期刊文献+
共找到261篇文章
< 1 2 14 >
每页显示 20 50 100
Evolutionary Safe Padé Approximation Scheme for Dynamical Study of Nonlinear Cervical Human Papilloma Virus Infection Model
1
作者 Javaid Ali Armando Ciancio +4 位作者 Kashif Ali Khan Nauman Raza Haci Mehmet Baskonus Muhammad Luqman Zafar-Ullah Khan 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第9期2275-2296,共22页
This study proposes a structure-preserving evolutionary framework to find a semi-analytical approximate solution for a nonlinear cervical cancer epidemic(CCE)model.The underlying CCE model lacks a closed-form exact so... This study proposes a structure-preserving evolutionary framework to find a semi-analytical approximate solution for a nonlinear cervical cancer epidemic(CCE)model.The underlying CCE model lacks a closed-form exact solution.Numerical solutions obtained through traditional finite difference schemes do not ensure the preservation of the model’s necessary properties,such as positivity,boundedness,and feasibility.Therefore,the development of structure-preserving semi-analytical approaches is always necessary.This research introduces an intelligently supervised computational paradigm to solve the underlying CCE model’s physical properties by formulating an equivalent unconstrained optimization problem.Singularity-free safe Padérational functions approximate the mathematical shape of state variables,while the model’s physical requirements are treated as problem constraints.The primary model of the governing differential equations is imposed to minimize the error between approximate solutions.An evolutionary algorithm,the Genetic Algorithm with Multi-Parent Crossover(GA-MPC),executes the optimization task.The resulting method is the Evolutionary Safe PadéApproximation(ESPA)scheme.The proof of unconditional convergence of the ESPA scheme on the CCE model is supported by numerical simulations.The performance of the ESPA scheme on the CCE model is thoroughly investigated by considering various orders of non-singular Padéapproximants. 展开更多
关键词 Nonlinear cervical cancer epidemic non-singular padéapproximants approximate solutions computational biology
下载PDF
A generalized Padé approximation method of solving homoclinic and heteroclinic orbits of strongly nonlinear autonomous oscillators 被引量:1
2
作者 李震波 唐驾时 蔡萍 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第12期78-84,共7页
An intrinsic extension of Pad′e approximation method, called the generalized Pad′e approximation method, is proposed based on the classic Pad′e approximation theorem. According to the proposed method, the numerator... An intrinsic extension of Pad′e approximation method, called the generalized Pad′e approximation method, is proposed based on the classic Pad′e approximation theorem. According to the proposed method, the numerator and denominator of Pad′e approximant are extended from polynomial functions to a series composed of any kind of function, which means that the generalized Pad′e approximant is not limited to some forms, but can be constructed in different forms in solving different problems. Thus, many existing modifications of Pad′e approximation method can be considered to be the special cases of the proposed method. For solving homoclinic and heteroclinic orbits of strongly nonlinear autonomous oscillators, two novel kinds of generalized Pad′e approximants are constructed. Then, some examples are given to show the validity of the present method. To show the accuracy of the method, all solutions obtained in this paper are compared with those of the Runge–Kutta method. 展开更多
关键词 generalized pad′e approximation method homoclinic and heteroclinic orbits strongly nonlinear oscillators
下载PDF
ORTHOGONAL POLYNOMIALS AND DETERMINANT FORMULAS OF FUNCTION-VALUED PADE-TYPE APPROXIMATION USING FOR SOLUTION OF INTEGRAL EQUATIONS 被引量:2
3
作者 顾传青 潘宝珍 吴蓓蓓 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2006年第6期853-860,共8页
To solve Fredholm integral equations of the second kind, a generalized linear functional is introduced and a new function-valued Padé-type approximation is defined. By means of the power series expansion of the s... To solve Fredholm integral equations of the second kind, a generalized linear functional is introduced and a new function-valued Padé-type approximation is defined. By means of the power series expansion of the solution, this method can construct an approximate solution to solve the given integral equation. On the basis of the orthogonal polynomials, two useful determinant expressions of the numerator polynomial and the denominator polynomial for Padé-type approximation are explicitly given. 展开更多
关键词 generalized linear functional function-valued padé-type approximation Fredholm integral equation orthogonal polynomial determinant formula
下载PDF
Degeneracy Cases of Generalized Inverse Function-Valued Padé Approximation 被引量:1
4
作者 潘宝珍 顾传青 《Journal of Shanghai University(English Edition)》 CAS 2004年第3期258-263,共6页
A new generalized inverse function-valued Padé approximation (GIFPA) was defined. Existence condition of GIFPA was given and its uniqueness theorem was proved. All possible degeneracy cases of GIFPA were discusse... A new generalized inverse function-valued Padé approximation (GIFPA) was defined. Existence condition of GIFPA was given and its uniqueness theorem was proved. All possible degeneracy cases of GIFPA were discussed and constructed. An example was given to illustrate its application. 展开更多
关键词 Generalized inverse function-valued padé approximation (GIFPA) degeneracy cases existence and uniqueness.
下载PDF
A Note on Pad Approximants Pairs as Limits of Algebraic Polynomials Pairs of Weighted Best Approximation in Orlicz Spaces
5
作者 F.E.Levis 《Analysis in Theory and Applications》 CSCD 2015年第3期253-259,共7页
In this short note, we show the behavior in Orlicz spaces of best approximations by algebraic polynomials pairs on union of neighborhoods, when the measure of them tends to zero.
关键词 Best approximation pair pad′e approximant pair Orlicz spaces.
下载PDF
Finite-dimensional approximation to global minimizers in functional spaces with R-convergence
6
作者 陈熙 姚奕荣 郑权 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2011年第1期107-118,共12页
A new concept of convergence (R-convergence) of a sequence of measures is applied to characterize global minimizers in a functional space as a sequence of approximate solutions in finite-dimensional spaces. A deviat... A new concept of convergence (R-convergence) of a sequence of measures is applied to characterize global minimizers in a functional space as a sequence of approximate solutions in finite-dimensional spaces. A deviation integral approach is used to find such solutions. For a constrained problem, a penalized deviation integral algorithm is proposed to convert it to unconstrained ones. A numerical example on an optimal control problem with non-convex state constraints is given to show the effectiveness of the algorithm. 展开更多
关键词 global optimization deviation integral variable measure R-convergence finite-dimensional approximation
下载PDF
Some Algebraic Properties of Generalized Inverse Matrix-Valued Padé Approximation
7
《Advances in Manufacturing》 SCIE CAS 2000年第4期275-278,共4页
关键词 MATH approximation pad Some Algebraic Properties of Generalized Inverse Matrix-Valued
下载PDF
Orthogonal Polynomials and Padé Approximation
8
作者 Faiz Ahmad (Department of Mathematics, Quaid i Azam University, Pakistan) 《Advances in Manufacturing》 SCIE CAS 1998年第2期24-27,共4页
The diagonal Padé approximants for exp ( x ), tan x and tanh x are obtained in a simple manner by using the property of Legendre polynomials that on P r1 (x) is orthogonal to every polynomial o... The diagonal Padé approximants for exp ( x ), tan x and tanh x are obtained in a simple manner by using the property of Legendre polynomials that on P r1 (x) is orthogonal to every polynomial of lower degree. Gauss's quadrature formula is used to find the denominators of some functions. 展开更多
关键词 orthogonal polynomials padé approximation
下载PDF
Function-valued partial Padé-type approximation method for estimating eigenvalues of Fredholm integral equation of the second kind
9
作者 顾传青 沈进东 《Journal of Shanghai University(English Edition)》 CAS 2007年第6期531-535,共5页
Abstract A new function-valued partial Padé-type approximation was introduced in the polynomial space, and an explicit determinant formula was derived by means of some orthogonal polynomials. This method can be a... Abstract A new function-valued partial Padé-type approximation was introduced in the polynomial space, and an explicit determinant formula was derived by means of some orthogonal polynomials. This method can be applied to estimating surplus eigenvalues of the Fredholm integral equation of the second kind when its partial eigenvalues have been known, and at the same time, it can be applied to solving the approximating solution of the given equation. 展开更多
关键词 linear functional function-valued partial padé approximation DETERMINANT Fredholm integral equation of thesecond kind eigenvalue.
下载PDF
EPSILON-ALGORITHM AND ETA-ALGORITHM OF GENERALIZED INVERSE FUNCTION-VALUED PAD APPROXIMANTS USING FOR SOLUTION OF INTEGRAL EQUATIONS 被引量:1
10
作者 李春景 顾传青 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2003年第2期221-229,共9页
Two efficient recursive algorithms epsilon_algorithm and eta_algorithm are introduced to compute the generalized inverse function_valued Padé approximants. The approximants were used to accelerate the convergenc... Two efficient recursive algorithms epsilon_algorithm and eta_algorithm are introduced to compute the generalized inverse function_valued Padé approximants. The approximants were used to accelerate the convergence of the power series with function_valued coefficients and to estimate characteristic value of the integral equations. Famous Wynn identities of the Pad approximants is also established by means of the connection of two algorithms. 展开更多
关键词 generalized inverse function_valued padé approximant epsilon_algorithm eta_algorithm integral equations
下载PDF
The Successive Approximation Broyden-like Algorithm for Nonlinear Complementarity Problems 被引量:1
11
作者 MAChang-feng LIANGGuo-ping 《Chinese Quarterly Journal of Mathematics》 CSCD 2003年第2期146-153,共8页
In this paper, we present a new form of successive approximation Broyden-like algorithm for nonlinear complementarity problem based on its equivalent nonsmooth equations. Under suitable conditions, we get the global c... In this paper, we present a new form of successive approximation Broyden-like algorithm for nonlinear complementarity problem based on its equivalent nonsmooth equations. Under suitable conditions, we get the global convergence on the algorithms. Some numerical results are also reported. 展开更多
关键词 nonlinear complementarity problem successive approximation Broyden-like algorithm global convergence
下载PDF
A Pfaffian Formula of the Generalized Inverse Function-Valued Padé Approximant Used in Solving Integral Equations
12
作者 李春景 顾传青 《Journal of Shanghai University(English Edition)》 CAS 2003年第4期318-321,共4页
The generalized inverse function-valued Padé approximant was defined to solve the integral equations. However, it is difficult to compute the approximants by some high-order determinant formulas. In this paper, t... The generalized inverse function-valued Padé approximant was defined to solve the integral equations. However, it is difficult to compute the approximants by some high-order determinant formulas. In this paper, to simplify computation of the function-valued Padé approximants, an efficient Pfaffian formula for the determinants was extended from the matrix form to the function-valued form. As an important application, a Pfaffian formula of [4/4] type Padé approximant was established. 展开更多
关键词 padé approximant DETERMINANT Pfaffian formula integral equation.
下载PDF
Distribution of Points of Interpolation and of Zeros of Exactly Maximally Convergent Multipoint Pad&eacute;Approximants
13
作者 R. K. Kovacheva 《Applied Mathematics》 2015年第5期737-744,共8页
Given a regular compact set E in , a unit measure μ supported by , a triangular point set , and a function f , holomorphic on E , let πβ,fn,m be the associated multipoint β-Padé approximant of order (n,m) . W... Given a regular compact set E in , a unit measure μ supported by , a triangular point set , and a function f , holomorphic on E , let πβ,fn,m be the associated multipoint β-Padé approximant of order (n,m) . We show that if the sequence πβ,fn,m , n∈Λ , ∧∈n,k are uniformly distributed on with respect to u as n∈Λ . Furthermore, a result about the behavior of the zeros of the exact maximally convergent sequence Λ is provided, under the condition that Λ is “dense enough”. 展开更多
关键词 Multipoint padé approximANTS Maximal Convergence Domain of m-Meromorphy
下载PDF
A New Class of Vector PadéApproximants in the Asymptotic Numerical Method: Application in Nonlinear 2D Elasticity
14
作者 Abdellah Hamdaoui Rachida Hihi +2 位作者 Bouazza Braikat Noureddine Tounsi Noureddine Damil 《World Journal of Mechanics》 2014年第2期44-53,共10页
The Asymptotic Numerical Method (ANM) is a family of algorithms for path following problems, where each step is based on the computation of truncated vector series [1]. The Vector Padé approximants were introduce... The Asymptotic Numerical Method (ANM) is a family of algorithms for path following problems, where each step is based on the computation of truncated vector series [1]. The Vector Padé approximants were introduced in the ANM to improve the domain of validity of vector series and to reduce the number of steps needed to obtain the entire solution path [1,2]. In this paper and in the framework of the ANM, we define and build a new type of Vector Padé approximant from a truncated vector series by extending the definition of the Padé approximant of a scalar series without any orthonormalization procedure. By this way, we define a new class of Vector Padé approximants which can be used to extend the domain of validity in the ANM algorithms. There is a connection between this type of Vector Padé approximant and Vector Padé type approximant introduced in [3, 4]. We show also that the Vector Padé approximants introduced in the previous works [1,2], are special cases of this class. Applications in 2D nonlinear elasticity are presented. 展开更多
关键词 VECTOR padé approximANTS ASYMPTOTIC Numerical Method NONLINEAR ELASTICITY
下载PDF
结构静态拓扑重分析的摄动-Padé逼近法 被引量:4
15
作者 黄海 陈塑寰 +1 位作者 孟光 郭克尖 《固体力学学报》 CAS CSCD 北大核心 2005年第3期321-324,共4页
提出一种拓扑修改的静态重分析的方法.该方法将所有新增加的自由度分步、逐次得增加到原结构上.在每一子步中利用过渡矩阵得到摄动基,并对摄动基进行正交化处理来进行Padé逼近,得到的近似解作为下一子步的原始解.循环结束时得到修... 提出一种拓扑修改的静态重分析的方法.该方法将所有新增加的自由度分步、逐次得增加到原结构上.在每一子步中利用过渡矩阵得到摄动基,并对摄动基进行正交化处理来进行Padé逼近,得到的近似解作为下一子步的原始解.循环结束时得到修改结构的近似解. 展开更多
关键词 拓扑修改 结构重分析 矩阵摄动pad6逼进 自由度递增 重分析 摄动 结构 逼近法 padE逼近 过渡矩阵
下载PDF
类Pade逼近方法在二维非线性振动系统的应用 被引量:8
16
作者 张琪昌 冯晶晶 王炜 《力学学报》 EI CSCD 北大核心 2011年第5期914-921,共8页
提出一种求解强非线性系统同异宿轨道解析解的改进类Pade逼近方法,该方法在分析带有扰动参数的系统时无需预先限定参数的取值范围.首先研究了具有三次非线性项的系统,分析其产生同宿或异宿轨道时参数的取值范围,分别提出直接体现参数的... 提出一种求解强非线性系统同异宿轨道解析解的改进类Pade逼近方法,该方法在分析带有扰动参数的系统时无需预先限定参数的取值范围.首先研究了具有三次非线性项的系统,分析其产生同宿或异宿轨道时参数的取值范围,分别提出直接体现参数的同宿及异宿解的设解通式,据此获得了一类强非线性下的自治系统方程的同宿及异宿解.其次,对于非自治系统,研究了具有三次非线性项系统的强迫振动,直接考虑扰动参数对整个系统的影响,得到了满足同(异)宿边界条件的周期解.最后,构造了两种不同形式的异宿解,从而减少了保守系统异宿解的计算量.借助数值模拟验证了该方法的有效性及精确性. 展开更多
关键词 pade逼近法 同异宿轨道 全局分岔 强非线性
下载PDF
深海超低频WKB反转简正波模型
17
作者 朴胜春 詹建康 《声学学报》 EI CAS CSCD 北大核心 2024年第4期784-802,共19页
提出了一种基于抛物柱函数的深海超低频WKB反转简正波模型。采用比较方程法,选择形式解为抛物柱函数的映射方程,给出了典型深海声速剖面情况下简正波方程的抛物柱函数WKB近似解和近似条件。数值分析了Epstein声速剖面环境下简正波本征... 提出了一种基于抛物柱函数的深海超低频WKB反转简正波模型。采用比较方程法,选择形式解为抛物柱函数的映射方程,给出了典型深海声速剖面情况下简正波方程的抛物柱函数WKB近似解和近似条件。数值分析了Epstein声速剖面环境下简正波本征函数的全局近似误差,求解了Munk声速剖面环境下的简正波声场。结果表明,所提方法与经典WKB近似方法和Langer变换方法相比全局近似误差更小,并且可将海水层看成一个整体,适用于求解深海超低频声传播问题。 展开更多
关键词 简正波模型 WKB近似 抛物柱函数 全局近似误差
下载PDF
集值向量拟均衡问题的Global近似对偶 被引量:6
18
作者 孟旭东 邓中书 龚循华 《南昌大学学报(理科版)》 CAS 北大核心 2016年第6期524-527,共4页
在适当条件下,研究集值向量拟均衡问题的Global近似对偶。首先引入了具Global有效性集值向量拟均衡问题及其对偶问题,然后借助于凸集拟内部的概念,讨论了集值向量拟均衡问题的ε-Global有效解与其对偶问题的ε-Global有效解之间的关系,... 在适当条件下,研究集值向量拟均衡问题的Global近似对偶。首先引入了具Global有效性集值向量拟均衡问题及其对偶问题,然后借助于凸集拟内部的概念,讨论了集值向量拟均衡问题的ε-Global有效解与其对偶问题的ε-Global有效解之间的关系,得到了集值向量拟均衡问题的对偶定理。 展开更多
关键词 集值向量拟均衡问题 global近似对偶 拟内部 集值映射
下载PDF
Pad逼近求解抛物型偏微分方程的并行算法研究 被引量:1
19
作者 李红云 沈为平 《计算力学学报》 CAS CSCD 2000年第4期428-434,共7页
一维抛物型偏微分方程可以用精细积分方法精确求解。当精细积分中的矩阵指数函数用Pad 逼近来代替时 ,可以得到一系列由简到繁、精度由低到高的差分格式 ,因而便于根据实际需要进行选取。常见的求解抛物型方程的差分格式如古典显式格式... 一维抛物型偏微分方程可以用精细积分方法精确求解。当精细积分中的矩阵指数函数用Pad 逼近来代替时 ,可以得到一系列由简到繁、精度由低到高的差分格式 ,因而便于根据实际需要进行选取。常见的求解抛物型方程的差分格式如古典显式格式、隐式格式及六点差分格式为其中的特例。Pad 逼近格式主要包括矩阵运算和线性方程组求解。本文利用 Pad 逼近格式对应的方程组系数矩阵为带状矩阵的特点 ,把原来在整个区域上求解的问题转化为分区域求解 ,在 TRANSPUTER并行机上实现了该问题的并行算法 ,并对该并行算法的时间复杂度进行了分析。算例结果表明 Pad 逼近并行算法有很好的计算效果和并行效率。 展开更多
关键词 抛物型偏微分方程 padE逼近 并行算法 时间复杂度
下载PDF
基于时域近似法的CLLC谐振变换器参数设计
20
作者 王国盛 刘胜永 罗慧友 《广西科技大学学报》 CAS 2024年第1期62-69,共8页
针对现行主流的基波分析法在电压增益计算时准确度较差,以及传统的谐振参数设计方法在对电池这类非阻性电源负载时存在参数难以确定的问题,提出基于时域近似法的CLLC谐振参数计算,解决了电压增益精确度和参数选取困难的问题。首先建立... 针对现行主流的基波分析法在电压增益计算时准确度较差,以及传统的谐振参数设计方法在对电池这类非阻性电源负载时存在参数难以确定的问题,提出基于时域近似法的CLLC谐振参数计算,解决了电压增益精确度和参数选取困难的问题。首先建立变换器的P、N、O等3种模态的时域方程,通过对运行时主要工作模式中PO、PN波形的简化,求出对应模式的电压增益公式,以电压增益范围和全局软开关的实现作为参数选取的约束条件,求出具体的谐振网络参数;然后利用MATLAB搭建仿真实验模型,实现全局软开关和电压增益要求,在谐振频率下工作效率均在95%以上。仿真实验结果验证了所提设计方法的可行性。 展开更多
关键词 CLLC谐振变换器 谐振网络参数 时域近似法 全局软开关
下载PDF
上一页 1 2 14 下一页 到第
使用帮助 返回顶部