基于OpenFlow的状态行为转发算法

OpenFlow标准的推出极大的促进了下一代互联网的发展。然而OpenFlow技术本身的结构也面临着挑战,由于OpenFlow交换机需要不断与Controller通信会增大延时,消耗网络带宽。本文针对OpenFlow交换机与Controller通信频繁的特点,提出了状态行为转发算法,该算法通过对转发表的访问频率方面进行优化,有效减少了OpenFlow交换机与Controller通信,降低了延时和带宽损耗。     

移动Ad hoc网络路由协议的ns模拟分析

Ad hoc网络是一种自组网,移动节点必须具备路由功能,那么路由协议选择至关重要。文章介绍了DSDV、DSR和AODV几种典型的路由协议。然后采用NS模拟的方法,得到了吞吐量、丢包率和端到端的延时性能分析图。通过对模拟结果的分析比较,给出这几种路由协议的优缺点及未来路由协议的发展方向。     

MANET路由协议在RPGM模型下的性能分析

本文首先对MANET网络中三种典型的路由协议DSDV、DSR和AOVD进行简单介绍,然后利用网络仿真工具NS2对MANET网络中这三种路由协议在RPGM群组移动模型下和不同移动节点数下的平均吞吐量、平均端到端时延、分组投递率和路由开销的仿真结果进行分析。     

成品油销售企业区域性物流配送系统的优化路径与策略

在提出区域性物流配送系统优化路径的基础上，从配送网点、配送运动以及配送信息等方面探究了我国成品油销售企业区域物流配送系统的优化策略和相关建议。     

基于不同节点移动模式的无线自组网路由协议性能分析

本文采用NS2网络仿真软件,随机建立包含100个节点的网络拓扑,在节点静止、缓慢移动和快速移动条件下,分别对AODV、DSR和DSDV三种路由协议的数据包端到端时延、抖动和吞吐量的变化趋势进行比较分析。仿真结果表明,在网络规模较大且网络拓扑变化不频繁的情况下,DSDV具有一定的优势;在网络规模较大且网络拓扑多变的情况下,AODV和DSR性能明显优于DSDV。     

基于AODV和AOMDV路由协议的多移动节点通信分析

针对项目中24个移动终端需要在无线自组网中进行联网通信的需求,为了使通信效率更高,需要选择一种能够适应节点移动带来拓扑变化的路由协议。文章对自组织网络中的AODV和AOMDV路由协议进行了比较和选择的过程。结合具体的仿真场景,通过NS2仿真平台对两种路由协议进行了协议性能测试。实验表明,在项目背景下,AOMDV的各项性能指标均优于AODV,且更加适合移动场景下多节点的通信。     

Dynamic vehicle routing with anticipation in disaster relief

Pickup and delivery problems (PDP), where locations may both receive and send goods, are an extension of the classical vehicle routing problem. This paper considers the application of a routing and scheduling problem for forwarding agencies handling less-than-truckload freight in disasters. The approach evaluates the benefits of dynamic optimization anticipating varying travel times (i.e., the availability of connections in this case) as well as unknown orders (i.e., the integration of demand regions on short-notice) in the specific environment of emergencies. The objective is to avoid delays and increase equipment utilization. We model a multi-stage mixed integer problem which is able to operate under variable demand and transport conditions.     

以均衡为目标的车辆调度问题研究

针对物流配送企业私人承包车辆以及均衡配送线路工作量等新的物流管理理念,提出新的车辆调度模型,将车辆调度问题（VRP）转换为车辆选型和车辆路径优化两个子问题,设计Ak-FirstFit混合算法解决车辆选型问题,运用遗传算法解决车辆路径问题。基于JAVA编写计算机程序,运行结果表明该两阶段算法能够在有效时间内得到满意解。与基于传统物流管理理念的模型进行比较,得出新的两阶段模型能充分体现兼顾效率与公平思想的结论,其理念在物流配送企业中具有相当的借鉴性和推广前景。     

Dispatching and routing of emergency vehicles in disaster mitigation using data fusion

The aim of this paper is to develop a robust methodology for the dispatching and routing of emergency vehicles (EVs) in a post-disaster environment with the support of data fusion. In this work, we consider an earthquake scenario with a large number of casualties needing medical attention. Given an influx of information (regarding casualties, road, traffic conditions, etc.), data are fused to provide estimates of the entities under consideration. We use this information to dispatch and route EVs to casualty pickup locations, followed by delivery to appropriate hospitals. Key factors here include patient priorities, clustering criteria, and distance. Similarly, factors affecting the dispatching of EVs from patient locations to hospitals include waiting time at hospital emergency rooms, hospital capacity, and distance. Routes must be generated for EVs by accounting for real-world road networks, existing road damage, congestion, and related issues. We develop a dispatching and routing simulation model, and utilize a case study to evaluate the performance of our proposed methodology.     

基于粒子群算法的应急物流配送车辆调度研究

结合应急物流配送的车辆优化调度问题,根据应急物流配送的突出特点,对应急物流配送车辆调度路径优化进行了探讨。并建立应急物流配送车辆调度模型,用粒子群算法对车辆的配送路径进行优化。最后通过对实例的分析,验证了本文所提出的模型、算法具有合理性和可行性。     

Secure smart grid communications and information integration based on digital watermarking in wireless sensor networks

As more and more wireless sensor nodes and networks are employed to acquire and transmit the state information of power equipment in smart grid, we are in urgent need of some viable security solutions to ensure secure smart grid communications. Conventional information security solutions, such as encryption/decryption, digital signature and so forth, are not applicable to wireless sensor networks in smart grid any longer, where bulk messages need to be exchanged continuously. The reason is that these cryptographic solutions will account for a large portion of the extremely limited resources on sensor nodes. In this article, a security solution based on digital watermarking is adopted to achieve the secure communications for wireless sensor networks in smart grid by data and entity authentications at a low cost of operation. Our solution consists of a secure framework of digital watermarking, and two digital watermarking algorithms based on alternating electric current and time window, respectively. Both watermarking algorithms are composed of watermark generation, embedding and detection. The simulation experiments are provided to verify the correctness and practicability of our watermarking algorithms. Additionally, a new cloud-based architecture for the information integration of smart grid is proposed on the basis of our security solutions.     

基于无线传感网的矿山井下通讯系统关键技术研究

基于无线传输协议,将无线通讯与有线通讯相结合,实现井下事故区域通讯系统的自愈,保障事故发生后矿井稳定的联络通讯、监测及定位;研究基于无线自组网技术与有线通讯相结合的自愈机理,开发可以自愈的通讯组件。文章基于码分多址的预约(ALOHA)防碰撞算法,结合传感网拓扑优化算法最优安置无线接收终端和路由,使传输监控系统达到传输最优目标。为井下监测、定位、通讯、安全预警、系统维护、跟踪、回放、查询、统计等重要数据和有用信息提供可靠传输支持,为井上营救提供重要依据。     

基于协同演化算法的物流配送车辆路径问题求解

针对物流配送车辆调度模型求解难的问题,以差异演化算法为基础,提供一种竞争型的协同演化算法来求解物流配送车辆路径模型．最后通过实例检验模型和算法的有效性,仿真结果表明协同差异演化算法求解物流配迭车辆路径模型具有一定的优越性。     

时变路网单车路径优化模型及算法

讨论了一类时变路网下单车辆配送路径优化问题,建立了基于时变路网以配送完成时间最早为优化目标的单车配送路径优化模型。在增加贪婪配送策略情况下,给出了车辆行驶时间满足FIFO规则的动态规划精确求解方法。数值算例验证了理论分析得到的结论。     

Information Communication Technology Utilization for Effective Emergency Management Networks

Effective communication and coordination are crucial aspects of emergency management. This study examines how organizational representatives perceive information communication technologies (ICTs) in communication and coordination with other organizations. Furthermore, it investigates whether the centrality of organizations in emergency management networks relates to ICT utilization. We found that although many central organizations in emergency preparedness networks have high levels of ICT utilization, ICTs are underused by central organizations in friendship networks and emergency response networks. An organization’s level of ICT utilization needs to match its organizational goal, mission, structure, ICT capacity, and the role that it plays within emergency management networks.     

Comparative evaluation of community-aware centrality measures

Influential nodes play a critical role in boosting or curbing spreading phenomena in complex networks. Numerous centrality measures have been proposed for identifying and ranking the nodes according to their importance. Classical centrality measures rely on various local or global properties of the nodes. They do not take into account the network community structure. Recently, a growing number of researches have shifted to community-aware centrality measures. Indeed, it is a ubiquitous feature in a vast majority of real-world networks. In the literature, the focus is on designing community-aware centrality measures. However, up to now, there is no systematic evaluation of their effectiveness. This study fills this gap. It allows answering which community-aware centrality measure should be used in practical situations. We investigate seven influential community-aware centrality measures in an epidemic spreading process scenario using the Susceptible–Infected–Recovered model on a set of fifteen real-world networks. Results show that generally, the correlation between community-aware centrality measures is low. Furthermore, in a multiple-spreader problem, when resources are available, targeting distant hubs using Modularity Vitality is more effective. However, with limited resources, diffusion expands better through bridges, especially in networks with a medium or strong community structure.

     

An adaptive distributed localisation in wireless sensor network

Many applications of wireless sensor networks (WSN) in industry can benefit from fine-grained localisation. In this paper, we propose an accurate, distributed localisation method which uses connectivity measurements to localise sensor nodes in WSN. The proposed method is based on a manifold learning embedding algorithm that adaptively emphasises the most accurate range measurements and naturally accounts for communication constraints within the WSN. Each node adaptively chooses a neighbourhood of sensor, updates its position estimate by minimising a local cost function and then passes this update to neighbouring sensors. Simulation results demonstrate that the proposed method is more robust to measurement errors than previous proposals and it can achieve comparable results using many fewer anchor nodes than previous methods.     

Node localisation in wireless sensor network based on self-organising isometric embedding

An accurate distributed localisation method which uses the connectivity measurement to localise nodes in wireless sensor network is proposed in this paper. The proposed method is based on self-organising isometric embedding algorithm that adaptively emphasises the most accurate range measurements and naturally accounts for communication constraints within the sensor network. Each node adaptively chooses a neighbourhood of sensors to update its estimated position by minimising a local cost function and then passes this update to neighbour sensors. Simulation demonstrated that the proposed method is more robust to measurement error than previous proposals and it can achieve comparable results using fewer anchor nodes than previous methods. The applications of the new method in logistics and transportation system monitoring are also illustrated in the paper.     

提高无线传感器网络的运行寿命方法

针对无线传感器网络的节点一般体积小,携带能量低,运算能力弱,能量一旦耗尽不可再生这一特点,本文提出提高网络运行寿命的方法。一方面,在网络节点运行时间上,将基站作为主控中心,根据系统的需求,采用有效的调度算法,来唤醒需要传输的无线传感器节点进行数据采集,然后将传输信息发送给簇头进行网络内传输,直至到达基站,从而获得传感器节点最小运行时间。另一方面,在网络内多跳通信时,靠近基站的簇头节点由于转发大量数据导致节点过早失效问题,本文提出一种不均匀分簇多跳算法,根据节点与基站距离调整簇首概率,能量优先为原则选择簇首,使据基站近的区域簇头多于据基站远的区域。     

带时间窗的应急救助物资配送车辆路径优化模型研究

在自然灾害突发后,必须将救助物资在规定的时间内运送到受灾点。针对带有时间窗的应急救助物资配送车辆路径优化问题进行研究,建立车辆路径优化模型并运用了蚁群算法进行求解,取得了较好的效果。