信号空间分集解码前传协同方法研究

在普通解码前传协同分集中,各协同用户之间的信道不对称性会对系统的性能产生一定的影响;同时,简单的重传信号并不是一种高效的利用协同分集的方式。该文提出了一种基于信号空间分集的解码前传协同方法,该方法的协同用户重传信号中包含自己的数据帧,并以信号空间分集的方法设计重传信号,这样既能够减小用户间信道的不对称性带来的影响,又提供了一种更为高效的信号分集方式。仿真实验结果证明该方法与非协同及普通解码前传协同方法相比能够获得更好的误码率性能。     

传播学学科地位的再认识

出现于二战以后的传播学,经过近６０年的发展,从没成为主导性的学科。面临时代提出的巨大课题,传播学也迎来了自身发展的最佳机遇,传播学研究的重心倾向媒介研究,传播的经济功能日趋重要,传播学的研究核心转向“信息人”研究。由于传播学在人文社会科学各学科中的特殊地位,传播学将成为学科部类之间联系的纽带。基于上述理由,传播学在不久的将来将成为人文社会科学的主导性学科。     

循环经济与交通运输可持续发展

阐述循环经济的基本内涵,论述用循环经济理念指导交通运输发展的必要性和意义,并提出了基于循环经济的交通运输发展战略构想。     

Gender Differences in Perceived Disciplinary Fairness

This exploratory study coded and analysed 120 behaviours on videotaped data of 111 male and 30 female managers engaged in disciplinary discussions with one of their unionized employees. Four categories of behaviour were coded: non‐verbal communication, speech characteristics, leadership and interactional justice. A factor analysis of the results generated 14 factors, ten of which were correlated with experts’ ratings of disciplinary fairness. Female managers exhibited significantly higher levels of seven of the ten behavioural factors. Female managers also made more supportive interruptions than male managers and took more time for the disciplinary discussion, both of which were positively correlated with disciplinary fairness. The results suggest that leadership and communication styles commonly found in females may lead them to be better equipped than male managers to manage employee discipline situations.     

Employee Drug Testing:

The authors examine the limitations of employee drug testing as a method of improving productivity and safety in the workplace. Attempts to modify licit and illicit drug use, including prohibition, are briefly reviewed, and the importance of social setting is underscored. The authors discourage the widespread use of employee drug testing because of problems in interpreting the significance of test results, laboratory errors, and possible civil liberties infringements. They propose that work performance be evaluated as a more reliable indicator of impairment, and they identify behaviors often associated with substance use. Finally, a protocol is recommended for the procurement and management of samples, laboratory standards and certification, and interpretation of test results, when testing is determined to be indispensible.     

基于遗传算法的无线传感器网络路径优化

提出使用遗传算法对无线传感器网络进行路径优化,考虑节点能耗和路由恢复时间等实际因素的影响,将这些影响作为路径优化问题的约束条件来处理;考虑各种约束条件和多种目标按照重要性的优先次序,使WSN有更长的寿命;对算法的各个环节进行了细致的分析,包括染色体的表示和编码、适应度函数的设计、遗传操作算子的设计及算法参数的分析和选取。大量的仿真实验证明,使用GA能找到WSN有效的优化路由。     

Getting out of the doghouse: The image repair strategies of Michael Vick

Michael Vick's federal dog-fighting conviction in 2007 made him notorious. Vick spoke publicly about his role in the dog-fighting operation only once before beginning a prison term. Three years after entering prison, he returned to National Football League action. By 2011, some in the media proposed that Vick had successfully rehabilitated his image and redeemed himself in the eyes of the public. This study examines the image repair strategies Vick employed at his August 27, 2007, press conference. It concludes that Vick chose appropriate strategies but did not fully develop one critical strategy: corrective action. The paper also explores Vick's strategic use of the third person and appeals to a supernatural being.     

IEEE 802.16无线信道快速突发均衡的实现

针对IEEE 802.16无线信道进行了仿真,提出了一种工作于该信道的16QAM突发模式的快速均衡器算法,该算法采用Neuman-Hoffman序列的扩展序列进行信道快速估计,及用均衡器系数预加载算法以提高收敛速度,仿真结果证明:算法收敛速度优于递归最小二乘算法。     

影响美国教育技术学发展的主要因素

技术发展、系统理论、学习与教学理论、传播理论、社会和实践领域是影响美国教育技术学发展的主要因素。社会需要是教育技术学发展具有必要性的保证;经济水平和政府支持提供了教育技术学发展的可能性。美国教育技术学的发展经历了媒体—传播、教育—设计、学习—绩效的几个发展阶段。     

相对时延对空时/时频调制系统性能的影响

在介绍空时/时频调制(ST-TFSK)系统原理的基础上,该文推导了在接收端已知相对时延条件下的非相干ML判决度量,讨论了在接收端未知相对时延条件下信噪比与系统误码率性能的关系,并将其结果与空时/频移键控(ST-FSK)系统的情形相比较。理论分析和仿真结果表明:低信噪比弱化了相对归一时延对ST-TFSK系统可靠性的影响;ST-TFSK系统对相对归一时延的敏感性弱于ST-4FSK系统。