固体压力传感器结构中的O形橡胶圈密封技术

本文主要阐述了以O形橡胶圈作为固体压力传感器的结构密封技术。对于O形橡胶圈的密封机理,性能及设计要求等进行了初步的探讨。     

叶片-轮盘榫联结构的接触分析

叶片与轮盘之间的榫联结构存在接触和摩擦组合运动,在较高的热-机械载荷作用下容易发生微动磨损并导致疲劳破坏.本文采用有限元法对叶片-轮盘榫联结构进行接触分析,计算不同摩擦系数和不同转速情况下的叶片榫头和轮盘榫槽之间的接触压力、接触滑动距离.结果表明,摩擦系数增大,榫联结构接触面上的接触压力和滑动距离减小;转速增加,则接触压力和滑动距离增大.     

消防供水的PLC控制系统设计

设计一种基于PLC的消防供水控制系统.系统具有手动/自动两种工作方式,自动方式下,由PID控制器调节变频器的输出频率,控制水泵电机的转速,调整供水流量,从而维持管网水压恒定.系统经调试已投入实际运行.     

基于数据融合的某涡扇发动机给定转速研究

针对试验室无法设计实现机械连动装置确定某涡扇发动机给定转速,在研究分析某涡扇发动机转速控制系统的工作机理和影响该型发动机给定转速因素的基础上,提出了一种确定该型发动机给定转速的数据融合算法。通过对基于数据融合确定的给定转速试验,结果表明:提出的数据融合算法结构简单、计算简便、计算结果的相对误差都在1%以内,将其用于确定某涡扇发动机的给定转速是完全可行的。     

一种基于变频调速的恒压供水控制系统

本文介绍了一种恒压供水系统的构成及设计原理。系统采用变顿器和智能供水控制器无级调节水泵的转速，并能根据水压的设定要求循环软启动水泵的数量使水压维持恒定。循环软启动的平稳切换技术有效地减小了系统的机械、电气冲击，将切换时的压力波动控制得很小，有效地提高了供水品质；丰富的功能指令和一系列自动报警保护措施显著延长了水泵和其它元件的寿命。     

由PLC控制的新型全自动变频恒压供水系统

介绍了一种已投入使用的基于PLC的恒压供水系统的构成和工作原理。系统采用变频调速方式自动调节水泵电机转速或加、减泵。改变以往“先切先投”方法,实现无冲击切泵,使水压过渡平稳。变频器故障时仍能自动运行,保证不间断供水。同时,故障消除后自启动,为“无人值守”全自动运行创造了条件。     

基于PLC双闭环控制供水系统的研究

设计以PLC为核心变频调速恒压供水控制器,采用双闭环自整定模糊PID控制算法,以水泵电动机的转速和管网水压为设定参数,实现恒压供水。该系统实时控制性能良好,节能效果显著。     

基于LabVIEW的PID控制草坪喷灌系统

基于LabVIEW的开发平台,采用传感器、数据采集卡与变频器开发自动喷灌系统。通过水泵转速的调节维持管网水压的恒定,达到自动喷灌和按需施水的目标,实现草坪喷灌的节水、节能、省工,并且喷灌质量也得到了一定的保障。     

基于变频器和PLC的恒压供水系统研究

为了解决目前供水系统中存在的电能、水资源浪费等问题,设计了一种基于PLC的变频恒压供水系统。系统以管网水压(或用户用水流量)为设定参数,通过控制变频器的输出频率和电压,从而自动调节水泵电机的转速,实现恒压供水的目的。     

嵌入式油井供水压力流量监控系统

为了监控油井供水系统,文中介绍了一个基于S3C2440A的嵌入式监控系统,叙述了系统设计原理和实现方法。该系统采用S3C2440A核心板作为嵌入式控制器,实现供水系统水压、流量实时数据采集、传输,利用嵌入式数据库进行数据存储,并移植了嵌入式Web服务器,使系统能独立地提供远程监控服务。该系统通过变频器调节油井注水泵电动机的转速,实现注水压力和水量调节。由于采用嵌入式系统监控水压和供水系统参数,大大提高了油井生产的信息化水平。远程监控系统减轻了工作人员的劳动强度,并提高了工作效率和可靠性。     

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.