关键词： Mathematical physics Particle physics and field theory  

摘要： In this paper, we investigate an inverse source problem of the time harmonic Maxwell equations at a fixed frequency, where the source consists of multiple point dipoles. An algebraic algorithm is proposed to identify the number, locations and moments of the dipoles from boundary measurements of tangential components of the electric and magnetic fields. Also, a Holder stability result is shown. The proposed algorithm is numerically verified.

关键词： Matrix extension   matrix factorization   algebraic number fields   symmetry   multiwavelets   orthogonal wavelet filter banks   algebraic wavelet filters  

摘要： As a finite dimensional linear space over the rational number field Q, an algebraic number field is of particular importance and interest in mathematics and engineering. Algorithms using algebraic number fields can be efficiently implemented involving only integer arithmetics. We observe that all known finitely supported orthogonal wavelet low-pass filters in the literature have coefficients coming from an algebraic number field. Therefore, it is of theoretical and practical interest for us to consider orthogonal wavelet filter banks over algebraic number fields. In this paper, we formulate the matrix extension problem over any general subfield of C (including an algebraic number field as a special case), and we provide step-by-step algorithms to implement our main results. As an application, we obtain a satisfactory algorithm for constructing orthogonal wavelet filter banks over algebraic number fields. Several examples are provided to illustrate the algorithms proposed in this paper.

关键词： 数学   算法   教学  

摘要： 算法它是高中数学在经历新课程改革之后而被新引入的教学内容，如此则就很有必要而对算法内容部分的教学现状来进行深入的调查研究以及分析。本文主要对高中数学新课程之中算法教学的内容而进行了简单介绍，以及对存在的问题进行论述并且分析了问题形成的原因，最后提出了应该从那些方面来改善算法的教学。

关键词： 算法   高中数学   循环   结构   理念  

摘要： 算法类问题首次被写入了高中数学教材中,现在的数学教学越来越能从功能的视野来进行教学,而算法在高中数学教学中的出现正是在这样的大背景下产生的.算法不仅仅是数学学科的重要组成,在伴随着各种技术高速发展的今天,算法已经随着计算机技术对社会各个方面的逐步融入,渐渐地成为现代人经常使用到并能够解决实际问题的重要方法手段之一.让学生带着浓厚的兴趣去建立算法的基本思想,算法类问题由于在高中阶段从内容上来说比较年轻,在教学中不可避免的存在这样或那样的问题,笔者结合自身教学实际总结出两大类问题并提出相应对策.

关键词： Multiobjective optimization  

摘要： Short-segment instrumentation for spine fractures is threatened by relatively high failure rates. Failure of the spinal pedicle screws including breakage and loosening may jeopardize the fixation integrity and lead to treatment failure. Two important design objectives, bending strength and pullout strength, may conflict with each other and warrant a multiobjective optimization study. In the present study using the three-dimensional finite element (FE) analytical results based on an L-25 orthogonal array, bending and pullout objective functions were developed by an artificial neural network (ANN) algorithm, and the trade-off solutions known as Pareto optima were explored by a genetic algorithm(GA). The results showed that the knee solutions of the Pareto fronts with both high bending and pullout strength ranged from 92% to 94% of their maxima, respectively. In mechanical validation, the results of mathematical analyses were closely related to those of experimental tests with a correlation coefficient of -0.91 for bending and 0.93 for pullout (P < 0.01 for both). The optimal design had significantly higher fatigue life (P < 0.01) and comparable pullout strength as compared with commercial screws. Multiobjective optimization study of spinal pedicle screws using the hybrid of ANN and GA could achieve an ideal with high bending and pullout performances simultaneously.

关键词： ALKALINITY   PH effect   ALGORITHMS   ACID-base chemistry   STOCHASTIC convergence  

摘要： The total alkalinity-pH equation, which relates total alkalinity and pH for a given set of total concentrations of the acid-base systems that contribute to total alkalinity in a given water sample, is reviewed and its mathematical properties established. We prove that the equation function is strictly monotone and always has exactly one positive root. Different commonly used approximations are discussed and compared. An original method to derive appropriate initial values for the iterative solution of the cubic polynomial equation based upon carbonate-borate-alkalinity is presented. We then review different methods that have been used to solve the total alkalinity-pH equation, with a main focus on biogeochemical models. The shortcomings and limitations of these methods are made out and discussed. We then present two variants of a new, robust and universally convergent algorithm to solve the total alkalinity-pH equation. This algorithm does not require any a priori knowledge of the solution. The iterative procedure is shown to converge from any starting value to the physical solution. The extra computational cost for the convergence security is only 10-15% compared to the fastest algorithm in our test series. [ABSTRACT FROM AUTHOR]

关键词： WIRELESS sensor networks   WIRELESS communication systems   COOPERATING objects (Computer systems)   SENSOR networks   ENERGY consumption   ENERGY management   POWER resources  

摘要： In wireless sensor networks, coverage holes are caused by energy depletion at some nodes, and the aim of this paper is to study how to utilize the redundant nodes with remaining energy. Particularly, this paper proposes a vector algebra based algorithm by exploring redundant nodes as an extra dimension for coverage compensation. This algorithm consists of two parts. One is to find the locations of potential redundant nodes for coverage compensation;and the other is to opportunistically select the best redundant nodes by jointly considering the hole boundaries and the remaining energy of nodes. Simulation results are provided to demonstrate that the proposed algorithm minimizes the energy consumption when repairing the holes for full coverage. Furthermore, compared with other algorithms, the proposed one exhibits better performance in terms of moving distance and energy consumption.

关键词： 车牌识别系统   车牌字符分割   灰度数学形态学   开运算   投影法   DM642  

摘要： 车牌识别系统是智能交通系统研究领域中的一个重要课题。车牌识别是通过抓拍过往车辆的图像,从汽车图像中将感兴趣的车牌部分定位分割出来,并分析识别出车牌的信息。利用这些信息和数据库里车牌数据进行比较判断,可以很好的监测和管理车辆。车牌识别系统被广泛的用于高速公路收费管理系统、停车场收费管理系统、小区物业管理、公路布控管理系统等,为实施车辆单双号限行等交通管制措施提供了一种有力的技术保障,帮助缓解了城市交通的压力。因此,对车牌识别技术的研究不仅具有重要的现实意义,也具有广阔的市场和巨大的商业应用前景。 车牌识别系统理论研究分车牌定位、字符分割、字符识别三大部分,其中车牌字符分割部分是本论文研究的重点。数字图像处理技术是研究车牌识别系统中主要的理论依据,因此,论文概括的介绍了数字图像处理技术基本知识。对车牌图像的预处理、车牌定位、字符分割、字符识别等技术进行了简单的分析和概述。 论文着重的研究了基于数学形态学的车牌字符分割算法。这是本文研究的重点。介绍了数学形态学理论,它是一门新兴的图像处理与分析学科,主要包括了膨胀、腐蚀、开运算、闭运算等技术部分。数学形态学具有对图像处理高效并且编程简单等优点,鉴于此,论文提出了基于水平垂直灰度开运算的车牌字符分割算法。通常定位后的车牌往往有一定的倾斜角度并且含有边框和铆钉,这些都会对字符的分割造成严重干扰。首先采用Hough变换检测车牌的倾斜角度,进行车牌的矫正,接着用水平垂直灰度开运算去除车牌的边框和铆钉,利用该算法能够在车牌定位不精确的情况下有效的去除车牌边框、铆钉及其它噪声,消除干扰突出字符。在此基础上运用传统的投影法以及车牌的先验知识进行字符间的分割,通过与边框去除不彻底的车牌字符分割比较,证明了用本论文的数学形态学算法有效的去除了车牌边框,提高了字符分割的效果。 论文最后介绍了基于DM642DSP开发平台的车牌字符分割算法的实现。对TI DSP芯片和技术进行了概括的介绍,分析了开发板的图像采集和图像显示这两个硬件组成模块。对系统软件进行了设计,介绍了算法移入DSP和DSP程序优化等内容。

关键词： 中职数学   算法   新课标  

摘要： 在现代社会计算机已经广泛应用在通讯、加工制造、自动控制、办公等生产生活中的各个领域,算法是计算软件的基础,具备算法思想已成为中职学生必备的一种职业素养。本文围绕算法及其教育价值,算法在中职数学教学中存的困难及解决对策进行探讨。

关键词： 经典问题   遗传现象   算法设计  

摘要： 在数学的发展史上,很多经典的数学问题被人们所传承.算法,是计算科学的重要组成部分,那么我们能否设计出一些合适的算法,用现代的科学技术帮我们解决这些经典的数学问题呢?下面给出几例,予以展示,供大家参考.1自守数人的相貌可以遗传,同样数字也可以遗传.例如:5;=25,25;=625,在这两个等式中:5和它的平方25,最后一位数字一模一样,25和它的平方625,最后两位数字一模一样,当然它们遗传的都是"尾巴",有没