(n，1，m)递归系统卷积码的盲识别

递归系统卷积码（RSC码）是Turbo码子编码器常采用的编码形式。针对(n,1,m)递归系统卷积码的盲识别问题,给出了完整的编码参数和生成多项式识别方法。首先,采用矩阵分析法先求得卷积码参数,避免后续识别生成多项式时因参数循环估计带来的额外计算量。然后,根据RSC码的特性推导出生成多项式识别模型,给出了模型的具体求解步骤,并对所采用的Walsh-Hadamard变换算法进行了介绍。最后,运用Matlab平台进行仿真验证。仿真结果表明,该方法容错性能明显优于常规方法,在误码率为10－2条件下成功识别概率能达到90%,对于Turbo码的进一步研究具有重要意义。     

基于删余等效的高码率卷积码的低复杂度译码方法

根据删余卷积码具有较低的译码复杂度这一特征，提出了一种适用于普通高码率卷积码的低复杂度译码方法。通过多项式生成矩阵表示法，推导了删余卷积码的等效多项式生成矩阵，给出了等效多项式生成矩阵的计算准则。在分析删余卷积码与相同码率普通卷积码的等效关系和区别的基础上，提出了高码率卷积码的删余等效并给出了计算高码率卷积码删余等效后原始码和删余矩阵的方法。以原始码和删余矩阵构成的删余等效结构为译码基础，实现了高码率卷积码的低复杂度译码，其译码复杂度与原始码相当。仿真结果表明，删余等效译码方法相对于正常译码方法，其性能损失很小。     

基于多项式遍历和码字相关的Turbo码盲识别

针对1/n码率Turbo码的盲识别问题,提出了一种基于多项式遍历和码字相关的检测识别方法。该方法首先对码字序列进行分组,利用分组验证的方法对数据中的卷积码进行快速检测,进而识别出Turbo码的码率;然后,利用欧几里得算法对Turbo码的分量编码器a的参数进行识别,进而通过对编码器b的遍历,恢复出伪随机交织序列;最后,通过与信息序列的码字相关,验证编码器b的参数是否正确,同时利用相关谱峰值所在位置识别交织器参数,实现了Turbo码的全部参数估计。仿真实验验证了该算法的有效性。对算法的误码适应能力进行的仿真分析表明,该方法能够在较高误码率条件下实现Turbo码的检测与识别。     

Turbo码的编码调制技术

本文研究了Ｔｕｒｂｏ码与网格编码调制相结合的Ｔｕｒｂｏ码编码调制技术，给出了３种Ｔｕｒｂｏ码与ＴＣＭ相结合的调制方案，并进行了比较。对方案三进行了计算机模拟，从模拟得到的性能曲线表明，其性能要优于传统的采用卷积码的ＴＣＭ调制。     

规则LDPC码在瑞利平坦衰落信道下的设计和仿真

针对规则LDPC码，采用了行列都均匀的(evenboth)随机构造H的方式，在瑞利平坦衰落信道下和卷积码的性能进行了对比，证明了规则LDPC码在中短帧传输下在瑞利平坦衰落信道的优异性能。这对LDPC码应用于实际无线通信系统具有重要参考价值。     

接近香农限的编织卷积码设计与仿真

本文主要阐述了斜纹编织卷积码的编码结构、迭代译码以及活性距离和交织器对其误码性能的影响等基本概念。通过系统仿真,在AWGN信道下发现斜纹编织卷积码的系统性能与系统传输帧长和编码器个数都有很大的联系,其误码性能十分接近香农限,且没有错误地板效应。     

基于中国剩余定理和贪婪算法扩展的QC-LDPC码

在缩短阵列码的基础上运用中国剩余定理（CRT）和贪婪算法提出了一种新颖的大围长、码长更加灵活的QC-LDPC构造方法,且所构造的码字的校验矩阵采用楼梯矩阵循环置换而成。与传统CRT构造方法相比,只需已知一个分量码——缩短阵列码,同时新构造QC-LDPC码码长与码率选择比较灵活,围长更大,如果围长一样,则使最短环数量尽可能地少。仿真分析表明：在误码率为10-6时,在相同码率和码长的条件下,利用所提出的构造方法所构造的girth-8(4,k)QC-LDPC码在加性高斯白噪声(AWGN)和瑞利衰落信道中分别与缩短阵列码相比可获得约1.2 dB和2.0 dB的净编码增益,与CRT码相比分别改善了0.3 dB和0.7 dB的净编码增益,且性能与Gallager随机码性能相似但编码复杂度大大降低。     

一种改进的基于中国剩余定理的QC-LDPC码构造方法

为增大QC-LDPC码围长的同时减少码中包含的短环,提高其纠错性能,提出了一种基于中国剩余定理（CRT）的QC-LDPC码改进联合构造方法。该方法将设计围长为g的长码长的QC-LDPC码的问题简化为设计一个围长为g的短分量码的问题,然后通过对其余分量码校验矩阵的列块进行适当置换,使得构造出的QC-LDPC码具有更少的短环和更优的性能,更适于可靠性要求较高的通信系统。仿真结果表明,与已有的CRT联合构造方法设计的QC-LDPC码相比,新方法构造的QC-LDPC码具有更少的短环,在误码率为10-6时获得了1.2 dB的编码增益。     

非正则LDPC码在DSP上的实现

首先简单介绍了非正则LDPC码的结构,给出了一种基于IEEE802.16e直接编码法生成的(576,288)非正则LDPC码的编译码原理。然后详细论述了其在TI定点DSP(TMS320C5510)上的定点化算法实现方式,并在经过C和部分汇编优化后将算法效率提高了70%以上,达到了实时系统要求。最后给出了该LDPC码与(2,1,7)卷积码在AWGN信道下的性能对比,表明这种中短码长的非正则LDPC码较卷积码有较大的纠错性能优势。     

VHF/UHF无线高速数据传输中的级联编码

介绍了在VHF/UHF无线通信系统中进行高速数据传输时 ,采用RS码与卷积码的级联码对传输的数据纠错编码以及对提高数据传输可靠性的影响 ,并在加性高斯白噪声信道环境下对能够达到的误码性能进行了仿真分析。     

An Analysis of the Ethical Codes of Corporations and Business Schools

Reports of ethical lapses in the business world have been numerous and widespread. Ethical awareness in business education has received a great deal of attention because of the number and severity of business scandals. Given Sarbanes-Oxley legislation and recent Association to Advance Collegiate Schools of Business International’s (AACSBI) recommendations, this study examined respective websites of Securities and Exchange Commission (SEC) regulated public companies and AACSBI-accredited business schools for ethical policy statement content. The analysis was accomplished by classifying ethical expressions into a framework consisting of the attributes of thematic content and focus/themes partially based on the 2004 research of Gaumnitz and Lere. Findings indicate that public companies have been diligent in presenting website ethical content that closely follows authoritative recommendations. Business schools appear not to have prioritized such disclosure to the extent done so by public companies. Although there was improvement between two samples taken in 2005 and 2007, this study provides evidence that many accredited business schools have little or no disclosed ethical expectations in their mission, vision, goals, or other similar types of statements on their websites. Additional findings provide several opportunities for future research.     

A Content Analysis of Whistleblowing Policies of Leading European Companies

Since the introduction of the U.S. Sarbanes-Oxley Act in 2002 and several other national corporate governance codes, whistleblowing policies have been implemented in a growing number of companies. Existing research indicates that this type of governance codes has a limited direct effect on ethical or whistleblowing behaviour whereas whistleblowing policies at the corporate level seem to be more effective. Therefore, evidence on the impact of (inter)national corporate governance codes on the content of corporate whistleblowing policies is important to understand their indirect impact on whistleblowing behaviour. This study analyzes the contents of whistleblowing policies, and parts of corporate codes of conduct and codes of ethics, describing such policies of 56 leading European companies. By classifying the contents in seven categories, an exploratory framework was created. General contents often identified were: applicability to all employees, a group-wide scope and an authoritative tone. The most common general violations to report were breaches of internal policies and external regulations or laws. The more specific violations most frequently mentioned were criminal offences and dangers to health and safety or the environment. Contacts to report to were the direct or indirect supervisors, a compliance officer or a confidential “hotline” facility. A confidentiality guarantee was common and anonymous reporting was often possible, though sometimes discouraged. Protection against retaliation is stated by ensuring that retaliation will not happen, prohibiting it or making it punishable. The requirement of good faith was frequently given. Finally, investigation of the report was often guaranteed. Surprisingly little information is given on the treatment of whistleblowers reporting an unfounded complaint in good faith, or reporting a violation they were involved in. The study’s findings are most relevant to companies without a whistleblowing policy or those that intend to benchmark their policies, and to pan-European standard setters.     

LT码中高效联合度分布的设计

度分布是影响数字喷泉码性能的关键因素。传统的经典度分布如理想孤子分布、鲁棒孤子分布、二进制指数分布等,由于其明显的性能缺陷,已不能满足日益增长的多媒体业务的需求。为了设计一种性能优良的度分布,提出了两种新的联合度分布设计方案。首先,将泊松分布和滑动-鲁棒孤子分布相结合,构成一个比例系数的联合度分布;然后,将泊松分布、理想孤子分布、滑动-鲁棒孤子分布这三种度分布相结合,构成两个比例系数的联合度分布;最后,通过仿真查找的方法确定两种方案中的比例系数的最优值。仿真结果表明,提出的两种新方案和已知的经典度分布、单比例系数的联合度分布相比较,在译码成功率、误码率等性能指标上都有大幅提升。     

Using Student Generated Codes of Conduct in the Classroom to Reinforce Business Ethics Education

This paper presents four different contexts in which students practiced implementing business ethics. Students were required to develop Codes of Conduct/Codes of Ethics as a classroom exercise. By developing these codes, students can improve their understanding of how and why codes of conduct are developed, designed, and implemented in the workplace. Using the three-phase content analysis process (McCabe et al.: 1999, The Journal of Higher Education 70(2), 211–234), we identify a framework consisting of 10 classifications that can be used to assess learning outcomes in embedded ethics education. By analyzing the different content within each classification, instructors were able to gain a better understanding of differing application of ethical principles. This analysis indicates that there needs to be more research on codes of conduct for smaller units within an organization and more integration of work group codes of conduct into the business curriculum.     

系统极化码的置信传播译码性能分析

置信传播（BP）算法可以为系统极化码提供软信息作为判决依据,也可以为系统极化码在级联迭代译码中提供交换软信息。在详细描述基于信道极化结构的置信传播算法基础上,比较了系统极化码在软信息判决方法和极化编码判决方法下错误率性能的差异。仿真结果表明,软信息判决方法可以提高系统极化码的误比特率,在高信噪比下误帧率方面也略有提高。     

Codes of Ethics,Orientation Programs,and the Perceived Importance of Employee Incorruptibility

The purpose of this study was to determine the degree to which the review of corporate ethics codes is associated with individuals’ perceptions of the importance of virtue ethics, or more specifically, employee incorruptibility. A convenience sample of individuals working for a university or one of several business organizations located in the Mountain West region of the United States was compiled with a self-report questionnaire. A usable sample of 143 persons representing both the public and private industries was secured for use in this study. The results of an analysis of covariance showed that reviewing ethics codes during employee orientation was positively related to individuals’ beliefs that incorruptibility is an important individual virtue. The managerial implications of the findings are discussed along with suggestions for future research.     

窗口大小自适应的空间耦合LDPC码译码算法

空间耦合低密度奇偶校验（Spatially-Coupled Low-Density Parity-Check,SC-LDPC）码具有接近香农限性能,基于置信传播译码算法,窗口译码（Windowed Decoding,WD）能够获得较小延时的同时也存在一定的局限性。为了进一步提高WD的译码性能,对SC-LDPC码的窗口译码算法提出了提前终止译码和动态调整窗口大小相结合的改进方法。该方法监测窗口大小的动态变化及相应窗口的平均迭代次数,通过加性高斯白噪声信道下的仿真分析,与传统窗口译码相比,其误码率降低,且计算复杂度更低。     

A Code of Ethics for CorporateCode of Ethics

Are corporate codes of ethics necessarily ethical? To challenge this notion, an initial set of universal moral standards is proposed by which all corporate codes of ethics can be ethically evaluated. The set of universal moral standards includes: (1) trustworthiness; (2) respect; (3) responsibility; (4) fairness; (5) caring; and (6) citizenship. By applying the six moral standards to four different stages of code development (i.e., content, creation, implementation, administration), a code of ethics for corporate codes of ethics is constructed by which companies can be ethically audited for compliance. The newly proposed code of ethics for corporate codes of ethics was then applied to four large Canadian companies representing a variety of industries: telecommunications; banking, manufacturing, and high technology. The ethical audit of the four companies' ethics programs based on the proposed code indicates that all four companies have room to improve the ethical nature of their codes of ethics (i.e., content, creation, implementation, administration).