九点控制器作用下的正弦跟踪仿真分析

九点控制器是根据偏差和偏差变化的大小在相平面上采用不同的作用力以达到控制要求的控制器。该文介绍在九点控制器作用下的正弦跟踪 ,借助于相平面工具详细地分析控制作用力参数Ki(i=0 ,± 1,± 2 ,± 3 ,± 4)对正弦跟踪稳定性能的影响 ,并给出了如何调整控制作用力参数以达到正弦跟踪性能的要求。     

九点控制闭环特性的研究与仿真

九点控制器是根据偏差和偏差变化的大小在相平面上采用不同的作用力使系统达到控制要求的控制器。本文首先在相平面上对控制力K0的作用范围进行了调整,用以消除稳态误差;其次,分析了九点控制系统的稳定性和抗干扰性能与九个作用力的关系;最后,仿真比较了单位阶跃输入时九点控制与闭环PID控制系统的抗干扰能力,仿真结果表明该控制器不仅能使开环不稳定系统稳定而且具有良好的抗干扰能力,验证了理论分析的有效性。     

九点五态控制器作用下迟延系统的稳定性分析

九点五态控制器是根据偏差和偏差变化率，在相平面上采用不同的作用力以达到控制要求的控制器。该文介绍了九点五态控制器分别在0型系统和Ⅰ型系统的迟延系统作用下稳定性分析，并且比较了在相同对象下施加不同的作用力和在不同对象下施加同样的作用力下的控制效果。从而得出：对于任意的带延迟的二阶对象在任意小的允许误差要求下，总能找到满足基本运行条件的一组作用力使控制系统满足允许误差要求，达到系统稳定。     

二十七点九态控制器及跟踪仿真分析

二十七点九态控制器是根据偏差、偏差的变化和偏差变化的变化所构成的相空间上采用不同的控制作用以达到满足控制要求的控制器.分析此控制器的九种不同的作用力在相空间和响应曲线的一一对应关系,通过作用力来研究响应曲线,进而揭示出三阶及高阶对象难以控制的原因;通过不同的三阶对象分别在单位阶跃、正弦和斜波下的跟踪仿真,可得出结论：在此控制器作用下对于不同的三阶对象（含不稳定的）,可以达到满意的控制效果.     

五态控制器及其二阶对象的稳定性仿真分析

该文介绍五态控制器的模型、控制作用。五态控制器是根据偏差和偏差变化率的大小在相平面采用不同的作用力以达到控制要求的控制器。将九种不同的二阶系统在五态控制器作用下进行稳定性仿真分析,可以得出结论：在五态控制器作用下通过改变作用力的大小,都可以使系统变为发散、等幅振荡、收敛稳定甚至使系统直接达到稳定状态而不管对象为何种二阶系统,也不管对象本身的稳定性特征(发散振荡、等幅振荡或稳定)。     

仿人智能控制器的研究及工程应用

介绍了仿人智能控制器的适用范围和基本算法,提出了改进的仿人智能控制器即九点控制器的优化控制策略.通过时工程设计中温度的控制方案设计,比较了九点控制器与PID控制器算法对系统动态性能的影响.九点控制器算法简单、系统响应速度快、参数整定简单,特别适合于无数学模型的控制对象.九点控制器的参数可进一步优化,从而转化为九点五态控制器.     

基于模糊九点控制器的自适应控制系统设计方法研究

由于传统自适应PID控制算法在线调节PID的三个参数难度较大,现将模糊九点控制器加入到自适应控制系统中,根据系统偏差e和偏差变化率ec的不同,将系统状态分为九神情况,运用模糊九点控制器进行参数自整定,调节系统在不同状态下的控制特性.该控制方法不依赖数学模型,切实有效,具有稳定型好,调节精度高等特点,是一种表达人类控制思...     

一种自调节灰色预测PID控制器

为提高传统PID控制的性能及扩大其适用范围,提出一种结合传统PID控制、灰色预测和全程快速非线性跟踪．微分器的自调节灰色预测PID控制器。利用灰色预测对系统的输出偏差和预测偏差进行合成形成一个综合偏差,用来代替传统PID控制中的实际偏差项。这样控制器既有预测系统未来行为的功能,又能根据预测模型精度自动调节控制器参数,能有效减小预测误差对系统的不利影响。同时用非线性跟踪．微分器代替差分法来提取微分信号,提高了微分信号的品质。仿真结果表明,与传统PID控制器相比,该控制器可获得更为优良的动态性能。     

基于模糊PID的无人水面艇直线路径跟踪

针对固定参数PID方法在无人水面艇直线路径跟踪控制中出现的大迴转问题,提出一种基于模糊PID的直线路径跟踪方法。在系统中增加模糊推理模块,利用航向与跟踪直线之间的偏差角以及无人艇位置与跟踪直线之间的距离误差,根据模糊推理的方法动态地调整PID参数。通过PID控制器实时调整左右两侧推进电机的输入电压,实现对给定直线路径的自主跟踪。仿真结果表明,在初始航向偏差角较大时,该方法克服了采用固定参数PID控制方法时出现的大迴转现象;在初始航向偏差角较小时,该方法在超调量以及调节时间方面的直线跟踪性能优于固定参数PID控制方法。     

神经网络相平面分区控制器研究与仿真

将神经网络的在线学习、即时调节功能与相平面分区的逻辑判断特性相结合提出了一种新的智能控制器———神经网络相平面分区控制器.该控制器将系统响应的基本性能与相应工况的控制作用力的划分和作用强度在相平面上建立起了实时的相互对应关系,从而使各分区内的控制参数能随着被控对象的变化在线自动调节参数,具有自适应能力.仿真结果表明,利用该方法设计的控制器闭环性能好、鲁棒性强.该方法为非线性控制提供了一种有效的控制器设计途径.     

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.     

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.     

法律信息库系统

本文分析了法律数据库的结构和特点，介绍了采用面向对象设计方法和超文本数据库技术开发和实现法律信息库系统将作为重要网络资源之一为不同用户进行法律咨询服务。     

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.     

International Journal of Automation and Computing Table of Contents

正~~     

Information for authors

正SCIENCE CHINA Information Sciences(Sci China Inf Sci),cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press,is committed to publishing highquality,original results of both basic and applied research in all areas of information sciences,including computer science and technology;systems science,control science and engineering(published in Issues with odd numbers);information and communication engineering;electronic science and technology(published in Issues with even numbers).Sci China Inf Sci is published monthly in both print and electronic forms.It is indexed by Academic OneFile,Astrophysics Data System(ADS),CSA,Cabells,Current Contents/Engineering,Computing and Technology,DBLP,Digital Mathematics Registry,Earthquake Engineering Abstracts,Engineering Index,Engineered Materials Abstracts,Gale,Google,INSPEC,Journal Citation Reports/Science Edition,Mathematical Reviews,OCLC,ProQuest,SCOPUS,Science Citation Index Expanded,Summon by Serial Solutions,VINITI,Zentralblatt MATH.     

Erratum to: Fast global kernel fuzzy c-means clustering algorithm for consonant/vowel segmentation of speech signal

正Erratum to:J Zhejiang Univ-Sci C(ComputElectron)2014 15(7):551-563doi:10.1631/jzus.C1300320The original version of this article unfortunately contained mistakes.Algorithm 6 should be as follows:Algorithm 6 FGKFCM-F clustering Input:(1)X={x_1,x_2,…,x_N},,x_iR~d,i=1,2,…,N,the dataset;(2)C,1C≤N,the number of clusters;(3)ε0,the stopping criterion;     

Journal of Zhejiang University-SCIENCE C (Computers & Electronics) Total contents

正~~     

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.