一种新的穿越战场监控区域最优化路径算法

现代战场密布用来监控敌对目标活动的传感器,由于电子探测设备的限制,只能探测敌方布置的部分监控传感器,因此如何穿越监控区域就成为了一个很重要的问题.结合实际提出动态Voronoi图的概念,只需知道部分传感器分布情况利用动态Voronoi图建立穿越模型,并把此模型映射为网络节点图,通过限制搜索区域,限定搜索方向,引入优化策略,提出一种新的快速Dijkstra搜索算法,寻找出一条最优路径.经仿真验证了算法的有效性.     

传感环境下基于局部Voronoi图的启发式反监控路径发现算法

针对移动对象通过传感区域时的安全问题,提出了一种基于局部Voronoi图(VT)的启发式反监控路径发现算法.首先,给出了一种基于局部Voronoi图的路径暴露风险近似估算模型.在该模型中,移动目标可依据当前探测到的传感器节点位置信息动态生成局部Voronoi图,并可依据定义的暴露风险计算公式近似估算出局部Voronoi图中各条边所对应路径的暴露风险.然后,在此基础上设计并实现了一种启发式的反监控路径发现算法.在该算法中,移动目标可首先基于局部Voronoi图确定自己的下一跳位置点候选集,然后再基于定义的启发式代价函数从候选集中选择一个风险代价最小的位置点作为其下一跳目标位置点.最后,沿着局部Voronoi图中对应的最小暴露风险路径移动到该目标位置点.理论分析和实验结果表明,所提算法具有良好的反监控性能,针对部署有n个传感器节点的区域,能够使得移动对象在不超过O(n log n)的时间内快速找到一条具有较低暴露风险的路径来穿越整个传感区域.     

可移动各向异性传感器网络的反监控算法

研究移动目标在可移动传感环境下的反监控问题,设计一种新的暴露模型,用于估计布置了大量可移动各向异性传感器节点的区域中,目标沿路径进行穿越时的暴露程度。基于该模型,利用各向异性Voronoi网格,提出一种判决算法,该算法使目标穿越监控区域时,可以选择合适的、暴露程度较小的穿越路径。理论分析和实验结果表明,该算法实用性和可靠性较高。     

智能目标穿越传感区域的改进算法

随着传感网络的发展,人们越来越多的应用它来进行监控.而智能目标在穿越传感区域时,是有能力寻找更好的路径来降低被传感网络探测到的风险的.针对智能目标该如何穿越传感区域的问题,分析了现有的穿越算法的不足,基于目标视野有限,不能一次了解到整个区域所有传感节点分布状况的情况,提出了一种基于局部Voronoi图的改进的算法:目标在前进的途中不断进行探测,如果发现新的传感器出现时,随时进行必要的调整来重新选择前进的路线.最后进行了仿真模拟试验,取得了较好的效果.该算法有效地减少了目标在穿越整个区域过程中的风险,具有积极的意义.     

移动传感器栅栏覆盖研究

栅栏覆盖保证当某个移动目标沿任意路径穿越监控区域时都能被检测到,适合于移动监测和边界保护等应用.随机部署静止传感器时,为保证栅栏覆盖需要大量节点,造成了不必要的浪费.本文利用可移动传感器进行栅栏覆盖,移动传感器随机部署后能够自动再部署,可以利用少得多的节点保证栅栏覆盖.本文研究了能量有效的栅栏覆盖再部署问题,并设计了一个集中式再部署算法,为所有节点计算最优的再部署位置.     

基于蛙跳算法的无线传感器网络节点重部署

针对传统无线传感器网络节点重部署覆盖方法没有进行子群节点局部搜索,导致方法存在覆盖率较低、节点连通性较差等问题,提出基于蛙跳算法的无线传感器网络节点重部署方法,初始化无线传感器网络节点,引入蛙跳算法,将全局的信息交换和子群局部搜索结合,确定无线传感器所能够探测的区域范围,利用微积分方法求解不规则区域,获取网络节点最优解,实现无线传感器网络节点的重部署.实验结果表明,研究方法覆盖率较高、节点连通性较好、节点能量较高,具有更好的应用价值.     

无线传感器网络中基于线性聚合的启发式穿越算法

当智能目标穿越敌方无线传感器网络的穿行时间受限时,现有基于广度优先搜索的穿越算法不能保证路径满足约束条件.为此,建立了一种穿越模型,并提出一种启发式的近似数值优化算法:k-shortest path-线性聚合启发式穿越路径算法(kSP-LAHTP).算法利用Voronoi图将连续路径问题域离散化,以曝露度和穿行时间为衡量指标,结合线性聚合的启发式路由机制,使目标实现满足时间约束值的最佳穿越.分析和实验结果表明:算法很好地解决了目标穿越时间受限情况下的穿越问题;且随系数k的增加,算法搜索路径更接近实际最佳.     

基于Voronoi的无线传感器网络栅栏覆盖策略

在栅栏覆盖研究中,针对节点部署区域存在无法被监测到的穿越路径的问题,将[Voronoi]图引入栅栏覆盖,划分整个部署区域,提出了基于[Voronoi]图的无线传感器网络栅栏覆盖策略,并监测部署区域是否存在栅栏覆盖空洞,以决定节点是否通过有限移动重新部署空洞区域,实现了对栅栏部署区域的有效覆盖。仿真实验结果表明,该算法提高了对监测区域的覆盖质量,以较低能耗和较少节点构建栅栏,达到预期覆盖要求。     

基于改进势场的有向传感器网络路径覆盖增强算法

路径覆盖是无线传感器网络目标监控领域的一个热点研究问题,在分析节点主感知方向可调模型的基础上,提出了一种基于改进势场的有向传感器网络路径覆盖增强算法(improved potential field based path coverage-enhancing algorithm,IPFPCA).该算法针对传统虚拟势场可能出现的局部极小导致覆盖增强失败问题设计了一种改进的势场函数,通过将相邻传感器节点对路径轨迹点的共同覆盖率引入到斥力计算中,有效引导节点的主感知方向调整,从而达到路径的高效覆盖.实验结果表明:对比已有的路径覆盖增强算法,IPFPCA可以消除节点的感知重叠区和盲区,最终实现网络路径的高效覆盖.     

基于数据融合确保目标检测精度的传感器节点布置

在使用无线传感器网络进行目标检测时,如何布置尽可能少的传感器节点而同时实现高的正确检测概率和低的误警率,是关键问题之一.采用数据融合技术,能实现传感器节点之间的协同,从而大幅提高目标检测精度.提出了用于目标检测的精度模型,分析了数据融合半径与传感器节点密度之间的关系,设计聚类方法将目标点组织成布置单元,从高密度单元到低密度单元布置传感器节点覆盖目标区域.仿真结果表明,算法在保证检测精度的同时能有效减少所使用的传感器节点数目.     

A grid-based coverage approach for target tracking in hybrid sensor networks

Most existing work on the coverage problem of wireless sensor networks focuses on improving the coverage of the whole sensing field. In target tracking, the interested coverage area is the emerging region of a motorized target, not the whole sensing field. As the motorized target moves, the emerging region is also dynamically changed. In this paper, we propose a grid-based and distributed approach for providing large coverage for a motorized target in a hybrid sensor network. The large coverage is achieved by moving mobile sensor nodes in the network. To minimize total movement cost, the proposed approach needs to solve the following problems: the minimum number of mobile sensor nodes used for healing coverage holes and the best matching between mobile sensor nodes and coverage holes. In the proposed approach, the above two problems are first transformed into the modified circle covering and minimum cost flow problems, respectively. Then, two polynomial-time algorithms are presented to efficiently solve these two modified graph problems, respectively. Finally, we perform simulation experiments to show the effectiveness of proposed approach in providing the coverage for a motorized target in a hybrid sensor network.     

A learning automata based scheduling solution to the dynamic point coverage problem in wireless sensor networks

The dynamic point coverage problem in wireless sensor networks is to detect some moving target points in the area of the network using as few sensor nodes as possible. One way to deal with this problem is to schedule sensor nodes in such a way that a node is activated only at the times a target point is in its sensing region. In this paper we propose SALA, a scheduling algorithm based on learning automata, to deal with the problem of dynamic point coverage. In SALA each node in the network is equipped with a set of learning automata. The learning automata residing in each node try to learn the maximum sleep duration for the node in such a way that the detection rate of target points by the node does not degrade dramatically. This is done using the information obtained about the movement patterns of target points while passing throughout the sensing region of the nodes. We consider two types of target points; events and moving objects. Events are assumed to occur periodically or based on a Poisson distribution and moving objects are assumed to have a static movement path which is repeated periodically with a randomly selected velocity. In order to show the performance of SALA, some experiments have been conducted. The experimental results show that SALA outperforms the existing methods such as LEACH, GAF, PEAS and PW in terms of energy consumption.     

Effective target tracking mechanism in a self-organizing wireless sensor network

Target tracking is an important sensing application of wireless sensor networks. In these networks, energy, computing power, and communication bandwidth are scarce. We have considered a random heterogeneous wireless sensor network, which has several powerful nodes for data aggregation/relay and large number of energy-constrained sensor nodes that are deployed randomly to cover a given target area. In this paper, a cooperative approach to detect and monitor the path of a moving object using a minimum subset of nodes while maintaining coverage and network connectivity is proposed. It is tested extensively in a simulation environment and compared with other existing methods. The results of our experiments clearly indicate the benefits of our new approach in terms of energy consumption.     

无线传感器网络中覆盖控制技术综述

覆盖控制是无线传感器网络应用的一个基本问题,反映了网络所能提供的"感知"服务质量,可以使无线传感器网络的空间资源得到优化分配,进而更好地完成环境感知、信息获取和有效传输的任务;立足于无线传感器网络的覆盖控制问题,分析了网络覆盖技术在国内外研究的现状与发展,指出了传感器网络覆盖算法中需要解决的问题,并提出了将多目标进化算法与智能计算技术用于动态覆盖控制技术研究设想。     

基于热释电红外传感器的多节点定位系统研究与设计

针对热释电红外传感器(PIR)在人体探测领域中越来越广泛的应用,研究设计了一种基于PIR的检测定位系统,可实时完成对人员目标入侵探测区域时的检测与定位,并预推出人员目标的行进轨迹;该系统由多个PIR感知节点组成,每个感知节点通过传感在动、静两种状态下对探测区域进行信息采集;最终融合多节点与不同状态下传感器采集的数据,算出各个传感器的探测角度值,以交叉定位的算法,得到目标的定位坐标;经实验证明,该系统运行稳定,检测灵敏,定位效果很好,拓宽了热释电传感器在定位定向方面的使用范围。     

一种基于分布式智能的网络机器人系统

提出了一种基于网络智能的分布式智能体系,构建并实现了基于分布式智能的网络机器人系统．通过赋予传感器以智能,将网络环境中的不同个体抽象为不同的智能节点．传感智能节点处理和传输多种层次的传感信息,实现传感智能的交互与共享．机器人节点以自主感知能力和“网络即插即用”机制为基础,根据任务的需要以及网络的传输状况,主动从网络中获取相应层次的智能和信息．实验表明,该体系有效地减轻了网络通信负担,提高了网络机器人系统的整体性能和智能水平．     

无线传感器网络中一种自适应目标跟踪协议

目标跟踪是无线传感器网络的一个基本应用,而能量高效是目标跟踪研究的一个重要目标.提出了一种自适应目标跟踪协议,该协议将传感器节点的状态分为睡眠状态、监测状态、跟踪状态三种状态;并对每个进行感应的传感器节点设置了节点权值,每个节点通过计算自己的节点权值来决策是否参与目标的跟踪,它在很大程度上减少了参与目标跟踪的节点数量.领导节点根据目标的运动速度来自适应地调整数据报告的频率,提高了能量利用率和跟踪精确度.模拟实验表明我们的算法具有良好的节能效果.     

基于网格扫描的实现目标点覆盖的确定性传感器节点部署方法

提出了一种确定性目标点覆盖算法,把目标点所在区域划分为若干正方形网格,从中选择最适合的网格作为下一个节点的放置位置;同时本文引入了概率感知模型,把节点能感知到目标点的最小感知概率值作为整体覆盖水平的评价指标,把节点能感知到目标点的个数及对它们的最小感知概率值作为网格的评价标准。该方法能使用最少的节点实现目标点覆盖并达到要求的总体覆盖水平,且能计算出较优的节点部署位置;对网格边长和感知概率下限的不同取值分别进行仿真实验。实验结果表明,网格边长越小,节点部署位置越精确;感知概率下限取值越大,总体覆盖性能越好,需要的节点越多。     

Unmanned Ground Vehicle Navigation in Coordinate-Free and Localization-Free Wireless Sensor and Actuator Networks

We present a set of algorithms for the navigation of Unmanned Ground Vehicles (UGVs) towards a set of pre-identified target nodes in coordinate-free and localization-free wireless sensor and actuator networks. The UGVs are equipped with a set of wireless listeners that provide sensing information about the potential field generated by the network of actuators. Two main navigation scenarios are considered: single-UGV, single-destination navigation and multi-UGV, multi-destination navigation. For the single-UGV, single-destination case, we present both centralized and distributed navigation algorithms. Both algorithms share a similar two-phase concept. In the first phase, the system assigns level numbers to individual nodes based on their hop distance from the target nodes. In the second phase, the UGV uses the potential field created by the network of actuators to move towards the target nodes, requiring cooperation between triplets of actuator nodes and the UGV. The hop distance to the target nodes is used to control the main moving direction while the potential field, which can be measured by listeners on the UGV, is used to determine the UGV’s movement. For the multi-UGV, multi-destination case, we present a decentralized allocation algorithm such that multiple UGVs avoid converging to the same destination. After each UGV determines its destination, the proposed navigation scheme is applied. The presented algorithms do not attempt to localize UGVs or sensor nodes and are therefore suitable for operating in GPS-free/denied environments. We also present a study of the communication complexity of the algorithms as well as simulation examples that verify the proposed algorithms and compare their performances.