Finitely Generated Torsion-free Nilp otent Groups Admitting an Automorphism of Prime Order

Let G be a finitely generated torsion-free nilpotent group and α an automorphism of prime order p of G. If the map φ : G-→ G defined by gφ= [g, α]is surjective, then the nilpotent class of G is at most h(p), where h(p) is a function depending only on p. In particular, if α3= 1, then the nilpotent class of G is at most2.     

Multiple-cell elements and regular multifractals

Based on fractal super fibers and binary fractal fibers, the following objectives are approached in this paper： First, the concept of multiple-cell elements is induced and abstracted. Second, through multiple-cell elements, the constructability of regular multifractals with strict self-similarities is confirmed, and the universality of the con- struction mode for regular multifractals is proved. Third, through the construction mode and multiple-cell elements, regular multifractals are demonstrated to be equivalent to generalized regular single fractals with multilayer fine structures. On the basis of such equivalence, the dimension formula of the regular single fractal is extended to that of the regular multifractal, and the geometry of regular single fractals is extended to that of regular multifractals. Fourth, through regular multifractals, a few golden fractals are constructed.     

A novel chaotic stream cipher and its application to palmprint template protection

Based on a coupled nonlinear dynamic filter (NDF), a novel chaotic stream cipher is presented in this paper and employed to protect palmprint templates. The chaotic pseudorandom bit generator (PRBG) based on a coupled NDF, which is constructed in an inverse flow, can generate multiple bits at one iteration and satisfy the security requirement of cipher design. Then, the stream cipher is employed to generate cancelable competitive code palmprint biometrics for template protection. The proposed cancelable palmprint authentication system depends on two factors: the palmprint biometric and the password/token. Therefore, the system provides high-confidence and also protects the user's privacy. The experimental results of verification on the Hong Kong PolyU Palmprint Database show that the proposed approach has a large template re-issuance ability and the equal error rate can achieve 0.02%. The performance of the palmprint template protection scheme proves the good practicability and security of the proposed stream cipher.     

电视节目审查管理系统组网方案选择

介绍利用数字有线电视技术,对广播电视播出大楼中来自各演播室和编辑记者制作的电视节目进行审查管理系统的建设,建立以数字电视前端平台为基础、以数字电视机顶盒为终端接收手段的电视节目审查管理系统,并利用大楼现有的网络资源和设备资源进行方案设计.     

基于ROAM算法的数字地面模型研究与实现

针对规则网格的数据量过大问题,采用了基于分块的ROAM算法进行多分辨率渲染,根据地形粗糙程度和视点位置,对地形进行有选择的细化,将庞大的三角形二叉树分为多个小二叉树,提高了地形构建效率,在此基础上建立地物要素模型,完成了数字地面模型的构建与多分辨率渲染.     

一个4000×8000规则LDPC码的解码器设计

随着LDPC码的广泛应用,尤其是在电池供电设备上的应用,解码器设计者面临的一个重大挑战就是如何减少其使用的存储器大小和存储器块数.行消息传递算法和基于置信传播的归一化算法的提出使得设计存储器的优化的解码器更为容易.对于一个普通的规则LDPC码来说,则存在一种性能良好且节省存储器的串行解码器结构,一个针对David MacKay的4000×8000规则LDPC码的解码器设计就是一个很好的例子.     

CORRECTION METHODS FOR STEADY INCOMPRESSIBLE FLOWS

1.IntroductionFOrsemi-periodicincompressiblefluidflows,S.C.R.Dennisandco-workers[1--4]solvethevorticity-streamfunctionformulationofthegoverningequationsbytheseriestruncationandfinitedifferencemethod.Sincenoboundaryconditionforthevorticity,theypropose...     

一种非对称规则采样PWM方法

讨论ＰＷＭ的一种非对称规则采样原理,给出宜于在线运算的简便算法。特别适合于单片机实现。     

Perturbation method in the problem of large deflections of circular plates with nonuniform thickness

In this paper the perturbation method about two parameters is applied to the problem of large deflection of a cricular plate with exponentially varying thickness under uniform pressure. An asymptotic solution up to the third-order is derived. In comparison with the exact solutions in special cases, the asymptotic solution shows a precise accuracy.     

自适应空间异常的目标跟踪

为了解决判别式空间正则项的目标跟踪算法在遮挡、旋转等因素干扰下失跟率较高的问题,该文提出一种自适应空间异常的目标跟踪算法.首先,在目标函数中加入自适应空间正则项,既缓解了边界效应带来的影响,又提高了滤波器对目标和背景区域的分辨能力;其次,根据每一帧的响应值计算验证分数,分析跟踪结果的可信度和异常情况;最后为目标模型和响...