110kV输电线路综合防雷措施探究

全面改善110 kV输电线路的防雷能力是保障可靠供电的重要任务。本文研究分析了雷电对110kV输电线路的危害,并根据110kV输电线路的实际应用特点提出了综合防雷措施,以期对全面改善110 kV输电线路的防雷能力能够有所借鉴。     

变电站智能化10kV中置开关柜选型和闭锁功能试验

介绍泉州电业局110kV西郊变电站10kV中置开关柜智能化改造的情况,提出10kV中置开关柜要达到智能化变电站规范和标准的要求。     

110kV单电源线路接地距离保护动作分析

分析了一起110kV单电源线路发生单相接地故障时,受电侧110kV主变中性点被击穿,引起线路电源端与受电侧接地距离保护动作跳闸的原因,并对保护配置提出合理建议。     

110kV变电运行管理方案分析

加强变电运行管理力度,提高管理水平对于电力企业的发展至关重要。本文介绍了变电运行管理的重要性和变电运行管理模式,并针对当前110kV变电运行管理中存在的问题,提出了相应的改进措施以确保110kV变电站安全运行。     

多主变并列运行变电站中性点运行方式的优选方法

介绍220kV主变中性点运行方式与零序保护、间隙保护的关系,并从110kV系统发生接地故障的角度进行分析,提出220kV变电站主变中性点运行方式的优选方法。     

贵阳电网110kV线路优化保护配置及整定计算的探讨

对贵阳地区电网运行现状的分析，针对其110kV线路保护的配置情况和整定计算，提出了优化方案。方案中，通过对110kV线路配置光纤电流差动保护，强化主保护，简化后备保护的整定原则，能够进一步提高110kV线路保护可靠性，有效地减轻维护工作难度，提高继电保护整定计算的工作效率，对运行方式的安排也提高了灵活性。     

变压器涌流导致差动保护误动的保护动作分析

针对110kV红旗变电站由于110kV线路保护重合不成功引起的主变差动保护误动，并结合保护录波和现场实际整定定值，对此保护误动情况进行原因分析，对于该类问题提出解决方案和防范措施。     

110kV变电站电压互感器故障原因分析

分析110kV变电站电压互感器故障的相关原因,并提出处理措施。     

110kV电站稳控装置与线路保护装置定值配合案例分析

本文通过一起并列运行双回线其中一回线路瞬时故障保护装置跳闸重合闸动作前稳控装置已动作切机的案例, 分析了110kV 并列运行双回线线路保护装置中距离III段动作时间、重合闸动作时间与110kV电站稳控装置切机动作时间失配的原因,总结了三者之间配合的基本原则;根据电网的实际运行情况,提出通过优化110kV线路保护距离III段动作时间、线路两侧重合闸动作时间来确保与稳控装置动作切机时间配合的解决方案,以避免重复发生线路瞬时故障重合闸动作之前稳控装置先行切机的类似事件,保证了机组发电的连续性及电网供电的可靠性,消除了110kV并列运行双回线线路保护装置与110kV电站稳控装置时间定值失配带来的不良影响。     

110kV变电站继电保护故障及应对措施

近年来，随着电力系统的不断发展，110kV变电站变的越来越多，然而，110kV变电站继电保护问题也变得越来越重要，是大家研究的焦点，所以，110kV变电站的继电保护措施要不断加强，本篇论文针对110kV变电站继电保护故障及应对措施进行了简单的论述，首先，本文先论述的是110kV变电站的继电保护故障类型、状态等，然后针对其故障论述了一些应对措施。     

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。     

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.     

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.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

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.