基于混沌粒子群的神经网络主汽温控制系统

研究火电厂锅炉主蒸汽温度控制优化问题,针对主汽温对象具有大惯性、大迟延、时变性和非线性系统,由于存在实时性和实时性差,传统的PID控制难以获得很好的控制效果,提出一种混沌粒子群优化神经网络的主汽温控制方法。采用RBF神经网络对PID参数进行在线整定,并通过混沌粒子群算法对RBF神经网络初始参数进行优化,不仅具有RBF神经网络的自适应能力,同时具有常规PID串级控制的特性,增强了系统对不确定因素的适应性。仿真结果表明,控制算法具有较好的鲁棒性和控制品质,抗干扰能力强,可为锅炉主蒸汽温度优化控制提供参考。     

基于DMC-PID串级主汽温控制系统的仿真研究

针对火电厂主汽温被控对象的大迟延，大惯性且模型不确定的特点，设计了基于预测-PID串级控制的主汽温控制系统，该系统将串级控制结构与预测控制算法相结合，内回路采用常规比例调节器，外回路采用动态矩阵控制器（DMC），既保持了预测控制的强鲁棒性和跟踪性能，又具有足够的抗干扰性，仿真结果表明，所设计的系统在控制品质，鲁棒性方面明显优于常规PID控制系统。     

火电厂过热汽温的优化控制算法研究

由于火电厂过热蒸汽温度控制具有大延迟、大惯性、非线性、强时变性的特性,传统PID控制算法难以实现良好的控制效果。为了优化火电厂过热汽温控制,提出了一种基于DMC的改进串级PID控制算法。该算法采用DMC改进主控制器输入参数,预测未来输出值,通过预测值与实际值的差值实现输入参数的校正。仿真结果分析表明,该算法与传统PID控制算法相比降低了过热蒸汽温度的超调量,缩短了汽温控制的过渡过程时间,提高了控制系统的抗扰动能力,使控制系统的动态性能和静态性能有了极大改善。     

基于神经网络预测控制的主汽温优化控制

火电厂锅炉主汽温不易直接测量,容易受到外界干扰,主汽温控制过程容易受到电力生产工艺因素的制约,所以采用常规的控制技术难以取得良好的优化控制效果.根据我国火电厂的实际情况,同时结合智能控制的发展现状,将火电厂锅炉主蒸汽温度作为研究对象,提出采用基于神经网络的预测控制策略对锅炉主汽温进行控制.神经网络具有的自适应学习能力能够很好地适应控制环境的变化,可以通过简单的工具自动进行特征提取,产生有用的数据.采用LSTM循环神经网络建立主汽温的预测模型以预测主蒸汽温度的未来输出值,同时进行反馈校正,克服外界因素对系统扰动所造成的预测误差,得到较为精确的主汽温预测值,最后根据二次性能指标建立优化器实现对控制量的滚动优化.     

新型SMITH预估控制算法在主汽温控制系统中的应用研究

大机组汽温控制对象具有大延时、大惯性的特性,采用常规和简单的控制方式难以取得满意效果。文章介绍了一种应用新型SMITH预估控制算法调节火电厂主汽温控制系统的设计方案,阐述了新型SMITH预估控制算法的原理、系统控制策略及结构,并在软件环境下对该系统与采用传统SMITH预估控制算法的控制系统进行了仿真比较。仿真结果表明,基于新型SMITH预估控制算法的主汽温控制系统能够克服大滞后、大惯性的系统特性,具有较强的抗内、外干扰和对象变化适应能力。     

ARX-Laguerre模型PID预测控制及其在过热汽温控制中的应用

针对火电厂过热汽温控制的特点,提出了一种基于ARX-Laguerre模型的PID预测控制算法(ALMPCPID),该算法使用增量式的ARX-Laguerre模型作为预测模型,将滚动优化的性能指标改为PID控制器的形式,并利用带遗忘因子的最小二乘递归方法对模型参数进行在线辨识。将ALMPCPID算法应用于过热汽温控制系统进行仿真研究,仿真结果表明该方法可有效应对过热汽温系统的特性变化带来的影响,控制效果优于常规预测控制策略,具有很好的应用价值。     

神经网络广义预测控制在锅炉燃烧系统中的应用

针对锅炉燃烧系统的非线性、大延迟、时变、干扰频繁等特点,以煤粉浓度为中间被调量,将神经网络、广义预测控制、串级控制相结合,设计了基于神经网络模型的广义预测串级控制系统.该控制方法克服了单纯PID控制对大惯性大延迟对象调节品质差、抗干扰性弱的缺点,神经网络预测器有效地补偿了传统预测控制基于线性模型的局限性.将该控制算法用于燃烧系统中主汽压力对象的控制,仿真结果表明该方法具有较强的跟踪性能和抗干扰能力及良好的动静态性能指标.     

火电厂锅炉主汽温控制策略的比较研究

锅炉的主汽温被控对象是一个大惯性、大迟延、非线性且对象变化的系统,常用的汽温控制系统有串级PID控制和基于BP神经网络的PID控制。串级PID控制一般能将主汽温控制在允许的范围内;基于BP神经网络的PID控制将神经网络所具有的自学习能力与PID控制器的鲁棒性相结合,能实现对非线性、大时滞系统模型的控制。对这两种策略在不同负荷下进行了实验仿真,该结果对当前电厂的经济性和安全性有一定参考价值。     

灰色预测神经网络PID控制研究

由于火电厂过热汽温控制系统的大惯性、大迟延和时变等特性，传统的串级PID控制方法不能适应负荷变化，因而难以取得满意的控制效果。因灰色预测具有少数据、贫信息且运算量小的优点，将灰色预测控制及神经网络相结合，提出了基于灰色预测的神经网络PID控制策略。仿真研究表明，该策略的控制效果优于常规的PID控制，能适应对象参数的变化并表现出良好的控制品质，具有较强的鲁棒性和自适应能力。     

循环流化床主汽温系统的模糊自适应控制

研究了循环流化床主汽温控制特性,然后基于自适应控制和模糊控制对传统Smith预估控制进行了改进,最后将改进的Smith预估控制算法应用于循环流化床主汽温控制,通过仿真表明,提出的控制算法能取得好的控制效果.     

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.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

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.     

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