基于IEC61850标准的工程开发方法研究

在分析IEC61850标准的变电站分层、面向对象的数据对象统一建模和抽象通信服务映射等内涵的基础上,从系统功能建模、信息模型构建、SCL文档配置、通信映射等方面入手,提出一整套的实践IEC61850标准的工程开发方法.以过程总线通信中跳闸命令传输为例,详细阐述了智能电子设备(IED)开发过程.基于该方法,不同厂商开发的IED具有互操作性,并使变电站自动化系统成为数字化系统.     

基于IEC61850/MMS的电力录波系统数据通信的实现

IEC61850是将来变电站无缝通信体系的基础,国内对IEC61850的研究还主要停留在理论层面上,对它的实际应用的研究并不多见,本文从实际应用角度出发,以故障录波通信系统为目标,采用了面向对象的技术,详尽分析了基于IEC61850的IED(故障录波器)的建模,传输中数据库的建立、数据链接以及ASCI到具体通信栈的映射的实现,并通过PC机得到模拟结果,取得了较理想的结果,为工业变电站自动化应用IEC61850做了前瞻性工作.     

基于VxWorks嵌入式实时操作系统的IEC61850数据通信实现

针对变电站IED之间的互操作性差、难以实现信息交互的问题,结合变电站技术改造,探讨了基于VxWorks嵌入式实时操作系统的IEC61850报文实现。借助VxWorks的Wind微内核提供的多任务环境、进程间通信和同步功能,讨论了任务调度策略、通信、同步和互斥机制,研究了信息模型的通信映射与快速报文传输服务,构建了实现IEC61850的信息模型实体,分析了快速报文在Wxvorks中的实现,给出了最优推荐方案。变压器经济运行自投切换初步实验结果表明,IEC61850变电站自动化最新国际标准的实施有利于采用最新通信技术实现对电力参数的监控,为系统拓展预留了广阔的空间。     

基于IEC61850标准的变电站通信管理机设计

为了将大量不支持IEC61850标准的智能电子设备接入采用IEC61850通信系统的变电站综合自动化系统中,在分析变电站通信管理机的功能要求及其在变电站通信系统中的应用方式的基础上,介绍了一种变电站通信管理机的软硬件总体设计方案。该通信管理机基于Atom 230微处理器和Linux嵌入式操作系统设计,具有多网口、多串口,满足多种智能电子设备的接入需求,可实现传统通信协议向IEC61850标准协议的转换功能。     

IEC61850在故障信息处理系统中的应用

IEC 61850"变电站通信网络和系统"是关于变电站自动化的最新国际标准,本文首先简单论述了故障信息处理系统的现状及标准化建设的必要性,然后详细介绍了IEC 61850对于故障信息处理系统的指导作用.文中提出了将故障信息处理系统子站看作是一个特殊功能的智能电子装置IED,介绍了遵循IEC 61850的保护装置的对象建模方法.     

解析智能变电站IEC61850数据集模型

如今在智能变电站中IED间的通讯形式从相互连通到互操作都得到了标准化,而IEC61850就是这一标准化的重要成果。IEC61850着手解决的就是不同变电站和不同供应商的设备之间的互操作性,从而满足变电站的需求。本文描述IEC61850的面向对象技术、UML建模技术以及应用视图模型和数据集模型的实现。     

基于IEC 61850的同步相量数据传输方法研究

目前,智能变电站同步相量测量系统仍然采用IEEE 1344规约并使用专用通道与主站进行通信,而未采用在智能变电站中普遍采用的IEC 61850标准通信,这既增加了电网建设投资,也给系统运维带来不便。针对上述问题,本文提出基于IEC 61850的同步相量数据传输方法,即将同步相量测量系统的传输方法映射到IEC 61850标准体系,并将现有的通讯服务所包含的功能在IEC 61850标准体系下找到实现的手段。首先针对高速的数据传输和快速控制提出实现方法,然后对IEC 61850服务不能完全实现的功能服务以规定的方式对功能做扩展填补缺陷。最后从统一变电站信息平台的角度,对本方案的前景进行了分析。结果表明同步相量测量系统转换到IEC 61850体系是可行的,并将为信息的联合分析提供了基础。     

基于工业以太网技术的IEC 61850协议应用分析

基于工业以太网技术分析,本文阐述了IEC61850协议的工作原理、建模方法和报文性能需求,介绍了在工业以太网中应用IEC61850标准的通信机制,探讨了在变电站自动化系统中引入RTPS模型的设计方法。     

数字故障录波器MMS服务设计与实现

针对IEC61850标准在数字化变电站及智能电子设备中广泛应用,采用IEC61850标准对故障录波器功能进行了建模,将该模型中的对象及服务映射到MMS中,设计了MMS服务端。调用思科MMS-EASE Lite源码包,降低了MMS PDU的设计难度,实现了录波器MMS通信服务功能,最后以录波器应答客户端调取服务器目录服务为例,抓取分析通信报文,验证了MMS通信准确性。     

基于IEC 61850和MMS的变电站监控设备网关研究

在分析当前变电站通信协议和IEC 61850标准及MMS特点基础上,提出一种基于IEC 61850和MMS的常规变电站设备网关系统结构,在保留原有监控系统软件和硬件资源情况下,将常规变电站设备接入IEC 61850环境,保护原始投资,节省资源,还能解决不同厂商设备的互操作问题。     

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。     

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.     

Enhancing a leaf radiative transfer model to estimate concentrations and in vivo specific absorption coefficients of total carotenoids and chlorophylls a and b from single-needle reflectance and transmittance

The relative concentrations of different pigments within a leaf have significant physiological and spectral consequences. Photosynthesis, light use efficiency, mass and energy exchange, and stress response are dependent on relationships among an ensemble of pigments. This ensemble also determines the visible characteristics of a leaf, which can be measured remotely and used to quantify leaf biochemistry and structure. But current remote sensing approaches are limited in their ability to resolve individual pigments. This paper focuses on the incorporation of three pigments—chlorophyll a, chlorophyll b, and total carotenoids—into the LIBERTY leaf radiative transfer model to better understand relationships between leaf biochemical, biophysical, and spectral properties.Pinus ponderosa and Pinus jeffreyi needles were collected from three sites in the California Sierra Nevada. Hemispheric single-leaf visible reflectance and transmittance and concentrations of chlorophylls a and b and total carotenoids of fresh needles were measured. These data were input to the enhanced LIBERTY model to estimate optical and biochemical properties of pine needles. The enhanced model successfully estimated reflectance (RMSE = 0.0255, BIAS = 0.00477, RMS%E = 16.7%), had variable success estimating transmittance (RMSE = 0.0442, BIAS = 0.0294, RMS%E = 181%), and generated very good estimates of carotenoid concentrations (RMSE = 2.48 µg/cm², BIAS = 0.143 µg/cm², RMS%E = 20.4%), good estimates of chlorophyll a concentrations (RMSE = 10.7 µg/cm², BIAS = − 0.992 µg/cm², RMS%E = 21.1%), and fair estimates of chlorophyll b concentrations (RMSE = 7.49 µg/cm², BIAS = − 2.12 µg/cm², RMS%E = 43.7%). Overall root mean squared errors of reflectance, transmittance, and pigment concentration estimates were lower for the three-pigment model than for the single-pigment model. The algorithm to estimate three in vivo specific absorption coefficients is robust, although estimated values are distorted by inconsistencies in model biophysics. The capacity to invert the model from single-leaf reflectance and transmittance was added to the model so it could be coupled with vegetation canopy models to estimate canopy biochemistry from remotely sensed data.     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).