简介:Dempster-Shaferevidencetheory(DStheory)iswidelyusedinbrainmagneticresonanceimaging(MRI)segmentation,duetoitsefficientcombinationoftheevidencefromdifferentsources.Inthispaper,animprovedMRIsegmentationmethod,whichisbasedonfuzzyc-means(FCM)andDStheory,isproposed.Firstly,theaveragefusionmethodisusedtoreducetheuncertaintyandtheconflictinformationinthepictures.Then,theneighborhoodinformationandthedifferentinfluencesofspatiallocationofneighborhoodpixelsaretakenintoconsiderationtohandlethespatialinformation.Finally,thesegmentationandthesensordatafusionareachievedbyusingtheDStheory.ThesimulatedimagesandtheMRIimagesillustratethatourproposedmethodismoreeffectiveinimagesegmentation.
简介:Anovelfibergratingvibrationdemodulationsystem,basedon2×2and3×3couplers,isdesigned.Basedonthephaseunwrappingalgorithm,thethree-wayasymmetricaloutputofthe3×3coupleranddemodulationstatecharacteristicsofthesystemwhenthevibrationsignalincludeshighharmonicwavesareanalyzedinsimulations.Theresultshowsthatwhenthethree-wayoutputisasymmetrical,themaximumdeviationofdemodulationsignalis1.625%,andwhenthevibrationsignalincludeshighharmonicwaves,themaximumdeviationofdemodulationsignalis0.9%.Thecorrespondingexperimentisconducted.Theexperimentalresultshowsthatthedynamicresolutionofthesystemis25.22nε/Hzwhenthevibrationpitchis5.5Hz.
简介:Forenhancingthe2.0μmbandfluorescenceofHo3+,acertainamountofWO3oxidewasintroducedintoHo3+/Tm3+/Yb3+tri-dopedtelluriteglasspreparedusingmelt-quenchingtechnique.Thepreparedtri-dopedtelluriteglasswascharacterizedbytheabsorptionspectra,fluorescenceemissionandRamanscatteringspectra,togetherwiththestimulatedabsorption,emissioncross-sectionsandgaincoefficient.TheresearchresultsshowthattheintroductionofWO3oxidecanfurtherimprovethe2.0μmbandfluorescenceemissionthroughtheenhancedphonon-assistedenergytransfersbetweenHo3+/Tm3+/Yb3+ionsundertheexcitationof980nmlaserdiode(LD).Meanwhile,themaximumgaincoefficientofHo3+at2.0μmbandreachesabout2.36cm-1.Anintense2.0μmfluorescenceemissioncanberealized.
简介:随着我国轨道交通快速发展,机车作业量大幅增加,导致调车作业任务繁重,保障作业安全更加重要。基于现行机车数量大、人为操作调车作业任务重影响列车安全运行的现状,采用无线调车机车信号和监控系统(STP),可辅助完成调车作业任务,减少人为操作失误,从而达到保障调车作业安全的目的。本文以包头车辆段增设STP系统工程为例,介绍该系统结构,并对其在设计和施工中需注意的问题进行分析举例论证。