一种IPv6无线传感器网络以太网接入网关的设计

为了实现将IPv6无线传感器网络接入以太网,在分析现有接入系统不足的基础上设计了一套接入系统.在该系统中,设计并实现了基于嵌入式处理器ATmega128、智能射频芯片CC2420以及网络控制芯片RTL8019的接入网关设备.该设备可以将基于IEEE802.15.4的IPv6无线传感器网络接入以太网.采用模块化设计,引入了硬件抽象层和设备适应层相结合的软件驱动模式.说明了系统中数据与协议转换的基本原理.实验表明通过该设备能够灵活地完成网络间通信,具有应用价值.     

基于IPv6的多传输模式

描述目前网络数据传输的特点,据此提出了一种全新的数据传输方式——基于Ipv6的多传输模式,并设计了具体的处理方式。分析其效率,将其与现有的传输方式进行比较,新的传输方式极大地提高了数据传输的效率。根据目标客户端的多少及路由器转发跳数的多少,该传输效率将提升1.36倍～2.76倍,从而有效地降低整个网络的数据流量。新的传输方式还可以应用于所有一对多或多对多的数据传输环境。     

Trust-based minimum cost opportunistic routing for Ad hoc networks

Recently, opportunistic routing has received much attention as a new design direction. It can exploit the wireless broadcast and more highly reliable opportunistic forwarding, so as to substantially increase the throughput of network. Due to dynamic topology, distributed collaboration, limited bandwidth and computing ability, the absence of enough physical protection in Ad hoc networks, opportunistic routing is vulnerable to attacks by malicious nodes. In order to alleviate the malicious behaviors, we incorporate the concept of trust to Ad hoc networks, build a simple trust model to evaluate neighbors’ forwarding behavior and apply this model to opportunistic routing for Ad hoc networks. A new trusted opportunistic forwarding model is proposed by choosing the trusted and highest priority candidate forwarder, then a trusted minimum cost routing algorithm (MCOR) is formally formulated, the correctness and effectiveness of this algorithm from theoretical analysis are also approved. Finally, MCOR algorithm is verified by simulation using nsclick software and compared its performance with the classic protocols: ExOR, TAODV and Watchdog-DSR. The simulation results show that MCOR scheme can detect and mitigate node misbehaviors. Furthermore, MCOR scheme outperforms the other protocols in terms of: throughput, delay, Expected ETX, security-gains and cost of routing.     

Quasi-finite-time control for high-order nonlinear systems with mismatched disturbances via mapping filtered forwarding technique

In this study, a quasi-finite-time control method for designing stabilising control laws is developed for high-order strict-feedback nonlinear systems with mismatched disturbances. By using mapping filtered forwarding technique, a virtual control is designed to force the off-the-manifold coordinate to converge to zero in quasi-finite time at each step of the design; at the same time, the manifold is rendered insensitive to time-varying, bounded and unknown disturbances. In terms of standard forwarding methodology, the algorithm proposed here not only does not require the Lyapunov function for controller design, but also avoids to calculate the derivative of sign function. As far as the dynamic performance of closed-loop systems is concerned, we essentially obtain the finite-time performances, which is typically reflected in the following aspects: fast and accurate responses, high tracking precision, and robust disturbance rejection. Spring, mass, and damper system and flexible joints robot are tested to demonstrate the proposed controller performance.     

RSNs中一种基于货币的数据转发算法

在综合RFID和无线传感器网络的RSNs中,无线移动设备存在冗余,因此可以为数据报文的转发提供帮助.提出一种基于货币的信使转发(MCR)启发式算法.该算法在每个报文传输前使用了门槛价格,并通过RSN网络架构中的移动信使将数据从源节点转发到访问点时集成了价格协商机制,或将报文转发给信使,是否将报文直接传输给访问点,取决于重要度函数以及与报文门槛价格相关的信使要价.仿真实验结果表明,与其他主流移动传输方案相比较,本文算法在能耗、成本和送达率方面的性能更优.     

一种基于地理位置信息的Ad hoc网络路由算法*

在Ad hoc网络等无线网络中,GPSR是一种健壮的地理路由协议,但是当有较多的分组传递给同一个目的节点时,其周边转发模式产生的过多跳数的路由会成为一个突出问题。在此分析的基础上,提出了一个优化的路由算法——OGPSR路由算法。在第一个分组经历了与GPSR算法相同的周边转发模式传递后,该路由算法能够减少很大一部分路由的跳数。     

To Forward or not to Forward – that is the Question

We introduced the use of two-hop forwarding to increase the throughput of an 802.11 network in our earlier work (Narayanan et al., Proceedings of IEEE WCNC’05, March 2005). Other researchers have also considered the benefits of forwarding in the 802.11 infrastructure mode to increase the total network throughput. But the high-data rate node that forwards data for other nodes will have to spend its energy transmitting this data. Previous work on forwarding implicitly assumed that in an enterprise network, the collective good is sufficient to justify this increased energy expense. However, it is important to address the advantages and the cost of participating in such schemes from the individual forwarding node’s perspective. Since a node cannot know whether there are other high-data rate nodes in the network capable and willing to forward data, it needs to assume that it is the only node with the capability to do so. In this paper, we focus our analysis on the cost benefit for such a forwarding node. We quantify the throughput improvement, medium access delay reduction and energy consumption for the forwarding node in a saturated network. The analysis and simulation results demonstrate that in a saturated network, participation in forwarding provides the high-data rate node with significant benefits in throughput and media-access-delay, while increasing the number of bits-per-joule even if it is the only node participating in data forwarding as suggested in this paper. The increase in the bits-per-joule is due to the reduction in the total amount of time needed by the high data rate node to transmit a given number of its own application bits. This results in savings in energy expenditure for the forwarding node. Based on these benefits, we conclude that it is unequivocally in the interest of a high data rate node to participate in two-hop forwarding schemes in 802.11 networks.     

基于Agent的国际海运货代系统的设计与实现

针对海运货代系统智能、灵活与个性化的需求,本文提出了基于Agent的个性化国际海运货代系统的设计思想与实现过程。针对海运货代业务复杂繁多的特点,本系统采用招标—投标—中标方式实现任务的灵活分配,同时为满足客户个性化与高质量的需求,本系统对一基于QoS的服务选择算法进行改进,文章证明该改进算法可以选择出满足客户个性化需求且服务质量最好的服务。     

BFD技术在提高专网可靠性中的应用

主要介绍了专网的拓扑结构,分析了影响网络可靠性的几个因素和专网可靠性存在的问题;双向转发检测技术(BFD)的工作原理、常见的故障检测机制、BFD技术优点、OSPF路由协议交互工作流程,最后提出了工程中需注意的几个问题。     

基于MPLS的VPN技术探究

目前各种形式的网络应用已深入到千家万户的日常生活中,人们对骨干网络互连设备的性能、网络安全性以及稳定性的期望值越来越高。MPLS VPN是一新兴的网络技术,它具有安全性高、可管理性好、可扩展性强、QoS保障等特点。文中就这种新兴的网络技术,介绍了其重要的组成部分,以及MPLS VPN的基本框架结构,提出了地域级MPLS VPN解决方案,从而来提高网络的利用率与效益并大大改善整个网络结构的弹性与可扩展性。