M2M物联网在电力系统信息采集终端中的应用

电力系统信息采集终端的要求主要体现在智能化、移动化、高可靠性、网络化等方面,本文根据电力系统信息采集终端的要求,从功率控制、节点分簇、网络部署等众多角度出发,研究了基于M2M协议的无线传感器网络拓扑控制方法,将某些复杂的网络动力学特征加以简化,使无线传感器网络拓扑成为无标独特性,最终使电力系统信息采集终端组网实现高可靠性和抗毁性。     

基于电力系统网络安全的风险控制

该文针对电力系统网络安全问题,对电力系统网络安全性进行了分析,进而确定专业管理和电力网络安全控制的要求,对影响电力系统网络安全性的各种因素进行研究,最终得到各种病毒、黑客等攻击形式的处理控制措施。     

现代电力系统自动发电控制实现与发展

针对现代电力系统自动发电控制(Automatic Generation Control,AGC)的基本原理及相关概念、控制策略及评价标准进行了简要论述。指出了目前我国区域互联电力系统AGC广泛采用的分层分区控制模式的实质为典型的FFC一TBC二级控制模式,阐明了在该模式下AGC控制存在经济性、协调性等方面的问题。就现代电力系统AGC向智能化、市场化、可兼容、分布式方向发展的现状和趋势进行了总结。最后,针对现代电力系统智能化调度的发展要求,进一步指出了AGC近期的研究方向和应用重点。     

基于混沌小扰动抑制的电力系统混沌振荡控制方法研究

针对电力系统在周期扰动下可能发生混沌振荡,影响电力系统稳定运行的问题,提出基于混沌小扰动抑制的电力系统混沌振荡控制方法。构建电力系统数学模型,模拟电力系统混沌振荡过程,确定扰动与混沌振荡之间的关系。根据电力系统实时运行数据的采集结果,计算混沌振荡信号特征参数,判定系统振荡状态,计算混沌扰动抑制控制量。在混沌振荡控制器的支持下,利用混沌小扰动抑制技术限制混沌振荡幅值,进而实现电力系统的混沌振荡控制任务。从实验结果中可以看出,与传统控制方法相比,优化设计方法控制作用下,电力系统的混沌振荡信号的幅值和频率更低,振荡幅值和频率的控制误差分别降低了约1.57db和0.015Hz,即优化设计方法的控制性能更优。     

改进的网型结构电力系统鲁棒重叠分散控制

研究一类多区域互联电力系统的特殊重叠分解及其鲁棒分散控制问题,提出一种新的互联电力系统重叠分解的方法。该方法根据电力系统本身的结构信息约束和大系统包含原理的约束条件,对系统进行重叠分解处理,使原系统扩展成为两两子系统;然后,在有机结构控制(OSC)的线性矩阵不等式(LMI)方法的基础上,为系统设计了改进的鲁棒分散控制器。以一个4区域网型结构电力系统为例进行仿真研究,其结果表明,所设计的控制器较直接使用LMI方法能使系统具有更令人满意的控制性能。     

基于MATLAB/SIMULINK的电力系统稳定性研究

本论文以MATLAB为仿真平台进行了电力系统稳定性研究的建模和动态仿真分析,介绍了MATLAB/SIMULINK的基本特点以及应用MATLAB实现电力系统仿真分析的基本方法和步骤。建立了一个单机——无穷大系统的仿真模型,从电力系统潮流、线路短路电流和电压、暂态稳定计算和分析几个方面进行了仿真研究。根据仿真结果与电力系统实际情况相比较可以看出,基于MATLAB/SIMULINK的电力系统仿真研究能较准确直观地考察暂态过程中电力系统的动态特性,为深入应用和学习电力系统相关知识,实现电力系统的运行与控制提供了大量的有用信息。     

电力市场条件下互联电力系统的分散H_∞控制

根据分散的自动发电控制AGC(AutomaticGenerationControl)的控制要求和电力市场的条件,研究了互联电力系统分散的鲁棒控制问题。采用虚拟控制区域的概念修正原互联电力系统的状态空间模型;利用大系统包含原理的约束和聚集条件将修正后的互联电力系统模型分解为各个子系统;根据LMI算法来设计可随时满足区域间功率交换合同的分散H∞自动发电控制器。此方法应用到受负载阶跃扰动的两区域互联电力系统中,结果表明了该方法的有效性,并且满足了电力市场条件下自动发电控制的要求。     

油田企业电力自动化控制装置研究

在油田企业中,电力系统包含着多个环节,主要有发电、变电、输电等,在电力系统中,输电线路之间的连接要依靠电力网络来实现,而且在配电环节,电力网络的作用也及其重要。随着科技的发展,油田企业的电力系统逐渐的实现了自动化控制,电力系统自动化控制的实现要依赖于控制装置,因此本文介绍了电力自动化控制技术的原理及分类,并分析了电力自动化控制装置的发展趋势。     

基于一种改进型逆凸不等式的混合攻击下多区域时滞电力系统的分布式控制

本文研究了混合攻击下多区域时滞电力系统的分布式协调控制问题。首先,考虑了一种基于混合攻击下（包括拒绝服务攻击和欺骗攻击）的多区域时滞电力系统,在拒绝服务攻击下,时滞电力系统的各个区域之间的通信将恶化为一种切换残余拓扑结构,它的时间特性建模成了模型依赖的平均停留时间的模型。在以负反馈控制为目标的欺骗攻击下,将其建模成了基于符号函数的模型。然后,为了在低惯性和混合攻击下获得时滞电力系统的弹性性能,采用了负荷频率控制与虚拟惯性控制相结合的弹性分布式策略,并将时滞电力系统的负荷频率控制问题转换为切换非线性切换系统控制问题。再通过采用合适的Lyapunov-Krasovskii泛函、改进型逆凸不等式、线性矩阵不等式技术以及切换系统方法,得到了多区域时滞电力系统的稳定性定理。并基于此定理,设计了负荷频率控制和虚拟惯性控制下的分布式控制增益。最后,建立仿真,针对三区域电力系统进行了仿真,仿真结果体现了本文所提出来的稳定性定理和设计的分布式控制增益的优势和有效性。     

电力系统稳定性的分散输出反馈控制

本文探讨了大系统分散输出反馈控制的设计方法,并将其应用于多机电力系统的稳定控制问题。文中提出了分散信息限制的等式表示形式,并给出了电力系统的分散输出反馈控制方案。最后针对某两机一负荷无穷大母线典型系统进行了设计和研究。研究结果表明:在非线性系统中,适当的分散输出反馈控制不仅比全局最优状态反馈控制简便,且可能取得更好的效果;文中提出的分散输出反馈控制方案具有效果好,易于实现,适应性较佳等优点,是一种很有应用前途的电力系统稳定控制方案。     

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.     

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.     

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.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate