无线传感网络中移动节点定位技术研究

现有的定位方式因为需要建立网络模型和能量消耗不平均的现象,故不适用于有少量节点随机移动的无线传感网络.针对此类无线传感网络中各节点的定位问题,在分析了定位的计算复杂度和能量损耗的前提下,提出了分簇定位算法,在簇的范围内对发生移动的节点采用接收信号强度测距(RSSI)与质心定位相结合(CLA)的方法进行定位.分析与仿真结...     

一种基于移动节点的无线传感器网络修复方法

传感器节点的随机部署不均匀或者由于负载不均导致有的节点能量提前耗尽,导致无线传感器网络出现覆盖空洞.针对已检测到的覆盖空洞,提出一种基于相切圆的修复算法,并从理论上证明该算法的可行性.算法的基本原理是以相邻2个边界传感器节点求它们相切圆的圆心位置,即新增加的移动节点的位置,通过反复求解相切圆的圆心位置来达到修复的目的.通过仿真实验证明:算法不仅能达到90％的修复覆盖率,而且修复后的冗余度相比其他算法也较低.     

考虑可靠性的给水管网水质传感器多目标优化选址模型

针对给水管网水质传感器有可能失效的情况,提出了考虑传感器可靠性的多目标优化选址模型(SPM-R).该模型在最大限度监测突发或者蓄意的污染事件之外,期望传感器选址具有一定的可靠性,即若某一传感器发生故障,存在其它传感器能够继续监测污染事件,并且由此造成的监测时间增加值在允许范围之内.结合一管网算例,首先利用EPANET软件随机模拟管网节点被注入污染物后各个节点污染物浓度变化情况,得到监测时间矩阵,然后,基于非支配排序遗传算法-Ⅱ(NSGA-Ⅱ)详细阐述了SPM-R模型的求解过程,并对计算结果进行了参数敏感性分析.     

无线网络下可信移动节点接入认证方案

将基于属性且无可信第三方的平台验证协议以及基于身份的加密协议应用到无线网络环境下节点接入认证模型中,提出一个无线网络环境下的可信移动节点接入认证方案。与现有的认证方案相比,基于可信平台的移动节点接入认证方案主要有以下特点：1)在验证移动节点用户身份的同时也验证了移动节点的平台身份;2)不仅提供了移动节点和网络代理间的双向认证,还提供了移动节点间的双向认证。分析表明,改进后的方案满足接入节点身份的匿名性。     

基于移动节点的无线传感器网络中的瓶颈节点

“瓶颈节点”是在无线传感器网络中由于随机部署的原因产生了连接两个或是多个区域的孤立节点。由于这类节点对网络的生存周期存在着很大的影响,提出一种分布式瀑布型移动方案。该方案减少了节点移动的距离并节约了节点移动所消耗的能量,同时也减少了网络覆盖初始化的时间;通过移动一定数量的节点到“瓶颈节点”的附近来均衡节点的通信量,进而延长了整个网络的生存周期。仿真实验结果表明,该方法可以有效地提高整个网络的生存周期,均衡了节点的能量消耗,并缩短了节点重定位时间。     

基于多功率移动锚节点WSN智能定位算法

为了降低定位成本及提高定位精度,提出了一种使用单个锚节点移动进行未知节点坐标计算的SAPSO-SMPMA算法.该算法采用单个移动锚节点游历定位区域,并通过功率控制发射不同功率的信标信号,未知节点利用收到的不同位置锚节点信息结合自适应权重粒子群算法计算节点坐标.考虑到实际应用时锚节点可能带有误差,故加入了锚节点矢量误差分析.仿真表明,本算法在充分考虑锚节点自身误差及大幅降低定位成本的情况下,定位精度仍然较高,是一种实用的定位算法.     

无线水位检测系统与压力传感器补偿方法的研究

一种基于ATmega16和FC222-CH的无线水位检测系统。该系统由无线通信模块、电源模块、AD转换模块、上位机模块组成,实现了水位的无线检测、运行故障报警等功能,并配以自行设计的LabVIEW 8.5上位机显示界面,使整套开发系统兼备可视化与实时性的双重要求。     

Pareto-based evolutionary computational approach for wireless sensor placement

Wireless sensor networks (WSNs) have become increasingly appealing in recent years for the purpose of data acquisition, surveillance, event monitoring, etc. Optimal positioning of wireless sensor nodes is an important issue for small networks of relatively expensive sensing devices. For such networks, the placement problem requires that multiple objectives be met. These objectives are usually conflicting, e.g. achieving maximum coverage and maximum connectivity while minimizing the network energy cost. A flexible algorithm for sensor placement (FLEX) is presented that uses an evolutionary computational approach to solve this multiobjective sensor placement optimization problem when the number of sensor nodes is not fixed and the maximum number of nodes is not known a priori. FLEX starts with an initial population of simple WSNs and complexifies their topologies over generations. It keeps track of new genes through historical markings, which are used in later generations to assess two networks’ compatibility and also to align genes during crossover. It uses Pareto-dominance to approach Pareto-optimal layouts with respect to the objectives. Speciation is employed to aid the survival of gene innovations and facilitate networks to compete with similar networks. Elitism ensures that the best solutions are carried over to the next generation. The flexibility of the algorithm is illustrated by solving the device/node placement problem for different applications like facility surveillance, coverage with and without obstacles, preferential surveillance, and forming a clustering hierarchy.     

无线传感网中移动节点的自适应定位算法

介绍了一种在无线传感网中针对移动节点的自适应定位算法,通过建立移动节点运动模型,借助运动模型估计信息辅助移动节点的定位,解决了只有2个或1个信标节点的无法定位的问题,本算法能够适应不同移动节点的运动状态,动态地调整定位时间间隔,从而既能提高节点定位的精度,也能在保证定位误差的情况下降低定位频率,节省定位能量的消耗,延长整个无线传感网的生存时间。     

无线传感器网络中移动目标的定位与跟踪

对侵入无线传感器网络中的目标,提出了一种移动节点和静态节点相结合的定位与跟踪方式.静态节点可以发现侵入传感器网络中的目标,移动节点与静态节点配合进一步确定目标的具体位置.仿真实验验证表明:该方法可以减少大规模的频繁移动节点,不需要过多地对移动节点的选择和运动进行特别复杂的计算,具有较好的定位精度和鲁棒性,对多目标的定位与跟踪研究有一定的启发作用.     

Relay node placement in structurally damaged wireless sensor networks via triangular steiner tree approximation

Wireless sensor networks (WSNs) have many applications which operate in hostile environments. Due to the harsh surroundings, WSNs may suffer from a large scale damage that causes many nodes to fail simultaneously and the network to get partitioned into multiple disjoint segments. In such a case, restoring the network connectivity is very important in order to avoid negative effects on the applications. In this paper, we pursue the placement of the least number of relay nodes to re-establish a strongly connected network topology. The problem of finding the minimum count and the position of relay nodes is NP-hard and hence we pursue heuristics. We present a novel three-step algorithm called FeSTA which is based on steinerizing appropriate triangles. Each segment is represented by a terminal. Each subset of 3 terminals forms a triangle. Finding the optimal solution for a triangle (i.e. connecting 3 segments) is a relatively easier problem. In the first step, FeSTA finds the best triangles and form islands of segments by establishing intra-triangle connectivity. Then in the second, disjoint islands of segment are federated. In the final step, the steinerized edges are optimized. The performance of FeSTA is validated through simulation.     

一种单移动锚节点的无线传感器网络定位算法

研究了无线传感器网络的节点定位算法,提出了一种利用一个移动锚节点来实现定位的新算法。该算法利用一个移动锚节点,按照规划好的路径遍历整个网络,当移动锚节点移动到未知节点的通信半径以内,未知节点就可以接收锚节点的位置信息。当未知节点接收到三个以上的处于其通信半径上的位置信息,就可以计算出未知节点的坐标。最后,通过仿真研究了该算法的特性,仿真结果表明该定位方法在定位误差、能耗等方面均表现出良好的性能。     

基于MDS技术与MCL方法的无线传感器网络移动节点定位算法

在MCL算法的基础上,结合改进的基于多维定标MDS(Multidimensional Scaling)的定位算法引进新的滤波条件,提出了一种移动节点定位算法.该算法通过在循环滤波部分引入新的限定条件,可以保留更靠近真实距离的预测样本,减小定位误差.仿真实验表明,该算法具有更好的定位精度.     

无线传感器网络中被捕获节点的检测技术综述

无线传感器网络在许多应用场合都需要采集比较敏感的数据,因此安全问题至关重要。一旦传感器节点被捕获,且没有采取相应的措施,该节点内的所有信息将会泄露。利用被捕获节点,攻击者可在网络内发起内部攻击,导致网络的安全性能急剧下降。如何检测被捕获节点,目前已有多种技术可以解决这个问题。文章对目前的检测技术作了总结,并对未来的研究方向做了展望。     

移动互联网在水利工程移动巡检中的应用

移动互联网因为其普遍性、高可携带性、安全性和应用多样性等特点,在政务、交通物流、警务等行业得到广泛应用。研究了将移动互联网技术应用到了水利工程移动巡检中,建立了移动终端、管理端和安全接入子系统。移动终端子系统主要用以完成数据下载、采集、上报功能。管理端子系统主要提供数据接口,并对采集的数据进行分析。安全接入子系统是在业务内网与互联网之间建立起一个安全的接入平台。本系统经测试,完全可以满足企业需求。     

Adjoint-based numerical method using standard engineering software for the optimal placement of chlorine sensors in drinking water networks

To obtain representative water quality simulations, unknown model parameters have to be updated by combining information from the water quality model and the sensor outputs. An adjoint-based numerical method has been developed to determine the optimal placement of chlorine sensors in drinking water networks at a low computational cost. From a practical engineering perspective, the proposed optimal placement corresponds to the set of sensors that minimizes the area in which the unknown model parameters cannot be identified. The numerical strategy is implemented in the hydraulic software EPANET. Using the adjoint framework, we develop and apply an adaptive strategy in a French drinking water network that provides the optimal placement from 1 sensor to 6 sensors. We show that the highest reduction of the non-identifiable area is obtained at the first stages of the adaptive strategy. After 4 sensors, a plateau is reached.     

Positioning device for outdoor mobile robots using optical sensors and lasers

We propose a novel method for positioning a mobile robot in an outdoor environment using lasers and optical sensors. Position estimation via a noncontact optical method is useful because the information from the wheel odometer and the global positioning system in a mobile robot is unreliable in some situations. Contact optical sensors such as computer mouse are designed to be in contact with a surface and do not function well in strong ambient light conditions. To mitigate the challenges of an outdoor environment, we developed an optical device with a bandpass filter and a pipe to restrict solar light and to detect translation. The use of two devices enables sensing of the mobile robot’s position, including posture. Furthermore, employing a collimated laser beam allows measurements against a surface to be invariable with the distance to the surface. In this paper, we describe motion estimation, device configurations, and several tests for performance evaluation. We also present the experimental positioning results from a vehicle equipped with our optical device on an outdoor path. Finally, we discuss an improvement in postural accuracy by combining an optical device with precise gyroscopes.     

基于时空特性的无线传感器网络节点故障诊断方法

无线传感器网络中故障节点会产生并传输错误数据,这将消耗节点的能量和带宽,同时会形成错误的决策。利用节点感知数据的空间相似性,提出了节点故障诊断的算法,通过对邻节点所感知的传感数据进行比较,从而确定检测节点的状态,并将测试状态向网络中其他相邻节点进行扩散。对于网络中存在的节点瞬时故障,通过时间冗余的检测方法,降低故障诊断的虚警率。该算法对实现故障节点的检测具有较好的性能,实验结果验证了算法的可行性和有效性。     

Methodology for leakage isolation using pressure sensitivity analysis in water distribution networks

Leaks are present to some extent in all water-distribution systems. This paper proposes a leakage localisation method based on the pressure measurements and pressure sensitivity analysis of nodes in a network. The sensitivity analysis using analytical tools is not a trivial job in a real network because of the huge non-explicit non-linear systems of equations that describe its dynamics. Simulations of the network in the presence and the absence of leakage may provide an approximation of this sensitivity. This matrix is binarised using a threshold independent of the node. The binary matrix is assumed as a signature matrix for leakages. However, there is a trade-off between the resolution of the leakage isolation procedure and the number of available pressure sensors. In order to maximise the isolability with a reasonable number of sensors, an optimal sensor placement methodology, based on genetic algorithms, is also proposed. These methodologies have been applied to the Barcelona Network using PICCOLO simulator. The sensor placement and the leakage detection and localisation methodologies are applied to several district management areas (DMA) in simulation and in reality.