简介:在Tikhonov正则化方法的基础上将其转化为一类l1极小化问题进行求解,并基于Bregman迭代正则化构建了Bregman迭代算法,实现了l1极小化问题的快速求解.数值实验结果表明,Bregman迭代算法在快速求解算子方程的同时,有着比最小二乘法和Tikhonov正则化方法更高的求解精度.
简介:在一般Banach空间中,使用迭代的方法,研究Ф-强增生算子方程解的逼近问题,建立了带有误差的Ishikawa迭代序列强收敛到解的条件.用Ф-强增生算子代替强增生算子,使以往的相应结果更具一般性.从而改进和推广了有关文献的相关结果.
简介: Inordertoactivelyutilizethenon-traditionalresourcesandreducethedependenceofchemicalindustryoncrudeoil,theMinistryofScienceandTechnologyhasincludedtheproject"Keytechnologyformanufactureofmassivechemicalsviaanon-oilbasedroute"inthe"NationalEleventhFive-YearScienceandTechnologySupportingPlan"andisnowcallingforapplicationforrelevantresearchprojects.……
简介:Nowadays,thepassword-basedremoteuserauthenticationmechanismusingsmartcardisoneofthesimplestandconvenientauthenticationwaystoensuresecurecommunicationsoverthepublicnetworkenvironments.Recently,Liuetal.proposedanefficientandsecuresmartcardbasedpasswordauthenticationscheme.However,wefindthatLiuetal.’sschemeisvulnerabletotheoff-linepasswordguessingattackanduserimpersonationattack.Furthermore,italsocannotprovideuseranonymity.Inthispaper,wecryptanalyzeLiuetal.’sschemeandproposeasecurityenhanceduserauthenticationschemetoovercometheaforementionedproblems.Especially,inordertopreservetheuseranonymityandpreventtheguessingattack,weusethedynamicidentitytechnique.Theanalysisshowsthattheproposedschemeismoresecureandefficientthanotherrelatedauthenticationschemes.