基于PSD器件的激光位移测距系统设计

提出了一种基于滨松S3931型号PSD器件和飞思卡尔Kinetis K60系列微控制器的激光位移测距系统.该测距系统主要利用了光学三角测量法的工作原理,将被测位移量通过光路系统转换为相应的微弱电信号,再由微弱电信号处理电路,经过放大、滤波、信号处理、A/D采集等一系列处理后,转换为实际位移量,并在LCD液晶显示屏上显示.本系统能够实现±5 mm范围内位移的快速测量,测量精度为30 μm,可以用于精密仪器尺寸测量、物体表面平整度检测等.     

光切法在动态表面粗糙度检测中的应用

应用光切显微镜、CCD摄像机、虚拟仪器和图像处理技术开发了表面粗糙度动态检测系统,利用光切法获得运动表面形貌,再使用图像处理技术提取轮廓特征计算评定参数。通过与触针式仪器进行测量对比实验,论证了检测系统能达到较高的精度。应用检测系统进行了动态检测实验,分析了样本表面的振动和运动速度对检测系统的影响。实验证明,在被测表面的振动幅度小于景深的前提下,该图像检测系统能够应用于动态检测表面粗糙度,适用的速度范围可达到:0￣2000rpm(3.14m/s)。     

锁相放大技术在光学式甲烷气体传感器中的应用

设计了一种基于近红外可调谐半导体激光吸收光谱的光学式甲烷气体传感器,传感器针对甲烷气体位于1653.722nm处的吸收谱线,应用锁相放大技术提取微弱的一次谐波幅度信号,实现对气体浓度的测量。重点分析了在光学式甲烷气体传感器中应用锁相放大的原理及关键技术。结果表明该传感器响应时间为10s,测量精度可达0.02%VOL。     

高精度圆柱直径大量程在线测量系统

高精度圆柱体是机械制造及各种高精度装备的核心器件,由于需求量大,其在线高精度检测是生产质量控制的关键环节.本文针对圆柱体直径高精度测量技术展开研究.设计V型测量平台,增大测量系统的量程,适应各种类型圆柱体测量.采用光学显微镜头、CCD摄像机和LED背景光源组件视觉系统,基于视觉检测技术实现高精度测量.实验数据显示,系统的重复测量精度在0.4 μm之内,绝对测量精度在3 μm之内,符合大部分高精度圆柱体的检测要求.     

三维焊接坡口轮廓图像测量系统

开发了一种三维焊接坡口轮廓图像测量系统，该系统基于光栅莫尔条纹投影原理，由LD、光栅副、滤光片、面阵CCD（Charged coupled device）及DSP图像信号处理等部分组成。分析了在恶劣的焊接现场条件下，莫尔条纹投影到焊接工件表面的噪声产生机理，提出并采用了中值滤波方法对采集的原始激光焊缝图像信号进行平滑处理。由CCD采集到的焊接坡口表面变形的莫尔条纹二维激光图像，经过图像信号处理软件后恢复焊接坡口的三维轮廓图像，获得焊缝中心、深度、宽度等参数的精确尺寸信息。该测量系统经过在轻便型焊接机器人上试用，其测试精度、实时性基本能满足要求。实验结果表明该方法简单可靠、效果明显。     

大口径光学组件面形检测系统关键算法研究

大口径光学组件面形检测系统中,激光光斑的分割、质心提取和背表面光斑的自动剔除算法关系到系统的检测精度。针对系统中多路光斑光强差异比较大的现象,提出了两次分割法,有效定位各光斑区域;通过比较不同质心提取算法的稳定性,选取灰度重心法提取激光光斑质心;采取基于特征的分类技术识别元件前表面反射光斑。实验结果表明,算法能精确稳定地提取光斑质心和有效识别前表面光斑,该方法已商用于光学组件面形检测系统。     

基于图像处理技术的石油筛管割缝在线监测

基于机器视觉技术,针对目前人工检测激光切割筛管的缝宽所存在的局限性和不确定性,设计了完整的实验测试设备。通过CCD相机对筛管割缝的图像进行采集,使用Sobel算法、Canny算法、高斯滤波等图像处理方法提取割缝宽度,实现了对割缝筛管的快速自动化高精度在线检测。试验结果表明,检测误差仅为17μm,为筛管的制造和使用行业提供了新的测量方法。     

几种激光光斑中心定位算法在应用中的比较

在光学测量中,激光光斑中心定位算法的精度和速度将直接影响到实际测量的精度和速度,因而中心定位算法的选择显得尤为重要。针对光学测量中的几种激光光斑中心定位方法,对灰度重心法、随机Hough变换法、最小二乘圆拟合处理激光光斑中心的性能进行了比较。比较结果表明,最小二乘圆拟合法不但具有很高的定位精度,而且具有很快的计算速度,...     

一种基于激光散射测量的高洁净表面微尘检测系统

光散射法测量是利用几何光学原理测量镜片表面的非接触测量方法,光束以一定角度照射到镜片表面后,由于表面非理想光滑,发生透射、反射、和散射现象,散射光的强弱则反映出镜片表面的加工精度、损伤或微尘。本文针对高洁净度镜片表面微尘检测设计一套检测方案,其中涉及激光器选型、低噪声光电前放设计、锁相放大电路设计等。     

用于靶球测量的激光共焦测头稳定性研究

为了解决微靶靶球在微靶装配体中的位置关系.介绍了一种基于动态主动调焦原理的光学非接触测头,这种测头能够测量具有强反射表面的高精度金属件和光学器件,解决了形貌检测领域的一个难题.微靶靶球是惯性核聚变中的关键部分,它的装配位置关系是否准确直接关系到"点火"的成败.由于微靶靶球的特殊性,利用共焦测头这种非接触测头对靶球中心位置进行检测,测量精度要求小于3 μm.根据共焦测头的原理,得出了被测面高度差和振动部件位移的数学关系式,并分析了音叉振动参数对测量结果的影响.试验结果表明:音叉振动频率波动对时间差的影响为0.14‰;音叉振动幅值波动对时间差的影响为6.8‰;时间差输出值的标准差为0.0044.能够满足测量微靶靶球中心位置的非接触,高精度和稳定性要求.     

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.