纸箱模切机控制系统设计

作为PLC控制的应用实例,介绍用于纸箱加工的模切机的PLC控制系统设计.描述了模切机的运动状况及控制要求对PLC控制的设计步骤进行了具体阐述.     

基于PLC技术的组合机床改造

作为PLC控制的应用实例,介绍用于缝纫机机壳加工的组合机床进行PLC控制改造。描述了组合机床运动状况及控制要求。对PLC控制设计及编程作了具体的阐述。     

PLC在数控定位控制系统中的应用

详述了用PLC控制步进电机实现数控系统的定位控制功能的方法、新型PLC的高速脉冲输出功能有效的避免了扫描周期的影响，完成快速移动和精密定位。     

MODICON-PLC分布式工业控制系统及其通信

介绍了由Modicon—Pie和IBMPC构成的分布式工业控制系统，着重描述了控制方案的确定以及PLC网络主站与分站之间的通信技术。     

PLC程序开发中的结构化编写方法

本文描述了软件工程中的结构化思想在PLC编程中的一种运用方法,为自控项目中的PLC编程提供了一种方法论。通过分层次的编程来构成PLC程序,采用这种方法可以实现多人协作,为大型的控制程序进行共同工作,编写出风格一致,稳健可靠的程序,文中通过一个例子对这种方法进行了说明。     

基于PLC的精密切割数控车床的实现

本文提出了一种适用精密切割的数控车床设计方案。该方案采用机械触发式传感器，通过控制车刀运动来触发传感器，PLC把传感器得到的信号传给数控系统。再由系统来进行相应的数据处理。机械触发式传感器与PLC的输入扩展端的连接线简单，而且易于维护．比用其它的传感器降低了成本。     

基于SIMATICS7 PLC的分布式控制系统实现

利用SIMATICS7 PLC、工业以太网和PROFIBUS总线组成了分布式控制系统．具体描述了系统的构成以及组态实现。系统在逻辑结构上分为两层：现场设备层和网络控制层．PROFIBUS用于现场设备层，网络控制层采用工业以太网。用STEP7软件完成了系统的组态及控制程序的编写，并以水箱液位控制为例．说明了用户程序编写及调试的方法。过程的上位机监控利用WINCC软件实现。     

组合式凹版印刷机彩色套准控制系统

介绍了凹版印刷机彩色套印控制系统的组成及原理。分析了利用开关量光电传感器检测Mark线间距以获取套印偏差信号的方法,并根据套印对象模型,提出了套准系统的一种专家控制规则。为印刷单元的套准予系统是以PLC为核心,整机集散控制系统是由586工业控制计算机和PLC构成。该系统运行结果良好。     

基于工业以太网的冶炼控制系统设计

以基于工业以太网的、由工控机和Quaraturm PLC构成的冶炼控制系统为例,描述了该系统的工作原理,给出系统的硬件组成框图,介绍了利用iFIX组态软件设计人机界面的方法,并讨论了系统的通讯方式以及控制方式等问题.     

PLC在金属印铁设备中的应用

介绍了以PLC为核心的金属印铁设备控制系统。主要包括控制系统硬件部分的构成和软件编程。着重介绍了以PLC、旋转编码器等电气元件代替复杂的继电器电路实现自动化控制的方法，讨论如何使用PLC内部丰富的功能指令进行同步运转控制，为相关企业实现印铁设备改造提供了一个经济实用的解决方案。     

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

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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

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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.