无线传输中短码长喷泉码的度分布优化算法

数字喷泉码是针对大规模网络数据分发而提出的一种新的信道编码方式。度分布是决定数字喷泉码译码性能的关键因素。为提高译码性能,针对应用于无线信道的喷泉码提出了一种度分布优化的算法。首先,根据理想孤子分布和鲁棒孤子分布产生度值序列,然后将该度值序列截短,在此基础上根据优化算法求解该序列中每个度值的最优概率,最后得到优化的度分布。仿真结果表明,本算法产生的度分布进行编译码产生的误码率低于鲁棒孤子分布和固定度分布,提高了译码性能。     

LT码新型度分布及其在电力线通信中的应用

Luby变换(Luby Transform,LT)码作为信道编码应用于电力线通信(Power Line Communication,PLC)，可实现电信号的可靠传输。度分布对LT码编译码性能的影响至关重要。为了得到更优的度分布，首先调整二进制指数分布(Binary Exponential Distribution,BED)中的度数比例，获得一种译码性能更优的改进的二进制指数分布(Improved BED,IBED)。然后，根据IBED在冗余度较小时译码成功率高，而冗余度增大后鲁棒孤子分布(Robust Soliton Distribution,RSD)的译码性能表现更佳的特点，通过求和归一化的方式将IBED与RSD两种度分布的优势进行有机结合，提出一种新型二进制鲁棒孤子分布(Binary RSD,BRSD)。仿真结果表明，与其他方法及传统的RSD相比，采用新度分布进行LT编码，可明显降低译码开销，并节约编译码耗时。将新型度分布应用于基于LT码的PLC系统中，能有效地抑制PLC信道中各种噪声对电信号的干扰，并提高通信效率。     

泊松过程的构成和检验

本文讨论了泊松过程的若干性质,给出了泊松过程的两种构成法及检验法,从而把泊松过程的检验化成了统计分布的检验,为泊松过程的应用提供了方便。     

一种咬尾双二进制Turbo码并行译码方案

针对双二进制Turbo译码使用并行、滑动窗联合译码技术时，其咬尾的编码构造和窗分割导致边界状态值难以获取的问题，提出了一种新咬尾Turbo码并行、滑动窗译码方案——扩展交叠方案。该方案采用了边界状态盲估计和滑动窗状态回溯两种新译码技术。相比于传统的边界状态度量传播方法（又称迭代法），新方法一方面提高了边界状态度量的准确性，从而加快了译码收敛速度，一定程度上减小了高信噪比下的性能损失；另一方面避免了存储前一次译码的迭代度量值，更有利于硬件设计。仿真表明，新方案在64左右的中等窗长下即可消除并行和滑动窗影响，逼近原始无并行无滑动窗译码的性能，且窗长越小，其相较传统迭代法带来的译码性能增益就越明显。该方案具有较好的实用性和应用价值，可以满足5G的高速率、低时延和低存储的数据传输要求。     

风险异质性在市场调研中的应用与扩展——人流量的统计分布探讨

本文结合非寿险精算中风险异质性研究方法,给出不同研究时间或研究地点人流量是否相同的判断准则,即人流量随机变量是否服从特定参数的泊松分布。并在此准则的基础上,进一步讨论了人流量不服从特定参数泊松分布的情形:将泊松参数视为随机变量,给出了3种基于不同先验信息的人流量分布形式。     

动态鲁棒补偿及其在改善跟踪伺服系统低速跟踪性能中的仿真验证

介绍了一种动态鲁棒补偿器的实现原理,并将其用来改善跟踪伺服系统的低速跟踪性能,仿真结果验证了该方法的有效性.     

风险异质性在市场调研中的应用与扩展——人流量的统计分布探讨

本文结合非寿险精算中风险异质性研究方法,给出不同研究时间或研究地点人流量是否相同的判断准则,即人流量随机变量是否服从特定参数的泊松分布。并在此准则的基础上,进一步讨论了人流量不服从特定参数泊松分布的情形:将泊松参数视为随机变量,给出了3种基于不同先验信息的人流量分布形式。     

基于有限域的QC-LDPC码编码协作通信及其联合迭代译码技术

为了提高系统的性能和易于工程实现,提出了基于有限域加群构造的QC-LDPC码,通过特殊的构造方法构造出满秩的QC-LDPC码并将之应用于编码中继协作通信系统的源节点和中继节点处,并由此构成了总体校验矩阵,导出了双层Tanner图,目的节点处采用基于双层Tanner图的联合迭代译码算法。仿真结果表明,误码率为10-5、迭代5次时,理想中继协作通信系统的性能好于非协作和非理想中继协作系统的性能,分别为1.3 dB和1 dB;并且S-D与R-D信道的信噪比相等时,S-R信道信噪比越高,非理想中继协作通信系统的性能越好。     

移动因特网不同流量下切换损失率研究

根据移动因特网中基本的硬切换和改进的半软切换算法时间流程仿真研究了 2种切换在泊松和自相似流量下的切换损失率。仿真数据表明 ,在网络负载均值相同的情况下 ,对于硬切换和半软切换 ,自相似流量的切换损失率要明显低于传统泊松流量 ,并通过分析泊松和自相似流量的概率密度函数尝试给出产生这一区别的原因。     

网络-信道联合编码的DmF协作通信技术

提出了一种采用网络-信道编码的解调前传(DmF)协作通信方案。与译码前传（DF）相比, DmF协作方式在中继处只对信号进行解调而非译码,因此,大大降低了中继节点的复 杂度。在由两个用户、一个中继节点和一个基站组成的通信模型中,采用LDPC信道编码 与网络编码结合的方式,构造了一种DmF协作传输方式。在基站处,通过构造的〖WTHX〗H〖 WTBZ〗矩阵对 来自两用户及中继的信号进行联合译码。仿真结果表明：所给方案的性能优于非协作方 式及无网络编码的协作通信方式,随着信噪比的增加这种优势会更加明显;另外,DmF的性 能与DF的非常接近,但其设备复杂度却大大降低,因此DmF比DF方式更具实用性。 同时,该方案在降低设备复杂度、减少延迟、有效对抗无线信道慢衰落、提高通信性能及频 谱利用率等方面都是非常有效的。     

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.     

扩展卷积码生成矩阵的统一表述

针对在删除卷积码识别过程中缺乏对扩展卷积码先验认知的问题,提出了一种求解母码与扩展卷积码生成矩阵的统一表述方法。通过分析编码器输入输出关系的基本物理意义,先后以(n,1,m)、(n,k,m)作为母码,构建了其与扩展后编码器多项式系数的对应关系模型,归纳和证明了扩展卷积码生成矩阵的统一表述定理。验证结果表明:该定理能够对扩展卷积码生成矩阵实现快速计算,为遍历和重建删除卷积码的删除图样和母码生成矩阵提供方便。     

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 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.     

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.     

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).     

一种新的缩短RS码迭代译码方案

为了在EPON中应用GF(256)标准RS码对信息帧长大于255位的信息流进行编码,并提高RS码的编码增益,提出了一种新的缩短RS码的编译码方案。该方案通过两个缩短RS码的交叠编码和互相迭代译码,可以提高编译码增益。RS码BM硬判决译码和chase软判决译码的计算机仿真表明,该方案对缩短RS码的软硬判决译码性能都有明显提高。     

Judgements about Computer Ethics: Do Individual, Co-worker, and Company Judgements Differ? Do Company Codes Make a Difference

When faced with an ambiguous ethical situation related to computer technology (CT), the individual's course of action is influenced by personal experiences and opinions, consideration of what co-workers would do in the same situation, and an expectation of what the organization might sanction. In this article, the judgement of over three-hundred Association of Information Technology Professionals (AITP) members concerning the actions taken in a series of CT ethical scenarios are examined. Respondents expressed their personal judgement, as well as their perception of their co-workers' judgement, and their understanding of the organization's judgement of the actions described in the scenarios. The findings show that there are differences in respondents' judgements for self, co-workers, and organization. Definitive patterns were also found between groups with and without organizational codes related to CT.