为移动代理构造一个安全运行虚环境

移动代理在其执行和迁移过程中涉及到的安全问题就是保护主机不受恶意代理的攻击,其中一个重要方面就是将由程序员的编程错误而造成的危险降到最低。这主要是通过代理程序设计语言来保证的。将代理程序限制在某个安全环境内执行－即为代理程序构造一个安全的运行虚环境为实现代理的安全性提供了基础。提出了一个有效地构造安全运行虚环境的算法。     

A base62 transformation format of ISO 10646 for multilingual identifiers

ISO 10646 Universal Character Set (UCS) is a 31‐bit coding architecture that covers symbols in most of the world's written languages. Identifiers in programming languages are usually defined by using alphanumeric characters of ASCII, which represent mainly English words. An approach for working around this deficiency is to encode multilingual identifiers into the alphanumeric range of ASCII. For case‐sensitive languages, an encoding that utilizes [0–9][A–Z][a–z] can be more space‐efficient for multilingual identifiers. This paper proposes a base62 transformation format of ISO 10646 called UTF‐62. The resulting string of UTF‐62 is within a [0–9][A–Z][a–z] range, a total of 62 base characters. UTF‐62 also preserves the lexicographic sorting order of UCS‐4. Copyright © 2001 John Wiley & Sons, Ltd.     

Automatic parallelisation for LTI MIMO state space systems using FPGAs. An optimisation for cost & performance

The parallelism attained by the use of Field Programmable Gate Arrays (FPGAs) has shown remarkable potential for accelerating control systems applications. This comes at a time when well established methods based on inherited serial Central Processor Units (CPUs) cannot guarantee solutions for the increasing execution speed demands. However, the transition from serial to parallel architectures represents a tremendous challenge due to overwhelming numbers of unexplored options and conflicting factors. The work presented achieves a parallelisation characterisation for generic MIMO systems using stand-alone FPGA implementations. The main contribution is that a very fine subset of possible serial/parallel implementations is obtained. This is used to achieve a flexible trade-off between cost and performance. Automatic optimisation of latency, occupied FPGA area and execution speed is attained and justified in respect to most of the feasible scenarios.     

Efficient solution of a class of partial integro-differential equation in reproducing kernel space

In [Y.l. Wang, T. Chaolu, Z. Chen, Using reproducing kernel for solving a class of singular weakly nonlinear boundary value problems, Int. J. Comput. Math. 87(2) (2010), pp. 367–380], we present three algorithms to solve a class of ordinary differential equations boundary value problems in reproducing kernel space. It is worth noting that our methods can get the solution of partial integro-differential equation. In this note, we use method 2 [M. Dehghan, Solution of a partial integro-differential equation arising from viscoelasticity, Int. J. Comput. Math. 83(1) (2006), pp. 123–129] to solve a class of partial integro-differential equation in reproducing kernel space. Numerical example shows our method is effective and has high accuracy.     

On local convergence of a Newton-type method in Banach space

In this study we are concerned with the local convergence of a Newton-type method introduced by us [I.K. Argyros and D. Chen, On the midpoint iterative method for solving nonlinear equations in Banach spaces, Appl. Math. Lett. 5 (1992), pp. 7–9.] for approximating a solution of a nonlinear equation in a Banach space setting. This method has also been studied by Homeier [H.H.H. Homeier, A modified Newton method for rootfinding with cubic convergence, J. Comput. Appl. Math. 157 (2003), pp. 227–230.] and Özban [A.Y. Özban, Some new variants of Newton's method, Appl. Math. Lett. 17 (2004), pp. 677–682.] in real or complex space. The benefits of using this method over other methods using the same information have been explained in [I.K. Argyros, Computational theory of iterative methods, in Studies in Computational Mathematics, Vol. 15, C.K. Chui and L. Wuytack, eds., Elsevier Science Inc., New York, USA, 2007.; I.K. Argyros and D. Chen, On the midpoint iterative method for solving nonlinear equations in Banach spaces, Appl. Math. Lett. 5 (1992), pp. 7–9.; H.H.H. Homeier, A modified Newton method for rootfinding with cubic convergence, J. Comput. Appl. Math. 157 (2003), pp. 227–230.; A.Y. Özban, Some new variants of Newton's method, Appl. Math. Lett. 17 (2004), pp. 677–682.]. Here, we give the convergence radii for this method under a type of weak Lipschitz conditions proven to be fruitful by Wang in the case of Newton's method [X. Wang, Convergence of Newton's method and inverse function in Banach space, Math. Comput. 68 (1999), pp. 169–186 and X. Wang, Convergence of Newton's method and uniqueness of the solution of equations in Banach space, IMA J. Numer. Anal. 20 (2000), pp. 123–134.]. Numerical examples are also provided.     

Vanishing point detection using cascaded 1D Hough Transform from single images

Vanishing point detection algorithms based on 2D histogramming techniques have been employed in a variety of computer vision systems. Previous algorithms achieved some good results but still failed to maintain a balanced performance in both accuracy and time. Recent research (Li et al., 2010) shows that, vanishing point detection could be converted to a 1D histogram search problem, which largely accelerates the procedure. In this paper, we further improve this idea and propose a complete scheme for vanishing point detection from images of the so called “Manhattan world”. We test our algorithm and some commonly used vanishing point detection methods on public database YorkUrbanDB and our own implemented database PKUCampusDB. Our algorithm shows significant performance improvements.     

爱伦·坡《阿芒提拉多的酒桶》的哥特空间批评

爱伦·坡的《阿芒提拉多的酒桶》是一部充满哥特色彩的短篇小说。该小说采用谋杀者蒙特利瑟自述的形式,讲述50年前他对弗图那多的谋杀,呈现了阴森酒窖里性格扭曲的蒙特利瑟活埋弗图那多的恐怖画面。借助当代文学批评理论中的空间话语研究该短篇小说中的哥特书写,从建筑场景、人物并置和叙事特征方面分析小说哥特空间的构建,进一步突出故事的哥特主题——恐怖、扭曲和死亡。     

一种优化的AP-CAPSA中文文本结构分析算法*

从段落向量空间模型、特征词权重等多个侧面分析比较了已有的文本结构分析算法,提出了优化的AP-CAPSA算法;给出了算法性能的评价准则,并在不同的语料集合上进行了测试。实验表明该方法能够更有效地反映文本的结构,为中文自动摘要系统奠定了重要的理论基础。