关键词： 形态学   数字水印   结构元素   离散小波变换  

摘要： 本文根据灰度图像数学形态学的特点以及小波的多尺度分辨特性,提出了一种鲁棒性较好的水印算法。首先,对载体图像和水印信息做预处理,第一个预处理是将载体图像做小波分解,分解的级数由水印信息量来确定,第二个预处理是对水印信息进行置乱;然后,对于小波分解得到的低频信息进行膨胀和腐蚀,并将膨胀的结果减去小波低频信息,同时将低频信息减去腐蚀的结果;接下来,在上一步得到的两个结果里同时嵌入有意义的水印;最后,利用小波逆变换重构含水印图像。实验结果证明,这个算法具有比较好的抗攻击性、不可见性。

关键词： 算法教学   高中数学   数学课程标准   《标准》   课改教材   学习要求   教育价值   上海市  

摘要： 算法是上海市高中数学二期课改教材（以下简称新教材）中新增加的内容．《上海市中小学数学课程标准（试行稿）》（以下简称《标准》）中，也对算法初步提出了学习要求和活动建议．本文试图对新教材中算法内容的定位、算法的教育价值以及算法教学中应注意的问题做一探讨．

关键词： Eigenvalues and eigenfunctions  

摘要： In this paper, we propose structured doubling algorithms for the computation of the weakly stabilizing Hermitian solutions of the continuous- and discrete-time algebraic Riccati equations, respectively. Assume that the partial multiplicities of purely imaginary and unimodular eigenvalues (if any) of the associated Hamiltonian and symplectic pencil, respectively, are all even and the C/DARE and the dual C/DARE have weakly stabilizing Hermitian solutions with property (P). Under these assumptions, we prove that if these structured doubling algorithms do not break down, then they converge to the desired Hermitian solutions globally and linearly. Numerical experiments show that the structured doubling algorithms perform efficiently and reliably. © 2007 Elsevier Inc. All rights reserved.

关键词： Real coded genetic algorithms   Binary coded genetic algorithms   Nonlinear curve fitting   Parameter estimation   Ordinary differential equations   Dynamic system identification  

摘要： In this study, parameter estimation in mathematical models using the real coded genetic algorithms (RCGA) approach is presented. Although the RCGA is similar with the binary coded genetic algorithms (BCGA) in terms of genetic process, it has few advantages such as high precision, non-existence of Hamming's cliff etc., over the BCGA. In this approach, creating initial population and selection procedure are almost the same with the BCGA, but crossover and mutation operations. The proposed approach is implemented on the second order ordinary differential equations modeling the enzyme effusion problem and it is compared with previous approaches. The results indicate that the proposed approach produced better estimated results with respect to previous findings. (C) 2008 Elsevier Ltd. All rights reserved.

关键词： Two-sided assembly line balancing   Mathematical model   Genetic algorithm   Localized evolution  

摘要： A two-sided assembly line is a type of production line where tasks are performed in parallel at both sides of the line. The line is often found in producing large products Such as trucks and buses. This paper presents a mathematical model and a genetic algorithm (GA) for two-sided assembly line balancing (two-ALB). The mathematical model can be used as a foundation for further practical development in the design of two-sided assembly lines. In the GA. we adopt file strategy of localized evolution and steady-state reproduction to promote Population diversity and search efficiency. When designing the GA components, including encoding and decoding schemes. procedures of forming the initial population, and genetic operators, we take account of the features specific to two-ALB. Through Computational experiments. the performance of the proposed GA is compared with that of a heuristic and an existing GA with various problem instances. The experimental results show that the proposed GA outperforms the heuristic and the compared GA. (C) 2007 Elsevier Ltd. All rights reserved.

关键词： Coefficient inverse problems   convexification algorithm   imaging of antipersonnel land mines  

摘要： We address the efficiency issue for the globally convergent convexification algorithm for coefficient inverse problems. By properly choosing the upper limit for pseudo-frequency and with quadratic polynomial approximations of the quantities which depend on the pseudo-frequency, we show that the algorithm can be made dramatically faster relative to the previous "tail-free" implementation. Numerical results from imaging and the mathematical modeling of antipersonnel land mines demonstrate that the algorithm can detect the location(s) of the inclusion(s) from the background medium, as well as correctly identify the material property of the inclusion(s) and the background. This indicates that the convexification algorithm may be applied in real-time to detect and image mine-like targets in the field.

关键词： Hopf bifurcations   oscillations   dynamical systems   quantifier elimination over the reals   logical inconsistency checking  

摘要： Symbolic methods to investigate Hopf bifurcation problems of vector fields arising in the context of algebraic biology have recently obtained renewed attention. However, the symbolic investigations have not been fully algorithmic but required a sequence of symbolic computations intervened with ad hoc insights and decisions made by a human. In this paper we discuss the use of algebraic and logical methods to reduce questions on the existence of Hopf bifurcations in parameterized polynomial vector fields to quantifier elimination problems over the reals combined with the use of the quantifier elimination over the reals and simplification techniques available in REDLOG. We can reconstruct most of the results given in the literature within a few seconds of computation time and extend the investigations on these systems to previously not analyzed related systems. Especially we discuss cases in which one suspects that no Hopf bifurcation fixed point exists for biologically relevant values of parameters and system variables. Here we focus on logical and algebraic techniques of finding sub conditions being inconsistent with the hypothesis of the existence of Hopf bifurcation fixed points.

关键词： integrators   mathematics computing   Symbolic algebra  

摘要： In this paper by means of computer experiment we study advantages and disadvantages of the heuristical method of "parallel integrator". For this purpose we describe and use implementation of the method in Mathematica. In some cases we compare this implementation with the original one in Maple.

关键词： 车辆数优化   能量函数   适应度函数   遗传模拟退火算法  

摘要： 研究了物流运输系统车辆数优化问题的数学模型,构造出了模拟退火算法的能量函数,根据该函数可以求最优车辆数,又可以求最优车辆数下的最优行驶路径.用遗传模拟退火算法实现了车辆数的优化计算与路径优化计算.