T样条调配函数线性无关性的判定算法

针对T样条调配函数的公开问题——T样条曲面表达式中的调配函数是否具有线性无关性,提出一种T样条调配函数线性无关性的验证算法.首先分析了T样条调配函数的数学性质,给出T样条调配函数线性无关的充要条件和充分条件,通过充分条件可以较容易地对一些特殊的T样条调配函数的线性无关性进行判定;然后结合充要条件和充分条件给出一种T样条调配函数线性无关性的验证算法.最后通过实例验证了该算法的有效性.文中结果对于开展T样条造型算法方面的研究有重要意义.     

基于双阶样条的代数双曲B样条升阶及割角算法

考虑代数双曲B样条曲线的升阶问题,从理论上证明了曲线的升阶可以理解为控制顶点的割角过程.为了实现代数双曲B样条曲线的升阶,文中构造了一组基函数——双阶代数双曲B样条基函数,这组基函数并不具有统一的阶数,而具有"双阶"性质.代数双曲B样条基函数与双阶样条基函数之间的变换公式可以导出曲线升阶的割角算法.     

代数双曲B样条基的几乎严格全正性

样条基的几乎严格全正性和曲线插值适定性关系密切,是几何造型中一个基本且重要的问题.文中证明了代数双曲B样条基具有几乎严格全正性:首先引入代数双曲B样条函数,通过嵌入节点算法推导出函数的零点数和变差数之间的关系;进一步,利用数学归纳法证明了该基具有几乎严格全正性.文中的证明方法直观且具有几何性,为造型中使用代数双曲B样条基奠定了更为完备的理论基础.     

T样条曲面在B样条曲面局部拼接中的应用

为解决相邻B样条曲面在局部拼接时由于曲面细分而加入冗余控制点的问题,利用T样条曲面良好的局部细分性,提出一种更有效的T样条曲面局部拼接法。将相邻B样条曲面精确转换为两张全行列T样条曲面;利用T样条曲面的局部均匀细分算法得到局部拼接边界上的一致性,在曲面上加入局部控制点;将局部细分后的曲面连续拼接为一张控制点更少的T样条组合曲面。与B样条曲面的细分拼接法相比,该方法在曲面细分时不加入任何冗余控制点,在局部拼接后能够得到一张更精简的组合曲面。     

基于矩阵融合的三次B样条曲线曲面加密算法

B样条曲线曲面是当前CAD/CAM造型系统中的核心部分。提出了一种基于系数矩阵融合的加密算法,并结合此算法将三次B样条曲线基函数的系数矩阵与三次Bézier曲线基函数的系数矩阵加以混合,实现了对三次B样条曲线曲面的加密,实验结果表明利用此算法生成的曲线曲面与原始的曲线曲面有一定的相似性,保证了三次B样条曲线曲面在信息传播中的安全性。     

基于C-B样条的Catmull-Clark细分曲面

为了解决 Catum ull- Clark细分曲面在工程上难以推广的问题 ,给出了一种基于 C- B样条的 Catumull-Clark细分曲面的算法 .C- B样条曲线是 B样条曲线的拓广 ,但它们的形状依赖于参数 α.由于新的曲面细分方法充分利用 C- B样条能够精确表示圆、椭圆等规则形体的特性 ,因而使通过此方法生成的细分曲面 ,除了在奇异点处能保持二阶导数连续外 ,还能够像 C- B样条曲线、曲面一样 ,精确地表示圆柱等常规曲面、统一工程曲面等的造型 ;同时它仍然保持细分曲面的造型特点 ,即能够解决 NU RBS曲面难以处理的任意拓扑结构的造型问题 ,另外 ,还可依赖控制参数 α的调节作用来增加造型的自由度 ,而且当 α→ 0时 ,它们就退化成 Catm ul- Clark细分曲面 .在工程图形上的应用实例表明 ,这种算法简单、有效 .     

λ、μ-B样条上可展曲面的几何设计

基于3D射影空间中点和平面间的对偶性这一重要思想,提出了两种直接、简单的可展曲面设计方法。该方法将可展曲面用具有调配函数的控制平面来表示,这种调配函数定义了一种新的带有λ、μ两个局部形状控制参数的分段多项式样条曲线,使新的可展曲面具有灵活的局部形状可调性和更强的描述能力,增加了造型的自由度。通过调节参数λ、μ可得到一族可展曲面,这族可展曲面保留了B样条曲面的特性,在λ、μ为特殊取值时所生成的可展曲面即为均匀B样条可展曲面,为曲面的设计提供了一种有效的新方法。     

代数曲面混合的切分结合S曲面补洞方法

该文首先采用代数曲线样条逼近的方法参数化混合边界,然后用三次样条曲面混合任意两个隐式代数曲面,实现样条曲面和基曲面之间光滑过渡.进一步,文中采用GB样条混合两张代数曲面,当混合边界为Lissajous曲线、二次曲线、三角函数曲线、双曲函数曲线、悬链线或螺旋线等特殊曲线时,可实现混合曲面精确插值边界曲线.而对于多个隐式代数曲面混合,又首次提出了G1连续的切分结合S曲面片补洞的方法,且每张曲面片的形状都可通过形状参数直观地进行调整.     

表驱动的细分曲面GPU绘制

为了充分利用GPU的并行计算能力高效地绘制递归定义的细分曲面,提出一种基于GPU的面分裂细分曲面的实时绘制算法.该算法通过离线预计算生成可以复用的细分查找表,它由细分矩阵组成,其大小仅与奇异点度数和最大细分深度线性相关,与输入网格无关;对于细分曲面控制网格的每个曲面片,如果包含2个或2个以上奇异点,则进行一次局部预细分;之后对于不规则曲面片,利用细分查找表由初始控制网格直接计算得到各细分层次上的控制顶点,无需逐层计算,从而最大限度地发挥GPU的并行处理能力;最后对各层次上的规则曲面片使用硬件细分着色器绘制,大大提高绘制效率.实验结果表明,文中算法可以高效地绘制细分曲面的极限曲面.     

基于隐式T样条的曲面重构算法

提出隐式T样条曲面，将T网格从二维推广到三维情形，同时利用八叉树及其细分过程，从无结构散乱点数据集构造T网格，利用曲面拟合模型将曲面重构问题转化为最优化问题；然后基于隐式T样条曲面将最优化问题通过矩阵形式表述，依据最优化原理将该问题转化成线性方程组，通过求解线性方程组解决曲面重构问题；最后结合计算实例进行讨论．该方法能较好地解决曲面重构问题，与传统张量B样条函数相比，能效地减少未知控制系数与计算量．     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

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.     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

基于AD9626的模拟信号采集存储卡设计

自然界的绝大部分信号都是以模拟的形式存在,因此模拟信号的采集转换存储在数字时代十分关键。文章讨论了在雷达信号处理领域基于AD9626的AD采集存储卡的设计原理、硬件结构和程序设计与芯片配置等问题,为今后相关领域的研究提供了可参考的方案。     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

A human-computer interface for non-computer specialists

The COM teleconferencing system was designed to be easy to use for both beginners and people with much computer experience. A number of design choices in organizing the human-computer interface were considered very carefully. These design problems are not unique for teleconferencing applications, but will appear in many other developments of human-computer interfaces for non-computer specialists. This report discusses naming conventions, menu format, user commands, help facility and the treatment of ‘type ahead’ from the users.