基于ZigBee技术的灵芝无线传感器监测网络

提出了一种监测灵芝生长环境的无线传感器网络(wireless sensor network)系统.传感器网络的节点由传感器部分、无线收发模块、单片机组成.节点传感器部分安装了温度传感器、湿度传感器、pH传感器、土壤水分传感器、光敏电阻传感器,并对相应的传感器工作原理进行了简单介绍.传感器网络的无线收发模块采用CC2420模块,传感器网络节点采用Atmega128单片机为其处理器.WSN的通信协议选择ZigBee协议.同时,进行了灵芝生长环境的传感器检测实验并对数据进行了分析探讨.     

无线传感器网络的能量有效性研究

传感器节点能量受限是WSN的一个关键问题,因此合理有效地使用现有能量延长WSN的生命周期便成了首要的设计目标。首先分析了WSN的能耗特性,然后从单个传感器节点和整个传感器网络两个方面给出了提高WSN能量有效性的策略。     

尾矿库安全监测低能耗无线传感器网络设计

针对传统无线传感器网络(WSN)因严格以"父子传承"方式传输数据,导致数据传输路径冗长、能耗过大、使用周期短的问题,提出一种以能耗最小为优化目标的数据传输树路由算法应用于有色金属尾矿库,并结合采用低功耗微处理器及闲时休眠、工作时激活的数据传输程序等措施,有效降低了网络系统的能耗。采用NS对采用优化的树路由算法及采用节能措施的WSN与采用传统树路由算法的WSN进行仿真,结果表明,采用研究提出的数据传输方式的WSN能有效地降低传感器节点的能耗及路径损耗,并提高了能耗均衡性,实现了整个网络能量的合理分配及降耗,保证尾矿库安全监测系统长期稳定运行。     

基于RCM2200的通用控制节点的研究

文章研究了基于RCM2200嵌入式系统通用控制节点的开发.介绍了通用控制节点的硬件设计、工作原理以及如何利用Dynamic C语言通过RCM2200核心模块接收串口请求帧并把采集的数据转换成TCP报文传输给当地局域网.结果表明,该控制节点能成功地实现串口接收命令和发送数据到本地局域网.     

基于WSN的风力发电运行监测系统LEACH协议改进研究

本文首先介绍了基于WSN的风力发电运行监测系统的结构,针对风电场的特殊模型,提出了使用LEACH协议作为其路由协议的方案.针对LEACH协议中簇头节点能量消耗过大和簇头节点与基站通信距离长的特点,提出以节点剩余能量来作为簇头节点选取的标准,同时通过限制簇内节点数目,在传输中提出簇内单跳、簇间多跳的路由方式,以减少簇头能量消耗,从而延长网络生存时间.最后使用MATLAB对LEACH及改进后的协议作仿真分析,验证了改进的有效性.     

矿井无线定位系统设计

本文设计了一种基于STM32的矿井无线定位系统,该系统主要由中心模块,节点和PC终端组成。节点负责矿井现场信息的收集,并通过无线网络将现场信息传送至中心模块,中心模块通过串口将数据传送至PC终端,从而实现PC终端对矿井现场的实时监控。     

离子型稀土原地浸析过程WSN监测系统

鉴于离子型稀土原地浸析开采工艺存在易导致山体滑坡、工业污水污染下游河床、浸矿液溶度逐步降低致使已浸出稀土离子再吸附等难题,设计了基于无线传感器网络(WSN)的采场监测系统。系统采用以Telos B为架构的网络节点,在各节点嵌入Tiny OS操作系统,利用高效的CTP协议和LPL模式传输数据,实现对多监测点、多参数进行实时采集与监测。     

MODBUS网络在PC电解中的应用

实现不同种自动化设备之间通信是系统集成的关键,基于Modbus协议的串口通信是较常用的方式之一.本文介绍了应用MV156-MCM模块实现ControlLogix与MODBUS网络的通讯方法,从而实现主从结构网络通讯.     

采用网络分割的OBS网络故障监测机制

提出了一种基于网络分割策略的圈覆盖光突发交换网络的故障监测机制,采用网络分割策略,大型的光突发交换网络被分割成便于故障管理的带有中心节点的环形子网或扇形子网,在每个子网内分别执行圈覆盖算法进行故障监测.计算和统计结果表明,该故障监测机制对于节点平均连通度大于3的网络具备网络开销小、故障定位率低等特点.     

基于骑士巡游的Mesh光网络链路故障定位策略

全光交换网络的链路故障定位方法需要具有快速性,同时有效降低资源开销.提出一种基于骑士巡游的光网络单链路故障定位策略,该策略首先根据网络的节点连通度进行节点分裂,将分裂后的网络节点映射到相应大小的m×n棋盘上,依据骑士巡游的思想利用探测信号定位网络中出现的单链路故障.仿真表明:该策略能够在利用较少的网络资源情况下,对网络中的单链路故障进行有效地定位.     

矿井无线传感器网络不同信道传输特性试验研究

为研究无线传感器网络信号在矿井巷道中的传播特性,解决无线传感器节点在巷道中合理布设等问题,采用CC2420、CC1020和CC1100 3种无线射频芯片,设计出分别在2.4 GHz、780 MHz和433 MHz频段工作的无线传感器节点,并选用某矿井作为试验环境,采用3种不同的发射功率（15,5,-5 dBm）对节点在矿井巷道中的接收信号强度（RSSI）和丢包率（PLR）进行了测试分析。试验结果表明,3种不同频段的无线传感器节点的接收信号强度值均随着收发距离的增大而减小,且信号的衰减符合对数模型。通过仿真发现,布设的节点采用15 dBm和5 dBm 2种发射功率时,无线信号基本覆盖了所有巷道,能满足矿井的数据通信需求。若考虑节点的功耗,优先选择5 dBm发射功率;若考虑无线通信距离和质量,优先选择15 dBm发射功率。因此,在矿井巷道环境中应用无线传感器网络时,780 MHz频段的传输性能最佳,发射功率可根据实际情况进行选择。     

On the determination of the stacking fault energy from extended nodes in Cu2NiZn

Stacking fault energies can be determined from the dimensions of extended dislocation nodes. Different theoretical treatments of the node problem have been published. The aim of the present paper is to compare the results obtained using the theories of Brown and Thöléen, Siems and Jøssanget al and to provide quantitative information about the dependence of the stacking fault energy for Cu₂NiZn on the model used. Extended nodes in networks with mesh size larger than the outer radius of the node (R) can be used for the determination of the stacking fault energy. Isolated nodes as well as network nodes are used to obtain the stacking fault energy in Cu₂NiZn, which appeared to be 33 ± 9 mJ/m².     

时域分析的多数据融合故障诊断方法

介绍了时域分析中的有纲量参数和无纲量参数,构建了多数据融合故障诊断系统。系统包含数据级、特征级和决策级融合诊断模块,并行BP神经网络作为特征级诊断模块,既克服了BP网络的缺点,又解决了D—S证据理论难以获得BPA的弊端。对液压泵进行应用试验,结果表明,该诊断系统充分利用了多数据的冗余信息,提高了诊断的可靠性和准确性。     

Extrinsic and intrinsic nodes in the gamma prime phase of a single crystal superalloy

Transmission Electron Microscopy has been used to examine the interaction of superdislocations to form nodes and networks in the γ′ phase of the cold deformed and annealed single crystal superalloy, SRR99. The formation of these “super nodes” is traced through various metastable configurations to form, eventually, extended “super nodes” which contain superlattice stacking faults. Several dislocations interacting are observed to form networks of such nodes having alternately intrinsic and extrinsic character. The extrinsic supernodes are found to be larger than the intrinsic supernodes with the implication that the superlattice extrinsic stacking fault energy is lower than the superlattices intrinsic fault energy.     

机电设备自动化故障诊断系统设计

为解决传统机电设备自动化故障诊断系统存在的精准度低、效果差的问题,提出了对自动化故障诊断系统进行优化设计方案,通过对机电设备自动化故障诊断系统的软硬件结构的优化设计,建立数据采集层、服务器层、命令交互层,并选用光时域反射仪NK2000故障光纤测试仪OTDR等作为系统硬件,通过信号转换为光信号形式,再经过光纤耦合器转换为电信号形式进行诊断。利用主动轮询采集方法采集故障数据,然后设立模块处理大量信息,最后利用模糊推理的方法定位故障位置,完成故障诊断系统的设计。     

Long-Term Wireless Structural Health Monitoring of the Ferriby Road Bridge

As part of an effective bridge management system, sensor networks can provide data to support both inspection and assessment. Wireless sensor networks (WSNs) have the potential to offer significant advantages over traditional wired monitoring systems in terms of sensor, cabling, and installation costs as well as expandability. However, there are drawbacks with WSNs relating to power, data bandwidth, and robustness. To evaluate the potential of WSNs for use in bridge management, a network of seven sensor nodes was installed on the Ferriby Road Bridge, a three-span reinforced concrete bridge. Three displacement transducer nodes were placed across cracks on the soffit of the bridge to measure the change in crack width. Three inclinometer sensor nodes were mounted on two of the elastomeric bearing pads to measure the change in inclination of the bearing pads while a final node monitored temperature in the box that contained the gateway. The installation of the WSN is discussed and data from this network is analyzed. Finally, the use of sensor networks to support inspection and assessment is discussed.     

Continuous Plume Monitoring Using Wireless Sensors: Proof of Concept in Intermediate Scale Tank

The current practice for monitoring of subsurface plumes involves the collection of water samples from sparsely distributed monitoring wells and laboratory analysis to determine chemical concentrations. In most field situations, cost and time constraints limit the number of samples that could be collected and analyzed for continuous monitoring of large, transient plumes. With the development of wireless sensor networks (WSNs), that allow sensors to be incorporated into a distributed wireless communication and processing system, the potential exists to develop new, efficient, economical, large-scale subsurface data collection and monitoring methods. This paper presents a proof-of-concept study conducted in a two-dimensional synthetic aquifer constructed in an intermediate scale test tank to demonstrate the feasibility of using WSN for subsurface plume monitoring. The tank was packed to represent a heterogeneous aquifer, and a sodium bromide tracer was used to create a plume. A set of ten wireless sensor nodes (motes) equipped with conductivity probes to measure electrical conductivity formed the network. Software for automated data acquisition was developed and tested. Results of two experiments conducted using this test system are presented. The lessons learned from the first experiment were used to make modifications to the way the sensors were placed, how they were calibrated and how the sensors were interfaced with the data acquisition system. The findings are used to identify future research directions and issues that need to be addressed before field implementations of a WSN based data collection system for plume monitoring.     

DeviceNet现场总线在铜冶炼余热锅炉中的应用

通过具体实例,详细介绍了DeviceNet现场总线在铜冶炼锅炉振打控制应用中的网络规划及系统配置、逻辑控制、上位监控诸项环节中的设计策略,重点阐述在做网络配置时,根据锅炉振打的实际安装位置,并且结合电气设计上的现场箱布置和桥架走向,计算各条网络距离,选择总线模块,分配网络站点。在做上位监控时要将总线模块的故障诊断信息引入PLC系统,便于网络维护。     

数据网络技术在故障诊断中的应用

Introduced the basic principle and structure of the grid computing technology, as well as the application combined with the fault diagnosis expert systems. Put forward that use grid node to construct integrated fault diagnosis system based on object model, experience rule, neural network model and practice, so that the aptitude and efficiency of the diagnosis system is improved. Researched on the method of applying the grid architecture in fault diagnosis based on OGSA. It also puts forward the method of fault diagnosis in LAN. Server is made up of grid nodes, which are used for spectrum diagnosis and data tendency diagnosis. Using web Service program, can realize accessing and grid calculating between clients and server. Besides, presented the system control flow.     

基于自适应滑模的多螺旋桨浮空器容错控制

针对多螺旋桨浮空器执行机构易发生故障的容错控制问题,同时考虑系统所受到的未知外部扰动和螺旋桨输入幅值的饱和约束,提出一种自适应滑模容错控制方法。建立浮空器的四自由度运动模型,系统分析矢量螺旋桨的故障类型,分为输出力的大小故障和矢量转角故障,得到浮空器执行机构的故障模型。基于自适应和滑模控制理论,由跟踪目标与系统当前状态偏差设计积分滑模面。针对未知外部扰动和执行机构偏移故障,设计相应的自适应律进行处理;针对螺旋桨输入饱和约束,应用Sigmoid函数设计跟踪轨迹进行处理。由此设计一种自适应滑模容错控制策略,利用Lyapunov稳定性理论证明了闭环系统的全局渐近稳定性能。以上海交通大学的多螺旋桨浮空器为模型,仿真验证了故障容错控制方法的有效性和鲁棒性。