Secure communications for cluster-based ad hoc networks using node identities

Ad hoc networks are self-configurable networks with dynamic topologies. All involved nodes in the network share the responsibility for routing, access, and communications. The mobile ad hoc network can be considered as a short-lived collection of mobile nodes communicating with each other. Such networks are more vulnerable to security threats than traditional wireless networks because of the absence of the fixed infrastructure. For providing secure communications in such networks, lots of mechanisms have been proposed since the early 1990s, which also have to deal with the limitations of the mobile ad hoc networks, including high power saving and low bandwidth. Besides, public key infrastructure (PKI) is a well-known method for providing confidential communications in mobile ad hoc networks. In 2004, Varadharajan et al. proposed a secure communication scheme for cluster-based ad hoc networks based on PKI. Since the computation overheads of the PKI cryptosystem are heavy for each involved communicating node in the cluster, we propose an ID-based version for providing secure communications in ad hoc networks. Without adopting PKI cryptosystems, computation overheads of involved nodes in our scheme can be reduced by 25% at least.     

二维扫描式水下电视控制系统的设计

由于受到水下环境的限制,水下电视系统一般不能实现全方位扫描。提出了一种新型的二维扫描式实时控制方案,并详细阐述了系统组成结构、软硬件设计。在船上或岸上使用该控制系统,可以对水下电视系统实施远程控制,并可以对水中运动目标进行水平360度,垂直90度的全方位扫描,不存在死角。     

一种分布式多策略数据库容灾系统

该文设计并实现了一种分布式多策略数据库容灾系统,该系统提供了多种备份和恢复策略,能快速有效地备份和恢复用户数据。当主数据库发生灾难时,能切换备用数据库为主数据库继续对外提供服务,保证业务的连续性。在主数据库失控"后,能销毁数据库上的数据,防止重要数据外泄。     

对我国通信技术创新发展的思考

经过多年努力,我国通信业取得长足发展,在大多数领域已具备了生产世界先进产品的能力,部分企业拥有了较强的技术研发能力。但与世界先进水平相比,仍存在一定差距,技术创新势在必行。对各国通信技术发展与创新历程进行了总结,初步提出我国通信技术创新体系框架,以及技术创新过程中应把握的几个关键点。     

High Altitude Platform Station (HAPS): A Review of New Infrastructure Development for Future Wireless Communications

This paper looks into the relatively new field of high altitude platform stations. HAPS is seen as a ‘middle ground’ between the terrestrial and satellite cases, and aims to exploit of the advantages of both types of system. Since HAPS is such a new field, this paper focuses on the technology behind a HAPS communications system, how this has developed, and compares it to the terrestrial and satellite equivalents. One important area that is being investigated is the applications for which HAPS should be used. This is a critical issue if a significant business case is to be made for HAPS. Worldwide HAPS projects and research issues are also highlighted. Finally, the review concludes with the remarks on the future of HAPS for wireless communications systems.     

卫星通信联合域抗综合干扰技术研究

分析当前卫星通信面临的多种干扰和抗干扰技术,提出综合考虑空域、时域和频域的联合域抗干扰的思想,阐述其未来的发展。针对现有的抗干扰技术和体制,探讨卫星通信联合域抗综合干扰技术,并对一些关键技术和体制的难点进行重点分析。     

大噪声干扰下的通信信号源定位挖掘算法仿真

研究通信信号源的优化定位问题.随着通信环境的复杂程度不断增加,环境中的随机干扰源会造成通信源信号频谱混合大量非线性噪声,噪声会对信号源频谱形成干扰,噪声频带和定位信号频带叠加时,传统的线性滤波器是在抑制噪声时,有用信号真实性差,检测微弱的通信信号源变得很困难,造成定位误差较大.提出了一种含噪混合通信数据中信号源定位挖掘算法.根据粒子运动状态方程,实现通信信号的滤波处理,为信号源定位提供准确的数据基础.利用通信节点同心圆定位方法,完成信号源定位.实验结果表明,利用改进算法进行通信信号源定位挖掘,能够提高定位的准确性,减小定位误差范围.     

网格服务的安全通信和访问控制

由于网格特性所依赖的平台是互联网,且其特性也决定了在使用中会遇到一系列安全问题,而其作为一种新兴的技术,必然会面临各种各样的挑战,因此研究网格安全通信问题就变得具有现实意义。从网格的研究现状出发,着重介绍网格服务的安全通信问题以及对网格访问控制进行探讨,提出几点构思。     

THE UNSOLVED MESSAGES OF PEARL HARBOR

In 1941, the United States Navy intercepted enough Japanese naval messages to predict the attack on Pearl Harbor if the code which protected them had been solved. The messages would have disclosed that, while the Japanese government cynically conducted diplomatic negotiations with the United States, the Japanese Combined Fleet under Admiral Isoroku Yamamoto, beginning as early as September 1941, systematically prepared ships, crews, weapons, tactics, and a complicated fuel supply system for the most ambitious operation ever undertaken by the Japanese navy. Details of Japan's intentions were hidden from Navy cryptanalysts because of limited manpower resources and because all Japanese navy codes were assigned a lower priority than Japanese diplomatic codes and German submarine threat.     

基于WindowsCE的空降部队快速集结系统的设计

介绍基于Windows CE平台下的空降部队快速集结系统的开发。包括整个系统的组成以及软硬件平台的结构,通过PB软件对嵌入式Windows CE操作系统内核的定制．并应用visual Studio2008开发GPS定位、无线通信应用系统软件．实现空降部队快速集结系统各项功能。经过测试,基于Windows CE平台下的空降部队快速集结系统能够准确获得GPS信息。定位误差和响应时间均能满足设计要求。