简介:Thepropagationoffemtosecondlaserpulseswithwavelengthsof1550nm,1064nm,800nmand700nm,respectively,whichareinthenormaldispersionregionofthenano-structuredphotoniccrystalfiber(N-PCF)withinterestingbroadbandnormaldispersionandhighlynonlinearproperties,isstudied.Fortheeffectofchirpvariationmainlyinducedbygroupvelocitydispersion(GVD)andself-phasemodulation(SPM),afterpropagationoverashortlength,thewavebreakingoccurs.Namely,oscillatorystructuresarepresentednearpulseedgesandsidelobesappearinthepulsespectrum.Inthecaseof800nm,afterthepropagationof20mm,asuperflatspectrumisobtained.Thebandwidthofthesuperflatspectrumisassociatedwiththedispersionlengthandthenonlinearlength.BychoosingN-PCFandlaserpulsewithappropriateparameters,abroadbandsuperflatspectruminashortlengthcanbeachieved.
简介:为3D网孔模型的watermarking的支持向量机器(SVM)的使用被调查。SVM广泛地为图象,声音,和录像watermarking被探索了,但是没在3Dwatermarking域被探索标明日期SVM的潜力。建议途径为嵌入的水位标为顶点的选择作为一个二进制分类器利用SVM。SVM被训练,特征向量源于eigen正常和从规范的3D网孔模型拿的顶点的一位1戒指邻居的表面正常之间的尖差别。SVM学会作为修正的适当或不恰当的候选人分类顶点以便提供水位标。试验性的结果证实建议算法对象网孔变光滑那样的攻击细微、柔韧,收割并且噪音增加。