基于多因素考虑的变压器故障概率模型

变压器在电力系统中意义重大,电力变压器一旦发生故障对电力系统将造成重大损失.在电力行业发展进程中,预防性检修及定期检修已不能满足当前的需要.因此研究基于在线监测的变压器故障诊断技术,获取当前变压器的健康状态,更好地对变压器的运行状况进行维护.综上所述:在线监测的变压器诊断技术对电力系统的安全运行具有非常重要的现实意义.当前的故障概率计算大多是针对可靠性的故障进行计算[1],没有综合考虑运行年限、已发生故障以及维修情况、运行经历等因素.因此得出的故障概率不是很准确,论文将从变压器运行的在线监测数据、运行年限、已发生的故障及维修情况、运行经历综合进行考虑,综合以上因素加权最后得出变压器整体的故障概率.     

Harris角点检测在电力设备状态监测中的应用

人们对电力设备的要求逐渐提高,电力设备的带电检测、在线监测、巡检和试验、运行工况、环境等是电力设备状态监测和评估发展的必然趋势。由于一些大型电力设备长期工作在户外恶劣的环境下,随着时间的推移,其性能会下降并逐渐降低用电可靠性。为了更好地实现对电力设备的监测并保证电力系统的正常运行,针对常见电力设备运行中出现故障的特点,该文采用Harris角点检测监控电力设备状态的方法来对电力系统中的运行设备进行监测。该方法将摄像头搜集的实时图像和正常运行的电力设备状态进行比较,根据比对采集到的图像焦点特征来判断正在运行的电力设备是否发生故障,以便于电力设备监测的工作人员及时采取合理的处理措施对已故障的设备进行保养和维护。该方法不仅减轻了维修人员的工作负担,还减少了因设备故障导致的用电事故,从而大幅度提高了电力系统的安全性和稳定性。     

C8051F020构成的RTU及故障监测系统

针对电力系统中变电站 RTU和远动通道出现故障的主要原因,提出在电力系统中远程故障监测的一种新方法。利用片上系统SoC C8051F020 构成嵌入式厂站端,用以监测变电站 RTU和远动通道工作状态,并利用GSM通信方式完成后台计算机与厂站端的数据交换,实现了变电站 RTU和远动通道故障的远程监测。     

考虑实时调度的电力系统配电网远程自动监控方法

利用目前方法对电力系统配电网远程自动监控研究时，存在监测故障次数与实际故障次数差距大、时间长、漏报率和误差率大的问题，为此提出考虑实时调度的电力系统配电网远程自动监控方法，通过构建实时调度模型对电力系统配电网进行分析，并确立电力系统的约束形式，分析完成后对电力系统中的配电网进行故障监测，从中获取最大小波奇异值，根据最大小波奇异值对配电网线路状况的反映，完成对电力系统配电网的远程监测。实验结果表明方法的精准度较高、实用性较强。     

风力发电系统监测管理与故障分析研究

广泛应用的风力发电系统对风力发电机组的维修和保养提出了更高的要求,在对风力发电机组故障隐患进行排查和预防性维修的过程中,状态监测及故障分析是不可或缺的重要手段。因此,在对风力发电机组监测管理与故障分析系统现状进行分析的基础上,阐述了相关状态监测与故障诊断的技术和方法,设计一种状态监测与故障诊断系统试验装置完成对风力发电系统故障问题的判断,为有效解决相关故障问题提供支撑。     

基于多技术融合的掘进机状态监测系统与维修技术研究

针对煤矿掘进机传统监测维修方式存在检测不到位、故障排查困难、维修成本较高、智能化不足等问题,开展了掘进机状态智能监测与维修技术的研究,将自主导航技术、在线监测技术和设备故障智能诊断技术融合,完成硬件选型和软件编程,搭建掘进机状态在线监测系统方案。结果表明,掘进机状态在线监测技术实现了设备运行参数远程化,在线监控设备运行状态,且故障识别响应时间仅为15s,异常在线排障和精准维修大大提高了设备维修效率。     

基于通信网络环境下的复杂电力系统连锁故障探究

自从我国实行改革开放以来,随着我国市场经济发展速度的加快,科学技术的发展和人们生活水平和质量的提高,各行各业对于用电的需求大幅增加,电力企业只有不断改进电力系统,对电力系统的故障进行预防和及时维修处理,才能适应社会发展的需要。本文通过对通信网络中的电力系统的概念、组成、特点等的介绍,对通信网络环境下电力系统的现状分析,并对通信网络中电力系统连锁故障进行陈述,提出相关应对措施,以促进我国电力系统的建设以及我国经济事业的蓬勃发展。     

新时期电力继电保护问题与维修技术探析

在继电保护在电力系统运行过程中起着重要的保护作用,对于安设了继电保护装置的电力系统来说,一旦发生电力故障,装置就会发出指令,断路器就会接受指令发出跳闸的命令,停止运行,发生故障的元件就能及时从电力系统上中断,将故障带来的损失最大化地减小,从而保障了用电的安全稳定,促进电力系统朝着稳健的方向运行。文章通过对这一问题的探究,从继电保护在电力系统中发挥的巨大作用入手探究了电力系统发生故障应当采取的维修措施,期望可以为同行提供一定的参考。     

关于电气设备的绝缘在线监测与状态检修分析

电气设备应用场所很广泛,有些场所的电力系统不能处于停止运行状态,所以在其出现故障时,维修人员一般会对其采取绝缘在线监测和状态检修方式,这两种方式都不需要停工,也不会对生产造成影响。维修人员要保证两种方式的有效性,电气设备才会重新恢复正常,处于安全运行状态。所以维修人员一开始就要掌握两种方式相关的技术能力与理论知识,能在检修中,快速得出结论,找到症结。     

基于家庭网络技术的燃气壁挂炉故障监测系统设计

从燃气壁挂炉维修与维护的局限性出发,提出基于家庭网络技术的燃气壁挂炉故障监测系统。该系统保留传统燃气壁挂炉显示面板和控制主板的通讯接口,硬件上串接一个故障跟踪模块。在家庭网络下,故障跟踪模块过滤出燃气壁挂炉的实时状态信息,通过网络上传到远程服务器。远程协助维修员通过上传的实时状态信息,在线给予用户故障剔除方案。本设计实现了燃气壁挂炉的远程维修与维护,为后续的燃气壁挂炉故障诊断风险分析提供了可靠的依据。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.