一个基于图像代数的并行图像处理环境

系统可用性和应用程序可移植性差是许多现有的并行图像处理计算结构难以获得实际应用的重要原因，基于Ritter提出的图像代数理论，研究、实现了一个并行图像处理环境．用户在并行计算结构上进行程序设计时，只需用图像处理环境提供的图像代数运算描述算法即可，处理环境能够根据用户算法的描述，依据一个时间开销模型，自动从并行实现函数库中提取出最优或近似最优的并行代码完成算法的运行，算法的并行实现和并行计算结构的硬件细节对用户透明。     

基于关系代数的XML数据查询

XML渐已成为Web上数据表示和交换的通用语言。为了有效地利用大量的XML文档，需要研究XML数据查询技术。提出了基于关系代数的XML数据查询方法。XML子句可以用关系代数表达式表示，并通过关系代数操作得到查询结果。该方法为查询XML数据提供了一种简洁和有效的手段。     

802．11MAC层切换过程的代数验证

802．11MAC层的切换过程是其协议的一个重要组成部分，它影响着网络的动态拓扑结构。利用π演算理论来进行分析，可以严格而规范地描述其切换过程。在本文中，首先建立了切换的π演算模型。然后通过推导，证明了模型的一致性。这将为802．11MAC层的研究提供一定的 参考和分析价值。     

OreintXA:一种有效的XQuery查询代数

XQuery是XML查询语言的推荐标准.现有的XQuery处理策略有两种方法,一种是基于核心语法一次一结点的方法,另一种是基于查询代数的一次一集合的方法.单独使用这两种方法都不能很好地处理XQuery查询.一方面,基于核心语法树的方法效率低,而且很难优化,而现有基于代数的方法又不能很好地满足XQuery的过程化查询语言的特性.描述了一个有效的XQuery代数系统--OrientXA.它是在总结现有的基于代数的XQuery查询工作、分析未解决的问题,并吸收了前述的两种策略的思想的基础上提出来的.它第一次提出了构造模式树的概念,其中的构造操作符能体现XQuery的灵活特征.由于操作符具有很强的表达能力,OrientXA能够表达W3C的用例和XMark测试集的所有查询.     

Using ambients to control resources

Current software and hardware systems, being parallel and reconfigurable, raise new safety and reliability problems, and the resolution of these problems requires new methods. Numerous proposals aim at reducing the threat of bugs and preventing several kinds of attacks. In this paper, we develop an extension of the calculus of mobile ambients, named controlled ambients, that is suited for expressing such issues, specifically denial of service attacks. We present a type system for controlled ambients, which makes static resource control possible in our setting, and enhance it with a rich notion of resources .     

Almost rotation-minimizing rational parametrization of canal surfaces

Almost rotation minimizing parametrization of the canal surface is given. The basic building block of our approach is the curve approximation scheme that enables us to construct a curve, called the parameter curve, on the canal surface that produces, when projected and rescaled, an almost parallel normal vector field on the spine curve. Its construction relies on our earlier methods and results on relating the geometry of the canal surface to the Lorentzian geometry of the Minkowski geometry via the Clifford algebra formalism. We then iteratively construct patches out of the parameter curves via suitable interpolation procedure. Furthermore, its rotational deviation, i.e., the angle deviation from the parallel (no rotation) frame along the spine curve, can be controlled with the use of the rotation deviation estimate of the parameter curves. Our numerical experiment shows that the rotation deviation is minuscule. When compared with other earlier results including our earlier one, our result fares extremely favorably. To facilitate the implement, a practitioners' summary is given in the appendix.     

基于方向余弦参量的物坐标系与世界坐标系间的坐标变换

借助物体上三点建立了物坐标系,并给出了其坐标轴的方向余弦计算式。利用矢量代数的方法,推导出以方向余弦为参量的物坐标系到世界坐标系的坐标变换矩阵;利用矩阵求逆的方法,推导出世界坐标系到物坐标系的坐标变换矩阵。作为推论,推导出两种特殊情况的坐标变换矩阵。文中推出的物坐标系与世界坐标系间的两个变换矩阵可作为任意两个坐标系间的坐标变换矩阵,故具有通用性。     

直觉模糊代数理想和直觉模糊商代数

引入了直觉模糊代数理想和直觉模糊商代数的概念 ,讨论了它们的一些性质 ,给出了直觉模糊代数理想的刻画     

New Bounds for Timed Event Graphs Inspired by Stochastic Majorization Results

In this paper, we develop new bounding methodologies of max-plus linear systems inspired by results dealing with comparison of stochastic processes. The methods developed in this paper are based on preorder and monotonicity. These methods allow us to obtain comparisons of timed event graphs (TEGs) by comparing their dater dynamical equations. We illustrate with a simple example of Baccelli and Hong (2000) that part of the results provides new approach for computing lower and upper bounds of the Lyapunov exponent of discrete event systems (DES). However the problem of the computation of bounds on Lyapunov exponent requires thorough investigations which are beyond the scope of this work.