智能电表在智能电网中的应用

与传统意义上的电能表不同,智能电表是智能电网的智能终端,既具有传统电表的用电量计量功能,又具有多种智能化功能,适应了新能源的使用和智能电网的发展。代表着未来节能型智能电网最终用户智能化终端的发展方向,智能电表在电网中的应用越来越广泛。对智能电表功能及应用的探析,不仅能够促进智能电网的现代化建设,实现电网信息化、自动化、互动化,而且还能够促进智能用电的实现。因而,须加强重视,对智能电表相关功能及具体应用进行具体分析,具有十分重要的意义。本文主要探讨智能电表的功能特点,并对智能电表在智能电网中的应用进行分析。     

新型智能电表的发展现状及发展趋势研究

在社会经济飞速发展的今天,为了满足人们生产生活用电的需求,智能电网概念得到了提出和发展,并逐渐成为我国电力行业发展的主要趋势。而智能电网中的重要设备——智能电表,也在电网中起到了关键的作用。本文通过对智能电网和新型智能电表概念、发展现状、工作原理做了深入研究,最终得出智能电表符合节能环保要求,兼有安全性、经济性、交互性等特点,因而新型智能电表是未来电表行业的不二之选。     

新型高安全性的智能电表自动化检定系统

随着智能电网工程的发展,智能电表自动化检定系统的安全性越来越受到人们的关注。为使智能电表的自动化检定系统得到大范围推广应用,在结合检测系统本身特点基础上,提出了一种新型高安全的智能电表自动化检定系统。通过结合椭圆曲线密码器技术,对智能电表自动化检定系统的安全可靠性进行初步的评测探索和研究。分析表明,提出的自动化检定系统具有高安全性和低资源消耗等优点,值得大力推广应用。     

安全增强的智能电网轻量级匿名认证方案

现有的智能电网身份认证方案大多存在计算成本高和认证流程复杂的问题,不适用于智能电网中资源受限的智能设备。而一些轻量级的方案却存在各种安全漏洞,这些方案都无法在效率和安全性之间实现所需的权衡。针对上述问题,基于椭圆曲线加密算法设计了一个增强的可证明安全的智能电网轻量级匿名认证方案。引入辅助验证器,摆脱在认证阶段对于电力供应商的依赖,在保护智能电表真实身份的条件下实现网关和智能电表之间的相互认证。同时,可以通过伪身份对恶意智能电表进行身份的溯源和撤销。通过在随机预言模型下的安全性分析和仿真工具ProVerif证明了方案具备较高的安全属性。性能分析表明,所提方案能够满足智能电网环境下对于安全性和高效性的要求。     

认清智能电表发展技术分析未来发展新趋势

智能电表是一种新型全电子式电表,在电能量计算、实时监控、自动控制、信息交互及数据处理等方面具有巨大优势。智能电表能够迅速准确地了解用户的用电情况,为此制定个性化的节电计划,这是智能电表明显区别于一般电表的地方。智能电表自出现之日起,凭借其强大的技术优势在智能电网中占据着重要地位。本文从智能电表优势入手,研究智能电表发展技术,并分析智能电表未来发展的新趋势。     

关于智能电表运行维护的几点建议和思考

智能电网已经成为21世纪各国电力系统的发展方向。智能电表作为智能电网的重要组成部分,是实现电网和用户间实时交互、提高服务水平,以及提高电能利用率和促进节能减排的重要手段。作为智能用电的终端,智能电表扮演了不可或缺的角色。本文对智能电表的发展和应用进行了回顾,并对目前智能电表的常见问题和日常维护进行分析讨论。     

智能电表的应用与发展前景分析

我国是一个用电量非常高的国家,因此电力系统发展的较为快速,为了迎接未来用电的新挑战,我国逐渐将电表向智能化转变,智能电表由此而被发明,智能电能够更好的记录电量的使用情况,减少人们在用电时造成的电能的浪费,相比于普通的家用电表,智能电表更加的安全,而且节能环保,同时智能电表也是智能电网中的重要的组成部分,是智能电网在我国电力系统得到实施的基础,本文主要对智能电表的应用与发展前景进行讨论,并简要介绍智能电表的使用优点,希望未来智能电表能够得到更好的发展。     

智能电网容错数据聚合方案

新一代智能电网的出现,极大地提升了电网的安全性与可靠性,这依赖于智能电表每15分钟发送一次数据,但是这可能会暴露用户的隐私,同时需要消耗很大的计算代价.于是数据聚合技术被引入,大多数现有聚合方案存在耗时大且当电表故障时系统无法正常运行等问题.针对上述问题,本文提出了一个智能电网中高效的支持错误容忍的数据聚合方案,具体来...     

智能电网中新型智能电表及集抄系统的运维策略分析

随着经济快速发展,人们对电力资源的需求越来越大,电力企业发展过程中各种新技术的应用,对电力行业的快速进步有十分重要的促进作用。现代化和智能化成为变电站发展过程中的一个重要趋势,智能电网中的智能电表以及集抄系统的运行和维护管理,成为当前电网发展过程中的一个重要组成部分。本文对智能电网中智能电表及集抄系统的运行维护策略进行分析和探讨,旨在提高智能电表和集抄系统的工作效率。     

智能电网的装表接电技术探究

随着我国科技的发展和进步,智能电网已经成为社会的发展必然趋势,该种现象在一定程度上可促进智能电表的推广使用。而智能电表的广泛应用为人们对电力需求管理打下良好的基础,能够有效促进电力营销,让电表接电面临新的挑战和机遇。本文主要对智能电网的装表接电技术进行分析。     

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).