一种名片图像的文字区块分割方法

(Department of Computer Science and Technology, East China Normal University, Shanghai 200062)     

一种基于可视图的机器人避障路径规划

该文首先提出用Minkowski和的工具将多边形机器人的路径规划问题转化为点机器人的情况,然后基于移动机器人的安全考虑,提出了一种改进的可视图法。该方法用尽可能远离障碍物的路径表示弧,先确定可能的路径点作为节点,然后考虑可能路径,建立结点间的弧,并用Dijkstra算法求出图中的最短路径。最后通过仿真研究表明,用文章提出的方法规划的路径可以达到或接近最优路径。     

连通支配集一种集中式近似算法

简单无向图的最小连通支配集问题是NP完全问题,目前还没有成熟解法。提出了一种用有序表构建独立集求解连通支配集的算法,算法从图中度最大的顶点开始将顶点加入到有序表中,并在加入过程中构建独立集,同时加入其他节点连接独立集使其成为连通集。当图中所有节点处理完成,有序表中标记为独立集的节点和连接节点就形成了一个连通支配集。实验表明算法生成的支配集较小,运行时间复杂度比较低。     

REMARKS ON JOHN DISKS

Let D■R2 be a Jordan domain,D*=R2\D,the exterior of D.In this article,the authors obtained the following results:(1)If D is a John disk,then D is an outer linearly locally connected domain;(2)If D* is a John disk,then D is an inner linearly locally connected domain;(3)A homeomorphism f:R 2 →R 2 is a quasiconformal mapping if and only if f(D)is a John disk for any John disk D■R 2 ;and(4)If D is a bounded quasidisk,then D is a John disk,and there exists an unbounded quasidisk which is not a John disk.     

基于下一代互联网技术的信息网格技术探析

该文首先解释了信息网格的定义,然后与网格计算技术进行了比较,接着讨论了信息网格的发展趋势、关键技术、典型应用,再接着讨论了使用信息网格的注意事项,最后论述了应用信息网格技术的意义,对广大计算机爱好者学习信息网格具有重要的理论和实践指导意义。     

Some Notes on Generalized Cyclotomic Sequences of Length pq

We review the constructions of two main kinds of generalized cyclotomic binary sequences with length pq (the product with two distinct primes). One is the White-generalized cyclotomic sequences, the other is the Ding-Helleseth(DH, for short)-generalized cyclotomic sequences. We present some new pseudo-random properties of DH-generalized cyclotomic sequences using the theory of character sums instead of the theory of cyclotomy, which is a conventional method for investigating generalized cyclotomic sequences. Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users. This work was supported in part by the Open Funds of Key Lab of Fujian Province University Network Security and Cryptology (Grant No. 07B005), the Funds of the Education Department of Fujian Province (Grant No. JA07164) and the Natural Science Foundation of Fujian Province of China (Grant No. 2007F3086).     

一个计算网络可靠度的递归算法

给出一个计算网络可靠度的有效算法,该算法的特点是结合概率论的有关知识和布尔代数运算：递归地调用一个简单、有效的概率公式来计算网络可靠度。该算法易于在计算机上操作和实现,从而适用于大型网络可靠度的定量计算。最后通过实例验证所给算法的有效性。     

具有区间时变时滞的离散Markov跳变系统鲁棒H∞控制

研究一类具有区间时变时滞的离散时间不确定Ｍａｒｋｏｖ跳变系统的时滞相关鲁棒H_∞ 控制问题．通过构造新的ＬｙａｐｕｎｏｖＫｒａｓｏｖｓｋｉｉ泛函,基于有限和不等式方法设计状态反馈控制器,使得闭环系统在容许不确定性下鲁棒稳定,且对能量有界的输入噪声满足一定输入输出H_∞ 增益．在新控制器存在条件中未引入任何自由变量矩阵,使之可更为有效地求解．基于锥补线性化的迭代算法可有效求解H_∞ 次优控制器．数值算例表明了所提出方法的有效性．     

Stability of nonlinear hybrid dynamical systems with time delay via sum of squares decomposition

Considering an infinite number of eigenvalues for time delay systems, it is difficult to determine their stability. We have developed a new approach for the stability test of time delay nonlinear hybrid systems. Construction of Lyapunov functions for hybrid systems is generally a difficult task, but once these functions are found, stability’s analysis of the system is straight-forward. In this paper both delay-independent and delay-dependent stability tests are proposed, based on the construction of appropriate Lyapunov-Krasovskii functionals. The methodology is based on the sum of squares decomposition of multivariate polynomials and the algorithmic construction is achieved through the use of semidefinite programming. The reduction techniques provide numerical solution of large-scale instances; otherwise they will be computationally infeasible to solve. The introduced method can be used for hybrid systems with linear or nonlinear vector fields. Finally simulation results show the correctness and validity of the designed method. Recommended by Editorial Board member Young Soo Suh under the direction of Editor Jae Weon Choi. The authors wish to express their thanks to Dr. A. Papachristodoulou and Dr. M. Peet for their helpful comments and suggestions. Mohammad Ali Badamchizadeh was born in Tabriz, Iran, in December 1975. He received the B.S. degree in Electrical Engineering from University of Tabriz in 1998 and the M.Sc. degree in Control Engineering from University of Tabriz in 2001. He received the Ph.D. degree in Control Engineering from University of Tabriz in 2007. He is now an Assistant Professor in the Faculty of Electrical and Computer Engineering at University of Tabriz. His research interests include Hybrid dynamical systems, Stability of systems, Time delay systems, Robot path planning. Sohrab Khanmohammadi received the B.S. degree in Industrial Engineering from Sharif University, Iran in 1977 and the M.Sc. degree in Automatic from University Paul Sabatie, France in 1980 and the Ph.D. degree in Automatic from National University, ENSAE, France in 1983. He is now a Professor of Electrical Engineering at University of Tabriz. His research interests are Fuzzy control, Artificial Intelligence applications in control and simulation on industrial systems and human behavior. Gasem Alizadeh was born in Tabriz, Iran in 1967. He received the B.S. degree in Electrical Engineering from Sharif University, Iran in 1990 and the M.Sc. degree from Khajeh Nasir Toosi University, Iran in 1993 and the Ph.D. degree in Electrical Engineering from Tarbiat Modarres University, Iran in 1998. From 1998, he is a Member of University of Tabriz in Iran. His research interests are robust and optimal control, guidance, navigation and adaptive control. Ali Aghagolzadeh was born in Babol, Iran. He received the B.S. degree in Electrical Engineering in 1985 from University of Tabriz, Tabriz, Iran, and the M.Sc. degree in Electrical Engineering in 1988 from the Illinois Institute of Technology, Chicago, IL. He also attended the School of Electrical Engineering at Purdue University in August 1998 where he was also employed as a part-time research assistant and received the Ph.D. degree in 1991. He is currently an Associate Professor of Electrical Engineering at University of Tabriz, Tabriz, Iran. His research interests include digital signal and image processing, image coding and communication, computer vision, and image analysis.     

基于游程编码的连通区域标记算法优化及应用

为提高空间液滴蒸发实验中图像实时反馈控制系统的鲁棒性,在液滴的边缘提取中采用了连通区域标记算法,并从两个方面对该算法进行了优化,从而在实时图像处理中获得较快的处理速度和较小的内存占用。一是在DSP实时图像处理中应用了游程编码来减少对象数量和存储所需空间;二是优化了Suzuki的连通区域标记算法,解决了该算法在一次扫描的赋值过程中可能会出现标记等价信息丢失的问题,通过改变对标记连接表的赋值,实现了只需要一次扫描就能获得完整的标记等价信息。实验结果表明,优化算法比传统算法运行速度更快并减少了内存占用。