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微分方程奇异摄动边界层问题的数值逼近解 被引量:2
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作者 余文波 《重庆师范大学学报(自然科学版)》 CAS 2009年第1期65-68,共4页
通过对抛物型偏微分方程和一阶双曲型偏微分方程奇异摄动问题的讨论,提出了在使边界层的特性不至于丧失的前提下的边界层格式。对一类在Ω1和Ω2上的抛物型奇异摄动的初、边值问题进行了进一步研究,利用渐近方法、差分方法和常微分方程... 通过对抛物型偏微分方程和一阶双曲型偏微分方程奇异摄动问题的讨论,提出了在使边界层的特性不至于丧失的前提下的边界层格式。对一类在Ω1和Ω2上的抛物型奇异摄动的初、边值问题进行了进一步研究,利用渐近方法、差分方法和常微分方程的二点边值问题的方法,求得了偏微分方程边界层问题的数值解。得到了当步长可取中等大小,h→0,τ→0,ε→0时,且当自由项函数和初、边值条件函数均为给定的充分光滑的函数,含有小参数ε(0<ε1)的一类偏微分方程奇异摄动问题的一致数值逼近解。并将此结论应用于实际问题中。 展开更多
关键词 抛物型 奇异摄动 边界层 数值逼近解
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The Degenerate Form of the Adomian Polynomials in the Power Series Method for Nonlinear Ordinary Differential Equations 被引量:2
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作者 Jun-Sheng Duan Randolph Rach 《Journal of Mathematics and System Science》 2015年第10期411-428,共18页
In this paper, we propose a new variation of the Adomian polynomials, which we call the degenerate Adomian polynomials, for the power series solutions of nonlinear ordinary differential equations with nonseparable non... In this paper, we propose a new variation of the Adomian polynomials, which we call the degenerate Adomian polynomials, for the power series solutions of nonlinear ordinary differential equations with nonseparable nonlinearities. We establish efficient algorithms for the degenerate Adomian polynomials. Next we compare the results by the Adomian decomposition method using the classic Adomian polynomials with the results by the Rach-Adomian-Meyers modified decomposition method incorporating the degenerate Adomian polynomials, which itself has been shown to be a confluence of the Adomian decomposition method and the power series method. Convergence acceleration techniques including the diagonal Pade approximants are considered, and new numeric algorithms for the multistage decomposition are deduced using the degenerate Adomian polynomials. Our new technique provides a significant advantage for automated calculations when computing the power series form of the solution for nonlinear ordinary differential equations. Several expository examples are investigated to demonstrate its reliability and efficiency. 展开更多
关键词 Power series method Adomian decomposition method Adomian polynomials Modified decomposition method Nonlinear differential equation
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Volterra Integral Equations and Some Nonlinear Integral Equations with Variable Limit of Integration as Generalized Moment Problems 被引量:1
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作者 Maria B. Pintarelli 《Journal of Mathematics and System Science》 2015年第1期32-38,共7页
In this paper we will see that, under certain conditions, the techniques of generalized moment problem will apply to numerically solve an Volterra integral equation of first kind or second kind. Volterra integral equa... In this paper we will see that, under certain conditions, the techniques of generalized moment problem will apply to numerically solve an Volterra integral equation of first kind or second kind. Volterra integral equation is transformed into a one-dimensional generalized moment problem, and shall apply the moment problem techniques to find a numerical approximation of the solution. Specifically you will see that solving the Volterra integral equation of first kind f(t) = {a^t K(t, s)x(s)ds a ≤ t ≤ b or solve the Volterra integral equation of the second kind x(t) =f(t)+{a^t K(t,s)x(s)ds a ≤ t ≤ b is equivalent to solving a generalized moment problem of the form un = {a^b gn(s)x(s)ds n = 0,1,2… This shall apply for to find the solution of an integrodifferential equation of the form x'(t) = f(t) + {a^t K(t,s)x(s)ds for a ≤ t ≤ b and x(a) = a0 Also considering the nonlinear integral equation: f(x)= {fa^x y(x-t)y(t)dt This integral equation is transformed a two-dimensional generalized moment problem. In all cases, we will find an approximated solution and bounds for the error of the estimated solution using the techniques ofgeneralized moment problem. 展开更多
关键词 Generalized moment problems solution stability Volterra integral equations nonlinear integral equations.
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Numerical Solution to Optimal Feedback Control by Dynamic Programming Approach:A Local Approximation Algorithm 被引量:3
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作者 GUO Bao-Zhu WU Tao-Tao 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2017年第4期782-802,共21页
This paper considers optimal feedback control for a general continuous time finite-dimensional deterministic system with finite horizon cost functional. A practically feasible algorithm to calculate the numerical solu... This paper considers optimal feedback control for a general continuous time finite-dimensional deterministic system with finite horizon cost functional. A practically feasible algorithm to calculate the numerical solution of the optimal feedback control by dynamic programming approach is developed. The highlights of this algorithm are: a) It is based on a convergent constructive algorithm for optimal feedback control law which was proposed by the authors before through an approximation for the viscosity solution of the time-space discretization scheme developed by dynamic programming method; b) The computation complexity is significantly reduced since only values of viscosity solution on some local cones around the optimal trajectory are calculated. Two numerical experiments are presented to illustrate the effectiveness and fastness of the algorithm. 展开更多
关键词 Curse of dimensionality Hamilton-Jacobi-Bellman equation optimal feedback control upwind finite difference viscosity solutions
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