Entities’ representation modes and their communication effects in collaborative design for SMEs

In distributed product development, Web-enabled collaborative design system with virtual reality (VR) function is good for representing the design features of 3D product entities in design communication. However, it is too expensive and complicated for most small and medium-sized enterprises (SMEs) to implement it. This paper explains that the series of still images, which also present the same efficiency in representing the design features of 3D product entities, can be easily produced at low cost and require less Internet bandwidth. In order to certify the weaknesses of the remote collaborative design system (RCDS) for the SMEs, this research started with a preliminary study to identify the unsatisfied problems associated with the mutual understanding between multi-disciplinary product development team members when using RCDS. Further investigation was presented as the perception/recognition ability experiment, which was conducted to use three types of 3D product entities representation, namely the group of still images, image-based VR and model-based VR, to certify the efficient product data visualization for remote design communication. This research concludes that the proposed representation mode and results of the research would be helpful for SMEs, which are relatively resource-restrictive, to handle the issues of remote design communication well.     

基于无线以太网和RSView32的自动化立体仓库监控系统

设计开发了1套基于无线以太网通信和RSView32组态监控软件的自动化立体仓库监控系统,介绍了该系统的主要功能、系统通信以及系统软件的设计及实现方法。     

光耦隔离技术在智能测控系统中的应用

在以单片机为核心构成的智能测控系统中,为提高系统的可靠性、稳定性,加强抗干扰能力,将MCU与外部信号进行电气隔离.在信号隔离传输中采用光电耦合器,并介绍了在智能测控系统中常用的数字量I/O、模拟量I/O、通讯等光耦隔离技术,在实际应用中已取得了良好的效果.     

光纤电流差动保护在应对冰灾期间采用公用通信网通道的改进措施

OPGW／ADSS光缆是一种电力网专用的通信媒体。由于充分利用线路走廊,具有施工方便、投资节省的优点,OPGW／ADSS技术被国内外大多数电力通信网所采用,成为最为主流、成熟的电力通信光缆,但在遭受冰灾时,会因为光纤通道中断而对电网的安全稳定运行造成影响,如南方电网在2008年冰灾期间的情形。介绍利用公用通信网增强电力通信抗灾能力的实例,并针对公用通信网是自愈环,电流差动保护不再适用的特点,提出了在光纤电流差动保护中增加光纤距离保护逻辑,应急期间仅使用纵联保护的技术方案。     

电力负荷管理系统中数据加密技术的研究

随着电力负荷管理系统的快速发展,对网络信息安全的要求也不断提高。通过对负荷管理系统传输数据特点的分析,结合电力负荷管理系统传输规约的协议要求,提出了一套数据加密和密钥管理的方案,该方案针对各种无线通信方式的不同特点,应用不同的加密算法,对协议的各个层次进行分别加密。最后对加密方案的性能进行了分析,其结果表明该方案有效地提高了系统的信息安全性能。     

Provably secure RSA‐type signature based on conic curve

In electronic communication and wireless communication, message authentication should be necessary. However, traditional method message authentication code (MAC) employs a symmetric cryptographical technique and it needs to keep a shared private key between two parties. For convenience, people now begins to use public key techniques to provide message authentication. In wireless communication, we shall save more space for message itself because of the limited resources. Therefore, we believe that our proposed digital signature scheme will be more fitful for this kind of communication due to the following merits: (1) in addition to inheriting the merits of RSA signature such as high verification efficiency, the proposed scheme also shows its advantage over RSA by resisting low public key exponent attack; (2) comparing with 1024 bits RSA, our digital signature scheme can sign 2048‐bit long message once, and generate a signature with 1025 bits length which doubles the capacity of the 1024‐bit RSA signature; (3) the scheme is provably secure and its security is tightly related to the hardness of conic‐based (CB)‐RSA assumption. Copyright © 2008 John Wiley & Sons, Ltd.     

基于VLAN技术的电子式互感器数字通讯的研究

基于以太网的电子式互感器数字输出方案使用组播/广播模式进行通讯,存在载波冲突、网络负载过重和广播风暴等问题。在分析了电子式互感器数字通讯和VLAN技术特点的基础上,对变电站网络建设和电子式互感器数字传输帧做了一定的改进,将VLAN技术应用于电子式互感器数字通讯中,使其利于互感器与二次设备利用组播/广播模式进行实时数据传输,从而提高了电子式互感器和二次设备之间通讯的实时性和可靠性。     

基于GPRS的分布式配电网络远程监控系统

介绍了一种基于GPRSModem的远程配电网监控系统,系统由主控中心和多个监控终端组成。采用GPRS通信方式,通讯速率高,费用低,组网方式灵活。终端对配电站的运行进行实时监测和控制,实现无人值守功能。主控中心完成对结果信息及故障原因的显示、存储、打印及对终端信息的维护管理功能。     

基于协议互补法的嵌入式工业以太网与现场总线协议转换器

首先介绍了MODBUS/TCP工业以太网协议和PROFIBUS-DP现场总线协议.从理论角度探讨了协议转换的实现方法,利用协议互补法原理研制出嵌入式MODBUS/TCP工业以太网与PROFIBUS-DP现场总线协议转换器.     

无线数据通信在动力供水远程监控中的应用

文章针对工业供水中存在的实际问题,基于先进的无线数据通信技术,提出了一个解决方案——动力供水远程监控管理系统。通过介绍Mobitex技术,分析设计了远程监控系统的硬件构成,同时对数据通信中的通信协议进行了合理的改造处理,开发了满足系统功能要求的监控软件,最后对该系统的实践应用情况进行了分析。