在电工与电子技术课程中融入素质教学的实践

针对当前教育改革的形势,对在《电工电子技术》课程改革中推行素质 教育的重要性和必要性进行了论述,结合实践介绍了把素质教育融入课程教学改革中的新模式。     

Internet中的页面价值快速算法模型研究

分析了普遍搜索引擎不能为用户提供具有个性化服务的原因,提出了基于页面内容与链接的页面价值快速算法,给出了算法的基本思想及对应的模型,并通过计算以转移概率矩阵为系数方程的特征值得到页面的价值。结果表明,新的模型能够以较少的计算量达到类似TFIDF算法的查全率。     

A resource-efficient and scalable wireless mesh routing protocol

By binding logic addresses to the network topology, routing can be carried out without going through route discovery. This eliminates the initial route discovery latency, saves storage space otherwise needed for routing table, and reduces the communication overhead and energy consumption. In this paper, an adaptive block addressing (ABA) scheme is first introduced for logic address assignment as well as network auto-configuration purpose. The scheme takes into account the actual network topology and thus is fully topology-adaptive. Then a distributed link state (DLS) scheme is further proposed and put on top of the block addressing scheme to improve the quality of routes, in terms of hop count or other routing cost metrics used, robustness, and load balancing. The network topology reflected in logic addresses is used as a guideline to tell towards which direction (rather than next hop) a packet should be relayed. The next hop is derived from each relaying node’s local link state table. The routing scheme, named as topology-guided DLS (TDLS) as a whole, scales well with regard to various performance metrics. The ability of TDLS to provide multiple paths also precludes the need for explicit route repair, which is the most complicated part in many wireless routing protocols. While this paper targets low rate wireless mesh personal area networks (LR-WMPANs), including wireless mesh sensor networks (WMSNs), the TDLS itself is a general scheme and can be applied to other non-mobile wireless mesh networks.     

HMRB:基于层状多环结构的应用层多播协议

提出HMRB（Hierarchical Rings Based）协议,并对其性能进行仿真评估.HMRB建立在层次多环拓扑之上,是-可扩展的应用层多播协议.该方案设计提出区间划分机制.通过该机制可以简单快速地建立起转发树转发数据.利用p2psim,对HMRB进行性能仿真并和NICE协议作比较.仿真结果表明：和NICE相比,HMRB带宽利用率高、平均路径长度小、链路压力低.     

Multifold node authentication in mobile ad hoc networks

An ad hoc network is a collection of nodes that do not need to rely on a predefined infrastructure to keep the network connected. Nodes communicate amongst each other using wireless radios and operate by following a peer‐to‐peer network model. In this article, we propose a multifold node authentication approach for protecting mobile ad hoc networks. The security requirements for protecting data link and network layers are identified and the design criteria for creating secure ad hoc networks using multiple authentication protocols are analysed. Such protocols, which are based on zero‐knowledge and challenge‐response techniques, are presented through proofs and simulation results. Copyright © 2007 John Wiley & Sons, Ltd.     

Loss and Noise Characteristics of Microwave Direct Modulated Optical Links

Loss and noise figure of optical links transmitting microwave signals —e.g. for remote antennas in wireless communications — are dealt with.Conditions are rather general and include arbitrary matching conditions, shotnoise, and laser relative intensity noise. Specific and somewhat surprisingcharacteristics are derived. Among others, it is shown, that — likepassive, purely microwave systems — noise figure is not proportional toelectrical loss and it can be even lower than loss itself. Optical powershould be as low as possible — this limit is mainly determined by therequired dynamic range of the system. Loss and noise figure were measured inan experimental setup. Results of the measurements proved the theoreticalfindings rather well. Preliminary results on the transmission of 32TCM signalsover the link are briefly presented.     

Locating the two-median of a tree network with continuous link demands

Typical formulations of thep-median problem on a network assume discrete nodal demands. However, for many problems, demands are better represented by continuous functions along the links, in addition to nodal demands. For such problems, optimal server locations need not occur at nodes, so that algorithms of the kind developed for the discrete demand case can not be used. In this paper we show how the 2-median of a tree network with continuous link demands can be found using an algorithm based on sequential location and allocation. We show that the algorithm will converge to a local minimum and then present a procedure for finding the global minimum solution.     

Stabilizing the monodromy of an open book decomposition

We prove that any mapping class on a compact oriented surface with non-empty boundary can be made pseudo-Anosov and right-veering after a sequence of positive stabilizations.      

上海7号信令链路负荷能力的测试

为了建成上海市 7号信令网 ,保证全网的安全割接过渡 ,需要对设计方案中正常工作时每根链路承担 0 2E的设计依据进行验证。因此 ,模拟实际情况 ,运用模拟呼叫机和人工拨测相结合的方式 ,对全网所有在用制式 :DMS 1 0 0、F 1 5 0、S 1 2 40 ,进行了满负荷实测。经过测试 ,积累大量数据 ,并得出相应结论 :DMS STP、F 1 5 0符合厂商设计指标 ,分别达到 0 49E、0 5 4E ;S 1 2 40没有符合要求 ,在保证通信质量的条件下 ,只能在 0 2 3E以下使用。另外 ,S 1 2 40系统只有 2根A链路时 ,若一根发生故障 ,另一根因超负荷而翻转 ,就必须将话务量降低到一定程度才能恢复。     

移动多媒体一体化解决方案--FLO技术探讨

对美国高通公司推出的MeidaFLO进行了介绍.特别就其FLO空中接口技术与另一种主流技术DVB-H进行了比较.作为一种全新的无线多媒体传输技术,FLO创新的一体化解决方案、优化编码方式、分层调制与手机高度集成等特性使得其在实现多媒体传输方面拥有其它技术无法比拟的优越性.