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差分演化的收敛性分析与算法改进 被引量:68
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作者 贺毅朝 王熙照 +1 位作者 刘坤起 王彦祺 《软件学报》 EI CSCD 北大核心 2010年第5期875-885,共11页
为了分析差分演化(differential evolution,简称DE)的收敛性并改善其算法性能,首先将差分算子(differential operator,简称DO)定义为解空间到解空间的笛卡尔积的一种随机映射,利用随机泛函理论中的随机压缩映射原理证明了DE的渐近收敛性... 为了分析差分演化(differential evolution,简称DE)的收敛性并改善其算法性能,首先将差分算子(differential operator,简称DO)定义为解空间到解空间的笛卡尔积的一种随机映射,利用随机泛函理论中的随机压缩映射原理证明了DE的渐近收敛性;然后,在"拟物拟人算法"的启发下,通过对DE各进化模式的共性特征与性能差异的分析,提出了一种具有多进化模式协作的差分演化算法(differential evolution with multi-strategy cooperating evolution,简称MEDE),分析了它所具有的隐含特性,并在多模式差分算子(multi-strategy differential operator,简称MDO)定义的基础上证明了它的渐进收敛性.对5个经典测试函数的仿真计算结果表明,与原始的DE,DEfirDE和DEfirSPX等算法相比,MEDE算法在求解质量、适应性和鲁棒性方面均具有较明显的优势,非常适于求解复杂高维函数的数值最优化问题. 展开更多
关键词 差分演化 渐近收敛性 压缩映射 随机算子 进化模式
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第Ⅱ、Ⅲ型膨胀映射的不动点定理 被引量:8
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作者 何松年 《中国民航学院学报》 2004年第5期50-51,54,共3页
3种膨胀映射的定义及其相应的不动点定理是由王尚志等首先提出和建立的。之后,何松年对第一型膨胀映射的不动点定理做了进一步讨论,现报道膨胀映射不动点定理研究工作的继续和深入,着重进一步研究第二型和第三型膨胀映射的不动点定理,... 3种膨胀映射的定义及其相应的不动点定理是由王尚志等首先提出和建立的。之后,何松年对第一型膨胀映射的不动点定理做了进一步讨论,现报道膨胀映射不动点定理研究工作的继续和深入,着重进一步研究第二型和第三型膨胀映射的不动点定理,给出了两个理论上更深刻、应用上更方便的新结果。 展开更多
关键词 压缩映射 膨胀映射 完备度量空间 不动点
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各向异性介质空间—波数混合域直流电阻率法三维数值模拟研究 被引量:3
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作者 戴世坤 凌嘉宣 +2 位作者 陈轻蕊 张莹 李昆 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2022年第7期2729-2740,共12页
将各向异性介质分成各向同性背景介质和各向异性异常介质,并提出一种空间-波数混合域方法实现了各向异性介质下直流电阻率法的三维数值模拟.不同于传统直流电阻率数值模拟方法,本文算法直接对空间域异常电位满足的偏微分方程沿水平方向... 将各向异性介质分成各向同性背景介质和各向异性异常介质,并提出一种空间-波数混合域方法实现了各向异性介质下直流电阻率法的三维数值模拟.不同于传统直流电阻率数值模拟方法,本文算法直接对空间域异常电位满足的偏微分方程沿水平方向进行二维傅里叶变换,使水平方向转换成波数域,保留垂直方向为空间域,可根据地下介质电流密度变化的快慢灵活剖分.这样可把空间域异常电位满足的三维偏微分方程转化成不同波数满足的一维常微分方程,把一个大规模三维数值模拟问题分解为多个一维数值模拟问题,利用一维有限单元法求解方程组,并通过采用压缩算子迭代计算,最终获得较为精确的数值解.与自适应有限单元法对比验证了本文算法的正确性;测试了算法的收敛性,结果表明在满足精度要求的情况下,算法的收敛性只与异常体和围岩之间的电导率差异相关,而与异常体大小和埋深无关;分析了算法计算效率,结果表明算法的计算效率与剖分网格节点成线性关系,算法可在微型计算机中较快计算出剖分节点总数超过千万的各向异性模型的结果;设计简单观测系统并验证其具有反映地下各向异性结构特性的能力;最后模拟异常体沿着不同方向旋转不同角度时的响应特征,对比分析可知异常体为各向异性情况下,沿不同方向旋转相同角度或沿同一个方向旋转不同角度,在同一个位置上测量得到的视电阻率有差异. 展开更多
关键词 空间波数混合域 二维正反傅里叶变换 有限单元法 压缩算子
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一种膨胀映射的不动点定理 被引量:2
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作者 何松年 《中国民航学院学报》 2003年第4期59-60,64,共3页
王尚志给出了若干种膨胀映射的概念,并证明了它们的不动点存在定理。对其中第一型膨胀映射的不动点定理做了进一步推广。
关键词 压缩映射 膨胀映射 完备度量空间 不动点
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MEAN VALUE OF ANALYTIC OPERATOR FUNCTIONS
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作者 喻小培 蹇明 《Acta Mathematica Scientia》 SCIE CSCD 1995年第4期468-473,共6页
In this paper, it is proved that if A is a normal proper contraction on Hilbert space H and F(z) = U(z) + iV(z) is operator-valued analytic on the unit disc Delta and 0 < p < 1, then parallel to F(A)parallel to(... In this paper, it is proved that if A is a normal proper contraction on Hilbert space H and F(z) = U(z) + iV(z) is operator-valued analytic on the unit disc Delta and 0 < p < 1, then parallel to F(A)parallel to(p) less than or equal to parallel to F(0)parallel to(p) + C-p (1 - parallel to A parallel to)(-2) [GRAPHICS] 展开更多
关键词 Hilbert space operator operator-valued function proper contraction
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Dissipative Properties of ω-Order Preserving Partial Contraction Mapping in Semigroup of Linear Operator
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作者 Akinola Yussuff Akinyele Kamilu Rauf +1 位作者 Aasa Moses Adebowale Omosowon Jude Babatunde 《Advances in Pure Mathematics》 2019年第6期544-550,共7页
This paper consists of dissipative properties and results of dissipation on infinitesimal generator of a C0-semigroup of ω-order preserving partial contraction mapping (ω-OCPn) in semigroup of linear operator. The p... This paper consists of dissipative properties and results of dissipation on infinitesimal generator of a C0-semigroup of ω-order preserving partial contraction mapping (ω-OCPn) in semigroup of linear operator. The purpose of this paper is to establish some dissipative properties on ω-OCPn which have been obtained in the various theorems (research results) and were proved. 展开更多
关键词 SEMIGROUP Linear operator DISSIPATIVE operator contraction Mapping and RESOLVENT
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带耗散项的广义BBM方程Cauchy问题 被引量:2
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作者 张卫国 韩效宥 《应用数学》 CSCD 北大核心 1991年第3期63-70,共8页
本文证明了带耗散项的广义BBM方程Cauchy问题■在C([0,∞),H^s(R))(s≥2)中解的存在性和唯一性,并证明了解在‖·‖_■范数意义下的稳定性.
关键词 BBM方程 耗散项 压缩算子 整体解
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I.I.D.STATISTICAL CONTRACTION OPERATORS AND STATISTICALLY SELF-SIMILAR SETS 被引量:2
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作者 HU DIHECollege of Mathematics and statistics, Wuhan University, Wuhan 430072, China. E-mail: dhhu@whu.edu.cn. 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2002年第4期461-468,共8页
I.i.d. random sequence is the simplest but very basic one in stochastic processes, and statistically self-similar set is the simplest but very basic one in random recursive sets in the theory of random fractal. Is the... I.i.d. random sequence is the simplest but very basic one in stochastic processes, and statistically self-similar set is the simplest but very basic one in random recursive sets in the theory of random fractal. Is there any relation between i.i.d. random sequence and statistically self-similar set? This paper gives a basic theorem which tells us that the random recursive set generated by a collection of i.i.d. statistical contraction operators is always a statistically self-similar set. 展开更多
关键词 Hausdorff metric Statistical contraction operator Statistically self-similar set Statistically self-similar measure
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Cahn─Hilliard方程的近似惯性流形 被引量:2
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作者 王碧祥 王守田 《兰州大学学报(自然科学版)》 CAS CSCD 北大核心 1994年第3期1-5,共5页
本文讨论Cahn-Hilliard方程解的长时间行为,通过压缩映象原理,对该方程构造了一个逼近惯性流形。
关键词 逼近惯性流形 C-H方程 偏微分方程
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On Hyperinvariant Subspaces of Contraction Operators on a Banach Space Whose Spectrum Contains the Unit Circle
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作者 Ming Xue LIU Department of Mathematics Guangdong Polytechnic Normal University Guangzhou 510665 P. R. China 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2008年第9期1471-1474,共4页
In this paper, we prove that every operator in a class of contraction operators on a Banach space whose spectrum contains the unit circle has a nontrivial hyperinvariant subspace.
关键词 Banach space contraction operator invariant subspace
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DIFFERENTIAL INEQUALITIES OF OPERATOR-VALUED ANALYTIC FUNCTIONS
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作者 蹇明 《Acta Mathematica Scientia》 SCIE CSCD 2001年第2期166-170,共5页
Some differential inequalities and integral inequalities for operator-valued an- alytic functions are investigated.
关键词 Proper contraction operator-valued analytic function differential inequality integral inequality
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A Study of Banach Fixed Point Theorem and It’s Applications
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作者 Md. Abdul Mannan Md. R. Rahman +2 位作者 Halima Akter Nazmun Nahar Samiran Mondal 《American Journal of Computational Mathematics》 2021年第2期157-174,共18页
This paper aims at treating a study of Banach fixed point theorem for mapping results that introduced in the setting of normed space. The classical Banach fixed point theorem is a generalization of this work. A fixed ... This paper aims at treating a study of Banach fixed point theorem for mapping results that introduced in the setting of normed space. The classical Banach fixed point theorem is a generalization of this work. A fixed point theory is a beautiful mixture of Mathematical analysis to explain some conditions in which maps give excellent solutions. Here later many mathematicians used this fixed point theory to establish their results, see for instance, Picard-Lindel of Theorem, The Picard theorem, Implicit function theorem etc. Also, we developed ideas that many of known fixed point theorems can easily be derived from the Banach theorem. It extends some recent works on the extension of Banach contraction principle to metric space with norm spaces. 展开更多
关键词 Metric Space Norm Space Complete Norm Space operator Banach Fixed Point Theorem UNIFORMITY Strong and Weak contraction SEMI-CONTINUOUS
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Viscosity Approximations by Generalized Contractions for Resolvents of Accretive Operators in Banach Spaces
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作者 Adrian PETRUSEL Jen-Chih YAO 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2009年第4期553-564,共12页
In this paper, we prove a strong convergence theorem for resolvents of accretive operators in a Banach space by the viscosity approximation method with a generalized contraction mapping. The proximal point algorithm i... In this paper, we prove a strong convergence theorem for resolvents of accretive operators in a Banach space by the viscosity approximation method with a generalized contraction mapping. The proximal point algorithm in a Banach space is also considered. The results extend some very recent theorems of W. Takahashi. 展开更多
关键词 viscosity approximation method accretive operator generalized contraction resolvent proximal point algorithm
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Free C *- algebras and the problem of uniqueness of extension in non-commutative Hahn-Banach Theorem
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作者 Zhang, LC Ma, JP 《Chinese Science Bulletin》 SCIE EI CAS 1997年第13期1076-1079,共4页
1 Introduction and main resultsARVESON in ref. [1] generalized the classical Hahn-Banach Extension Theorem for linear func-tionals to the self-adjoint linear closed subspace of C~* -algebras. From then on numerous au-... 1 Introduction and main resultsARVESON in ref. [1] generalized the classical Hahn-Banach Extension Theorem for linear func-tionals to the self-adjoint linear closed subspace of C~* -algebras. From then on numerous au-thors have given various generalizations of the non-commutative Hahn-Banach-Arveson Theo-rem of ref. [1]. The following extension theorem is due to G. Wittstock. 展开更多
关键词 Free C* -algebras complete contraction HEREDITARY C* -subalgebras operator spaces.
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正算子补问题中的几个性质
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作者 裴君莹 杜鸿科 《陕西师大学报(自然科学版)》 CSCD 北大核心 1997年第1期121-122,共2页
正算子补问题中的几个性质裴君莹杜鸿科(陕西师范大学数学系,西安710062;第一作者,女,24岁,硕士研究生)设H1,H2是两个Hilbert空间,B(H1,H2)表示所有由H1到H2的有界线性算子全体之集.若H1=... 正算子补问题中的几个性质裴君莹杜鸿科(陕西师范大学数学系,西安710062;第一作者,女,24岁,硕士研究生)设H1,H2是两个Hilbert空间,B(H1,H2)表示所有由H1到H2的有界线性算子全体之集.若H1=H2=H,则B(H1,H2)记为B... 展开更多
关键词 希尔伯特空间 正算子补问题 线性算子
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保测线性算子的一个注记 被引量:1
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作者 郭新伟 《东北师大学报(自然科学版)》 CAS CSCD 北大核心 2001年第1期11-15,共5页
研究了复的可分Lebesgue空间Lp(S ,∑ ,μ)上保测线性算子的谱性质 ,证明了在 1≤p≤ 2条件下 ,若m是关于T不变的非退化的Gauss测度 ,那么T的旋转特征向量全体张成全空间Lp(S ,∑ ,μ) .
关键词 不变测度 GAUSS测度 特征算子 可缩算子 旋转特征向量 线性算子
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自收缩性的演化算法及其在布局优化问题中的应用 被引量:1
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作者 李景治 康立山 陈毓屏 《计算机工程与应用》 CSCD 北大核心 2003年第10期85-89,96,共6页
布局优化问题是现代工程应用中广泛存在的一类组合优化问题,但在理论上它却属于NPC(NP-Complete)问题,如果需考虑性能约束,则问题将更难于求解。论文基于演化算法自适应,自组织,自学习的特性,针对布局优化问题自身的特点,提出了一种自... 布局优化问题是现代工程应用中广泛存在的一类组合优化问题,但在理论上它却属于NPC(NP-Complete)问题,如果需考虑性能约束,则问题将更难于求解。论文基于演化算法自适应,自组织,自学习的特性,针对布局优化问题自身的特点,提出了一种自收缩性的演化算法(SCEA)。该算法采用浮点编码方式,定义了二元实向量类型的适应值及适应值间的严格偏序关系。算法借鉴日常生活中的一个简单事实—振动容器则装物更多,引入了三类自适应性的收缩算子(其中第三类特别适用于带性能约束的布局优化问题)。此外,文中使用了对带约束的函数优化问题特别有效的多父体杂交算子,并且针对带性能约束的布局优化问题,提出了“零性能约束初始化”过程。文后,引用了两个带性能约束的布局优化问题的已知例子和一个作者构造的较大规模布局优化问题的例子,实验结果表明,前两个问题对比目前已知最好结果无论在求解时间或结果的精度上均有较大突破,后一个问题也获得了相当好的结果,从而充分验证了算法的有效性和可行性。 展开更多
关键词 自收缩性 演化算法 组合优化问题 布局优化问题
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Numerical modeling of 3D DC resistivity method in the mixed space-wavenumber domain 被引量:1
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作者 Dai Shi-Kun Ling Jia-Xuan +4 位作者 Chen Qing-Rui Li Kun Zhang Qian-Jiang Zhao Dong-Dong Zhang Ying 《Applied Geophysics》 SCIE CSCD 2021年第3期361-374,432,433,共16页
Forward modeling is the basis of inversion imaging and quantitative interpretation for DC resistivity exploration.Currently,a numerical model of the DC resistivity method must be finely divided to obtain a highly accu... Forward modeling is the basis of inversion imaging and quantitative interpretation for DC resistivity exploration.Currently,a numerical model of the DC resistivity method must be finely divided to obtain a highly accurate solution under complex conditions,resulting in a long calculation time and large storage.Therefore,we propose a 3D numerical simulation method in a mixed space-wavenumber domain to overcome this challenge.The partial differential equation about abnormal potential is transformed into many independent ordinary differential equations with different wavenumbers using a 2D Fourier transform along the x axis and y axis direction.In this way,a large-scale 3D numerical simulation problem is decomposed into several 1D numerical simulation problems,which significantly reduces the computational and storage requirements.In addition,these ordinary 1D differential equations with different wavenumbers are independent of each other and high parallelelism of the algorithm.They are solved using a finite-element algorithm combined with a chasing method,and the obtained solution is modified using a contraction operator.In this method,the vertical direction is reserved as the spatial domain,then grid size can be determined flexibly based on the underground current density distribution,which considers the solution accuracy and calculation efficiency.In addition,for the first time,we use the contraction operator in the integral equation method to iterate the algorithm.The algorithm takes advantage of the high efficiency of the standard Fourier transform and chasing method,as well as the fast convergence of the contraction operator.We verified the accuracy of the algorithm and the convergence of the contraction operator.Compared with a volume integral method and goal-oriented adaptive finite-element method,the proposed algorithm has lower memory requirements and high computational efficiency,making it suitable for calculating a model with large-scale nodes.Moreover,different examples are used to verify the high adaptab 展开更多
关键词 3D DC numerical simulation a mixed space-wavenumber domain 2D Fourier transform contraction operator
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关于算子谱集理论中的Von Neumann不等式的研究
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作者 王刚 程正兴 《西安交通大学学报》 EI CAS CSCD 北大核心 2004年第4期436-438,共3页
首先,应用泛函分析的基本理论给出关于压缩算子的VonNeumann不等式的一个证明.其次,构造了一个Hermitian代数,并说明其中VonNeumann不等式不必成立.再次,应用KyFan的结果把解析函数论中几个简单而重要的结论转化到Hilbert空间算子函数上来.
关键词 Von Neumann不等式 压缩算子 Riesz—Dunford积分 正规算子 酉算子
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压缩算子与等距算子的拟相似
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作者 严子锟 《福建师范大学学报(自然科学版)》 CAS CSCD 1995年第1期19-22,共4页
本文给出了压缩算子与酉算子(非酉等距算子)拟相似有相同本质谱的充要条件,并且证明了亚正常算子与等距算子如果稠相似必有相同的本质谱。
关键词 压缩算子 等距算子 拟相似 本质谱
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