Galois域上m序列的游程、分量序列和向量序列

本文讨论了Golois域上m序列的游程、分量序列和向量序列。得到了游程的重要特性:n-1长的零游程是等间隙的;证明了分量序列是素域上的m序列;求出了向量序列的线性复杂度、极小多项式、周期和自相关函数。     

扩散输出序列的构造与分析

基于钟控、缩减生成器的构造思想,结合个别元素控制扩大输出的方式构造了一种新型伪随机序列生成器—扩散输出生成器。分析得到其生成序列—扩散输出序列的周期、线性复杂度及游程分布。文中进一步改变扩散输出组,得到一组伪随机序列,分析得到相应序列的周期和线性复杂度,实现对扩散输出生成器的拓展.     

广义自缩序列的游程长度

广义自缩序列是一类新型的序列密码.游程长度是衡量序列伪随机性质的一个重要指标,一个好的伪随机序列应该具有短的游程长度.本文利用m序列的伪随机性质,研究了广义自缩序列的游程长度,得到如下结果:广义自缩序列族中除两个序列(全0序列和全1序列)外,其余序列的游程长度不超过n×n-2.5n+3,在n为偶数的情况下,游程长度不超过n×n/2-1.25n+3.     

广义自收缩序列特例的扩展

论文给出了一种GF(3)上的自收缩序列的特例[1],解决了它的最小周期,并分析了其中1-游程的分布情况及长度为1的2-游程的分布情况,得到了长度为1的1-游程与2-游程相对平衡,由此,GF(3)上的广义自收缩序列具有较好的密码性质,适用于流密码系统的应用。     

一种非线性最大长度伪随机序列发生器的设计

伪随机序列在众多领域得到应用,研究伪随机序列的产生具有重要意义.基于m序列,首次提出采用特征函数构造非线性最大长度移位寄存器反馈函数.运用这种方法,构造了一类非线性反馈函数.根据该类反馈函数,设计了非线性伪随机序列发生器,并在FPGA(EPF10K)上得到实现.结果表明,该序列发生器生成的伪随机序列,周期长度,平衡特性、游程特性与m序列相同,非线性度较之得到提高,是难得的序列.     

基于m-序列的二元零相关区序列构造新方法

基于伪随机序列,提出一种二元零相关区序列构造方法。该方法利用伪随机序列的游程特性,通过在伪随机序列的适当位置进行插值,使生成的序列具有一定长度的零相关区。为了提高序列的丰富性,提出两种扩展方法:一种基于交织技术,通过构造移位序列,使交织序列的周期增大而零相关区不变;另一种方法将零相关区序列与Hadamard矩阵的行向量按位相乘,该方法能够增加零相关区序列数量的同时不改变序列的周期。数值仿真证明了所提方法的有效性。     

GF(3)上一类广义自缩序列的伪随机性

在GF(3)上构造了一类广义自缩序列的新模型,经过分析和计算,证明了新型广义自缩序列的最小周期为:2×3n－1,并对新序列的1长1-游程的个数进行精确的统计,计算出0-游程,1-游程,2-游程的分布非常均衡。研究得出此类新序列不但保持了GF(2)上第四类广义自缩序列良好的伪随机性,而且在此基础上得出一些新的密码学指标,相比之下各项指标都有很大的提高,并与GF(3)上其它广义自缩序列相比具有更好的密码学特性。     

GF（3）上若干类广义自缩序列的伪随机性

在GF（3）上讨论了所构造的四类广义自缩序列的伪随机性,这四类广义自缩序列具有很多优良的性质,同时也证明了这四类广义自缩序列的最小周期都达到最大值：2×3n-1;0-游程,1-游程,2-游程分布非常均衡,这一点是其他GF（3）上广义自缩序列所不具有的优点;研究表明：此四类新序列不但保持了GF（2）上第四类广义自缩序列良好的伪随机性,并与GF（3）上其它广义自缩序列的性质相比具有更好的密码学特性。     

二维缩控生成器的构造与分析

论文基于三元伪随机序列,将钟控生成器和缩减生成器结合进行二维输出,构成一种新型伪随机序列生成器—二维缩控生成器,由其生成的二维缩控序列具有大周期和高线性复杂度,能够抵抗诸如B-M算法等综合算法攻击,且证明了序列游程长度为1或2,数据率为8/9,符号分布基本平衡等性质。因此,二维缩控生成器适合在流密码系统中应用。     

二进制序列的Tseng游程定理

本文研究了二进制序列游程相关函数中的Tseng游程的性质,导出了Tseng游程与序列中各种游程长度的游程数之间的关系,为了证明定理的需要,文中引入了游程串,链接元等新概念,证明了几个定理。这些定理不仅清楚地描述了原序列中不同游程长度的游程数对相关函数的旁瓣的影响,而且还揭示了存在可确定码字类型的定型常数.     

基于剪接系统的有向哈密顿路问题分析

首先给出了剪接系统模拟有向哈密顿路问题的思想;然后通过此剪接系统所产生语言的性质对有向哈密顿路问题进行分析,给出了有向图存在哈密顿路的充要条件.在我们的构造中,模拟问题的剪接系统至多运行n-2步,其中n是模拟问题的规模.     

Design of binary sequences with tunable exponential autocorrelations and run statistics based on one-dimensional chaotic maps

This paper describes simple design methods of chaotic binary sequences with prescribed exponential autocorrelation properties and run statistics. We employ one-dimensional piecewise monotonic onto maps and a simple threshold function for generating such sequences. Some examples of such designs are also given. Furthermore, bounds on run statistics are discussed and compared to the result for sequences of general binary random variables.     

激光在含有光学元件的湍流中传输时的光束偏转

光学元件可能抑制或者加强大气湍流对激光传输性能的影响.研究了激光束在含有光学元件的湍流大气中的传输问题.根据空间滤波器原理,推导了激光束的随机偏转的解析表达式.作为一个特例,研究了高斯光束通过含有单个凸透镜的湍流大气的光束偏转,对其进行了数值计算,并与不存在光学元件时的光束漂移进行了对比.研究表明:不论光束是准直还是非准直的,光束偏转整体上都随传输距离的增加而增加,变化趋势基本一致,当传输距离相等时,存在凸透镜时的光束偏转都要小于不存在透镜时的光束漂移,激光传输性能得到改善.     

Fluctuations of the group path and the group-delay time of waves obliquely reflected by a plane-layered medium

The spatial correlation properties of the group path and the group-delay time of a radio signal leaving a random plane-layered reflecting medium similar to the ionosphere are considered. The spatial-correlation distances for the group path lying in the incidence plane and oriented perpendicularly to this plane are obtained for various angles of propagation of a wave entering the medium. It is shown that, when a radio signal is scattered by isotropic irregularities of the medium’s permittivity, regular refraction results in anisotropic fluctuations of the signal’s characteristics and the degree of anisotropy grows with the sounding angle.     

Resynthesis of combinational logic circuits for improved path delayfault testability using comparison units

We propose a resynthesis method that modifies a given circuit to reduce the number of paths in the circuit and thus improve its path delay fault testability. The resynthesis procedure is based on replacing subcircuits of the given circuit by structures called comparison units. A subcircuit can be replaced by a comparison unit if it implements a function belonging to the class of comparison functions defined here. Comparison units are fully testable for stuck-at faults and for path delay faults. In addition, they have small numbers of paths and gates. These properties make them effective building blocks for resynthesis to improve the path delay fault testability of a circuit. Experimental results demonstrate considerable reductions in the number of paths and increased path delay fault testability. These are achieved without increasing the number of gates, or the number of gates along the longest path in the circuit. The random pattern testability for stuck-at faults remains unchanged     

四频差动激光陀螺自适应程长控制技术

为了减小四频差动激光陀螺(FMDLG)对外界干扰的敏感性,设计了自适应程长控制系统使之工作于最佳工作点。对FMDLG的程长进行小抖动正弦调制,利用相敏检波技术从光强中提取调制信号的基波和二次谐波幅度。上述两个信号和光强一起用来实现自适应程长控制,它包括自动增益控制、自动调制幅度控制和程长控制3个环路。实验表明,自适应控制可有效消除光学和电子元件参量以及光强变化对控制系统的影响,而且可使FMDLG稳定地工作在最佳工作点上,从而降低其磁灵敏度。     

HQD-RRT*: a high-quality path planner for mobile robot in dynamic environment

Mobile robots have been used for many industrial scenarios which can realize automated manufacturing process instead of human workers. To improve the quality of the optimal rapidly-exploring random tree ( RRT* ) for planning path in dynamic environment, a high-quality dynamic rapidly-exploring random tree ( HQD-RRT* ) algorithm is proposed in this paper, which generates a high-quality solution with optimal path length in dynamic environment. This method proceeds in two stages: initial path generation and path re-planning. Firstly, the initial path is generated by an improved smart rapidly-exploring random tree ( RRT* -SMART) algorithm, and the state tree information is stored as prior knowledge. During the process of path execution, a strategy of obstacle avoidance is proposed to avoid moving obstacles. The cost and smoothness of path are considered to re-plan the initial path to improve the path quality in this strategy. Compared with related work, a higher-quality path in dynamic     

设计任意序列的一种新方法

提出了采用规则序列及其合成的新方法来设计任意序列。这种新方法既可使设计变得十分简单,又能保证所设计的电路必定能自启动。尤其值得注意的是,这种新方法可以方便地实现。（1）序列长度可改变;（2）序列中“1”游程、“0”游程的长度及其排列可改变;（3）多个同步序列的设计这三种过去较为困难的设计。     

随机森林在程序分支混淆中的应用

程序中的路径信息在程序执行过程中会被动态地泄露,基于路径敏感技术的逆向工程可自动地收集程序中的条件跳转指令,从而理解程序的内部逻辑.为了缓解路径信息泄露,提出了一种基于随机森林的路径分支混淆方法,将逆向分析路径分支信息的难度等价于抽取随机森林规则的难度.鉴于随机森林分类器可被视为一种黑盒,其内部规则难以被提取且分类过程与路径分支行为相似,因此经过特殊训练的随机森林可以在功能上替代路径分支.将该方法部署于SPECint-2006标准测试集中的6个程序进行实验,实验结果表明该混淆方法有效地保护了路径分支信息,引发的额外开销较低,具有实用性.     

A Geometric Interpretation of Fading in Wireless Networks: Theory and Applications

In wireless networks with random node distribution, the underlying point process model and the channel fading process are usually considered separately. A unified framework is introduced that permits the geometric characterization of fading by incorporating the fading process into the point process model. Concretely, assuming nodes are distributed in a stationary Poisson point process in ${BBR}^d$ , the properties of the point processes that describe the path loss with fading are analyzed. The main applications are single-hop connectivity and broadcasting.