关键词： Sparse matrix   Genetic algorithm   Simulation-based optimization  

摘要： We present a framework for optimizing the distributed performance of sparse matrix computations. These computations are optimally parallelized by distributing their operations across processors in a subtly uneven balance. Because the optimal balance point depends on the non-zero patterns in the data, the algorithm, and the underlying hardware architecture, it is difficult to determine. The Hogs and Slackers genetic algorithm (GA) identifies processors with many operations - hogs, and processors with few operations - slackers. Its intelligent operation-balancing mutation operator swaps data blocks between hogs and slackers to explore new balance points. We show that this operator is integral to the performance of the genetic algorithm and use the framework to conduct an architecture study that varies network specifications. The Hogs and Slackers GA is itself a parallel algorithm with near linear speedup on a large computing cluster. (C) 2010 Elsevier B.V. All rights reserved.

关键词： 字符分割   二维Renyi熵   数学形态学   边缘检测  

摘要： 汽车牌照字符分割是车牌识别过程中的关键步骤,直接影响到字符识别的效果。传统的方法对车牌图像质量要求较高,且抗干扰能力较差。提出一种基于Renyi熵和数学形态学边缘检测的车牌字符投影分割算法,首先用二维Renyi熵最大阈值法对车牌图像做二值化处理,然后用形态学腐蚀运算进行边缘检测,再去除车牌边框,最后通过投影分割提取车牌字符。仿真实验表明,基于Renyi熵最大阈值法和数学形态学边缘检测车牌图像预处理使得车牌字符边缘清晰,降低了噪声的干扰,有利于进行字符投影分割。该算法分割速度快,鲁棒性好,可获得比传统方法更好的分割效果。

关键词： 数学形态学   腐蚀   膨胀   Hough变换   谱线探测  

摘要： 数学形态学是综合了多学科知识的交叉学科,是一种非线性的图像分析理论,己成为图像处理的重要工具之一。文章简单介绍了数学形态学和二值形态学的基本运算—腐蚀和膨胀,并提出了基于数学形态学的乐谱谱线探测算法。实验结果证明,与Hough变换探测直线算法相比,该乐谱谱线探测算法具有运算速度快、效率高、抗噪声能力强等优点。

关键词： 数学公式   识别   结构分析   表结构   支配关系  

摘要： 在线手写数学公式输入作为一种自然、快速的数学公式输入方法有着很大的应用前景。基于识别通用数学公式结构的范畴,提出了在线手写数学公式结构识别的算法。首先定义了数学公式结构的分形、支配关系并扩展了硬约规,同时根据手写公式的特点提出了最小生成树(MST)算法中一种新的权值计算方法,在此基础之上应用最小生成树算法和统计学的方法进行公式结构分析。与其他经典算法比较,所提算法扩大了识别的结构,同时识别正确率有所提高。

关键词： Numerical range   Indefinite inner product   J-Hermitian matrix   Noninterlacing eigenvalues  

摘要： In this article, tracial numerical ranges associated with matrices in an indefinite inner product space are investigated. The boundary equations of these sets are obtained, and the case of the boundary being a polygon is studied. As an application, a numerical algorithm for plotting the tracial numerical range of an arbitrary complex matrix is presented. Our approach uses the elementary idea that the boundary may be traced by computing the supporting lines.

关键词： Matrix *-algebra   Block-diagonalization   Group symmetry   Schur decomposition   Skew-Hamiltonian Schur decomposition  

摘要： An algorithm is proposed for finding the finest simultaneous block-diagonalization of a finite number of square matrices, or equivalently the irreducible decomposition of a matrix *-algebra given in terms of its generators. This extends the approach initiated by Murota-Kanno-Kojima-Kojima. The algorithm, composed of numerical-linear algebraic computations, does not require any algebraic structure to be known in advance. The main ingredient of the algorithm is the Schur decomposition and its skew-Hamiltonian variant for eigenvalue computation.

关键词： Logistics   Biomass supply   Bioenergy  

摘要： Many linear programming models have been developed to study the logistics and determine the best setup for bioenergy chains. Most use network structures built from nodes with one or more depots and arcs connecting these depots. Each depot is a source of a certain biomass type. Nodes can also represent a biomass storage point or a production facility (e.g., power plant) where the biomass is used. Arcs represent transport routes between depots. To combine GIS spatial studies with linear programming models, it is necessary to design a network from a digital map. In this research a mathematical calculation method is developed to select the actual points on the map for the locations of a bioenergy plant that will then be considered as biomass destinations in a network model. The base data for this model is city's locations and the bioenergy they required, given in GIS maps (shape files), although also it can be the points where the biomass is produced. The limits of the studied area should be defined in advance, for example, a country, a province or a region. Criteria selection for plant location is two: all the energy produced by the plant should be used;the cost to transport the energy produced should be minimal. With these criteria, the cities are grouped in sets, which should be supplied by a power energy plant. Each plant supplying a given subset of cities will be located in the center of gravity specified by the coordinates and the energy required by each city in the subset. The algorithm provides the locations of points where plants that transform biomass into bioenergy for a group of cities are placed. The points to locate plants are then taken as destination nodes in the network when the logistics models are implemented. In the next step, the network is analyzed by linear programming techniques to supply the optimal location for the power plants or factories depending on the available biomass sources. In this paper a practical example applied to Spanish rural re

关键词： 车牌定位   数学形态学   结构元素   边缘检测  

摘要： 在汽车牌照识别系统中,车牌定位是整个识别模块实现的前提,目前车牌定位的方法多种多样,各有所长,但存在着计算量大或定位准确率不高等问题。边缘检测是常用的车牌定位方法,边缘检测的质量决定了车牌图像的最终定位结果。一般人们习惯于用基于梯度和基于模板的算子提取边缘,但这类算子都不能很好地滤除噪声,因而给噪声图像边缘检测带来了困难。根据数学形态学原理与方法,提出一种扩展数学形态学车牌图像边缘检测算子,并结合水平和垂直投影进行车牌定位。实验结果表明,该算法不仅能成功提取车牌图像边缘,而且能很好地滤除噪声,从而实现准确车牌定位。

关键词： 数学教学   算法   多样化   主体  

摘要： 算法多样化是新课标倡导的重要数学教学理念,它可以促进全体学生主动参与,体现学生的主体地位,发挥每个学生的潜能。在数学教学中教师要引导学生参与计算原理和方法的探索过程,让学生善于发现问题、思考问题、探索规律。

关键词： 数学高考   2010年   试题评析   算法   概率   计算机科学   必修教材   新课标  

摘要： 算法不仅是数学及其应用的组成部分，也是计算机科学的重要基础．算法初步作为新课标新增于必修教材的唯一全新并单独成章的内容，势必作为高考的一个新考点，也倍受命题者的青睐．