MANET节点移动模型仿真研究

移动自组网（MANET）节点移动特性对网络拓扑结构有重要影响,在合理的节点移动模型下对网络性能的评估才真实可靠。通过对网络仿真软件NS2进行拓展,实现个体、群体和具有地域限制的节点移动模型,提出物理链路和路由协议2个层面的评估准则,给出不同类节点模型对路由协议性能的影响程度。对研究和评估MANET的路由协议有重要的参考价值。     

基于微分方程的移动自组网病毒传播模型研究

在移动自组网(MANET)中,针对节点的移动性导致网络拓扑结构动态变化的特点,利用微分方程提出MANET中的病毒传播模型,并对构建的微分方程系统进行平衡点存在性和稳定性分析,得出病毒传播的阈值及消亡条件,从而进一步研究节点移动速度、通信半径、免疫成功率和免疫失效率对MANET中病毒传播的影响。选取相应的实验参数,对系统进行仿真实验,结果验证了实验仿真与理论分析的一致性。     

MANET环境中多角色的分簇信任评估模型研究

MANET是一种自组网络工作组,其将节点划分为固定节点和移动节点.在MANET环境下网络拓扑结构不断发生变化,网络节点之间相互协作完成互联与通信.正是由于移动MANET环境下路由的复杂性,网络中角色的信任评估机制对于网络的安全性具有非常重要的作用.对多角色节点的信任值进行研究,构建多角色的分簇信任评估模型,将节点角色划分为簇头、簇成员、网管、代理4种类型,从节点的相关度、信任值和移动性等多方面因素进行分析,计算簇头节点的信任值,并通过代理节点进行监督计算,构建基于簇透、代理和网关节点的简化网络,以节点分配关系计算节点的可信度,以NS2仿真检验模型的有效性,得出结果表明,研究的多角色的分簇信任评估模型能够较快、较为准确地检测出恶意节点,保证了移动网络应用的安全性.     

一个应用于移动Ad Hoc网络管理的簇生成算法

移动Ad hoc网络(mobile Ad hoc network,简称MANET)作为一种新型移动无线通信网,与其他通信网络相比独有的特性增加了网络管理的难度.目前对MANET网络管理的研究处于起步阶段,一些标准尚未制定,而且像存在单向链路和节点的相对移动性这类问题也在研究中被忽视.为此,提出了一个利用令牌机制与最小节点标识相结合,适用于层次性管理结构的基于图的MANET簇生成算法,以及对MIB(management information base)的建议性改进.算法充分考虑了网络存在的单向链路和节点的相对移动性,提高了网络管理的灵活性和可扩展性,为MANET的网络管理提出了一种新方法.     

基于主动网络的MANET协议栈的仿真设计

主动网络是一个开放的、可扩展的、可编程的网络系统.MANET(移动自组织网络)是由一组无线移动节点组成的,临时的、多跳的、无基础设施支持的无中心网络.上述两种网络都被看作新一代Intemet网络的研究热点,但是对于它们的研究目前仍局限在各自的领域.为了同时获得两种网络的优秀特性,提出了一种基于主动网络思想的MANET通信协议栈的设计方案.利用OPNET仿真软件,该协议栈的基本功能已经得到了初步实现.通过配置该协议栈,仿真节点既能够传输主动网络数据,又具有MANET节点的移动性与自组织能力.     

MANET移动模型分析与仿真实验

根据随机性、时间相关、空间相关、地理受限等特性对于MANET移动模型进行了分类研究，结合3种实际应用，包括战场环境、事件场景、参观展览，比较移动模型与之相应的特点和适用范围，研究了移动模型混合使用的可行性。利用ANSIM工具对其中常用的几种移动性模型进行仿真试验，比较了RW、RD、GM模型对节点平均邻居数、平均跳数、节点间连通性的影响，并进行了校园区内障碍物模型下节点移动的场景模拟。     

MANET中移动预测方法研究

MANET具有网络资源有限、网络中的节点可以任意移动、网络拓扑结构变化迅速等特点，导致了重路由操作的频繁发生，极大地消耗了网络资源，降低了网络性能。网络节点运动的预测在很大程度上有利于解决这个问题。本文首先讨论了MANET的移动特性和链路预测的可行性，然后对各种链路预测的基本原理和方法进行了分析与比较，最后探讨了该问题进一步的研究工作。     

多维MANET可靠性建模研究

移动自组织网络(MANET,Mobile Ad hoc Network)是一种不依赖固定基础设施且不需要中心控制的动态无线网络。由于其开放自治的无线网络环境及无中心、动态拓扑等特性,导致MANET无法保障通讯的持续性,同时容易受到各种安全攻击。因此相对于传统网络,MANET在网络的可靠性上存在很大的局限性。综合考虑了影响MANET可靠性的两大因素,即节点移动性和安全攻击,提出了多维MANET可靠性模型,并对模型结果进行了实验分析,进一步指出了影响MANET系统可靠性的关键参数。     

一种基于随机游走和共点的社交网络拓扑模型

研究移动社交网络拓扑模型,有助于在更深层次上理解移动社交网络的结构特性和进行相关安全软件的开发。根据移动社交网络的高度动态性,提出了基于随机游走的有向网络拓扑模型,通过上一状态的节点累计连接时间和共点个数变化来决定当前节点状态。仿真实验表明,构造的移动社交网络拓扑模型符合真实移动社交网络环境下具有幂律特性的拓扑结构。     

多跳无线移动Ad Hoc网络路由协议的研究分析

无线移动Ad Hoe网络(MANET)作为可移动分布式多跳无线网络，没有预先确定的网络拓扑或网络基础设施以及集中控制．为了在如此的网络中促进通信，路由协议主要用于在节点之间发现路径．Ad Hoe网络路由协议的主要目的是网络拓扑的动态变化、任意两个节点之间建立一个使得通信总费用和带宽消费最少的正确和有效的通信路径．描述了设计移动Ad Hoe网络路由协议所面临的问题以及对它们的评价，详细比较了七种典型无线移动AdHoe网络路由协议的特性和功能，即DSDV，CGSR，WRP，AODV，DSR，TORA和ABR，为进一步的研究提出了新的课题．     

The impact of mobility on Mobile Ad Hoc Networks through the perspective of complex networks

Mobile Ad Hoc Networks (MANETs) are wireless networks where nodes’ exchange of messages does not rely on any previously deployed infrastructure. Portable devices that are capable of wireless communication have become extremely popular making possible the establishment of wide ubiquitous networks. Users connected to such networks can access the provided services anywhere and anytime.Nevertheless, this architecture suffers from a highly unstable topology since links between nodes break constantly due to users’ movement. Mobility has a paramount influence on the network topology. Therefore, it is of utmost importance to understand the impact of mobility in MANETs. In this work, we perform a thorough analysis on how mobility shape the behavior of MANETs. Our range of observation varies from general MANETs composed of walking users to a next generation of MANETs formed by vehicles moving either in a city environment or in a highway scenario, namely Vehicular Ad Hoc Networks (VANETs). Our analyses are performed observing the networks through the perspective of complex networks. We were able to identify underlying characteristics of these networks and showed how these observations can be used to improve the performance of MANETs.     

Genetic algorithms with immigrants schemes for dynamic multicast problems in mobile ad hoc networks

In this paper, the problem of dynamic quality-of-service (QoS) multicast routing in mobile ad hoc networks is investigated. Lots of interesting works have been done on multicast since it is proved to be a NP-hard problem. However, most of them consider the static network scenarios only and the multicast tree cannot adapt to the topological changes. With the advancement in communication technologies, more and more wireless mobile networks appear, e.g., mobile ad hoc networks (MANETs). In a MANET, the network topology keeps changing due to its inherent characteristics such as the node mobility and energy conservation. Therefore, an effective multicast algorithm should track the topological changes and adapt the best multicast tree to the changes accordingly. In this paper, we propose to use genetic algorithms with immigrants schemes to solve the dynamic QoS multicast problem in MANETs. MANETs are considered as target systems because they represent a new generation of wireless networks. In the construction of the dynamic network environments, two models are proposed and investigated. One is named as the general dynamics model in which the topologies are changed due to that the nodes are scheduled to sleep or wake up. The other is named as the worst dynamics model, in which the topologies are altered because some links on the current best multicast tree are removed. Extensive experiments are conducted based on both of the dynamic network models. The experimental results show that these immigrants based genetic algorithms can quickly adapt to the environmental changes (i.e., the network topology changes) and produce high quality solutions following each change.     

具有多出入口区域的节点移动和分布研究

在Ad Hoc网络的仿真研究中,节点移动模型的选择会严重影响到网络的拓扑结构和通信协议的性能.然而,现有移动模型大多是为理想环境设计的,不能适用于真实环境.在理想移动模型RWP(Random Waypoint)的基础上,提出了具有多出入口区域的RWP节点移动模型(RWP with entrances,RWPWE).在该模型中,区域出入口是节点进出区域的必经之地,节点在区域内的移动符合RWP节点移动模型,通过引入域内停留概率来完成节点在区域内外移动的转移,并从节点移动速度、移动时间、移动路程和空间分布概率等几个方面研究了区域出入口的影响.理论分析和实验仿真的结果表明,由于出入口的存在,与RWP模型相比节点的移动更加复杂,节点的空间分布也显著不同,这些差别将会影响到网络的拓扑性能和对网络协议的评价.     

Mobility-sensitive topology control in mobile ad hoc networks

In most existing localized topology control protocols for mobile ad hoc networks (MANETs), each node selects a few logical neighbors based on location information and uses a small transmission range to cover those logical neighbors. Transmission range reduction conserves energy and bandwidth consumption, while still maintaining network connectivity. However, the majority of these approaches assume a static network without mobility. In a mobile environment network connectivity can be compromised by two types of "bad" location information: inconsistent information, which makes a node select too few logical neighbors, and outdated information, which makes a node use too small a transmission range. In this paper, we first show some issues in existing topology control. Then, we propose a mobility-sensitive topology control method that extends many existing mobility-insensitive protocols. Two mechanisms are introduced: consistent local views that avoid inconsistent information and delay and mobility management that tolerate outdated information. The effectiveness of the proposed approach is confirmed through an extensive simulation study.     

Dynamic backup routes routing protocol for mobile ad hoc networks

Mobile Ad Hoc Networks (MANETs), which provide data networking without infrastructure, represent one kind of wireless networks. A MANET is a self-organizating and adaptive wireless network formed by the dynamic gathering of mobile nodes. Due to the mobility of mobile nodes, the topology of a MANET frequently changes and thus results in the disability of originally on-the-fly data transmission routes. The dynamic properties of MANETs are therefore challenging to protocol design. To cope with the intrinsic properties of MANETs, Dynamic Backup Routes Routing Protocol (DBR²P), a backup node mechanism for quick reconnection during link failures, is proposed in this paper. DBR²P is an on-demand routing protocol and it can set up many routes to reach a destination node in a given period. Even when a link fails, those routes from the source node to the destination node can be analyzed to obtain backup routes to sustain quick reconnection. The information of backup routes can be saved in a specific on-the-route node and enables backup routes to be found immediately in situation regarding disconnection. As a result, DBR²P could more thoroughly improve the quality of routing protocol than those proposed in the past.     

基于资源传输节点拓扑紧密性的链路预测方法

针对现有基于网络拓扑结构的局部相似性RA指标未考虑传输节点拓扑紧密性的问题,提出一种节点拓扑紧密性指标及链路预测方法。根据多跳节点资源传输情况确定重要传输节点,基于传输节点周围拓扑集聚程度对拓扑紧密性进行量化,并根据传输节点紧密性对共同邻居传输资源量的影响刻画节点间相似性。实验结果表明,该方法具有较高的普适性,所提相似性指标适合于Precision标准,与CN、AA和CAR等现有相似性指标相比,具有较高的预测精度。     

基于时间距离与拓扑距离的连通性模型

网络连通性是描述网络性能的一项重要指标.机会传感网络中,节点移动导致网络的拓扑呈动态变化,这使得机会传感网络连通性的表征面临挑战.建立机会传感网络的连通性模型,有助于对机会传感网络的优化和维护.针对机会传感网络拓扑频繁变化的特点,基于时空图理论构建其连通性模型,描述拓扑演化规律;根据消息的可达性,考虑消息传输的时间特性和空间特性,定义了时间距离和拓扑距离,采用统计产品与服务解决方案软件（SPSS）分析其相关性,结果表明,时间距离和拓扑距离无明显相关性;采用网络快照间的时间距离与拓扑距离构建整网连通性模型.实验结果表明,所提出的模型能够从整体上刻画出机会传感网络的连通性;与基于Katz中心性的网络连通度模型相比,该模型能够更好地反映整网连通度的变化.     

基于双焦点离心测距的移动无线传感网定位算法

为解决移动传感网在拓扑流动性较高情形下存在的定位精度不高、数据传输能力不理想等不足,提出基于双焦点离心测距机制的移动传感网高效定位算法.对多跳路径进行弧度处理,构建基于弧度路径析构的节点椭圆定位机制,将直线路径析构为椭圆弧度边长,避免因裁弯取直而导致定位距离出现偏移,结合锚节点坐标已知的特性,对待定位终端坐标进行精度修...     

加权迭代节点匹配算法及其在语言网络中的应用

复杂网络间节点匹配在很多领域中均具有重要现实意义。然而,传统的节点匹配算法通常只利用网络的局部拓扑信息,在对拥有高对称性的真实网络作用时往往会失效。为了克服这一缺点,我们近期利用网络拓扑信息和连边权重信息,提出了一种新型的同时来计算不同网络间节点相似度的方法,并在此基础上设计了一种加权迭代节点匹配算法。将该算法在高度拓扑对称仿真网络对和真实中英文语言网络对上分别进行了测试,结果表明加权迭代节点匹配算法在此类网络上优于纯拓扑迭代节点匹配算法。     

一种基于图形数据库的快速电力网络拓扑分析方法

提出了一种基于图形数据库的通用拓扑分析方法,将多状态设备映射为多节点,每个节点的父对象都为此设备,将设备连接抽象为连接电缆节点和连接关系,每种设备的电气属性都抽象为节点和关系的属性,在将网络的拓扑信息入库后,组合利用图形数据库中的多种图形分析算法,并结合电力网络应用开发出相连节点连通性分析和停电范围检测算法,基于此开发的电网停电范围监测系统和变电站智能开票操作票程序该方法具备高可用性和高性能,取得了良好的效果．