参数d迭代逼近的GM(1,1)模型及其在技术创新中的应用

首先论述了参数d迭代逼近求解的GM(1,1)模型基本思路.其次,给出了此模型的参数估计与算法,即:1)估算出初始a_l,根据GM(1,1)模型a,c,d之间的关系,由a_l求得C_l,d_l;2)迭代d_l→d_(l+1),再计算a_(l+1),c_(l+1)及平均相对误差mape_l,mape_(l+1);3)多次迭代d_l→d_(l+1),直至|mape_(l+1)-mape_l|ε时,可得mape最小时的最优参数a,c,d值.然后,从理论与实证方面,证明模型是无偏的,且在参数d迭代过程中,a总能取到有意义的值.最后将模型应用于企业技术创新领域之中.     

应用均值不等式求圆锥体积的最大值

求满足一定条件时圆锥体积的最大值 ,通常可采用三角法处理 .能否采用均值不等式来求 ,是很多学生和教师很关心的问题 ,经过仔细深入地探讨 ,笔者发现圆锥全面积一定、或圆锥轴截面三角形周长一定、或圆锥侧面积一定时 ,圆锥体积的最大值可采用均值不等式求解 .例 1　已知圆锥的全面积为πa2 (a >0 ) .求圆锥体积的最大值 .解　设圆锥的高为h ,底面圆的半径为r ,体积为V ,则有πr2 +πrr2 +h2 =πa2 ,∴a2 =r2 +rr2 +h2=r2 +r r2 + 18h2 + 18h2 +… + 18h2≥r2 +r 99r2 188(h2 ) 8=r2 + 3· 1243r109h89=r2 + 1243r109h89+ 1243r109h89+124…     

由线性递推关系求数列的通项公式

在学习数列的过程中,根据递推关系求数列通项是常见的一类问题.这些递推关系除了等差等比外,还有an+1=-ban/can+d,an+1+an=f(n),Sn=f(an),an+2=pan+1+qan等几个典型类型.其中最后一个类型是线性表达式,即递推公式中涉及到的项都是一次的,著名的斐波那契数列an+2=an+1+an(1)就属于这种类型.一些考题也属于这个类型,例如,an+2+an+1=6an(2009宁夏高考),an+2=2an+1-an(2014河西区一模),等等.这个类型的一般形式是r0an+ r1an+1+r2an+2+…+rkan+k=0(2),其中k是正整数,r0,r1,…,rk是固定常数,且r0≠0,r1,r2,…,rk不全为0.对于k=2的情形,求通项公式也可以用累加法等进行尝试,但是对于k≥3的情形,这些办法就有限制.笔者发现可以利用“平移作用”和“因式分解”得到一种通用的求通项的简单方法,在此阐述.     

巧求一类复数模的最值

常遇到如下一类题型:已知复数|z+a+bi|=r,求|z+c+di|的最值(这里a,b,c,d,r为实常数)。这类题型有多种解法,而利用图象法解此类题,则显得直观形象,新颖巧妙。     

Graphic sequences with a realization containing intersecting cliques

Let r≥ 1, k≥ 2 and Fm1 ,...,mki;r denote the most general definition of a friendship graph, that is, the graph of Kr+m1 , . . . , Kr+mk meeting in a common r set, where Kr+mi is the complete graph on r + mi vertices. Clearly, | Fm1 ,...,mki;r | = m1+ ··· + mk + r. Let σ(Fm1 ,...,mki;r , n) be the smallest even integer such that every n-term graphic sequence π = (d1, d2, . . . , dn) with term sum σ(π) = d1 + d2 + ··· + dn ≥σ(Fm1 ,...,mki;r,n) has a realization G containing Fm1 ,...,mki;r as a subgraph. In this paper, we determine σ(Fm1 ,...,mki;r,n) for n sufficiently large.     

The smallest degree sum that yields potentially Kr,r-graphic sequences

We consider a variation of a classical Turán-type extremal problem as follows: Determine the smallest even integer σ(Kr,r, n) such that every n-term graphic sequence π = (d1, d2,..., dn) with term sum σ(π) = d1 + d2 +…+ dn ≥σ(Kr,r, n) is potentially Kr,r-graphic, where Kr,r is an r × r complete bipartite graph, i.e. πr has a realization G containing Kr,r as its subgraph. In this paper, the values σ(Kr,r,n) for even r and n ≥ 4r2 - r - 6 and for odd r and n ≥ 4r2 + 3r - 8 are determined.     

椭圆的两个有用的性质

性质 1　如图 1 ,T1 ( -t,0 )、T2 (t,0 ) ( 0 b>0 )的长轴A1 A2 上关于椭圆中心O对称的两定点 ,P是椭圆上的动点 ,当点P沿着弧A2 PB2 从A2 向B2 运动时 ,则∠T1 PT2 逐渐变大 ,并且当点P与点B2 重合时 ,∠T1 PT2 达最大值 .证明　连结OP ,记 ｜PT1 ｜=r1 ,｜PT2 ｜=r2 ,在△POT1 中 ,｜OP｜=d ,由余弦定理知r21 =t2 +d2 - 2tdcos∠POT1 ①同理r22 =t2 +d2 + 2tdcos∠POT1 ②由① +②得r21 +r22 =2t2 + 2d2又在△PT1 T2 中 ,由余弦定理知cos∠T1 PT2 =r21 +r22 - 4t22r1 ·r2③因为△T1 …     

一类修正牛顿法的收敛域

设非线性方程 F(x)=0 (1) 其中F:DR~n→R~n是Fréchet可导算子。为求(1)的解x=x~*,通常用著名的牛顿迭代 x_(n+1)=x_n-(F′(x_n))~(-1)F(x_n),n=0,1,2,… (2) 有时为了取得更好效果,需要使用阻尼牛顿迭代 x_(n+1)=x_n-λ_n(F′(x_n))~(-1)F(x_n),n=0,1,2,… (3) 其中λ_n∈[0,1]称为阻尼因子。 迭代点列(2),(3)敛速虽高,缺点是要用到计算代价高昂的导算子,因此有导算子被近似替代所导出的种种修正牛顿迭代     

应用构造法解题举例

一、构造函数例1 已知实数a,b,c,d,e,f,g,h满足: 求h 的取值范围. 解构造函数f(x)=7x2+2(a+b+c+d +e+f+g)x+a2+b2+c2+d2+e2+f2+g2,     

算术图一个猜想的证明

Ａｃｈａｒｙａ和Ｈｅｄｇｅ提出猜想：(i)若圈Ｃ_4t＋１( t≥1, t∈N) 是(k, d )－算术图，则Ｋ＝２ｄｔ+ 2r ( r≥0, r∈N ) ; ( ii) 若圈C_4t＋3是(k, d )-算术图, 则k= (2t+ 1) d + 2r ( r≥0, r∈N ). 本文证明了上述猜想为真.     

Iterative methods for solving fredholm integral equations

A Gauss-Seidel type of iterative method is described for solving the non-linear Fredholm integral equation. The analysis shows that this method may be expected to converge faster than the standard iterative method.     

Some supplementary results on the 1+\sqrt 2 order method for the solution of nonlinear equations

Summary Recently an iterative method for the solution of systems of nonlinear equations having at leastR-order 1+ for simple roots has been investigated by the author [7]; this method uses as many function evaluations per step as the classical Newton method. In the present note we deal with several properties of the method such as monotone convergence, asymptotic inclusion of the solution and convergence in the case of multiple roots.     

关于ρ(L_(r,w))、ρ(J_w)的最小值

本文证明了当线性方程组系数矩阵 A之 Jacobi迭代矩阵 B=L+ U≥ 0 ,ρ( B) <1时 Gauss-Seidel法之迭代矩阵 G=L1,1的谱半径 ρ( G) =ρ( L1,1)是 ρ( Lr,w) ( 0≤ r≤w≤ 1 ,w>0 )中的最小值 ,即此时 Gauss-Seidel迭代是 AOR法中收敛最快的迭代法 .并且对 JOR法 (谱半径为 ρ( Jw) )和 SAOR法也作了相应的论述 .     

A method for computing the tension parameters in convexity-preserving spline-in-tension interpolation

Summary This paper is concerned with the problem of convexity-preservng (orc-preserving) interpolation by using Exponential Splines in Tension (or EST's). For this purpose the notion of ac-preserving interpolant, which is usually employed in spline-in-tension interpolation, is refined and the existence ofc-preserving EST's is established for the so-calledc-admissible data sets. The problem of constructing ac-preserving and visually pleasing EST is then treated by combining a generalized Newton-Raphson method, due to Ben-Israel, with a step-length technique which serves the need for visual pleasantness. The numerical performance of the so formed iterative scheme is discussed for several examples.     

Ideals of Ultrafilters on the Collection of Finite Subsets of an Infinite Set

Let J be an infinite set and let , i.e., I is the collection of all non empty finite subsets of J. Let denote the collection of all ultrafilters on the set I and let be the compact (Hausdorff) right topological semigroup that is the Stone-Cech Compactification of the semigroup equipped with the discrete topology. This paper continues the study of that was started in [3] and [5]. In [5], Koppelberg established that (where K( S) is the smallest ideal of a semigroup S) and for non empty she established . In this note, we show that for such that is infinite, is a proper subset of and , where .     

Iterative continuation and the solution of nonlinear two-point boundary value problems

In this paper we present a unified function theoretic approach for the numerical solution of a wide class of two-point boundary value problems. The approach generates a class of continuous analog iterative methods which are designed to overcome some of the essential difficulties encountered in the numerical treatment of two-point problems. It is shown that the methods produce convergent sequences of iterates in cases where the initial iterate (guess),x ₀, is far from the desired solution. The results of some numerical experiments using the methods on various boundary value problems are presented in a forthcoming paper.     

关于PageRank的广义二级分裂迭代方法

本文研究计算PageRank的迭代法,在Gleich等人提出的内/外迭代方法的基础上,提出了具有三个参数的广义二级分裂迭代法,该方法包含了内/外迭代法和幂迭代法,并研究了该方法的收敛性.基于该方法的收缩因子的计算公式,讨论了迭代参数可能的选择,通过参数的选择能有效提高内/外迭代法的收敛效率.     

On nondecreasing sequences of regularization parameters for nonstationary iterated Tikhonov

Nonstationary iterated Tikhonov is an iterative regularization method that requires a strategy for defining the Tikhonov regularization parameter at each iteration and an early termination of the iterative process. A classical choice for the regularization parameters is a decreasing geometric sequence which leads to a linear convergence rate. The early iterations compute quickly a good approximation of the true solution, but the main drawback of this choice is a rapid growth of the error for later iterations. This implies that a stopping criteria, e.g. the discrepancy principle, could fail in computing a good approximation. In this paper we show by a filter factor analysis that a nondecreasing sequence of regularization parameters can provide a rapid and stable convergence. Hence, a reliable stopping criteria is no longer necessary. A geometric nondecreasing sequence of the Tikhonov regularization parameters into a fixed interval is proposed and numerically validated for deblurring problems.     

约束Fractional Tikhonov正则化的模迭代方法

反问题是现在数学物理研究中的一个热点问题,而反问题求解面临的一个本质性困难是不适定性。求解不适定问题的普遍方法是:用与原不适定问题相“邻近”的适定问题的解去逼近原问题的解,这种方法称为正则化方法.如何建立有效的正则化方法是反问题领域中不适定问题研究的重要内容.当前,最为流行的正则化方法有基于变分原理的Tikhonov正则化及其改进方法,此类方法是求解不适定问题的较为有效的方法,在各类反问题的研究中被广泛采用,并得到深入研究.     

A Two-Sided Interval Iterative Method for the Finite Dimensional Nonlinear Systems

For the nonlinear system $$x=g(x)+h(x)+c, x\in R^n,$$ where $g$ and $h$ are isotone and antitone mappings respectively, a two-sided interval iterative method is presented, the initial condition of the two-sided iterative method is relaxed, and the convergence of the two methods are proved.