一类广义自缩序列的伪随机性

在序列密码中,加密和解密所用的密钥序列都是伪随机序列。序列密码体制的安全强度取决于密钥流,因而伪随机序列生成器的设计与分析一直是序列密码研究的中心课题。文章利用计算机编程计算,对大量的比特串进行分析,通过选择适当的比特串101、1011、1101、11100、111010和111011,分析其出现次数的奇偶性,证明了广义自缩序列b(ak+1+ak+2)的最小周期在所有1 024种情形下全部达到最大,即2n-1;同时证明了该序列具有良好的低阶自相关性。     

广义自缩序列b(ak-2)和b(ak+2)的最小周期

讨论了b（ak-3），b（ak-2），…，b（ak＋2），b（ak＋3）等广义自缩序列的最小周期，通过选择适当的比特串并分析其个数的奇偶性，在大多数情形下证明了它们的最小周期达到最大，即2^n-1。     

GF(q)上一类新型的广义自缩序列

设计了GF(q)上一类新型的广义自缩生成器。GF(q)上的广义自缩序列族B(a)具有群结构和线性结构,这些序列之间具有良好的互相关性和均衡性。当n≥2时,族B(a)中不少于(q-1)/q的序列具有最小周期2×q^n-1,最后给出了各种情况下线性复杂度的上界。     

一类广义拟压缩映射序列不动点的迭代算法

在凸度量空间内,把广义Ishikawa迭代序列推广到一类广义拟压缩映射序列,并证明了广义Ishikawa失代收敛于这类广义拟压缩映射序列的唯一公共不动点。     

广义拟压缩映射序列公共不动点的迭代算法

在凸度量空间内,把广义Ishkawa失代序列推广广义拟压缩映射序列,并证明了广义Ishikawa迭代序列收敛于广义拟压缩映射序列的唯一公共不动点。     

拟压缩映射序列和广义Ishikawa迭代

在凸度量空间内,对拟压缩映射序列定义广义Ishikawa迭代序列·证明了广义Ishikawa迭代序列收敛于拟压缩映射序列的唯一公共不动点.     

更广义拟压缩的广义Ishikawa型迭代

在凸度量空间内,引入了更广义拟压缩映射序列和广义Ｉｓｈｉｋａｗａ型迭代序列。证明了广义Ｉｓｈｉｋａｗａ型迭代序列收敛于更广义拟压缩映射序列的唯一公共不动点。     

广义拟压缩映射序列与广义Ishikawa迭代

在凸度量空间内，对广义拟压缩映射序列定义了广义Ｉｓｈｉｉｋａｗａ迭代序列。证明了广义Ｉｓｈｉｉｋａｗａ迭代序列收敛于广义拟压缩映射序列的唯一公共不动点。     

凸度量空间内非线性映射的迭代算法

在凸度量空间内 ,对非线性广义拟压缩映射序列定义了带误差的 lshikawa迭代序列 ,证明了带误差的 lshikawa迭代序列收敛于非线性广义拟压缩映射序列的唯一公共不动点。     

更广义拟压缩映射序列与带误差的Ishikawa迭代

在凸度量空间内 ,对更广义拟压缩映射序列定义了带误差的Ishikawa迭代序列 ,证明了带误差的Ishikawa迭代序列收敛于更广义拟压缩映射序列的唯一公共不动点 ,并改进和推广了一些文献的主要结果 .     

跳频扩频系统的两种混沌扩频序列

介绍了跳频扩频通信系统的原理，给出了两种利用Chebyshev混沌映射产生数字混沌序列的方法，验证比较了其特性，结果均可满足扩频码的要求，同时搭建混沌跳频扩频系统进行了仿真，仿真结果证明了方法的正确性．     

英语专业学生程式语知识及模仿与背诵策略

大量研究表明,模仿和背诵对英语学习具有重要的促进作用。在以英语为外语的学习环境下,学习者往往缺乏足够的可理解性输入,背诵是增强学习者可理解性输入的一种有效途径,尤其是对程式语的学习来说,通过背诵和模仿,学习者可以积累大量的程式语知识,有利于学习者的语言输出。对英语专业本科生的程式语知识进行考察,并对模仿与背诵策略的使用情况进行调查,结果表明,英语专业本科生对模仿策略具有较高的认可度,但在背诵方面,他们往往重视单词的背诵和记忆,而相对忽略了句子、对话或语篇的背诵和记忆,这造成了他们对程式语的掌握不够理想。     

Notes on q-ary interleaved sequences

(f(x),m)-interleaved sequences over Fq have been proposed and studied.Roughly speaking,an (f(x),m)-interleaved sequence is a sequence which is made of (or say,interleaved by) m component sequences with a common characteristic polynomial (f(x)(∈Fq [x]).In this note,(f(x),m)-interleaved sequences are studied further.As a result,it is made clear how their minimal characteristic polynomials,linear spans and periods are determined by their component sequences.And also,their period distribution and the number of (f(x),m)-interleaved sequences with maximal linear spans are derived.Furthermore,a large number of interleaved sequences with the lowest correlation among all the (f(x),m)-interleaved sequences are constructed.     

Measurement of anomalously high hydration of (dA)n.(dT)n double helices in dilute solution

Different DNA sequences have different physical properties, which seem to be important for their biological function. In particular, (dA)n.(dT)n has many unusual features, which include resistance to conformational changes in a variable chemical environment, an unusual thermodynamics of interaction with ligands, and the inability to reassociate into nucleosomes. Short A.T base-pair runs also play a critical role in DNA bending. It is believed that hydration of DNA is an important factor in determining the physical chemical and biological properties of different regions of DNA. Until now, however, it has not been possible to study the details of the hydration of DNA in dilute solution with sufficient sensitivity and precision. Moreover, it was not known if different base sequences differ in the extent of their hydration. Indirect evidence that (dA)n.(dT)n can be hydrated to a greater extent than other DNA sequences may be inferred from a recent study of the binding of drugs to polynucleotides. Here we used a novel high-precision technique measuring ultrasonic velocity to obtain direct estimates of the extent of hydration of various oligo- and polynucleotides in dilute solution. We report that different DNA sequences differ in their hydration, and that (dA)n.(dT)n in particular has an anomalously high level of hydration.     

A symmetry-related sequence-structure relation of proteins

Proteins have regular tertiary structures but irregular amino acid sequences. This made it very difficult to decode the structural information in the protein sequences. Here we demonstrate that many small α protein domains have hidden sequence symmetries characteristic of their pseudo-symmetric tertiary structures. We also present a modified method of recurrent plot to reveal this kind of the hidden sequence symmetry. The results may enable us to understand part of the relations between protein sequences and their tertiary structures.     

Notes onq-ary interleaved sequences

(f(x), m)-interleaved sequences over Fq have been proposed and studied. Roughly speaking, an (f(x), m)-interleaved sequence is a sequence which is made of (or say, interleaved by)m component sequences with a common characteristic polynomial (f(x)(∈ Fq[x]). In this note, (f(x), m)-interleaved sequences are studied further. As a result, it is made clear how their minimal characteristic polynomials, linear spans and periods are determined by their component sequences. And also, their period distribution and the number of (f(x), m)-interleaved sequences with maximal linear spans are derived. Furthermore, a large number of interleaved sequences with the lowest correlation among all the (f(x), m)-interleaved sequences are constructed.     

Banach空间中积分-微分方程两点边值问题的解

利用R1中两点边值问题的Green函数,讨论了Banach空间中含有一阶导数的二阶积分-微分方程两点边值问题解的存在性.在可验证的条件下,从问题的上下解出发构造序区间[u0,v0]上的迭代序列,利用单调迭代方法,证明了所构造的序列分别收敛于这一问题解的C2最大解与C2最小解.     

A new approach for generating function sequences—Hybrid Bridge functions derived from Walsh functions

This paper reviews the essence of the Walsh and Bridge functions from the point of view of the recursive relationship; it also unifies their expressions. A new kind of function—the hybrid Bridge function—is constructed from the definition of the hybrid matrix, in which the row vectors are taken from the Walsh and Bridge function matrices. We also propose a new approach for generating function sequences; one that uses the column vectors of the hybrid Bridge function matrix as the new function sequences. These sequences are able to adjust the number of zeroes flexibly; thus, resolving the constraint on the application of excessive zeroes in Bridge function sequences, while at the same time maximizing the research field for function sequences. Through strict mathematical analysis, it is proved that when the initial matrix order of the parent matrices and the similarity of the hybrid matrices meet certain conditions, the hybrid function sequences exhibit good orthogonal characteristics. This provides a theoretical basis for its further applications in communication systems.     

基于语料库的“名词＋名词”结构用法分析

“名词＋名词”结构经常在文章中提供大量信息。然而不同语域中的“名词＋名词”结构有着它们各自不同的特点。本文旨在传统语法理论和语料库研究的基础上，对科技英语和普通英语里的名词＋名词结构进行了量化分析，从而得出名词＋名词结构在不同语域中的特点．在调查研究过程中，对科技英语中的名词＋名词与普通英语中的名词＋名词做了详细对比分析，结果发现科技英语中存在较多名词＋名词结构．并且其分布和构成也和普通英语有很大区别。最后，对名词＋名词所表现的语意关系进行分类总结，使得科技英语和普通英语中名词＋名词特点更加清晰明了。     

CCD降噪技术的理论分析

在简要介绍回顾CCD噪声产生的基础上,总结了几种常用的CCD抑制噪声的方法,对这些方法的特点、应用场合进行了较为详尽的说明,并分别给出了各种方法的原理电路以及时序波形。