基于城市公共交通移动模型的协作延迟容忍网络路由策略

如何利用有限的传输机会可靠地传送车载服务感知信息是智能交通发展的“瓶颈”问题,利用公共交通中车辆的运动规律,提出基于节点之间机会接触来进行消息的逐跳转发策略,同时结合公共交通系统自身的特点,设计了一种基于公共交通移动模型的协作延迟容忍网络（DTN）路由算法TF。首先,根据公共交通移动模型自身的特点,将公交、长途客车等节点按其运动路径进行分组,提出一种基于固定运动路径分组的DTN路由算法;然后,将出租车、行人类节点定义为自由节点,并设计了一种基于转发因子控制的DTN路由策略作为分组路由机制的补充。仿真结果表明,与Epidemic、Prophet以及SAW路由算法相比,TF路由算法具有较高的消息投递率和较低的平均延迟。     

基于DTN的地震救助移动模型及路由策略的研究

通过分析地震救援在黄金时间内的特性需求,在随机路径点模型和随机方向模型的基础上提出了基于DTN(delay tolerance network,DTN)的地震救助移动模型.在该模型下分别对灾民自救和救援队救助两个阶段进行研究,并提出了适合于地震救援系统的路由策略,通过机会网络仿真环境ONE进行仿真实验并验证了该移动模型和路由策略的正确性.     

DTN网络的延时模型分析

DTN(delay-tolerant network)是从ad hoc,WSN(wireless sensor network)等自组织无线网络中抽象出来的一种网络模型.其典型特征是节点之间的链路间歇性中断且中断持续时间较长,以至于在任意时刻源节点和目的节点间可能不存在路径,人们对DTN的研究尤其是对路由机制的研究已经很深入,但是作为路由算法所依赖的重要信息--延时--的分析模型还没有建立起来,从DTN数据包的投递过程出发,建立起DTN的延时模型,并利用排队论的相关知识进行分析,找出系统中各特征参数之间的关系,给出一般的结论,并对某些情形进行仿真,实验的数据显示理论结果和仿真数据拟合的很好.     

适用于VANET仿真的车辆合成运动模型

车载自组网(VANET)是移动Ad Hoc网络技术在交通领域的应用,已成为智能交通系统一项非常有前景的技术.准确反映节点运动方式的运动模型对于提高仿真实验准确性至关重要.首次利用了实际的卫星地图信息,在考虑实际道路环境特点基础上实现了新的节点运动模型--车辆合成运动模型,将该模型与随机路点模型和曼哈顿模型进行了对比,并在根据西安城区卫星地图构建的仿真场景中分别采用3种节点运动模型,利用QualNet仿真平台评估了不同节点运动模型对路由协议性能的影响.结果表明,节点运动模型对协议性能影响很大,分析认为合成运动模型更适合于VANET仿真研究.     

HMM改进Ad hoc网络延时的模型及抗毁性研究

为了更高效地处理无线移动自组织(Ad hoc)网络中的延时问题,采用了隐马尔科夫模型(HMM)进行移动方位的评估.HMM求解实现了Ad网络3个基本问题的求解,设计了移动节点观察的模型,MATLAB仿真表明参数值完全正确,符合观察要求.对模型进行抗毁性试验,网络的连通度较好,表明了抗毁性较强;节点最多发生在公共区域,表明网络连通性比较强.这一研究对于Ad hoc网络实际应用的拓展具有一定的价值.     

节点移动状态感知的社会化延迟容忍网络路由策略

针对延迟容忍网络因节点移动的时空特性变化导致网络性能下降的问题,建立半马尔可夫模型描述节点的移动过程,预测未来时刻节点处于某一地理区域的概率和节点间在未来时间段内的连接状态;同时,采用节点移动状态感知机制,对所预测结果的准确程度进行评估,进而提出了节点移动状态变化自适应的消息转发策略。仿真结果表明,基于节点移动状态感知的路由策略在网络交付率、开销比率及消息投递平均延时方面能够提升DTN的性能。     

无线传感器网络中的线性移动目标运动参数捕获方法

移动目标跟踪即移动目标的运动路径与参数获取在无线传感器网络应用中具有重要的研究价值.采用移动目标节点与信标节点间的TOA测量方法,提出了无线传感器网络中移动目标运动参数的捕获方法.通过建立移动目标运动参数的估计模型,本文首先推导了线性移动目标初始位置及移动速度估计的非约束线性最小二乘(ULLS)和约束线性最小二乘(CLLS)方法.将估计模型松弛为凸优化的半正定规划(SDP)问题,又设计了运动参数捕获的SDP算法.仿真分析结果表明,在3种所设计算法中ULLS算法的估计误差最大,SDP算法其次,CLLS算法的估计误差最小.随着采样周期的增加,初始位置的估计误差亦稍有增大,但速度估计误差却在减少.更多的采样点数量有利于增加测量信息量,可以有效减少位置及速度估计误差.     

自组网Random Direction移动模型点空间概率分布的研究

在无线自组网的研究中，研究移动模型点的空间概率分布是研究自组网协议的仿真评价和分析移动自组网许多相关特性(例如网络连通性、最小生成树、平均路径长度、网络容量等)的重要的基础问题．针对自组网经常使用的Random Direction移动模型运动节点的空间分布进行了研究，给出了一维及二维情况下运动节点空间概率分布的精确公式．研究结果为基于Random Direction移动模型的证明、仿真与应用提供了严格的理论依据．     

一种Ad Hoc网络群组移动模型

全面介绍了当前群组移动模型的研究进展,分析了不同群组移动模型的特点和应用范围,针时现有移动模型不能有效反映群组节点运动过程中行为特性的不足,提出了基于Gibbs分布模拟退火的群组移动(Gibbs sampler based simulated annealing group mobility,简称GGM)模型,并与目前广泛采用的参考点群组移动(reference point group mobility,简称RPGM)模型进行仿真比较,分析了两种群组移动模型对网络协议性能评价与网络拓扑的影响.仿真结果表明,通过选择不同的Gibbs势函数,GGM模型能够有效描述群体运动过程中的聚集行为、分散行为和列队行为;模型比较的结果也表明,不同的移动模型对Ad Hoc网络协议性能具有不同的影响.     

三维水下移动传感网多目标有向路径覆盖增强研究

水下传感网中实现多个移动目标的协同追踪任是一个技术难题,针对这个问题论文提出了一种分布式的多目标有向路径覆盖增强算法。在实际的三维水下传感网中,水下传感器节点会随着水流运动而移动,被追踪的目标具有自主行动能力。假设移动规律遵从Meandering Current Mobility模型,多个运动目标沿着基于概率的Random Walk移动模型轨迹运动。在论文提出的算法中,覆盖运动路径的传感器节点通过两跳邻居节点范围内的水下传感器节点协同决策来实现最大化路径覆盖,通过调整水下传感器节点自身的有向覆盖方向达到多目标轨迹路径有向覆盖率平均值最大,并使多目标轨迹路径有向覆盖率标准方差尽量小。最后论文通过MATLAB软件仿真来验证分布式覆盖增强算法的有效性,能够显著提高多个移动目标的路径覆盖率。     

基于极端学习机的MANET移动性预测模型

针对移动自组织网络移动性在管理无线网络带宽资源可用性方面的重要性,为了更好地规划连续服务可用性和有效能源管理以提升网络的整体服务质量,提出了一种基于极端学习机的MANET移动性预测模型。利用ELM对MANET中的任意节点进行建模;假设已知每个移动节点当前的移动性信息（位置、速度和运动方向角度）,以这种方式预测节点未来的位置和相邻节点之间未来的距离;基于几个标准移动性模型,产生更加真实、精确的移动性预测,从而更好地捕捉任意节点直角坐标系之间现有交互/相关性。使用标准移动性模型的仿真结果验证了所提模型的有效性,实验结果表明,提出的预测模型明显改进了传统基于多层感知器的模型,此外,当预测相邻节点之间未来距离时,避免了当前算法对预测精度的限制。     

Automatic mobility status estimation in wireless self-organised networks

Wireless sensor networks and ubiquitous computing are rapidly increasing in popularity and diversity. For many applications of these systems the mobility status of devices forms part of the operating context on which self-organisation is based.This paper describes a novel technique by which wireless devices such as sensor nodes can deduce their own mobility status, based on analysis of patterns in their local neighbourhood. The Self-Detection of Mobility Status algorithm (SDMS) uses a reinforcement learning inspired mechanism to combine the indications from five mobility metrics. For many systems in which a neighbour table is maintained through regular status messages or other interaction, the technique incurs no additional communication overhead. The technique does not require that nodes have additional information such as absolute or relative locations, or neighbourhood node density.The work considers systems with heterogeneous time-variant mobility models, in which a subset of nodes follows a random walk mobility model, another subset follows a random waypoint mobility model (i.e. has intermittent movement), some nodes have group mobility and there is a static subset.We simulate these heterogeneous mobility systems and evaluate the performance of SDMS against a number of metrics and in a wide variety of system configurations.     

SmallWorld Model-Based Polylogarithmic Routing Using Mobile Nodes

The use of mobile nodes to improve network system performance has drawn considerable attention recently. The movement-assisted model considers mobility as a desirable feature,where routing is based on the store-carry-forward paradigm with random or controlled movement of resource rich mobile nodes.The application of such a model has been used in several emerging networks,including mobile ad hoc networks(MANETs),wireless sensor networks(WSNs),and delay tolerant networks(DTNs).It is well known that mobility increases the capacity of MANETs by reducing the number of relays for routing,prolonging the lifespan of WSNs by using mobile nodes in place of bottleneck static sensors,and ensuring network connectivity in DTNs using mobile nodes to connect different parts of a disconnected network.Trajectory planning and the coordination of mobile nodes are two important design issues aiming to optimize or balance several measures, including delay,average number of relays,and moving distance.In this paper,we propose a new controlled mobility model with an expected polylogarithmic number of relays to achieve a good balance among several contradictory goals,including delay,the number of relays,and moving distance.The model is based on the small-world model where each static node has"short"link connections to its nearest neighbors and"long"link connections to other nodes following a certain probability distribution.Short links are regular wireless connections whereas long links are implemented using mobile nodes.Various issues are considered,including trade-offs between delay and average number of relays,selection of the number of mobile nodes,and selection of the number of long links.The effectiveness of the proposed model is evaluated analytically as well as through simulation.     

机器人自组网的运动控制模型仿真研究

机器人自组网具有较高的军事和民用价值;基于机器人通用运动学模型,对传统自组网的节点运动模型——随机路点和随机方向移动模型进行了修改,为机器人自组网中的节点建立了运动控制模型,并建立了机器人自组网的网络模型,对几种运动模型进行了仿真分析;结果表明,在机器人自组网的仿真场景中网络性能有所恶化;达到了较为真实地仿真机器人自组网的目的,得出的结论对机器人自组网的仿真研究具有一定的参考价值。     

High dynamic adaptive mobility network model and performance analysis

Since mobile networks are not currently deployed on a large scale, research in this area is mostly by simulation. Among other simulation parameters, the mobility model plays a very important role in determining the protocol performance in MANET. Based on random direction mobility model, a high dynamic adaptive mobility network model is proposed in the paper. The algorithms and modeling are mainly studied and explained in detail. The technique keystone is that normal distribution is combined with uniform distribution and inertial feedback control is combined with kinematics, through the adaptive control on nodes speed and prediction tracking on nodes routes, an adaptive model is designed, which can be used in simulations to produce realistic and dynamic network scenarios. It is the adaptability that nodes mobile parameters can be adjusted randomly in threedimensional space. As a whole, colony mobility can show some rules. Such random movement processes as varied speed and dwells are simulated realistically. Such problems as sharp turns and urgent stops are smoothed well. The model can be adapted to not only common dynamic scenarios, but also high dynamic scenarios. Finally, the mobility model performance is analyzed and validated based on random dynamic scenarios simulations.     

Modeling mobility in disaster area scenarios

This paper provides a model that realistically represents the movements in a disaster area scenario. The model is based on an analysis of tactical issues of civil protection. This analysis provides characteristics influencing network performance in public safety communication networks like heterogeneous area-based movement, obstacles, and joining/leaving of nodes. As these characteristics cannot be modeled with existing mobility models, we introduce a new disaster area mobility model. To examine the impact of our more realistic modeling, we compare it to existing ones (modeling the same scenario) using different pure movement and link-based metrics. The new model shows specific characteristics like heterogeneous node density. Finally, the impact of the new model is evaluated in an exemplary simulative network performance analysis. The simulations show that the new model discloses new information and has a significant impact on performance analysis.     

AUV辅助的水下传感器网络时钟同步算法

针对当前水下传感器网络中的时钟同步难题,设计了一种三元阵被动定位自主水下航行器（ AUV）模型,并基于此模型提出了AUV辅助的时钟同步（ AUV-Sync）算法。该算法通过AUV与节点之间相对运动过程中进行的信息交换来对节点相对距离进行估计,进而基于相对距离计算单向传播时延来降低由于节点移动性所导致的误差。最后,通过两轮加权最小二乘法进行线性回归来估计时钟同步的参数。仿真结果表明：在存在节点漂移的动态水下传感器网络环境中,该算法较其他相关算法有更高的精度。     

基于蒙特卡罗算法煤矿井下人员定位研究

对比分析几种常用的无线传感器网络节点定位方法.针对煤矿井下节点移动性可能导致普通的定位算法变得不精确,提出了蒙特卡罗定位(Monte Carlo Localization)算法.该方法利用物体运动的连续性,通过选取合适的模型完成移动节点位置预测与定位.经仿真验证在低密度锚节点环境下,蒙特卡罗方法位置估计误差明显低于其它方法,提高了移动节点定位算法的准确性.     

An environment-aware mobility model for wireless ad hoc network

Simulation is a cost effective, fast and flexible alternative to test-beds or practical deployment for evaluating the characteristics and potential of mobile ad hoc networks. Since environmental context and mobility have a great impact on the accuracy and efficacy of performance measurement, it is of paramount importance how closely the mobility of a node resembles its movement pattern in a real-world scenario. The existing mobility models mostly assume either free space for deployment and random node movement or the movement pattern does not emulate real-world situation properly in the presence of obstacles because of their generation of restricted paths. This demands for the development of a node movement pattern with accurately representing any obstacle and existing path in a complex and realistic deployment scenario. In this paper, we propose a general mobility model capable of creating a more realistic node movement pattern by exploiting the concept of flexible positioning of anchors. Since the model places anchors depending upon the context of the environment through which nodes are guided to move towards the destination, it is capable of representing any terrain realistically. Furthermore, obstacles of arbitrary shapes with or without doorways and any existing pathways in full or part of the terrain can be incorporated which makes the simulation environment more realistic. A detailed computational complexity has been analyzed and the characteristics of the proposed mobility model in the presence of obstacles in a university campus map with and without signal attenuation are presented which illustrates its significant impact on performance evaluation of wireless ad hoc networks.