺动脉器质性病变组肺动脉血流速度(4.21±0.91m/s)明显高于B组肺动脉无器质性病变组(1.93±0.32m/s)。2.A组及B组患者治疗后肺动脉血流速度某些低于治疗前,自身对照研究差异具有统计学意义。结论超声心动图医生对肺动脉峰值血流加速的病因可以做出正确判断。
简介:摘要:本文结合IPAT扩展模型和情景分析方法对中国整体、城镇、农村三个层面居民生活碳排放增长路径进行情景预测,探究中国居民生活碳排放达峰时间及达峰数值。研究结果表明:基准情景和高碳情景下,到2050年,中国整体、城镇、农村居民生活碳排放总量均难实现达峰;低碳情景下,中国整体、城镇、农村居民生活碳排放总量达峰时间分别是2046年,2045年和2046年,碳排放峰值分别为73亿t、56亿t和17亿t;强化情景下,中国整体、城镇、农村居民生活碳排放总量达峰时间均在2040年,碳排放峰值分别为63亿t、47亿t和16亿t。中国居民生活碳排放峰值研究是中国能否实现减排目标的基础之一。基于此,提出中国居民生活部门专门性减排举措,如提高居民人口素质、提升居民绿色理念等有助于中国整体实现2030峰值目标。
简介:摘要近年来,我国的汽车行业发展迅速,在汽车中,车门是非常重要的组成部分。车门限位系统对车门的开闭有着极其重要的作用,随着对车门开闭要求的提高,对限位系统也提出了全新的设计要求。文章主要针对车门限位系统的力学性能研究,着重分析限位系统的各个零部件的受力情况、应力分布、应变分布、开关门换挡力,探寻最佳的结构设计和参数匹配。
简介:一个模型(贝叶斯的海洋的前面察觉,BOFD)海表面温度(SST)在卫星的前面察觉--导出的SST图象基于阀值间隔被介绍,在象气候、环境的研究或渔业那样的不同应用程序被过去常。模型首先由使用一个Sobel算法模板计算SST坡度。根据坡度价值,阀值间隔被一个坡度决定累积直方图。根据这阀值间隔,前面候选人能被获得,优先的概率和可能性的能是计算的。候选人是否是前面点,能被使用贝叶斯的决定理论决定。模型在自台湾东面的菲律宾海流向日本的暖流前面区域的部分的先进很高分辨率的辐射计图象上被评估。结果与使用方法在文学建议了的几SST前面察觉获得的那些相比。这比较证明BOFD不仅压制噪音和小规模的前面,而且保留连续前面。
简介:Weinvestigatethetargetandintensitydependenceofplateauinhigh-orderabovethresholdionization(HATI)bysimulatingthetwo-dimensional(2D)momentumdistributionsandtheenergyspectraofphotoelectronsinHATIofraregasatomsthroughusingthequantitativerescatteringmodel.Thesimulatedresultsarecomparedwiththeexistingexperimentalmeasurements.ItisfoundthattheslopeoftheplateauintheHATIphotoelectronenergyspectrumhighlydependsonthestructureofelasticscatteringdifferentialcrosssection(DCS)oflaser-inducedreturningelectronwithitsparention.Theinvestigationsofthelong-andshort-rangepotentialeffectsintheDCSsrevealthattheshort-rangepotential,whichreflectsthestructureofthetarget,playsanessentialroleingeneratingtheHATIphotoelectronspectra.
简介:Alow-thresholdRamaneffectinakilowattytterbium-dopednarrowbandfiberamplifiersystemisreported.TheRamanStokeslightat1120nmisachievedwiththetotaloutputpowerofonly~400W,indicatingthattheRamanthresholdofthiskilowattcodirectionalpumpedcontinuouswavefiberamplifierismuchlowerthanthepredictedvalueestimatedbytheclassicformula.Tofigureoutthemechanismofthisphenomenon,simulationsbasedonthegeneralstimulatedRamanscattering(SRS)modelareanalyzedindicatingthatthekeyfactoristhecouplingbetweenfour-wavemixing(FWM)andSRS.Thesimulationresultsareingoodagreementwithourexperiments.