合作学习不是数学课堂教学的“型秀”

随着课程改革的不断进展和深入,新理念在课堂中不断地尝试和运用,教学的组织形式也在发生新变化．其中“合作学习”所产生的互动效应正逐渐为大家所接受,这种互动为学生提供了动手、动口、动脑的时间和空间．由传统的“教师讲一学生学”转化为“教师为主导,学生为主体”的合作教学方式,很好的促进了学生的有效学习和主动发展性,使数学课堂不再枯燥、乏味,教师和学生有效地融合在知识的殿堂中．     

基于和积和最大积的信念传播算法的收敛性分析

在介绍马尔可夫网络和标准信念传播(Belief Propagation,BP)算法的基础上,以具有4个隐含结点的无环马尔可夫网络为例,详细分析了基于和积和最大积的BP算法收敛性,结果表明,在网络为无环马尔可夫网络时,基于和积的BP算法收敛于全局最优解,而基于最大积的BP算法在任何初值条件下,只要经过有限次迭代,BP算法必收敛到唯一固定点,若算法有唯一最优点,则此固定点为最优点.以实证分析为工具,研究BP算法收敛性,可作为BP算法基础理论研究的一次有益尝试.     

补充养老、医疗保险的财税处理

补充养老保险、医疗保险是在基本养老保险、医疗保险基础上,政府以政策指导和政策优惠为导向,用工单位和员工共同出资,以资金积累和运作增值为主要特征,以提高出资单位员工的养老待遇为主要特点的社会保险的重要组成部分。     

抛物线的弓形面积的最大值探求

在通径为2p的抛物线C中,给定一条长度为a的动弦AB,当弦AB在抛物线C上运动时,由弦AB和抛物线C所围成的弓形面积是否存在最大值呢?如图1所示,本文就这个问题进行探讨.     

基于模糊相似比较的模具报价方法的研究

为克服模具报价工作对报价人员经验的依赖性,简化报价操作,在分析了报价系统的要求和传统的模具报价进程的基础上,提出了利用模糊数学来提取模具报价领域中专家的经验,模拟专家行为,根据预测技术理论,得出模具价格的模糊相似比较法构想.在此基础上,推导其公式.以冲裁模为研究对象,阐述了工件特征集合构成、模糊相似关系和权值、贴近度计算等关键问题.从理论上为模具报价这一实际问题的解决提供了基本原则和方法.     

关于保持距离映射的Aleksandrov问题

设E,F为实Hilbert空间,f:E→F为一映射,本文证明了在一定条件下,若f保距离a和b(其中,a,b为两个正实数),则f为一个仿射等距,从而部分地解决了Aleksandrov在1970年提出的Aleksandrov问题。     

基于ELM算法的羊肉水分含量的快速无损检测

在近红外光谱900-1700nm的波长范围内采集南疆羊肉的光谱数据,来研究水分含量的快速无损检测.为减弱非目标因素对光谱的影响,采用SNV和去趋势法对光谱数据进行预处理.为降低建模的复杂度,去除共线性的影响,采用连续投影算法和相关系数法相结合选取8个特征波长变量,最后使用PLS和ELM算法分别进行建模.实验表明,与采用全光谱波段建模相比,采用特征波长变量建模,PLS和ELM算法的运行时间都大大缩短,并且在运行时间和预测精度上,ELM算法均优于PLS算法.ELM算法采用8个特征波段变量建模,预测精度达到0.9768,均方误差为4.4291e-04,相关系数为0.7603,运行时间可控制在1e-04s之下,这可为研发羊肉水分含量的便携式检测装置提供理论参考.     

基于休假时间的贮备系统的二维更换策略模型

研究两个不同型部件和一个修理工组成的冷贮备可修系统,在考虑了预防修和使用的优先权的条件下,以部件1的故障次数N及预防维修时长T为策略,利用几何过程和更新过程理论,建立了以修理工休假时间为目标函数,以费用率和停机时间为约束条件的优化模型.在部件1寿命分布函数已知的情况下,证明了系统经长期运行修理工平均休假时间随T是单调增加的,最后通过数值例子验证了最优的策略(T~*,N~*)的存在性.     

基于图方法的自回归和双线性时间序列模型系数的检验

自回归和双线性时间序列模型被表示为时间序列链图模型.在此基础上, 证明了自回归和双线性模型的系数为其他时间序列分量给定的条件下的条件相关系数.然后提出基于图的检验方法来检验自回归和双线性模型系数的显著性, 模拟结果表明此方法在水平和功效方面表现很好.     

树的离心率矩阵的最大特征值（英文）

图的离心率矩阵是从其距离矩阵构造的,保留了距离矩阵的每一行每一列的最大值,其余元素均为0.[Discrete Math.,2022,345(1):112662,11 pp.]确定了在点数和直径相同且直径为奇数的前提下其离心率矩阵具有最大特征值的树.本文将探讨在点数和直径相同且直径为偶数的前提下其离心率矩阵具有最大特征值的树.     

RECENT PROGRESS ON SPHERICAL HARMONIC APPROXIMATION MADE BY BNU RESEARCH GROUP ——In memory of Professor Sun Yongsheng

As early as in 1990, Professor Sun Yongsheng, suggested his students at Beijing Normal University to consider research problems on the unit sphere. Under his guidance and encouragement his students started the research on spherical harmonic analysis and approximation. In this paper, we incompletely introduce the main achievements in this area obtained by our group and relative researchers during recent 5 years （2001-2005）. The main topics are： convergence of Cesaro summability, a.e. and strong summability of Fourier-Laplace series; smoothness and K-functionals; Kolmogorov and linear widths.     

A unified approach to certain problems of best local approximation

In this paper we study best local quasi-rational approximation and best local approximation from finite dimensional subspaces of vectorial functions of several variables. Our approach extends and unifies several problems concerning best local multi-point approximation in different norms.     

Boundedness for commutators of multipliers on Hardy type spaces

In this paper, we study the commutators generalized by multipliers and a BMO function. Under some assumptions, we establish its boundedness properties from certain atomic Hardy space Hb^p（R^n） into the Lebesgue space L^p with p 〈 1.     

THE 8~(th) INTERNATIONAL CONGRESS ON INDUSTRIAL AND APPLIED MATHEMATICS

<正>August 10-14,2015Beijing,ChinaThe International Congress on Industrial and Applied Mathematics(ICIAM)is the premier international congress in the field of applied mathematics held every four years under the auspices of the International Council for Industrial and Applied Mathematics.From August 10 to 14,2015,mathematicians,scientists     

Towards Excellence in Science Chinese Academy of Sciences

<正>May 26,2014,Beijing Science is a human enterprise in the pursuit of knowledge.The scientific revolution that occurred in the 17th Century initiated the advances of modern science.The scientific knowledge system created by     

Bounds for the zeros of polynomials

Let P(z)=∑↓j=0↑n ajx^j be a polynomial of degree n. In this paper we prove a more general result which interalia improves upon the bounds of a class of polynomials. We also prove a result which includes some extensions and generalizations of Enestrǒm-Kakeya theorem.     

Boundedness of commutators related to Marcinkiewicz integrals on hardy type spaces

In this paper, the authors study the boundedness of the operator [μΩ, b], the commutator generated by a function b ∈ Lipβ(Rn)(0 ＜β≤ 1) and the Marcinkiewicz integrals μΩ, on the classical Hardy spaces and the Herz-type Hardy spaces in the case Ω∈ Lipα(Sn-1)(0 ＜α≤ 1).     

Jacobi polynomials used to invert the laplace transform

Given the Laplace transform F(s) of a function f(t), we develop a new algorithm to find an approximation to f(t) by the use of the classical Jacobi polynomials. The main contribution of our work is the development of a new and very effective method to determine the coefficients in the finite series expansion that approximation f(t) in terms of Jacobi polynomials. Some numerical examples are illustrated.     

Generalization of the interaction between Haar approximation and polynomial operators to higher order methods

In applications it is useful to compute the local average empirical statistics on u. A very simple relation exists when of a function f（u） of an input u from the local averages are given by a Haar approximation. The question is to know if it holds for higher order approximation methods. To do so, it is necessary to use approximate product operators defined over linear approximation spaces. These products are characterized by a Strang and Fix like condition. An explicit construction of these product operators is exhibited for piecewise polynomial functions, using Hermite interpolation. The averaging relation which holds for the Haar approximation is then recovered when the product is defined by a two point Hermite interpolation.