确定任意简单多边形平移时碰撞部位的扫描算法

设Ｐ和Ｑ为平面内任意两个互不相交的简单多边形,若Ｐ沿方向ｄ平移时与Ｑ碰撞,采用平面扫描法,通过提取多边形的单调链,给出了求其碰撞部位的算法,最坏情况下,算法的时间复杂性为Ｏ（ｍ＋ｎ）ｌｏｇ（ｍ＋ｎ）,其中ｎ和ｍ分别为多边形Ｐ与Ｑ的边数,与现有的算法相比,降低了时间复杂性。     

平面内任意简单多边形的旋转可移动性

设Ｐ和Ｑ为平面内两个互不相交的简单多边形,若Ｐ在平面内绕某点旋转,文中讨论了其旋转可移动性问题,通过提取多边形的单调链,采用曲线扫描法,给出了求其最大可旋转角度及碰撞部位的算法,与现有的算法相比,降低了时间复杂性。     

平面内多边形沿曲线定姿态刚体移动时的碰撞判定算法

设σ为平面内的正则曲线，Ｐ与Ｑ为平面内的两简单多边形，本文讨论Ｐ沿曲线σ作定姿态刚体移动时是否Ｑ相碰撞的问题，并给出Ｏ（ｍｎ）时间的最坏情况下的最优算法，这里ｍ与ｎ分别Ｐ与Ｑ的顶点数。     

基于圆形窗口的简单多边形裁剪算法

提出了一种新颖而实用的圆形窗口Ｖ对多边形Ｐ的裁剪算法。它将多边形Ｐ的边视为有向线段，通过引入多边形顶点的入边和出边交点的概念，深入研究了Ｐ被Ｖ裁剪后的区域确定问题，给出了作出Ｐ在Ｖ内部分的定理     

二面体群作用下简单多边形的分类

针对简单多边形的分类问题,将对称情况看成是相同类别进行分类来简化分类数,提出一种分类方法.首先分析简单多边形顶点的凹凸性,根据简单多边形顶点处凸点和凹点的分布情况,定义了简单多边形的标记矩阵;然后利用标记矩阵将简单多边形的分类问题归结为二面体群作用在状态集(全体标记矩阵组成的集合)上的轨道划分问题;最后利用熟知的Pólya计数定理求解轨道的个数,并给出了新的分类公式.实验结果表明,当简单多边形边数为6时,采用文中方法的分类数小于原来分类数,并且随着边数的增大,这种差距逐渐变大.     

一种平面简单多边形核的求解算法

平面简单多边形的核是该多边形内部的一个点集,该点集中任意一点与多边形边界上一点的连线都处于这个多边形内部。可见核的这一性质在摄像机定位等问题上得到了应用,本文提出了一种简单多边形核求解的新方法,该方法不仅可以判断核的存在性,而且可以得到核多边形顶点序列。给出的算法容易理解,便于实现,可以广泛地应用于此类问题的求解。     

确定简单多边形旋转时碰撞部位的扫描算法

给定平面内任意两个互不相交的简单多边形Ｐ是Ｑ。若Ｐ在平面内绕０点旋转时与ＡＱ碰撞,讨论其碰撞部位的判定问题,通过分析多边形关于０点的单调边,在平面扫描算法的榧耻提出了曲线扫描法,给这一总理２的Ｏ（（ｍ＋ｎ）ｌｏｇ（ｍ＋ｎ））算法,与现有的算法相比,降低了时间复杂性,这一方法在计算几何和计算机图形学等领域具有一定的理论和实吓价值。     

一种求多边形平移重叠面积最大值的快速算法

设Ｐ和Ｑ是平面上的２个简单多边形，ｔ∈Ｒ２是平面上任意矢量，多边形Ｐ与Ｑ的平移重叠面积函数定义为Ａｒ（ｔ）＝Ａｒｅａ（Ｐ∩（ｔ＋Ｑ）），这里ｔ＋Ｑ表示Ｑ平移了ｔ后形成的多边形。为快速求解平移重叠面积函数的最大值，本文提出了一种优化计算策略，它包括在全局上组合应用遗传算法和最速上升算法快速搜索函数最大值和在局部上利用修正的扫描线算法来快速计算函数值。     

带有给定切线多边形的C5连续有理样条曲线

描述了一种与给定多边形相切的有理样条曲线的算法。在算法中,所有的有理样条曲线的控制点可以通过对多边形的顶点简单计算产生。所构造的曲线对多边形具有保形性。曲线可以局部修改。最后给出了两个算例。     

判断点与多边形拓扑关系的改进算法

为了解决射线法不能有效地判断点在复杂多边形内或外的问题,根据射线与多边形边界相交的特性,分析射线所经过的多边形的不同类型顶点,提出了对顶点数加1、加2和加3的运算方法。通过判断交点个数的奇偶性,改进了射线法,并给出了计算模型和算法的详细步骤,简单有效的将现有的射线法扩展到更复杂的多边形中,能准确的判断点与多边形的位置关系。4种不同算法对比分析结果表明,该算法能解决其它3种算法存在的问题,并且在简单多边形和复杂多边形中都是有效的。     

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.