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迭代学习控制综述 被引量:40
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作者 李仁俊 韩正之 《控制与决策》 EI CSCD 北大核心 2005年第9期961-966,共6页
系统地论述了迭代学习控制的发展和研究现状,包括学习算法及其各种分析方法、与其他控制技术的结合及其应用都作了的总结.重点对迭代学习控制研究的前沿问题:基于频域分析的迭代学习控制、基于2-D理论的迭代学习控制、基于Lyapunov直接... 系统地论述了迭代学习控制的发展和研究现状,包括学习算法及其各种分析方法、与其他控制技术的结合及其应用都作了的总结.重点对迭代学习控制研究的前沿问题:基于频域分析的迭代学习控制、基于2-D理论的迭代学习控制、基于Lyapunov直接法的迭代学习控制、最优化迭代学习控制和采样迭代学习控制进行阐述.最后讨论了目前研究中存在的问题及未来的研究方向. 展开更多
关键词 迭代学习控制 压缩映射 2一D理论 LYAPUNOV直接法 最优控制
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Banach不动点定理的一个推广 被引量:9
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作者 江正华 《南京大学学报(自然科学版)》 CAS CSCD 北大核心 2014年第1期9-13,共5页
Banach不动点定理(亦称Banach压缩映照原理)是泛函分析中最重要又经典的定理之一,对这一定理的研究颇有意义.本文通过对Banach不动点定理数学本质的研究,适当放宽了不动点定理条件中对压缩映照的要求,将Banach不动点定理作了推广并加以... Banach不动点定理(亦称Banach压缩映照原理)是泛函分析中最重要又经典的定理之一,对这一定理的研究颇有意义.本文通过对Banach不动点定理数学本质的研究,适当放宽了不动点定理条件中对压缩映照的要求,将Banach不动点定理作了推广并加以严格的证明,从而放宽了该定理的适用范围.文章最后给予实例来说明应用Banach不动点定理的推广形式可以处理一些在Bnanach不动点定理无法判断情形下的问题,进一步有力地彰显出Banach不动点定理的推广形式其应用的宽泛性. 展开更多
关键词 压缩映照 BANACH不动点定理 迭代
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三维迭代函数系统植物模拟 被引量:5
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作者 董春胜 荣霞 《辽宁工程技术大学学报(自然科学版)》 CAS 北大核心 2014年第5期712-715,共4页
为实现对自然界树木的逼真模拟,以迭代函数系统为基础,定义了三维空间上的变换矩阵,建立了三维植物生成模型,以一组压缩仿射变换生成的图像为例,通过调整已有IFS码的比例系数,可实现树木生长过程的模拟;通过调整IFS码的参数来控制树枝... 为实现对自然界树木的逼真模拟,以迭代函数系统为基础,定义了三维空间上的变换矩阵,建立了三维植物生成模型,以一组压缩仿射变换生成的图像为例,通过调整已有IFS码的比例系数,可实现树木生长过程的模拟;通过调整IFS码的参数来控制树枝旋转角度,可模拟出树枝受到风力影响时的形态;通过对已有图像变换观察角度,可获得同一树木不同视点生成的图像.研究结果表明:针对性地调整IFS码,可完成自然界树木的逼真模拟. 展开更多
关键词 分形 迭代函数系统(IFS) 仿射变换 植物模拟 参数控制 压缩映射 树木三维建模 吸引子
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一组新的不动点定理
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作者 张昌斌 《郧阳师范高等专科学校学报》 1989年第1期16-23,共8页
本文引进了映射的范数的概念,并利用它改进了的方法,放宽了不动点定理的条件,使之不仅适用于压缩映射与紧映射的和映射,而且也适用于下述三种映射与紧映射的和映射:收缩且一致局部压缩的映射、扩张映射、准扩张且一致局部扩张的映射。另... 本文引进了映射的范数的概念,并利用它改进了的方法,放宽了不动点定理的条件,使之不仅适用于压缩映射与紧映射的和映射,而且也适用于下述三种映射与紧映射的和映射:收缩且一致局部压缩的映射、扩张映射、准扩张且一致局部扩张的映射。另外,我们还得一个一致局部扩张映射不动点定理与一个准扩张映射不动点定理。 展开更多
关键词 压缩映射 收缩映射 一致局部压缩映射 扩张映射 准扩张映射 一致局部扩张映射 紧映射 映射的范数 δ-可链度量空间
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Fixed Point Curve for Weakly Inward Contractions and Approximate Fixed Point Property
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作者 P.Riyas K.T.Ravindran 《Analysis in Theory and Applications》 2013年第4期342-347,共6页
In this paper, we discuss the concept of fixed point curve for linear interpolations of weakly inward contractions and establish necessary condition for a nonex- pansive mapping to have approximate fixed point property.
关键词 Nonexpansive mapping contraction weakly inward contraction approximate fixedpoint property.
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A GENERALIZATION OF CLARKE'S FIXED POINT THEOREM 被引量:1
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作者 SONG WEN 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 1995年第4期463-466,共4页
This paper proposes a formally stronger set-valued Clarke's fixed point theorem. By this theorem we can improve a fixed point theorem for weakly inward contraction set-valued mapping of D. Dowing and W.A. Kirk.
关键词 contraction mapping fixed point weakly inward metric spaces.
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一类随机级数的收敛性及和的分布 被引量:1
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作者 汪明瑾 《烟台师范学院学报(自然科学版)》 1996年第4期272-273,共2页
设x1,x2,…,xn是独立同分布的随机变量序列,P(0≤x1≤1)=1且P(x1=1)<1.证明了随机级数∞n=1(-1)n-1x1x2…xn的收敛性,并提供了一种求和S=∞n=1(-1)n-1x1x2…
关键词 随机级数 收敛性 压缩映象 随机变量序列
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Better Hausdorff Dimension Estimations of Quadratic and Cubic Functions' Julia Sets
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作者 方丽萍 张春红 《Journal of Beijing Institute of Technology》 EI CAS 2006年第1期123-126,共4页
More accurate Hausdorff dimension estimations of Julia sets for two simple functions are given by the methods of composition mapping and invariant set of contraction mapping. For quadratic function fc ( z ) = z^2 ... More accurate Hausdorff dimension estimations of Julia sets for two simple functions are given by the methods of composition mapping and invariant set of contraction mapping. For quadratic function fc ( z ) = z^2 + c(c ∈^C), the range of parameter c is expanded largely and a result on the Hausdorff dimension of its Julia set is gained. Similarly, a better result is obtained for cubic function fc(z) = z^3 + c(c ∈ ^C). 展开更多
关键词 COMPOSITION contraction mapping invariant set Hausdorff dimension
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ON A NONLINEAR VOLTERRA-HAMMERSTEIN INTEGRAL EQUATION IN TWO VARIABLES
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作者 Le Thi Phuong Ngoc Nguyen Thanh Long 《Acta Mathematica Scientia》 SCIE CSCD 2013年第2期484-494,共11页
Using a fixed point theorem of Krasnosel'skii type, this article proves the exis- tence of asymptotically stable solutions for a Volterra-Hammerstein integral equation in two variables.
关键词 Volterra-Hamnmrstein integral equation in two variables the fixed point theo-rem of Krasnosel'skii type contraction mapping completely continuous asymp-totically stable solution
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Existence of Nonoscillatory Solutions for a Second-Order Nonlinear Neutral Delay Differential Equation
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作者 Zhen Yu GUO 《Journal of Mathematical Research and Exposition》 CSCD 2011年第3期503-508,共6页
A new second-order nonlinear neutral delay differential equation r(t) x(t) + P(t)x(t-τ) + cr(t) x(t)-x(t-τ) + F t,x(t-σ1),x(t-σ2),...,x(t-σn) = G(t),t ≥ t0,where τ 0,σ1,σ2,...,σn ≥ ... A new second-order nonlinear neutral delay differential equation r(t) x(t) + P(t)x(t-τ) + cr(t) x(t)-x(t-τ) + F t,x(t-σ1),x(t-σ2),...,x(t-σn) = G(t),t ≥ t0,where τ 0,σ1,σ2,...,σn ≥ 0,P,r ∈ C([t0,+∞),R),F ∈ C([t0,+∞)×Rn,R),G ∈ C([t0,+∞),R) and c is a constant,is studied in this paper,and some sufficient conditions for existence of nonoscillatory solutions for this equation are established and expatiated through five theorems according to the range of value of function P(t).Two examples are presented to illustrate that our works are proper generalizations of the other corresponding results.Furthermore,our results omit the restriction of Q1(t) dominating Q2(t)(See condition C in the text). 展开更多
关键词 nonoscillatory solution second-order neutral delay differential equation contraction mapping.
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Simple Proofs of Upper and Lower Envelopes of Van Der Pauw’s Equation for Hall-Plates with an Insulated Hole and Four Peripheral Point-Contacts
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作者 Udo Ausserlechner 《Journal of Applied Mathematics and Physics》 2022年第3期960-999,共40页
For plane singly-connected domains with insulating boundary and four point-sized contacts, C<sub>0</sub> &#8230;C<sub>3</sub>, van der Pauw derived a famous equation relating the two trans-... For plane singly-connected domains with insulating boundary and four point-sized contacts, C<sub>0</sub> &#8230;C<sub>3</sub>, van der Pauw derived a famous equation relating the two trans-resistances R<sub>01,23</sub>, R<sub>12,30</sub> with the sheet resistance without any other parameters. If the domain has one hole van der Pauw’s equation becomes an inequality with upper and lower bounds, the envelopes. This was conjectured by Szymański et al. in 2013, and only recently it was proven by Miyoshi et al. with elaborate mathematical tools. The present article gives new proofs closer to physical intuition and partly with simpler mathematics. It relies heavily on conformal transformation and it expresses for the first time the trans-resistances and the lower envelope in terms of Jacobi functions, elliptic integrals, and the modular lambda elliptic function. New simple formulae for the asymptotic limit of a very large hole are also given. 展开更多
关键词 Conformal mapping contraction Process Doubly Connected Domains ENVELOPES Hall Plate Large Hole Angle Sheet Resistance Small Hole Angle Van Der Pauw
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Some Result of Stability and Spectra Properties on Semigroup of Linear Operator
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作者 Kamilu Rauf Akinola Yussuff Akinyele +2 位作者 Mfon Okon Etuk Rafiu Obashola Zubair Moses Adebowale Aasa 《Advances in Pure Mathematics》 2019年第1期43-51,共9页
This paper consists of some properties of a new subclass of semigroup of linear operator. The stability and spectra analysis of ω-order preserving partial contraction mapping (ω-OCPn) are obtained. The results show ... This paper consists of some properties of a new subclass of semigroup of linear operator. The stability and spectra analysis of ω-order preserving partial contraction mapping (ω-OCPn) are obtained. The results show that operators on the proposed ω-OCPn are densely defined and closed. Several existing results in the literature are contained in this work. 展开更多
关键词 contraction mapping SEMIGROUP BANACH Space RESOLVENT and BOUNDED Operator
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Convergence of Discrete Adomian Method for Solving a Class of Nonlinear Fredholm Integral Equations
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作者 Ibrahim Lotfy Hassan Alkalla Reda Abdo Abd-Elmonem Ayman Mohamed Ali Ahmed Gomaa 《Applied Mathematics》 2013年第1期217-222,共6页
In recent papers the solution of nonlinear Fredholm integral equations was discussed using Adomian decomposition method (ADM). For case in which the integrals are analytically impossible, ADM can not be applied. In th... In recent papers the solution of nonlinear Fredholm integral equations was discussed using Adomian decomposition method (ADM). For case in which the integrals are analytically impossible, ADM can not be applied. In this paper a discretized version of the ADM is introduced and the proposed version will be called discrete Adomian decomposition method (DADM). An accelerated formula of Adomian polynomials is used in calculations. Based on this formula, a new convergence approach of ADM is introduced. Convergence approach is reliable enough to obtain an explicit formula for the maximum absolute truncated error of the Adomian’s series solution. Also, we prove that the solution of nonlinear Fredholm integral equation by DADM converges to ADM solution. Finally, some numerical examples were introduced. 展开更多
关键词 NONLINEAR FREDHOLM INTEGRAL EQUATIONS contraction mapping Adomian Decomposition Method QUADRATURES Techniques
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Switching Regimes in Economics: The Contraction Mapping and the &omega;-Limit Set
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作者 Pascal Stiefenhofer Peter Giesl 《Applied Mathematics》 2019年第7期513-520,共8页
This paper considers a dynamical system defined by a set of ordinary autonomous differential equations with discontinuous right-hand side. Such systems typically appear in economic modelling where there are two or mor... This paper considers a dynamical system defined by a set of ordinary autonomous differential equations with discontinuous right-hand side. Such systems typically appear in economic modelling where there are two or more regimes with a switching between them. Switching between regimes may be a consequence of market forces or deliberately forced in form of policy implementation. Stiefenhofer and Giesl [1] introduce such a model. The purpose of this paper is to show that a metric function defined between two adjacent trajectories contracts in forward time leading to exponentially asymptotically stability of (non)smooth periodic orbits. Hence, we define a local contraction function and distribute it over the smooth and nonsmooth parts of the periodic orbits. The paper shows exponentially asymptotical stability of a periodic orbit using a contraction property of the distance function between two adjacent nonsmooth trajectories over the entire periodic orbit. Moreover it is shown that the ω-limit set of the (non)smooth periodic orbit for two adjacent initial conditions is the same. 展开更多
关键词 NON-SMOOTH Periodic ORBIT Differential Equation contraction mapping Economic Regimes NON-SMOOTH DYNAMICAL System
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Positive eigenvalue-eigenvector of nonlinear positive mappings
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作者 Yisheng SONG Liqun QI 《Frontiers of Mathematics in China》 SCIE CSCD 2014年第1期181-199,共19页
We show that an (eventually) strongly increasing and positively homogeneous mapping T defined on a Banach space can be turned into an Edelstein contraction with respect to Hilbert's projective metric. By applying t... We show that an (eventually) strongly increasing and positively homogeneous mapping T defined on a Banach space can be turned into an Edelstein contraction with respect to Hilbert's projective metric. By applying the Edelstein contraction theorem, a nonlinear version of the famous Krein- Rutman theorem is presented, and a simple iteration process {T^kx/||T^kx||} ( x ∈ P^+) is given for finding a positive eigenvector with positive eigenvalue of T. In particular, the eigenvalue problem of a nonnegative tensor A can be viewed as the fixed point problem of the Edelstein contraction with respect to Hilbert's projective metric. As a result, the nonlinear Perron-Frobenius property of a nonnegative tensor A is reached easily. 展开更多
关键词 Nonnegative tensor Edelstein contraction strongly increasing homogeneous mapping eigenvalue-eigenvector
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闸下出流及带有压板出口的水流收缩系数 被引量:1
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作者 倪汉根 刘亚坤 《水动力学研究与进展(A辑)》 CSCD 北大核心 2000年第2期141-147,共7页
本文采用保角变换法 ,给出了计及重力影响的平板闸下泄流时水流竖向收缩系数ε的计算方法 ,给出了不同闸孔开度 ab 和不同相对水头 Ha 时的具体计算结果 ,研究表明 Ha 值对ε有一定的影响。文中还给出了在常用几何参数 (压板坡度、收缩... 本文采用保角变换法 ,给出了计及重力影响的平板闸下泄流时水流竖向收缩系数ε的计算方法 ,给出了不同闸孔开度 ab 和不同相对水头 Ha 时的具体计算结果 ,研究表明 Ha 值对ε有一定的影响。文中还给出了在常用几何参数 (压板坡度、收缩比、相对水头 )范围内带有压板出口的水流竖向收缩系数。 展开更多
关键词 闸下出流 保角变换 收缩系数 水流 压板出口
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关于自反Banach空间框架下的连续伪压缩映象 被引量:1
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作者 孙利娟 《郑州大学学报(工学版)》 CAS 北大核心 2010年第5期121-124,共4页
考虑了一类含有连续强伪压缩映象的粘滞迭代隐性算法.在自反的Banach空间框架下,基于迭代方法针对满足弱嵌入条件的连续伪压缩非自映象,建立了不动点序列的强收敛定理,并证明了该不动点恰为某一非线性变分不等式的唯一解.所得结果改进了... 考虑了一类含有连续强伪压缩映象的粘滞迭代隐性算法.在自反的Banach空间框架下,基于迭代方法针对满足弱嵌入条件的连续伪压缩非自映象,建立了不动点序列的强收敛定理,并证明了该不动点恰为某一非线性变分不等式的唯一解.所得结果改进了Moudafi的含有压缩映象的粘滞迭代隐性算法,并把其空间框架从实Hilbert空间推广到了自反的实Banach空间. 展开更多
关键词 BANACH极限 非扩张映象 伪压缩 变分不等式
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A NEW ALGORITHM FOR MONOTONE INCLUSION PROBLEMS AND FIXED POINTS ON HADAMARD MANIFOLDS WITH APPLICATIONS
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作者 Shih-sen CHANG Jinfang TANG Chingfeng WEN 《Acta Mathematica Scientia》 SCIE CSCD 2021年第4期1250-1262,共13页
In this article,we propose a new algorithm and prove that the sequence generalized by the algorithm converges strongly to a common element of the set of fixed points for a quasi-pseudo-contractive mapping and a demi-c... In this article,we propose a new algorithm and prove that the sequence generalized by the algorithm converges strongly to a common element of the set of fixed points for a quasi-pseudo-contractive mapping and a demi-contraction mapping and the set of zeros of monotone inclusion problems on Hadamard manifolds.As applications,we use our results to study the minimization problems and equilibrium problems in Hadamard manifolds. 展开更多
关键词 Monotone inclusion problem quasi-pseudo-contractive mapping demi-contraction mapping maximal monotone vector field quasi-nonexpansive mappings Hadamard manifold
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偏序度量空间上ρ或σ-拟收缩的两个映射的公共不动点
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作者 朴勇杰 《重庆师范大学学报(自然科学版)》 CAS CSCD 北大核心 2018年第2期71-76,共6页
【目的】在偏序的度量空间上讨论两个映射的公共不动点的存在问题。【方法】研究在具有偏序的实度量空间上满足由两个实函数ρ和σ决定的拟收缩条件的两个映射的性质。【结果】得到了这两个映射在连续或非连续条件下具有唯一公共不动点... 【目的】在偏序的度量空间上讨论两个映射的公共不动点的存在问题。【方法】研究在具有偏序的实度量空间上满足由两个实函数ρ和σ决定的拟收缩条件的两个映射的性质。【结果】得到了这两个映射在连续或非连续条件下具有唯一公共不动点的存在定理,同时给出了不动点存在定理。【结论】所得结果推广和改进了已有文献中的相应结论。 展开更多
关键词 映射ρ 映射σ 拟收缩 公共不动点
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On Characterization of Iterative Approximation for Asymptotically Pseudocontractive Mappings
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作者 曾六川 《Journal of Mathematical Research and Exposition》 CSCD 北大核心 2005年第2期279-286,共8页
Let C be a nonempty bounded closed convex subset of a Banach space X, and T : C → C be uniformly L-Lipschitzian with L ≥ 1 and asymptotically pseudocontractive with a sequence {kn}(?)[1, ∞), limn→∞ kn = 1. Fix u ... Let C be a nonempty bounded closed convex subset of a Banach space X, and T : C → C be uniformly L-Lipschitzian with L ≥ 1 and asymptotically pseudocontractive with a sequence {kn}(?)[1, ∞), limn→∞ kn = 1. Fix u ∈ C. For each n ≥ 1, xn is a unique fixed point of the contraction Sn(x) = (1 - (tn)/(Lkn))u + (tn)/(Lkn)Tnx(?)x ∈ C, where {tn}(?)[0,1). Under suitable conditions, the strong convergence of the sequence{xn}to a fixed point of T is characterized. 展开更多
关键词 fixed point asymptotically pseudocontractive mapping uniform Lipschitzian mapping uniform normal structure Banach contraction principle.
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