无线协作Mesh网

异构无线网络的融合是当前无线网络的发展趋势。针对融合过程中遇到的诸如传输模式选择、负载平衡、路由和切换之类的问题,文章提出了一种新的网络融合架构：无线协作Mesh网。该架构基于无线Mesh网的网络结构,并通过协作通信进一步优化其结构、提升其性能。该架构能充分发挥Mesh技术高频谱效率、动态自组织的优点和协作通信高分集增益、高能量效率的优点,可为无线网络融合提供一种有效的解决方案。     

On the impact of a more realistic physical layer on MANET simulations results

Network simulation tools are frequently used to analyze the performance of MANET protocols and applications. Currently they offer only simple wireless communication models that neglect many radio propagation effects. In this paper, we integrate a more realistic physical layer model into a simulation tool. It consists of a radio propagation model and a model of wireless transmission errors. They have been evaluated against real-world measurements. We prove that such more realistic models change simulation results considerably. To the best of our knowledge, no other study of MANETs has been performed so far with such a detailed physical layer model. Hence, this paper also gives new insights on the performance of MANETs in real outdoor environments.     

Security of polarization-shift keying chaos optical communication system

To evaluate the security of a chaos optical communication system employing the polarization-shift keying (PolSK) modulation technology, its chaos characteristic needs to be verified. In this paper, an analysis was done for the signal of this system. Three methods were used to judge whether the signal was maintaining chaos characteristics or not: watching the strange attractor in three-dimensional phase space, computing the largest Lyapunov exponent by the equation which meets and Wolf's method, and evaluating the self-power spectrum density function. As a result, the strange attractor was clearly watched, the largest Lyapunov exponent was positive 0.0364 and 0.0106 respectively,and the self-power spectrum was wide and continuous with the noise background. The evaluation of chaos for the signal transmitted in the system is therefore presented. On the other hand, the minimal embodied dimension of the signal was given by the false nearest neighbors (FNN) method and it reached 6, which showed the higher dimension chaos characteristics of the system.Adding the analysis of the ability of anti-attack for the system, it is concluded that the system has higher security than the normal chaos masking schemes.     

增强安全系统中独特码通信原则

要害系统要求高等级安全性。根据增强安全系统中独特码形成原理,提出了独特码保真通信原则,包括独立通信原则、独特码信道中不可预存独特码信息原则和独特码每一个事件均必须以相同方式处理原则,并给出了数学证明和例证。     

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.     

基于规则推理的刀具材料智能选择系统

以难加工材料和硬质合金刀具为研究对象,针对它们各自的切削加工性,利用基于规则(RBR)推理方法,以Visual C++ 6.0为开发工具,SQL Server 2000为后台数据库开发平台,建立了一个刀具材料的智能选择系统。该系统具有准确、快速、方便的优点,适用于切削难加工材料的硬质合金刀具材料选择。     

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。