Decentralized fault detection and isolation in wireless structural health monitoring systems using analytical redundancy

One of the most critical issues when deploying wireless sensor networks for long-term structural health monitoring (SHM) is the correct and reliable operation of sensors. Sensor faults may reduce the quality of monitoring and, if remaining undetected, might cause significant economic loss due to inaccurate or missing sensor data required for structural assessment and life-cycle management of the monitored structure. This paper presents a fully decentralized approach towards autonomous sensor fault detection and isolation in wireless SHM systems. Instead of physically installing multiple redundant sensors in the monitored structure (“physical redundancy”), which would involve substantial penalties in cost and maintainability, the information inherent in the SHM system is used for fault detection and isolation (“analytical redundancy”). Unlike traditional centralized approaches, the analytical redundancy approach is implemented distributively: Partial models of the wireless SHM system, implemented in terms of artificial neural networks in an object-oriented fashion, are embedded into the wireless sensor nodes deployed for monitoring. In this paper, the design and the prototype implementation of a wireless SHM system capable of autonomously detecting and isolating various types of sensor faults are shown. In laboratory experiments, the prototype SHM system is validated by injecting faults into the wireless sensor nodes while being deployed on a test structure. The paper concludes with a discussion of the results and an outlook on possible future research directions.     

基于零打扰测试背板的无线传感器网络测试平台

精确的网络运行状态监视和性能评估对于无线传感器网络的研究和实际部署具有极为关键的意义,而现有的测试技术和测试平台对无线传感器网络的自身运行存在一定的打扰,测试数据的精度也受限于传感器节点的硬件配置.针对现有测试技术和测试平台的缺陷,提出了内部侦听的测试方式,并进一步研发了基于零打扰测试背板的无线传感器网络测试平台.测试平台首先通过由额外的测试背板直接捕获传感器节点内部互连信号,产生测试数据;然后测试数据经由额外的传输网络传送到测试服务器,进行解析和预处理;最后,远程访问客户端通过订阅机制访问测试服务器上的测试数据,并对其分析和处理.测试平台在避免对无线传感器网络正常运行产生干扰的前提下,实现对运行时刻的无线传感器网络的高精度零打扰的透明测试.实验结果表明,基于零打扰测试背板的无线传感器网络测试平台可以对无线传感器网络进行信号分析、协议验证,并对性能进行精确的评估,     

Agent-based artificial immune system approach for adaptive damage detection in monitoring networks

This paper presents an agent-based artificial immune system approach for adaptive damage detection in distributed monitoring networks. The presented approach establishes a new monitoring paradigm by embodying desirable immune attributes, such as adaptation, immune pattern recognition, and self-organization, into monitoring networks. In the artificial immune system-based paradigm, a group of autonomous mobile monitoring agents mimic immune cells (such as B-cells) in the natural immune system, interact locally with monitoring environment, and respond to emerging problems through simulated immune responses. The presented immune-inspired monitoring paradigm has been applied to structural health monitoring. The “antibody” of a mobile monitoring agent is a pattern recognition algorithm tuned to a certain type of structural damage pattern. The mobile monitoring agent performs damage diagnosis based on structural dynamic response data. Mobile monitoring agents communicate with each other and collaborate with network components based on agent interaction protocols defined in agent standards, the Foundation for Intelligent Physical Agents standards. A mobile agent system embedded in sensor nodes supports the selective generation, migration, communication, and management of mobile monitoring agents automatically. The active structural health monitoring is achieved by distributing mobile monitoring agents to the sites where they are needed. The structural damage diagnosis using mobile monitoring agents and artificial immune pattern recognition method has been tested using a scaled steel bridge structure. The test result shows the feasibility of using this approach for real-time structural damage diagnosis.     

用于大坝安全监测的长距离WSNs节点设计

针对大坝安全监测的需求,结合无线传感器网络的特点,设计了一种基于JN5139无线射频模块的用于大坝安全监测的无线传感器网络节点。简要介绍了无线传感器网络的典型网络结构,重点描述了无线传感器网络节点的硬件和软件设计,并通过在野外环境下搭建簇—树型网络,对传感器网络进行测试。实验结果表明节点数据采集准确,传输可靠。     

基于WSNs的军用机场仓库环境监测系统设计

对军用机场后方仓库的环境参数进行实时监测,是保证武器装备正常存储,防止发生意外事故的重要措施。针对军用机场现有仓库环境监测系统的不足,将WiFi无线传感器网络（ WSNs）应用在仓库环境监测系统中,与现有的视频监控局域网融合,解决了传统监测系统组网难、成本高的问题。系统的传感器节点采集环境参数,通过WiFi模块和局域网将数据传送至监测中心的服务器,服务器中的软件采用B/S结构,对数据进行分析、处理、存储和显示。实验结果表明：该监测系统数据采集精度高、效率高,网络通信稳定,能够满足设计要求。     

面向目标跟踪的混合WMSN设计与实现

设计了一个面向目标跟踪的混合无线多媒体传感器网络,主要实现了低功耗的无线图像传感器节点、无线温度传感器节点和服务器软件。对节点和单Sink下的网络性能进行了测试。结果表明：相比较于Cyclops和MeshEye,无线图像传感器节点的处理速度分别从8 MHz和55 MHz提高到240 MHz;处理器工作在188 MHz时的能耗是52.7 mA,低于Imote在104 MHz时的66 mA工作电流;当错包率接近0时,网络实际带宽约36 kb/s;基于Shape Matching的目标跟踪数据处理策略有效地降低了能量消耗。     

基于ZigBee的无线传感器网络设计与实现

无线传感器网络是由部署在监测区域内大量的廉价微型传感器结点组成,具有传感器节点密度高,网络拓扑变化频繁,以及节点的功率、计算能力和数据存储能力有限等特点。该文介绍了ZigBee网络与GSM/GPRS网络相结合实现远程监测的无线传感器网络的软件与硬件总体设计方法。     

基于Zig Bee技术的大坝安全监测WSNs节点设计

针对无线传感器网络(WSNs)在大坝安全监测中的需求,结合大坝安全监测传感器网络和ZigBee技术的特点,提出一种基于射频芯片CC2430的WSNs大坝安全监测系统解决方案。简要介绍了传感器网络体系结构,重点阐述了其网络节点的硬件设计和软件设计。并在实验室环境下搭建了一个簇-树型传感器网络,对传感器网络进行了测试并对节点进行了标定。实验表明:节点采集传感器数据准确,在实验室环境下数据传输可靠、准确,数据丢失率为0。     

基于ZigBee技术的无线传感器网络及其应用研究

无线传感网络是当前国内外传感器技术领域的热点研究课题,着重研究了基于ZigBee技术的无线传感器网络节点的软硬件设计,实现了ZigBee无线传感器网络节点的设计,并运用该无线传感节点建立了基于ZigBee技术的无线结构健康监测系统,利用模式匹配的方法实现了基于无线传感器网络的载荷定位和结构紧固件失效的实时监测.     

用于环境监测的ZigBee无线传感器节点设计

温室环境监测采用基于ZigBee技术的智能网络化传感器有着很明显的优势。ZigBee网络容量大、功耗低、易于扩充并且支持自组织组网。该文设计了一种ZigBee无线传感器监测节点,介绍了基于ZigBee协议构建的无线数据采集网络,包括传感器节点的软、硬件设计。实验证明：节点工作状况良好,整个网络具有较高的可行性,可以实现对环境温湿度、光强等信息进行实时、准确的监测。     

基于ZigBee网络的大坝安全监测系统的设计与实现

为了能够有效应用于无线传感器网络的大坝安全监测系统,设计了ZigBee无线传感器网络的硬件模块和服务器软件系统。分析了ZigBee无线通信的原理,给出了从大坝监控中心到底层的通讯方式,说明其结构、功能。重点阐述其在采集大坝数据后如何实现通讯,在监控中心对底层模块的控制,对其中涉及的关键技术进行了较为详细的叙述。     

Optimal control of mobile monitoring agents in immune-inspired wireless monitoring networks

This paper studies optimal control of mobile monitoring agents in artificial-immune-system-based (AIS-based) monitoring networks. In AIS-based structural health monitoring (SHM) networks, the active structural health monitoring is performed by a group of mobile monitoring agents equipped with damage pattern recognition algorithms. The mobile monitoring agents mimic immune cells in the natural immune system and patrol a structure to detect damage patterns using their receptors (feature vectors), damage pattern recognition algorithms, and the dynamic response data of the structure. The optimal control of mobile monitoring agents includes agent generation and distribution. The generation of mobile monitoring agents is optimized to minimize the response time for the mobile monitoring agents to diagnose structural damage in a sub-network and maximize the average affinity of monitoring agents′ receptors to the damaged sensor data feature vector. The objective functions for distributing mobile monitoring agents are to increase the detection probability and extend network life by balancing energy consumption of sensor nodes in the network. The presented optimization algorithms are developed using multi-objective genetic algorithms. The impact of the algorithm parameters on the performance of the algorithm is also investigated.     

基于无线传感器网络的定位系统设计

无线定位应用需求日益增长,研究无线传感器网络的定位应用具有重要意义。首先介绍基于无线传感器网络的定位系统的软硬件结构,然后从能量消耗、网络通信量和可靠性等方面来分析和选择移动结点的工作方式,并提出了使信标结点实现动态快速组网、提高网络通信效率和通信链路稳定性等所采取的措施,最后给出了在TinyOS下传感器结点的程序结构和实现,以及在服务器端实现的改进的加权质心定位算法。     

Secure data aggregation in wireless sensor networks: A comprehensive overview

Wireless sensor networks often consists of a large number of low-cost sensor nodes that have strictly limited sensing, computation, and communication capabilities. Due to resource restricted sensor nodes, it is important to minimize the amount of data transmission so that the average sensor lifetime and the overall bandwidth utilization are improved. Data aggregation is the process of summarizing and combining sensor data in order to reduce the amount of data transmission in the network. As wireless sensor networks are usually deployed in remote and hostile environments to transmit sensitive information, sensor nodes are prone to node compromise attacks and security issues such as data confidentiality and integrity are extremely important. Hence, wireless sensor network protocols, e.g., data aggregation protocol, must be designed with security in mind. This paper investigates the relationship between security and data aggregation process in wireless sensor networks. A taxonomy of secure data aggregation protocols is given by surveying the current “state-of-the-art” work in this area. In addition, based on the existing research, the open research areas and future research directions in secure data aggregation concept are provided.     

基于Zig Bee网络的温室节水灌溉系统设计

为了实施有效的温室节水控制,设计了一种基于Zig Bee网络的温室节水灌溉系统。硬件部分以CC2430构建无线土壤水分传感器网络,包括无线传感器节点、控制节点、协调器节点;软件部分包括底层节点数据的采集和传送、协调器节点数据接收和发送、监控终端管理3个部分。采用LabVIEW对上位机监控软件进行了开发,人机交互界面友好。该系统实现了土壤含水量的自动采集,并根据作物的需水状况进行自动灌溉。实验结果表明:该系统具低功耗、低成本、可靠性好、安装维护方便等特点,通过合理设置控制参数,可以实现节水的目的。     

基于无线传感器网络的远距离结构健康监测

针对复合材料结构健康监测的特点和需求,实现了一套基于无线传感器网络(WSNs)的远距离结构健康监测系统。系统构成包括前端传感监测子系统、WSNs子系统和远终端监控子系统。为了扩大系统的监测范围,降低系统网络功耗及成本,提高系统的稳定性、智能性和抗毁性,研究了自制的无线传感节点、多跳路由技术及小型化配接电路,改进了终端程序和网络节点程序。实验证明:相对于传统有线的监测方式,基于WSNs的结构健康监测具有灵活性高、负重轻、成本低、搭建移动方便、维护容易等优点。     

基于簇头功能分化的无线传感器网络成簇算法

以LEACH为基础演化而来的各类算法在簇头选举时始终包含有“随机选择”的成分,导致无线传感器网络在拓扑结构的优化和能量消耗的均衡上受到限制。从分化簇头功能和优化功能节点选举机制的角度出发,提出一种分化簇头功能的分布式算法,引入功能节点推荐机制,弱化簇头选举中的随机成分,分化簇头功能,将以往簇头管理节点、融合数据、转发信息的三大功能分别由管理节点、融合节点、转发节点3个功能节点来承担。仿真数据表明,提出的分簇算法能有效优化簇内拓扑结构、提高节点能量消耗均衡性,能够延长网络生存周期15％~20％。     

无线传感器网络在文物保护中的应用

无线传感器网络是计算、通信和传感器三项技术结合的产物,被视为环境监测和建设监测的一个发展方向,有着广泛的应用领域,文物保护是其潜在的应用领域之一.介绍无线传感器网络的特点及其在文物保护中应用的必要性,提出博物馆文物保护系统无线传感器网络构建方案,以及无线传感器网络节点、汇节点和博物馆监控中心软件等部分的设计方案.与传统的文物保护系统相比,该系统具有易于扩充,测量准确等特点.     

基于CC2530无线传感网络的环境监测系统的设计

研究如何构建一个适合我国环境监测的ZigBee无线传感网络系统。针对ZigBee网络环境的特性,构建ZigBee服务器硬件与软件平台,基于ZigBee的无线网关,通过通用分组无线服务GPRS实现Internet对ZigBee网络各节点进行数据采集、控制、监控及状态显示等功能。