关键词： 改进的形态学滤波   瞬时无功功率   谐波检测  

摘要： 传统数学形态学滤波算法中,当结构元素过长时,会对滤波算法的延时性以及硬件成本等方面造成不良影响。针对此种局限性,提出了一种结构元素变长度的数学形态学滤波算法,即通过对腐蚀和膨胀运算加入比例系数进行改进,以改进后所形成的腐蚀和膨胀新运算法则构建均值组合滤波器,使改进后的数学形态滤波器能够在保证精度的同时,大幅度降低滤波器对结构元素长度的需求。最后,将改进后的形态滤波器应用到以瞬时无功功率理论为基础的谐波检测算法中,仿真结果表明改进后的算法具有存储量需求低和快速响应的性能。

关键词： Cyclic scheduling problem   Flexible job shop   Mixed integer linear programming   Genetic algorithm   Simulated annealing  

摘要： Product orders are usually released with a cyclic manner, in the part manufacturing industries. Hence, scheduling cyclic jobs instead of single jobs is more practical in the real manufacturing environment. In this paper, a flexible job shop scheduling problem with cyclic jobs is studied. In this problem, jobs must be delivered in determined batch sizes with definite time intervals. This problem is practical for many manufacturing systems such as automotive parts making industries. Whereas jobs are repeating infinitely during time, a framework is suggested to break down the infinite programming horizon to smaller periods. Then a mixed integer linear programming (MILP) model is presented to schedule jobs in this short term horizon. The goal of the proposed model is minimizing the total cost including delay costs, setup costs and holding costs. Since the problem is well-known as NP-hard class, the proposed MILP model is effective just for small size problems. Therefore, two algorithms based on genetic and simulated annealing (SA) algorithms are developed to solve real size problems. The numerical experiments are used to evaluate the performance of the developed algorithms. Results show that the proposed genetic algorithm (GA) has a better performance than the SA algorithm. Also some intelligent approaches are presented and examined in the proposed algorithms. Results show the efficiency of the presented intelligent approaches as mutation operators for the proposed GA.

关键词： algebraic rearrangement distance   contig ordering problem   next generation sequencing   permutation group  

摘要： Assembling a genome from short reads currently obtained by next-generation sequencing techniques often results in a collection of contigs, whose relative position and orientation along the genome being sequenced are unknown. Given two sets of contigs, the contig ordering problem is to order and orient the contigs in each set such that the genome rearrangement distance between the resulting sets of ordered and oriented contigs is minimized. In this article, we utilize the permutation groups in algebra to propose a near-linear time algorithm for solving the contig ordering problem under algebraic rearrangement distance, where the algebraic rearrangement distance between two sets of ordered and oriented contigs is the minimum weight of applicable rearrangement operations required to transform one set into the other.

关键词： Photoshop   跟我学   背景图片   填充颜色   选项栏   锚点   矢量图形   橡皮带   数学算法   贝塞尔  

摘要： 钢笔是Photoshop中形状选择的终极工具,同时也能用来创建各种复杂的形状。软件和版本:Photoshop CS6或更高版本下载网址:***跟我学:创建精确的剪切路径1绘制路径从工具面板中选择钢笔工具,放大画面,在需要抠选的对象边缘任意位置上单击鼠标新建路径。接着沿对象边缘单击创建第二个调整点。

关键词： 全班交流   课堂教学法   最优化   目标意识   个体特点   问题解决   认知结构   知识建构   角色定位   独特体验  

摘要： 近日,到某小学听了一节“8加几”的研究课,课中有一环节：对于8＋6,同桌讨论怎么算,然后全班交流如下。方法一：6分成2和4,8＋2=10,10＋4=14。方法二：8分成4和4,4＋6=10,4＋10=14。方法三：从6开始数,数8个数：6,7,8,9,10,11,12,13,14。方法四：因为9＋6=15,所以8＋6=14。之后安排学生读方法一、二,接着老师问学生有没有最喜欢的方法？一学生答：“方法一”。师追问：“为什么？”学生回答：“简便”,然后老师要求学生用喜欢的方法解题。

关键词： Nonlinear algebraic equations   Differentiable invariant manifold   Descent vector   Newton equation   Double optimal iterative algorithm (DOIA)   Affine Krylov subspace  

摘要： For an n-dimensional linear equations system, Liu (2014) has derived a double optimal solution in an affine m-dimensional Krylov subspace with m << n. An iterative algorithm, based on the double optimal solution of the Newton equation Bu = F in (x) over dot = lambda u, is proposed to solve a system of nonlinear algebraic equations F(x) = 0 with dimension n. By optimizing two merit functions, u can be explicitly solved in the affine Krylov subspace. The resulting double optimal iterative algorithm (DOIA) is proven to be absolutely convergent with the square residual norm parallel to F parallel to(2) being reduced by parallel to B(k)u(k)parallel to(2) at each iteration, and very time saving by merely inverting an m x m positive definite matrix one time at each iterative step. We can prove that such an algorithm leads to the largest convergence rate without needing to invert the n x n matrix B. Some numerical examples are used to evaluate the performance of the DOIA, where very fast convergence rates and saving the CPU time to find the solutions are observed. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： linear algebra   cellular method   basic operation   fast algorithm of matrix multiplication  

摘要： This paper proposes fast algorithms for the cellular operation D = C +Sigma(xi)(l=1) A(l)B(l) that are based on hybrid multiplication algorithms for matrices of orders n = 3 mu (mu > 1) and n = 6 mu (mu > 0) and are characterized by the lowest computational complexity in comparison with well-known algorithms. The multiplicative, additive, and overall complexities of the mentioned algorithms are estimated.

关键词： Vehicle routing problem   stochastic time-dependent network   robust optimization   ant colony algorithm  

摘要： This article addresses the stochastic time-dependent vehicle routing problem. Two mathematical models named robust optimal schedule time model and minimum expected schedule time model are proposed for stochastic time-dependent vehicle routing problem, which can guarantee delivery within the time windows of customers. The robust optimal schedule time model only requires the variation range of link travel time, which can be conveniently derived from historical traffic data. In addition, the robust optimal schedule time model based on robust optimization method can be converted into a time-dependent vehicle routing problem. Moreover, an ant colony optimization algorithm is designed to solve stochastic time-dependent vehicle routing problem. As the improvements in initial solution and transition probability, ant colony optimization algorithm has a good performance in convergence. Through computational instances and Monte Carlo simulation tests, robust optimal schedule time model is proved to be better than minimum expected schedule time model in computational efficiency and coping with the travel time fluctuations. Therefore, robust optimal schedule time model is applicable in real road network.

关键词： Optimal experimental design problem   A-optimality  

摘要： We develop and analyse a first-order algorithm for the A-optimal experimental design problem. The problem is first presented as a special case of a parametric family of optimal design problems for which duality results and optimality conditions are given. Then, two first-order (Frank-Wolfe type) algorithms are presented, accompanied by a detailed time-complexity analysis of the algorithms and computational results on various sized problems.

关键词： Numerical algorithms   LU factorization   QR factorization   Stability   Performance  

摘要： This paper introduces hybrid LU-QR algorithms for solving dense linear systems of the form Ax = b. Throughout a matrix factorization, these algorithms dynamically alternate LU with local pivoting and QR elimination steps based upon some robustness criterion. LU elimination steps can be very efficiently parallelized, and are twice as cheap in terms of floating-point operations, as QR steps. However, LU steps are not necessarily stable, while QR steps are always stable. The hybrid algorithms execute a QR step when a robustness criterion detects some risk for instability, and they execute an LU step otherwise. The choice between LU and QR steps must have a small computational overhead and must provide a satisfactory level of stability with as few QR steps as possible. In this paper, we introduce several robustness criteria and we establish upper bounds on the growth factor of the norm of the updated matrix incurred by each of these criteria. In addition, we describe the implementation of the hybrid algorithms through an extension of the PaRSEC software to allow for dynamic choices during execution. Finally, we analyze both stability and performance results compared to state-of-the-art linear solvers on parallel distributed multicore platforms. A comprehensive set of experiments shows that hybrid LU-QR algorithms provide a continuous range of trade-offs between stability and performances. (C) 2015 Published by Elsevier Inc.