查询词典 codes

Both LDPC codes and OFDM technology are studied in this paper. The working and the results obtained are summarized as follow:1. The definition of LDPC codes and its coding/decoding ideas are systematically summarized, a general algorithm of changing any parity-check matrix to lower triangular form, which is suitable for quick encoding, is given out, along with a girth checking algorithm. Absolutely random LDPC codes construction is improved, a new half random construction of LDPC codes with linear time coding and no 4-cycles is brought out.

系统地阐述了低密度校验码的定义及编译码原理，提出了一种将任何校验矩阵变换成适于快速编码的近似下三角形式的通用算法及一种围长检测算法，对完全随机的校验矩阵构造法进行了改进，提出了一类消除4环且可近似线性编码的校验矩阵半随机构造法，仿真表明，在高编码效率情况下，改进后的半随机构造法，其性能稍优于完全随机构造法，并可以线性时间编码，因此更适合实际应用。

The performance of Golomb codes for arbitrary probability distributions is analyzed, and then a class of universal codes called extended 7 codes is constructed based on Golomb codes.

论文分析了任意分布下Golomb码的性能，并在Golomb码的基础上构造了一类通用的扩展γ码。

The main function of this system is to implement automatic analysis of malicious codes'attacking behavior by the dynamical analyzing method. The system has the flowing characteristics: 1 Automatizing the malicious codes analyzing flow which includes the attack information collection, the attack information analysis and the attack recovery. 2 Collecting comparatively detailed attack information. 3 Detecting many kinds of automatic running techniques of malicious codes. 4 Detecting a kind of attack technique of hiding information in registration table and several kinds of attack techniques of hiding process. 5 Implementing visual show of attack reports. 6 Preventing attack from diffusing by the technique of virtual machine. 7 Detecting some new malicious codes.

该系统的主要功能是对恶意代码的攻击行为进行自动化分析，该系统采用的分析方法是一种恶意代码的动态分析方法，该系统具有以下特点：1实现了恶意代码分析流程自动化，包括攻击信息收集、攻击信息分析和攻击恢复的自动化。2收集较全面的攻击信息。3实现了对恶意代码的多种自启动技术的检测。4实现了检测一种在注册表中进行信息隐藏的攻击技术和几种进程隐藏的攻击技术。5攻击报告可视化显示。6通过虚拟机技术防止攻击扩散。7能够检测到一些新出现的恶意代码。

The first part of this thesis is basic on the generalized Hamming weights of linear codes over rings and arranged as follows: In section one, we first introduced the definition of generalized Hamming weights and weight hierarchy over binary field GF (2) and its extension to nonlinear codes over GF (2) and linear codes over rings.

本文的第一部分就是围绕环上线性码的广义Hamming重量这个课题展开的，主要内容如下：第一节，首先介绍了GF(2)上线性码的广义Hamming重量和重量分级的概念，以及这些概念是如何被推广至非线性码及环上的线性码上的。

Since the 2-D perfect difference codes have a MUI cancellation property and cross-correlation much lower than that of conventional 2-D spectral/spatial codes, such as Maximal-area matrices codes, the proposed system can completely eliminate the MUI and effectively suppress the PIIN.

由於二维完美相差码系具有一多使用者干扰相消特性，并且其交叉相关系数系远小於传统之二维频谱/空间码，如最大面积矩阵码maximal-area matrices codes， i.e。

As to cyclic codes over finite chain rings, we study their stucture and develop the Fourier Transform method to finite chain rings. The permutation groups of cyclic codes and their extended codes are investigated using their Mattson-Solomn polynomials.

对于有限链环上的循环码，我们研究了它们的结构，并把傅立叶变换的方法推广到有限链环，用循环码的Mattson-Solomn多项式对循环码及其扩展码的置换群进行了研究。

The permutation groups of cyclic codes and their extended codes are investigated using their Mattson-Solomn polynomials. SDq codes over finite fields are byte-organized and they can correct any single error and dete

有限域上的SD_q码是一类按字节组织的，能纠正发生的所有单个错误，同时能检测发生在同一字节内的两个相邻错误的纠错码；我们对有限域F_q上SD_q码的线对界在q＞3，b＞2时给出了一个改进界。

Recently, many coding experts have studied much of the Z_4-cyclic code(which is not necessarily linear) and its Gray map, and obtained a set of equivalent conditions in which a family of cyclic codes are linear, and the condition that this family codes are self-dual cyclic, and in this condition Nechaev-Gray image of the cyclic codes are self-dual cyclic.

近年来，已有编码学家对Z 4-循环码和Z 4上的映射作了深入研究，得到一类循环码是线性码的一系列等价条件，以及这类线性码是自对偶线性循环码的条件，在此条件下它的Nechaev-Gray像也是自对偶线性循环码。

The 1-generator quasi-cyclic codes and their duals are the most frequently encountered QC codes in the literature. Séguin discusses the construction and the enumeration of 1-generator QC codes in the special case where the prime factorization of x~m — 1 is the same in IF_qn as in IF_q.

单生成元的拟循环码及其对偶码是拟循环码中研究最多的一种。Séguin在要求x~m-1在F_q及F_中具有相同的分解的条件下，讨论了单生成元的拟循环码的结构及计数。

In this dissertation, it is showed that, in the split linear case, and are precisely the expurgated quadratic residue codes and , respectively, from which one can study the quantum quadratic residue codes via the quadratic residue codes.

本文证明了分裂型线性量子二次剩余码的两个相伴码和恰好就是经典删余二次剩余码和，由此我们可以通过经典二次剩余码理论来研究量子二次剩余码。

Article 144 The Government of the Hong Kong Special Administrative Region shall maintain the policy previously practised in Hong Kong in respect of subventions for non-governmental organizations in fields such as education, medicine and health, culture, art, recreation, sports, social welfare and social

第一百四十四条香港特别行政区政府保持原在香港实行的对教育、医疗卫生、文化、艺术、康乐、体育、社会福利、社会工作等方面的民间团体机构的资助政策。原在香港各资助机构任职的人员均可根据原有制度继续受聘。

Small wonder, then, that the Chinese spend more in the shop than any other group of foreign visitors do .

这样的小惊喜，使中国顾客比任何国家的人消费得更多。