Coordination of discrete‐time multi‐agent systems via relative output feedback

This paper investigates the joint effects of agent dynamic and network topology on the consensusability of linear discrete‐time multi‐agent systems via relative output feedback. An observer‐based distributed control protocol is proposed. A necessary and sufficient condition for consensusability under this control protocol is given, which explicitly reveals how the intrinsic entropy rate of the agent dynamic and the eigenratio of the undirected communication graph affect consensusability. As a special case, multi‐agent systems with discrete‐time double integrator dynamics are discussed where a simple control protocol directly using two‐step relative position feedback is provided to reach a consensus. Finally, the result is extended to solve the formation and formation‐based tracking problems. The theoretical results are illustrated by simulations. Copyright © 2010 John Wiley & Sons, Ltd.     

Organizational Norm Congruency and Interpersonal Familiarity in E‐Mail: Examining Messages From Two Different Status Perspectives

Relying on SIDE theory, this 2 × 2 experimental design tested the effects of adherence to organizational norms and interpersonal familiarity in e‐mail messages from both superior and subordinate perspectives. Results reveal that using norm‐congruent e‐mail messages account for over 50% of the variance in both superior and subordinate attitudes toward the message and between 30% and 56% of the variance in perceptions of source credibility. Data from the superiors indicate that norm congruent e‐mail messages account for 14.4% of the variance in message compliance. Results from subordinates reveal an interaction effect that is consistent with SIDE‐based predictions. Subordinates believe superiors are most likely to comply with e‐mail requests from unfamiliar subordinates that are crafted in a manner congruent with organizational norms.     

Exploring Privacy Management on Facebook: Motivations and Perceived Consequences of Voluntary Disclosure

This study examined the perceived motivations and consequences of voluntary disclosure of Facebook active users using a survey administered to college students in a public‐speaking course. College‐age students who took the survey were motivated to use Facebook because they perceived their relationships improved with friends and family, although using Facebook could become negatively habit forming. The research suggests that users of Facebook use it more for disclosing to distant friends rather than to close friends, which is divergent from most early disclosure research that equates disclosure with intimacy. This research utilizes Communication Privacy Management Theory for the theoretical framework.     

Virtual worlds as knowledge management platform – a practice‐perspective

Virtual worlds, as electronic environments where individuals can interact in a realistic manner in form of avatars, are increasingly used by gamers, consumers and employees. Therefore, they provide opportunities for reinventing business processes. Especially, effective knowledge management (KM) requires the use of appropriate information and communication technology (ICT) as well as social interaction. Emerging virtual worlds enable new ways to support knowledge and knowing processes because these virtual environments consider social aspects that are necessary for knowledge creating and knowledge sharing processes. Thus, collaboration in virtual worlds resembles real‐life activities. In this paper, we shed light on the use of Second Life (SL) as a KM platform in a real‐life setting. To explore the potential and current usage of virtual worlds for knowledge and knowing activities, we conducted a qualitative study at IBM. We interviewed IBM employees belonging to a special workgroup called ‘Web 2.0/virtual worlds’ in order to gain experience in generating and exchanging knowledge by virtually collaborating and interacting. Our results show that virtual worlds – if they are able to overcome problems like platform stability, user interface or security issues – bear the potential to serve as a KM platform. They facilitate global and simultaneous interaction, create a common context for collaboration, combine different tools for communication and enhance knowledge and knowing processes.     

Analysis of frequency‐selective impedance loading of transmission lines for dual‐band couplers

This article proposes an analytical design methodology for dual‐band hybrid couplers and baluns structures for any arbitrary frequency ratio using a stub‐loaded transmission line. An analysis of changing the impedance behavior of the stub, is carried out for the two bands of operation, which along with a dispersive analysis, emphasizes certain conditions where the existing methodology is not applicable. In addition, an extra degree of freedom has been included to increase the solutions for a given frequency ratio, thus providing greater flexibility and feasibility of the proposed structure. The design methodology is experimentally validated with the design and fabrication of dual‐band branch‐line and rat‐race couplers for various commercial frequency bands. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE , 2011.     

基于Trace的并行性能模拟任务任务映射方法

针对Trace驱动的并行性能模拟问题,提出基于Trace信息指导的映射方法CO-LP3M。CO-LP3M利用从Trace中提取的目标应用程序的通信特征,以宿主机物理进程间通信次数最小化为目标,兼顾计算负载均衡,生成并行模拟任务到宿主机的映射。对Jacobi3D和HPL两个程序进行实验改为：对HPL程序进行实验(注：此处本来是两个程序的,后来为了缩减篇幅就删掉了其中的一个),结果表明CO-LP3M可有效提高并行模拟性能,相对于常见的映射方式,模拟性能最多提高14.7%。在此基础上给出CO-LP3M的扩展技术SCO-LP3M。     

基于m叉树与DH协议的组密钥协商协议

为在动态对等通信环境下提高群组密钥协商的高效性与可扩展性,提出一种将m叉树结构与DH协议有机结合的组密钥协商协议。该协议与TGDH协议相比,通过采用m叉树结构,降低树的高度,减少计算量,与GDH协议相比,通过采用逐层式协商,降低通信开销。采用可变m叉树平衡该协议的计算开销与通信开销,使之同时适用广域网与局域网环境。     

可重构计算的硬件任务调度算法

提出一种可以减少数据传输量的调度算法RDMS。通过在调度过程中综合考虑任务中数据的关联性、硬件任务的资源利用率及内部任务之间的通信量,采用动态编程方法,减少微处理器和FPGA可重构协处理器之间的通信量及FPGA可重构资源的消耗。实验结果表明,RDMS能提高映射在FPGA器件上硬件任务的整体性能,有效降低通信开销和重构开销。     

SA-SVR在移动通信话务量预测中的应用

根据移动通信话务量的时间序列,采用基于模拟退火(SA)算法对超参数选择的支持向量回归机(SVR)进行建模预测。比较ARIMA、人工神经网络和SVR 3种模型的预测效果,并对比研究网格法、遗传算法和SA 3种SVR超参数选择方法对预测效果的影响。实验结果表明,SA-SVR预测精度高、耗时少,是一种预测移动通信话务量的有效方法。