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。     

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。     

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。     

一种高可靠性的MANET网络改进AODV路由协议

针对普通AODV路由协议存在的路由发现和路由维护巨大开销问题,提出了一种改进的AODV路由协议。仿真结果表明,改进的AODV路由协议能有效地减少路由开销和端到端传输时延,提高协议效率和可靠性。     

移动自组织网络跨层QoS保证机制研究

在无线网络技术飞速发展的今天,无线移动自组织网络(Ad Hoc网络)的随时随地接入性,使其具有广阔的应用前景。但是同时Ad Hoc网络又有其脆弱性的一面,如由于节点移动导致网络拓扑动态多变以及链路连接的动态变化,无线信道具有不稳定性,业务流具有很强的突发性等,这些都使得网络中业务流的QoS得不到有效保障。因此,本文以跨层设计为思路,重点研究了Ad Hoc网络中MAC层和路由层技术。     

基于城市计算网络的信息交互建模

文章首先基于复杂网络节点的分析、粒子群算法原理综合节点个体属性和状态转换对节点移动的影响,建立具体的城市计算网络节点移动模型;其次利用传播模型的传播机制和社会网络研究理论,实现社会网络影响力建模;最后综合城市计算网络节点移动模型和社会网络影响力模型,提出“城区信息交互度”概念。     

基于聚类技术的NT网络拓扑推测方法研究

网络拓扑推测是网络管理中一项非常重要的技术，及时获取准确的网络拓扑对于改进网络协议和优化网络性能起着关键的作用。本文首先给出了NT的概念、依赖树模型，然后用聚类算法计算兄弟节点的度量函数值，最后在此基础上提出了完整的基于聚类技术的NT网络拓扑推测算法，该算法有着广泛的适应能力和扩展能力。     

基于复杂网络的闭环供应链风险传播模型构建及仿真

根据闭环供应链的结构特征,设计闭环供应链演化网络,并从风险对抗能力出发改进灾害蔓延动力学模型,以构建闭环供应链风险传播模型。仿真结果表明:闭环供应链网络中的风险传播范围与初始风险值、初始攻击节点数量成正相关;网络对抗风险能力与节点企业风险阈值和风险恢复能力分布的平均程度成正相关,且只有当风险阈值系数超过关键风险阈值系数时才能有效控制和预防风险的传播;度大蓄意攻击与随机攻击比度小蓄意攻击对网络风险传播的影响大,且制造商作为闭环供应链网络的中心节点,当其受到风险攻击时对网络造成的影响较大。     

Ad Hoc网络QoS保证机制研究

随遇通信时代主张无线网络为最合适的通信网络,而无线自组织多跳网络(Ad Hoc Networks)以其独特的特性为随时随地的访问提供了不可替代的技术支持[1]。但是同时Ad Hoc网络又有其脆弱性的一面,如由于节点移动导致网络拓扑动态多变,这会使得网络中业务流的Qo S得不到有效保障。将IEEE802.11e协议应用在Ad Hoc网络中,可以解决大网络服务保障性能的问题。     

PMIPv6的移动自组织网络邻居节点的快速发现机制研究

为有效改善车辆道路安全、降低交通拥塞,采用移动自组织网络使路网中的各车辆所采集的交通信息能与周边其他车辆共享,是智能交通系统中常用的技术方案。由于交通信息与车辆地理位置有高度的相关性,但目前网络中每个移动节点并没有地理位置资讯,在应用层中无法有效区分移动节点的地理位置。文章提出一种基于IPv6移动代理协议(Proxy Mobile IPv6,PMIPv6)邻居节点的快速发现机制,对每个移动节点在注册/切换后可以快速找寻到邻近的移动节点,并通过该机制的节点注册切换、注册切换所需网络延迟、以及Binding Cache更新所需成本进行性能分析,能有效解决移动自组织无线网络中移动节点快速识别邻居节点的问题。     

Study on the evolutionary optimisation of the topology of network control systems

Computer networks have been very popular in enterprise applications. However, optimisation of network designs that allows networks to be used more efficiently in industrial environment and enterprise applications remains an interesting research topic. This article mainly discusses the topology optimisation theory and methods of the network control system based on switched Ethernet in an industrial context. Factors that affect the real-time performance of the industrial control network are presented in detail, and optimisation criteria with their internal relations are analysed. After the definition of performance parameters, the normalised indices for the evaluation of the topology optimisation are proposed. The topology optimisation problem is formulated as a multi-objective optimisation problem and the evolutionary algorithm is applied to solve it. Special communication characteristics of the industrial control network are considered in the optimisation process. In respect to the evolutionary algorithm design, an improved arena algorithm is proposed for the construction of the non-dominated set of the population. In addition, for the evaluation of individuals, the integrated use of the dominative relation method and the objective function combination method, for reducing the computational cost of the algorithm, are given. Simulation tests show that the performance of the proposed algorithm is preferable and superior compared to other algorithms. The final solution greatly improves the following indices: traffic localisation, traffic balance and utilisation rate balance of switches. In addition, a new performance index with its estimation process is proposed.     

Computing systemic risk using multiple behavioral and keystone networks: The emergence of a crisis in primate societies and banks

What do the behavior of monkeys in captivity and the financial system have in common? The nodes in such social systems relate to each other through multiple and keystone networks, not just one network. Each network in the system has its own topology, and the interactions among the system’s networks change over time. In such systems, the lead into a crisis appears to be characterized by a decoupling of the networks from the keystone network. This decoupling can also be seen in the crumbling of the keystone’s power structure toward a more horizontal hierarchy. This paper develops nonparametric methods for describing the joint model of the latent architecture of interconnected networks in order to describe this process of decoupling, and hence provide an early warning system of an impending crisis.     

Network of companies: an analysis of market concentration in the Italian stock market

In this paper we propose an adjustment to the Herfindahl–Hirschman concentration index for explicitly considering the role of the topology of financial economic networks on market concentration. The case study of the Italian stock market serves for outlining the relevance of the shareholding network in the measurement of effective concentration. Moreover, we deepen the analysis of the network comparing network centrality measures, that are a well known method for understanding the relative relevance of network nodes. The correlations among them show their relation, and the fact that none of them can completely substitute the information contained in the size of companies. Such analysis constitutes the base for randomized experiments aiming at understanding to which extent the topology of this financial economic network is constraining the market concentration, so we derive and comment the results on the maximum value of HH \(_{i}\) under the scale-free constraint. We also show the fragility of the network under random rewiring, both unconstrained and constrained by the network topology.     

Modeling node heterogeneity in latent space models for multidimensional networks

Multidimensional network data can have different levels of complexity, as nodes may be characterized by heterogeneous individual-specific features, which may vary across the networks. This article introduces a class of models for multidimensional network data, where different levels of heterogeneity within and between networks can be considered. The proposed framework is developed in the family of latent space models, and it aims to distinguish symmetric relations between the nodes and node-specific features. Model parameters are estimated via a Markov Chain Monte Carlo algorithm. Simulated data and an application to a real example, on fruits import/export data, are used to illustrate and comment on the performance of the proposed models.     

A social activity and physical contact-based routing algorithm in mobile opportunistic networks for emergency response to sudden disasters

Sudden disasters such as earthquake, flood and hurricane necessitate the employment of communication networks to carry out emergency response activities. Routing has a significant impact on the functionality, performance and flexibility of communication networks. In this article, the routing problem is studied considering the delivery ratio of messages, the overhead ratio of messages and the average delay of messages in mobile opportunistic networks (MONs) for enterprise-level emergency response communications in sudden disaster scenarios. Unlike the traditional routing methods for MONS, this article presents a new two-stage spreading and forwarding dynamic routing algorithm based on the proposed social activity degree and physical contact factor for mobile customers. A new modelling method for describing a dynamic evolving process of the topology structure of a MON is first proposed. Then a multi-copy spreading strategy based on the social activity degree of nodes and a single-copy forwarding strategy based on the physical contact factor between nodes are designed. Compared with the most relevant routing algorithms such as Epidemic, Prophet, Labelled-sim, Dlife-comm and Distribute-sim, the proposed routing algorithm can significantly increase the delivery ratio of messages, and decrease the overhead ratio and average delay of messages.     

Interdicting interdependent contraband smuggling,money and money laundering networks

This paper focuses on the problem of interdicting the interdependent contraband smuggling, money and money laundering (ICSML) networks of a transnational criminal organization (TCO). There are four interdependencies among these networks: money flows from the physical contraband smuggling network to the money network, monetary support from the money network flows to the smuggling network, money flows from the money network to the laundering network and incentives from the laundering network flow to the physical and money networks. The goal of the TCO is to maximize a (weighted) balance between the profit and scale of the contraband smuggling business. The goal of law enforcement is to minimize the best possible performance of the TCO. A bi-level integer programming model is built to address the two-player nature of this decision-making environment that specifically captures the interdependencies of the criminal networks. A dual-based reformulation is applied to address the bi-level problem. Case studies of applying this reformulation technique to realistic data sets are presented with a particular focus on understanding how inaccurate information about the structure of the ICSML networks impacts the performance of interdiction decisions. Sensitivity analysis is performed to analyze this impact by examining selected interdictions for perturbations of the network. Insights obtained include an understanding of effective interdiction policies for these types of networks and what type of information is most critical to capture in order to make effective interdiction decisions.     

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。