查询词典 codes

The topics covered include the basic concepts of information theory--entropy, mutual information, channel capacity, information rate, Shannon's noiseless coding theorem and Shannon's fundamental coding theorem; modeling of information sources--zero-memory and Markov models; modeling of information channels--BSC and BEC channels, additivity of information and cascaded channels; construction of compact source codes--Kraft inequality, compact codes, Huffman and LZW compression codes; and analysis and design of error-control channel codes--Hamming distance, binary linear codes and the parity-check matrix, Hamming codes, checksum codes, cyclic codes and the generator polynomial and CRC codes.

课程的内容包括：信息论的基本概念（熵、交互信息、信道容量、信息率、 Shannon无噪声编码定理和Shannon基本编码定理）、信源模型（无记忆模型和Markov模型）、信息信道模型（BSC 和 BEC模型、信息的可加性和级联信道），紧致信源编码设计（Kraft不等式，紧致编码，Huffman 和LZW压缩编码）以及差错控制信道码的设计与分析（海明距离，二元线性码，奇偶校验矩阵，海明码，校验和，循环码，生成多项式和CRC码）。

Some common used channel codes are introduced, and emphasis is placed on linear block codes, cyclic codes, BCH codes, RS codes, convolutional codes and the promising turbo codes, which is planned to be implemented in the third locomotive communication systems. Their performance is analysed and compared. And some method to reduce errancy is submitted, also the interleaved technique is introduced.

文章介绍了几种常用的信道编译码方案，如线性分组码，循环码，BCH码，RS码，卷积码等，分析和比较了它们的性能，并对第三代移动通信系统的选用码Turbo码作了简要介绍，对提高纠错性能提出了若干改进方案，同时介绍了交织技术减少差错的作用。

At last, By using the factorization properties of cyclotomic polynmials on finite fields and the construction characteristic of cyclic codes, we present the relation of the period distribution of cyclic codes and the period distribution of their dual codes, establish the explicit formula for the number of the codewords without inner-period of the cyclic codes and their dual codes, find the method for computing the dimension and the period distribution of narrow-sense primitive BCH codes,and study the inverse question of period distribution of cyclic codes.

最后，利用有限域上分圆多项式的分解特性和循环码的构造特点，揭示了循环码的周期分布与其对偶码周期分布之间的内在联系，确定了一般循环码及其对偶码内无内周期码字的精确计数公式，决定了狭义本原BCH码的维数与周期分布，讨论了循环码周期分布的反问题。

The general decoding method for Turbo codes provided by the invention adopts enhanced Max-Log-MAP algorithm, makes use of Max-Sum semiring property in the generalized distribution law and combines and simplifies measure and calculation of forward and backward status of traditional binary Turbo codes, which means combining grid graph of traditional binary Turbo codes in nature to ensure that the status measure and calculation of the traditional binary Turbo codes have the same calculation expression way with that of the duobinary Turbo codes so that a general decoding device can both decode the traditional binary Turbo codes and duobinary Turbo codes.

本发明提出的Turbo码通用译码方法采用增强型Max-Log-MAP算法，利用广义分配率中的Max-Sum半环性质，对传统二进制Turbo码的前向和后向状态度量计算进行合并简化，从本质上也就是对传统二进制Turbo码的网格图进行合并，使得传统二进制Turbo码的状态度量具有和双二进制Turbo码一样的计算表达方式，从而使得通用译码装置对于传统二进制Turbo码和双二进制Turbo码都可实现。

Prange first began to study cyclic codes over finite field in 1957 and Berkelamp first began to investigate negacyclic codes over finite field in 1968,but the codes over finite rings didnt received much attention until the 1990s due to the works of Nechaev in 1991 and Hammons in 1994,which showed that well-known nonlinear codes such as Kerdock and Preparata codes are constructed from linear codes over finite rings.

Prange(1957)和Berkelamp(1968)分别首先开始研究有限域上的循环码和负循环码，直到上世纪90年代，Nechaev(1991)和Hammons(1994)通过有限环上的线性码构造出著名的非线性码如Kerdock码和Preparata码，有限环上的码才受到广泛关注。

For k≥1, an isometry φ between codes over Zsubscript P(superscript k+1 and codes over Z(subscript P^2) is introduced and used to give a generalization of the Gray map φ: Z(superscript n subscript 4)→F(superscript 2n subscript 2). Furthermore, by means of this isometry, the concept of negacyclic codes is extended to codes over the ring Zsubscript P(superscript k+1. A characterization of these codes in terms of their images under φ is given. It is also shown that the generalized Gray map image of the 1-P(superscript k-cyclic code is a distance-invariant quasi-cyclic code.

文章引入了Z下标 P(上标 k+1码和Z(下标 P^2)码之间的等距同构φ(k≥1)；利用φ把Gray映射φ：Z(上标 n 下标 4)→F(上标 2n 下标 2)推广为φ：；而且利用φ，负循环码概念被推广到Z下标 P(上标 k+1码，得到了1-P(上标 k-循环码；依据等距同构φ，给出了这些码的表示；也证明了1-P(上标 k-循环码在推广的Gray映射下的像是距离不变的准循环码。

This invention provides a method for transferring third party landing based on IP network including: a door network station carries a ciphered KEY generated randomly by a service server to send a link request to a third party network station so as to avoid transmission of user ciphered codes and ensure absolute security of user codes, besides, since the third party network station calls back the Web server by copying the ciphered KEY to verify the cryptographic key so as to secure the absolute safety of shaking hands, since the door network station does not transfer user ciphered codes with the third party network station, which is not necessary to synchronize with the door station about codes, thus the requirement of complicated maintenance to synchronization on ciphered codes to the third party is reduced.

本发明提供了一种基于IP网络转接第三方登陆的方法，其关键是，由门户网站携带业务服务器随机生成的加密KEY向第三方网站发送链接请求，避免了用户密码的传输，因而保证了用户密码的绝对安全性。再有，由于第三方网站通过复制加密KEY回调Web服务器，由Web服务器进行密钥验证，因而又保证了握手的绝对安全性。应用本发明，由于门户网站与第三方网站之间不传递用户密码，使得第三方网站无需与门户网站进行密码同步等机制的处理，在大大提高安全性的同时，降低了对第三方网站对于密码同步机制等复杂维护的要求。

In chapter three, the author studies channel coding and decoding techniques, that is Woven codes. On the basis of other researchers'results, the author presents a four-port soft input and soft output module, in order to facilitate iterative decoding process of concatenated codes. This module is not only suit for decoding a concatenated code with non RSCs as its constituent codes, but also it can provide soft information output of both codeword and information bits, so it can be applied to decoding a Turbo code and joint detection and decoding. Taking into consideration serial and parallel concatenated Turbo code, the author proposes a combined code, with 2 outer codes and 2 inner cods as its constituent codes, i.e., 2×2 Woven code.

本文的第三章研究编码技术，在前人研究成果的基础上，为了模块化地对此级联码进行迭代译码，提出了一种模块化的软输入软输出四端口处理模块，此模块可用来处理非RSC卷积码为子码的级联码，并且可以提供码字和信息比特的软信息输出，是一种模块化很强的处理模块，可用于传统的Turbo码的迭代译码，尤其在迭代均衡和迭代检测的系统中并把它运用到B3G的系统设计中。

Features Internet Updateable (with purchase of CP9137)- Trilingual Display Screen - Displays freeze frame data (snapshot of the operating conditions at the time of the fault)- Review data off-vehicle - Battery Powered - Reads and erases Diagnostic Trouble Codes and turns off check engine light - Retrieves all Generic OBD II trouble codes (P0), their definitions and pending codes - Enables user to quickly and easily link to their vehicle - Large easy-to-read LCD screen provides the Diagnostic Trouble Codes and their descriptions - Extremely user friendly menu provides:- Monitor Status and I/M Readiness to determine if vehicle is ready for an emissions test.

特点互联网更新（购买cp9137 ）-三种语言显示屏幕-显示器冻结帧数据（快照的操作条件，在时间的断层）-审查数据越野车-电池供电-内容和泯灭诊断故障码和关闭检查发动机轻-返回所有的通用的o bd二故障码（ p 0），其定义和解释，有待码-使用户能够迅速，轻松地链接到自己的汽车-大型易于阅读的液晶显示屏幕提供诊断故障码及其说明-非常方便用户菜单规定：-监察地位和我/米准备，以确定如果汽车已经准备好了排放测试。

About the existence of duadic codes, Ward and Zhu(1994) obtained necessary and sufficient conditions for existence of duadic abelian codes, Zhang(1997) gave the existent conditions for such codes by some parameters and obtained necessary and sufficient conditions for existence of central duadic group algebra codes.

对duadic群代数码的存在性问题，Ward和朱烈(1994)解决了域上duadic阿贝尔码存在性；张胜元(1997)年用参数形式给出更具体的判定条件和中心duadic群代数码存在的充分必要条件。

Salt is good, but if the salt becomes flat and tasteless, with what do you season it?

14：33 盐本是好的，盐若失了味，可用什么叫它再咸呢？

He reiterated that the PLA is an army of the people under the leadership of the Communist Party of China.

他重申，人民解放军是在中国共产党领导下的人民军队。