关键词： 小学数学教学   算法多样化   数学课程标准   数学教学改革   学习数学   教学平台   班级集体   学生  

摘要： 《小学数学课程标准》明确提出＂应重视口算,加强估算,提倡鼓励算法多样化＂,这无疑给小学数学教学改革带来了新的活力.所谓小学数学算法的多样化,就是在小学数学教学中,先让不同层次的学生经历探索的过程,去发现算法,然后在课堂教学平台上由一些学生展示各自的算法,必要时教师补充算法,再通过班级集体和教师的力量对呈现的算法进行分析、比较和优化,使学生感悟算理,形成适合自己个性的算法,最后把获得的算法用于自己的学习和生活中，从中体验学习数学的快乐．

关键词： 有理数加法   运算法则   运算律   加法运算   运算过程   绝对值  

摘要： 1问题的提出下面是七年级第一学期期末质量检测的一道试题。试题阅读下列内容,并完成相关问题。小明说：＂我定义了一种新的运算,叫※（加乘）运算。＂然后他写出了一些按照※（加乘）运算的运算法则进行运算的算式：（＋4）※（＋2）=＋6;（-4）※（-3）=＋7;

关键词： 数学算法   计算机编程   优化  

摘要： 数学算法应用在计算机的编程过程中,可以实现编程的优化,使计算机编程结构更完善,可以去掉计算机程序中的多余的部分,使计算机编程运行速率得到提升。根据这个原因,文章介绍了数学运算方法和计算机编程的关系,与之结合进行分析数学算法对计算机编程的优化。

关键词： 切削液   模糊数学   神经网络  

摘要： 以机械加工工艺过程中切削液为研究对象,从机加工产品的精度,加工成本,零件的寿命,零件的质量,加工的速度与效率,环境的影响等方面来研究机械加工过程和产品的生产质量等相关问题。切削液的选择是采取了一个多目标,多方案,多原则的过程。文章提出一种以模糊数学和神经网络BP算法为基础的切削液选择方法,实现了对切削液识别和分析。文章以基本模糊数,建立起切削液选择方案模型;以大量的切削数据用神经网络BP算法建立应用识别模型。从结果中对比以前的选择方法,发现选择的效果有待提高,在加工质量保证的情况下,文章从经济性,效率性,环保性等角度的优化。切削液的选择在机械加工的质量上有着重要的作用,合理的选择切削液对能明显改善机加工产品质量。

关键词： 直线检测   数学形态学   车牌定位   检测模板  

摘要： 汽车车牌区域定位时受到外界复杂环境干扰常导致定位率降低,为了有效解决此问题,提出了一种直线检测并配合数学形态学的方法对车牌区域进行定位。首先对车牌图像进行了图像预处理,然后利用直线检测模板对矩形的车牌区域进行滤波处理,检测出车牌垂直和水平两个方向的直线边缘从而实现车牌的精确定位。实验结果表明,在保证精度的同时,提高了车牌定位的速度,可以快速准确地定位出车牌。

关键词： Jet transport   Polynomial algebra   Subdivision algorithms   ODE polynomial propagation  

摘要： The Jet Transport method has emerged as a powerful tool for the numerical integration of ordinary differential equations;it uses polynomial expansions to approximate the flow map associated to the differential equation in the neighbourhood of a reference solution. One of the main drawbacks of the method is that the region of accuracy becomes smaller along the integration. In this paper we introduce a procedure to determine a ball covering the set of given initial conditions that keeps the accuracy of the integration within a selected threshold. The paper gives detailed explanations of the algorithm illustrated with some examples of applicability, as well as a comparison with a previous existing method for the same purpose. (C) 2018 Elsevier B.V. All rights reserved.

关键词： Concurrent systems   dataflow analysis   constant-treewidth graphs   algebraic path properties   shortest path  

摘要： We study algorithmic questions wrt algebraic path properties in concurrent systems, where the transitions of the system are labeled from a complete, closed semiring. The algebraic path properties can model dataflow analysis problems, the shortest path problem, and many other natural problems that arise in program analysis. We consider that each component of the concurrent system is a graph with constant treewidth, a property satisfied by the controlflow graphs of most programs. We allow for multiple possible queries, which arise naturally in demand driven dataflow analysis. The study of multiple queries allows us to consider the tradeoff between the resource usage of the one-time preprocessing and for each individual query. The traditional approach constructs the product graph of all components and applies the best-known graph algorithm on the product. In this approach, even the answer to a single query requires the transitive closure (i.e., the results of all possible queries), which provides no room for tradeoff between preprocessing and query time. Our main contributions are algorithms that significantly improve the worst-case running time of the traditional approach, and provide various tradeoffs depending on the number of queries. For example, in a concurrent system of two components, the traditional approach requires hexic time in the worst case for answering one query as well as computing the transitive closure, whereas we show that with one-time preprocessing in almost cubic time, each subsequent query can be answered in at most linear time, and even the transitive closure can be computed in almost quartic time. Furthermore, we establish conditional optimality results showing that the worst-case running time of our algorithms cannot be improved without achieving major breakthroughs in graph algorithms (i.e., improving the worst-case bound for the shortest path problem in general graphs). Preliminary experimental results show that our algorithms perform favor

关键词： Evolutionary computation   term operation   idemprimality   term continuity   randomizing algorithms  

摘要： The first paper in this series introduced the notion of term to term operation continuity for finite groupoids, and proved that two testable conditions on a finite groupoid imply that it is term continuous (TC). The second presented an evolution inspired algorithm for finding terms for operations, and gave experimental evidence that, in general, it was successful exactly when the groupoid was both idemprimal and TC. In this paper, we describe a new class of algorithms for finding terms which brings these results together. Theorems about idemprimality and term continuity show how each of these two properties impact our algorithms. They lead to a final explanation for the success of our algorithms when the groupoid is both idemprimal and TC.

关键词： Shape matching   Partial matching   RMS distance   Convex subdivision   Local minimum  

摘要： We consider the problem of minimizing the RMS distance (sum of squared distances between pairs of points) under translation between two point sets A and B, in the plane, with m = vertical bar B vertical bar << n = vertical bar A vertical bar, in the partial-matching setup, in which each point in B is matched to a distinct point in A. Although the problem is not known to be polynomial, we establish several structural properties of the underlying subdivision D-B,D-A of the plane and derive improved bounds on its complexity. Specifically, we show that this complexity is O(n(2)m(3.5)(e ln m + e)(m)), so it is only quadratic in vertical bar A vertical bar. These results lead to the best known algorithm for finding a translation for which the partial-matching RMS distance between the point sets is minimized. In addition, we show how to compute a local minimum of the partial-matching RMS distance under translation, in polynomial time.