接触网绝缘子泄漏电流在线监测装置设计

为有效地预测接触网绝缘子污秽水平,提高接触网运行安全可靠性,设计了一种基于ARM的接触网绝缘子泄露电流在线监测装置。通过传感器采集泄露电流和环境湿度预测绝缘子污秽水平,从而判断绝缘子是否应该进行清洗。选取了FQBJ—25/8—760P复合绝缘子为研究对象,在饱和空气湿度下,利用在线监测装置进行人工污秽实验。利用实验数据拟合污秽水平与泄漏电流的关系曲线,为确定接触网绝缘子泄漏电流在线监测装置的预警值提供指导。基于污闪发展三区段思想,提出接触网绝缘子安全运行区、污秽清理区及危险区。     

用改进的静电探头测量绝缘子表面电荷

设计了用于绝缘子表面静电荷的测量装置。得到了圆柱型绝缘子的表面电荷分布图。实验研究表明设计的电荷测量装置具有分辨力高、电荷泄漏少的优点。     

基于图像伺服的接触网绝缘子自动水冲洗车

目前铁路绝缘子维护领域内还没有自动水冲洗设备,本文提出了捕获跟踪与瞄准系统对绝缘子进行自动冲洗维护。在绝缘子识别的基础上,进一步设计出基于图像的视觉伺服系统(IBVS,Image-Based Visual Servoing)控制方法,调整冲洗水炮炮管及摄像机姿态对绝缘子进行瞄准,来完成绝缘子冲洗工作。该方法主要思路为写出特征函数的差并使其最小,特征函数是通过两个雅可比矩阵及其伪逆矩阵建立起图像与冲洗装置控制量之间的关系,最后达到控制目的。本文使用Matlab对IBVS控制方法进行验证,该方法控制双自由度冲洗装置精确性达到要求,可实现绝缘子冲洗瞄准。     

一种中压开关柜绝缘子泄漏电流在线监测装置的设计

介绍了一种中压开关柜绝缘子泄漏电流在线监测装置的设计方法,给出了装置总体设计方案,详细介绍了放大电路、滤波电路、信号调理电路及电磁兼容设计,并采用低电压作用下的等效阻容网络测试了该装置的性能。当装置输入4V左右正弦波时,输出电压为2.2～3.8V,输出电流为10～14mA,均满足设计要求,且电压和电流波形匹配良好;在一定的相移前提下,该装置的输出波形与实测波形基本一致,表明其能够实现中压开关柜绝缘子泄漏电流的在线监测功能。     

融合PHOG和BOW-SURF特征的接触网绝缘子缺陷检测方法

绝缘子图像中存在的噪声对提取绝缘子细节纹理特征具有较大影响,单个特征描述子不能描述绝缘子的更多细节纹理特征,而提取到绝缘子细节纹理特征的多少直接影响了绝缘子缺陷检测的精度和速度.针对以上问题,提出改进快速导向滤波算法和融合PHOG与BOW-SURF特征来实现绝缘子缺陷的精确检测.首先,采用改进的快速导向滤波算法对接触网绝缘子原始图像进行滤波;然后,提取绝缘子滤波后图像的PHOG和BOW-SURF特征;最后,将两者融合后送入SVM分类器进行训练,实现绝缘子缺陷的检测.实验结果表明,该方法检测绝缘子缺陷的精度为100%,平均每张图像的处理时间为0.039s,为接触网悬挂状态检测监测装置对图像分析及缺陷检测奠定了必要的基础.     

电网绝缘子等值附盐密度智能测试仪的研制

介绍了电网绝缘子等值附盐密度智能测试仪的研制,详细阐明了有关工作原理和设计关键。测试仪以AT89系列单片机89C52作为核心器件,利用其运算功能直接测量出绝缘子清洗液的等值附盐密度。对决定电网绝缘子的清扫周期,有效防止电网大面积污秽闪络事故的发生有明显的作用。     

对瓷支柱绝缘子振动声波探伤的探析

瓷支柱绝缘子在输电线路中主要起到绝缘和制成的作用,因此绝缘子自身质量直接关系到电力输送的安全性和稳定性。由于瓷支柱绝缘子长期暴露在外,工作环境较为恶劣,如果制作工艺不符合规范,就会导致绝缘子出现裂缝或者缺陷,从而造成安全隐患。因此,需要借助专业的仪器设备对绝缘子进行全方位系统的检测。本文组要分析振动声波探伤方法,通过分析完好绝缘子和含有缺陷绝缘子的振动波形图的特点,获取缺陷所在范围,也进一步验证了该方法对瓷支柱绝缘子探伤的可行性。     

绝缘子检测机器人运动控制系统设计

针对绝缘子检测机器人运动控制系统设计,讨论了系统组成,设计了绝缘子的检测机器人运动控制系统设计.改变了人工检测绝缘子劳动时间长,危险性高,检测效率低的现状.探讨了绝缘子检测机器人运动控制系统,设计了软件实现方法和流程;随着智能电网概念的提出和发展,一种可以替代人工进行绝缘子检测的机器人成为电力系统发展的需求.本文在设计了绝缘子自由移动的机器人,该机器人可搭载现有的检测设备,完成绝缘子串的零值检测任务.     

高压架空输电线路绝缘子串抗风偏性能自动测试方法

为了提高高压架空输电线路绝缘子串抗风偏性能,需要进行高压架空输电线路绝缘子串抗风偏性能自动测试,提出一种基于防风偏智能分析数学建模的高压架空输电线路绝缘子串抗风偏性能方法,根据线路防风偏设计标准,参考设计风偏系数,结合架空输电线路绝缘子类型、绝缘子结构高度、绝缘子串、导线距杆塔最小电气安全距离等参数构建性能测试的约束参量模型,根据线路运行经验,进行防风偏智能分析数学模型设计,结合特征分析和智能算法对高压架空输电线路绝缘子串的抗风偏能力进行计算分析。结果表明,采用该方法能有效实现对高压架空输电线路绝缘子串抗风偏性能自动测试,计算结果准确可靠,提高了高压架空输电线路绝缘子串抗风偏性能,对架空输电线路绝缘子串的抗风性能参数的准确估计能力较好。     

基于电磁波检测的高压低零值瓷绝缘子判别技术及应用

瓷质绝缘子因常年暴露在户外，容易受到雷击、雨雪、污闪的影响导致绝缘击穿而成为零值绝缘子。为优化提升零值绝缘子的损伤辨识精度，提出一种基于电磁波检测的高压零值绝缘子判别技术。利用磁天线阵列的方向性与组阵压缩磁天线感知信号空间，使磁天线屏蔽压缩空间外的噪声和干扰信号。设计宽频带磁天线采集系统，通过宽、窄频磁天线接收零值瓷绝缘子在高压状态下的放电电磁脉冲信号，利用FFT技术对采集信号进行数据处理，根据频谱波形的幅度波动即可判断被测绝缘子是否存在放电现象以及放电严重程度。现场实验印证了所提方法的有效性和实用性。     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

法律信息库系统

本文分析了法律数据库的结构和特点，介绍了采用面向对象设计方法和超文本数据库技术开发和实现法律信息库系统将作为重要网络资源之一为不同用户进行法律咨询服务。     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

International Journal of Automation and Computing Table of Contents

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Information for authors

正SCIENCE CHINA Information Sciences(Sci China Inf Sci),cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press,is committed to publishing highquality,original results of both basic and applied research in all areas of information sciences,including computer science and technology;systems science,control science and engineering(published in Issues with odd numbers);information and communication engineering;electronic science and technology(published in Issues with even numbers).Sci China Inf Sci is published monthly in both print and electronic forms.It is indexed by Academic OneFile,Astrophysics Data System(ADS),CSA,Cabells,Current Contents/Engineering,Computing and Technology,DBLP,Digital Mathematics Registry,Earthquake Engineering Abstracts,Engineering Index,Engineered Materials Abstracts,Gale,Google,INSPEC,Journal Citation Reports/Science Edition,Mathematical Reviews,OCLC,ProQuest,SCOPUS,Science Citation Index Expanded,Summon by Serial Solutions,VINITI,Zentralblatt MATH.     

Erratum to: Fast global kernel fuzzy c-means clustering algorithm for consonant/vowel segmentation of speech signal

正Erratum to:J Zhejiang Univ-Sci C(ComputElectron)2014 15(7):551-563doi:10.1631/jzus.C1300320The original version of this article unfortunately contained mistakes.Algorithm 6 should be as follows:Algorithm 6 FGKFCM-F clustering Input:(1)X={x_1,x_2,…,x_N},,x_iR~d,i=1,2,…,N,the dataset;(2)C,1C≤N,the number of clusters;(3)ε0,the stopping criterion;     

Journal of Zhejiang University-SCIENCE C (Computers & Electronics) Total contents

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A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.