迭代·递归·一类函数的周期性

求已知函数f(x)的n次迭代式f(f(…(f(x))))的明显表达式,是一个古老、有趣而又困难的问题。本文先指出函数迭代与递归数列的关系;然后给出求函数迭代式的一种简便方法——递归法,最后探讨一类函数的周期性。一、设f(x)是定义在D上的函数,记     

Clifford分析中高阶T算子的L~p可积性

首先定义了定义于R~n取值于A_n(R)的高阶T算子并讨论了它在Lγ空间中的性质.其次,估计了T算子的模,并引入了修正的高阶Teodorescu算子T~*.接下来,根据Banach压缩映射原理证明了算子T~*存在唯一的不动点.最后,证明了Mann迭代序列强收敛于T~*的不动点,进而给出了一个奇异积分方程解的迭代序列.     

代数图递归迭代函数系与开集条件（英文）

本文研究R上一类代数图递归迭代函数系的开集条件与代数参数β之间的关系.我们证明若图递归迭代函数系满足开集条件且递归图是几何型的,则βs必是一个代数整数,其中s为图递归迭代函数系不变集的最大的Hausdorff维数.     

一类算子变换的n次迭代

将定义两个从A类算子到亚正规算子的变换T~(*)的n次迭代T_n及算子变换T~(*)的n次迭代T_n~(*),并给出它们具有的一些性质.     

学习理论中核函数逼近的Jackson型不等式（英文）

从微分算子角度理解核函数空间,借助经典Fourier变换研究核函数逼近问题.应用Fourier乘子算子和算子半群定义了一种光滑模,证明其与一种基于微分算子的K-泛函的等价性,由此给出了刻画核函数逼近收敛性的Jackson不等式.进一步证明,如果微分算子为Riesz势算子或Bessel势算子,逼近的收敛性可以转化为卷积算子逼近.特别地,给出了再生核Hilbert空间逼近的一种上界估计.     

关于转移函数的收敛性

本文研究了参数连续Markov链中转移函数的逼近.运用算子半群方法,讨论了q-矩阵的截断矩阵对应Q-函数的收敛问题;引进q-矩阵的Yosida逼近矩阵,证明了任意Q-过程可以由一列有界Q-过程逼近.并给出了最小Q-函数收敛的q-矩阵条件.推广了相关工作.     

博弈的统计演化分析

首先定义了具有确定分布的随机环境中的基于适应度的平均选择算子,然后证明了主体战略集上的任一概率密度在平均选择算子的迭代过程中收敛于平均适应度函数的最大集上的某一分布,然后就多主体的博弈问题定义了平均选择算子,并以此为基础证明了平均选择算子的不动点就是博弈的纳什均衡.     

关于正弦椭球的迭代不等式

通过新定义的正弦椭球的定义和性质,得到了正弦椭球的体积不等式并给出了等式成立的充分必要条件.此外,本文利用迭代方法,进一步建立了关于正弦椭球算子Λ_2~*和Λ_(-2)~*的迭代不等式.     

关于分形插值函数的连续性和可微性

获得了由迭代函数系统(IFS)定义的两类分形插值函数具有Hlder连续性的充分条件,给出了这两类分形插值函数连续可微的充要条件,并证明了可微分形插值函数的导函数是由关联IFS生成的分形插值函数.     

广义e-ω-凹算子的不动点及其应用

给出广义e-ω-凹算子的定义,在假设算子A不是锥映射的前提下,得到了广义e-ω-凹算子的不动点的存在唯一性以及单调迭代列.最后,将主要结果应用到一类Hammerstein型积分方程中去.     

Construction of fractal surfaces by recurrent fractal interpolation curves

A method to construct fractal surfaces by recurrent fractal curves is provided. First we construct fractal interpolation curves using a recurrent iterated functions system (RIFS) with function scaling factors and estimate their box-counting dimension. Then we present a method of construction of wider class of fractal surfaces by fractal curves and Lipschitz functions and calculate the box-counting dimension of the constructed surfaces. Finally, we combine both methods to have more flexible constructions of fractal surfaces.     

Effect of change point and imperfect debugging in software reliability and its optimal release policy

This article presents a software reliability growth model based on non-homogeneous Poisson process. The main focus of this article is to deliver a method for software reliability modelling incorporating the concept of time-dependent fault introduction and fault removal rate with change point. Also in this article, a cost model with change point has been developed. Based on the cost model optimal release policy with change point has been discussed. Maximum likelihood technique has been applied to estimate the parameters of the model. The proposed model has been validated using some real software failure data. Comparison has been made with models incorporating change point and without change point. The application of the proposed cost model has been shown using some numerical examples.     

一类不确定混沌系统的自适应同步

讨论了混沌系统的同步问题 .对一类不确定混沌系统 ,提出了一个新的自适应同步方法 ,可使响应系统在自适应控制器的控制下 ,实现与不确定混沌系统的同步 .最后给出了一个设计实例 .     

AN EMBEDDED BOUNDARY METHOD FOR ELLIPTIC AND PARABOLIC PROBLEMS WITH INTERFACES AND APPLICATION TO MULTI-MATERIAL SYSTEMS WITH PHASE TRANSITIONS

The embedded boundary method for solving elliptic and parabolic problems in geometrically complex domains using Cartesian meshes by Johansen and Colella （1998, J. Comput. Phys. 147, 60） has been extended for elliptic and parabolic problems with interior boundaries or interfaces of discontinuities of material properties or solutions. Second order accuracy is achieved in space and time for both stationary and moving interface problems. The method is conservative for elliptic and parabolic problems with fixed interfaces. Based on this method, a front tracking algorithm for the Stefan problem has been developed. The accuracy of the method is measured through comparison with exact solution to a two-dimensional Stefan problem. The algorithm has been used for the study of melting and solidification problems.     

Lightning modeling and protection zone of conducting rod using Monte Carlo technique

Lightning strike is a harmful process and protection from lightning using conducting rods has been a subject of discussion for decades. In particular, there have been a lot of researches regarding the protection zone of a single conducting rod. This is important for the purpose of installing them to protect complex building structures. In the present article, the protection zone of a conducting rod has been obtained by Monte Carlo simulation method. The lightning process has been modeled for computer simulation. The authors have presented a new Monte Carlo modeling of lightning path. The origin of the downward stepped leader and the magnitude of peak current of the return stroke have appropriate random distributions. The obtained results are compared with already available experimental results present in various literatures. It is shown that this technique is reliable and in fair agreement with the established theories for finding protection zone of conducting rods.     

Game theoretical treatment of material accountability problems Part II

In a previous paper, the optimal strategy for an inspection authority which has to safeguard material on the basis of material accountability principles has been determined with game theoretical methods: Sets of reasonable inspection and diversion strategies have been defined, and a saddlepoint of the overall probability of detection forn inventory periods during the reference time under consideration has been determined. In this paper it is shown that, with respect to the probability of detection, performing a single inventory is superior to performing a multiple inventory. A justification is given for the use of multiple inventories when the detection time is also concerned.     

Chaos in a topologically transitive system

The chaotic phenomena have been studied in a topologically transitive system and it has been shown that the erratic time dependence of orbits in such a topologically transitive system is more complicated than what described by the well-known technology "Li-Yorke chaos". The concept "sensitive dependency on initial conditions" has been generalized, and the chaotic phenomena has been discussed for transitive systems with the generalized sensitive dependency property.     

Aplicación de métodos computacionales en la evaluación de la respuesta aeroelástica de puentes soportados por cables

The possibilities of computational methods for assessing the response of cable supported bridges under wind action are considered in this work. The main objective is to study the possibilities of substituting wind tunnel campaigns by computer based analyses, particularly at the early design stage. The preliminary proposed design for a continuous cable-stayed bridge with two main spans of 650 m and a single box girder deck has been considered as a case study. The force coefficients of the deck cross-section have been computed and the unsteady response associated to vortex-shedding has been simulated using CFD commercial software. Furthermore, an in-house piece of software has been employed to obtain the response for flutter and buffeting phenomena adopting the hybrid approach; with that purpose the experimental flutter functions of a similar box girder deck were adopted. The computational results have been validated by comparison with similar experimental results published by other researchers. It has been verified that the set of adopted methods offers reliable results with moderate costs; therefore, the proposed approach is very suitable at the early design stage of long span bridges or at conceptual design works.     

Fitted Mesh Method for a Class of Singularly Perturbed Differential-Difference Equations

This paper deals with a more general class of singularly perturbed boundary value problem for a differential-difference equations with small shifts. In particular, the numerical study for the problems where second order derivative is multiplied by a small parameter $ε$ and the shifts depend on the small parameter $ε$ has been considered. The fitted-mesh technique is employed to generate a piecewise-uniform mesh, condensed in the neighborhood of the boundary layer. The cubic B-spline basis functions with fitted-mesh are considered in the procedure which yield a tridiagonal system which can be solved efficiently by using any well-known algorithm. The stability and parameter-uniform convergence analysis of the proposed method have been discussed. The method has been shown to have almost second-order parameter-uniform convergence. The effect of small parameters on the boundary layer has also been discussed. To demonstrate the performance of the proposed scheme, several numerical experiments have been carried out.