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THE REGULARIZED SOLUTION APPROXIMATION OF FORWARD/BACKWARD PROBLEMS FOR A FRACTIONAL PSEUDO-PARABOLIC EQUATION WITH RANDOM NOISE
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作者 狄华斐 容伟杰 《Acta Mathematica Scientia》 SCIE CSCD 2023年第1期324-348,共25页
This paper deals with the forward and backward problems for the nonlinear fractional pseudo-parabolic equation ut+(-Δ)^(s1)ut+β(-Δ)^(s2)u=F(u,x,t)subject o random Gaussian white noise for initial and final data.Und... This paper deals with the forward and backward problems for the nonlinear fractional pseudo-parabolic equation ut+(-Δ)^(s1)ut+β(-Δ)^(s2)u=F(u,x,t)subject o random Gaussian white noise for initial and final data.Under the suitable assumptions s1,s2andβ,we first show the ill-posedness of mild solutions for forward and backward problems in the sense of Hadamard,which are mainly driven by random noise.Moreover,we propose the Fourier truncation method for stabilizing the above ill-posed problems.We derive an error estimate between the exact solution and its regularized solution in an E‖·‖Hs22norm,and give some numerical examples illustrating the effect of above method. 展开更多
关键词 regularized solution approximation forward/backward problems fractional Laplacian Gaussian white noise Fourier truncation method
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APPROXIMATION ANALYSES FOR FUZZY VALUED FUNCTIONS IN L_1(μ)-NORM BY REGULAR FUZZY NEURAL NETWORKS 被引量:4
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作者 Liu Puyin (Dept. of System Eng. and Math., National Univ. of Defence Tech., Changsha 410073) 《Journal of Electronics(China)》 2000年第2期132-138,共7页
By defining fuzzy valued simple functions and giving L1(μ) approximations of fuzzy valued integrably bounded functions by such simple functions, the paper analyses by L1(μ)-norm the approximation capability of four-... By defining fuzzy valued simple functions and giving L1(μ) approximations of fuzzy valued integrably bounded functions by such simple functions, the paper analyses by L1(μ)-norm the approximation capability of four-layer feedforward regular fuzzy neural networks to the fuzzy valued integrably bounded function F : Rn → FcO(R). That is, if the transfer functionσ: R→R is non-polynomial and integrable function on each finite interval, F may be innorm approximated by fuzzy valued functions defined as to anydegree of accuracy. Finally some real examples demonstrate the conclusions. 展开更多
关键词 FUZZY VALUED simple function regular FUZZY neural network L1(μ) approximation Universal approximator
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APPROXIMATION CAPABILITIES OF MULTILAYER FEEDFORWARD REGULAR FUZZY NEURAL NETWORKS 被引量:2
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作者 Liu PuyinDept. of Math., National Univ. of Defence Technology,Changsha 410073 Dept. of Math., Beijing Normal Univ.,Beijing 100875. 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2001年第1期45-57,共13页
Four layer feedforward regular fuzzy neural networks are constructed. Universal approximations to some continuous fuzzy functions defined on F 0 (R) n by the four layer fuzzy neural networks are shown. At f... Four layer feedforward regular fuzzy neural networks are constructed. Universal approximations to some continuous fuzzy functions defined on F 0 (R) n by the four layer fuzzy neural networks are shown. At first,multivariate Bernstein polynomials associated with fuzzy valued functions are empolyed to approximate continuous fuzzy valued functions defined on each compact set of R n . Secondly,by introducing cut preserving fuzzy mapping,the equivalent conditions for continuous fuzzy functions that can be arbitrarily closely approximated by regular fuzzy neural networks are shown. Finally a few of sufficient and necessary conditions for characterizing approximation capabilities of regular fuzzy neural networks are obtained. And some concrete fuzzy functions demonstrate our conclusions. 展开更多
关键词 regular fuzzy neural networks CUT preserving fuzzy mappings universal approximators fuzzy valued Bernstein polynomials.
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PARTIAL REGULARITY FOR STATIONARY NAVIER-STOKES SYSTEMS BY THE METHOD OF A-HARMONIC APPROXIMATION
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作者 Yichen DAI Zhong TAN 《Acta Mathematica Scientia》 SCIE CSCD 2020年第3期835-854,共20页
In this article,we prove a regularity result for weak solutions away from singular set of stationary Navier-Stokes systems with subquadratic growth under controllable growth condition.The proof is based on the A-harmo... In this article,we prove a regularity result for weak solutions away from singular set of stationary Navier-Stokes systems with subquadratic growth under controllable growth condition.The proof is based on the A-harmonic approximation technique.In this article,we extend the result of Shuhong Chen and Zhong Tan[7]and Giaquinta and Modica[18]to the stationary Navier-Stokes system with subquadratic growth. 展开更多
关键词 Stationary Navier-Stokes systems controllable growth condition partial regularity A-harmonic approximation
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Three-dimensional magnetotelluric regularized inversion based on smoothness-constrained model
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作者 童孝忠 柳建新 +2 位作者 郭荣文 刘海飞 龚露 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第2期509-513,共5页
How to get the rapid and stable inversion results and reconstruct the clear subsurface resistivity structures is a focus problem in current magnetotelluric inversion. A stable solution of an ill-posed inverse problem ... How to get the rapid and stable inversion results and reconstruct the clear subsurface resistivity structures is a focus problem in current magnetotelluric inversion. A stable solution of an ill-posed inverse problem was obtained by the regularization methods in which some desired structures were imposed to stabilize the inverse problem. By the smoothness-constrained model and approximate sensitivity method, the stable subsurface resistivity structures were reconstructed. The synthetic examples show that the smoothness-constrained regularized inversion method is effective and can be reasonable to reconstruct three-dimensional subsurface resistivity structures. 展开更多
关键词 MAGNETOTELLURIC regularized inversion approximate sensitivity smoothness-constrained model
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Three-dimensional inversion of borehole-surface electrical data based on quasi-analytical approximation 被引量:5
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作者 Wang Zhigang He Zhanxiang Liu Haiying 《Applied Geophysics》 SCIE CSCD 2006年第3期141-147,共7页
3D inversion of borehole-surface electrical data for complex geo-electrical models is still a challenging problem in geophysical exploration. We have developed a program for 3D inversion to borehole-surface electrical... 3D inversion of borehole-surface electrical data for complex geo-electrical models is still a challenging problem in geophysical exploration. We have developed a program for 3D inversion to borehole-surface electrical data based on the quasi-analytical approximation (QA) and re-weighted regularized conjugate gradient method (RRCG) algorithms using Visual Fortran 6.5. Application of the QA approximation to forward modeling and Frechet derivative computations speeds up the calculation dramatically. The trial calculation for synthetic data of theoretical model showed that the program is fast and highly precise. 展开更多
关键词 Borehole-surface electrical method quasi-analytical approximation integral equation method re-weighted regularized conjugate gradient method
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A meshless method for the nonlinear generalized regularized long wave equation
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作者 王聚丰 白福浓 程玉民 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第3期35-42,共8页
This paper presents a meshless method for the nonlinear generalized regularized long wave (GRLW) equation based on the moving least-squares approximation. The nonlinear discrete scheme of the GRLW equation is obtain... This paper presents a meshless method for the nonlinear generalized regularized long wave (GRLW) equation based on the moving least-squares approximation. The nonlinear discrete scheme of the GRLW equation is obtained and is solved using the iteration method. A theorem on the convergence of the iterative process is presented and proved using theorems of the infinity norm. Compared with numerical methods based on mesh, the meshless method for the GRLW equation only requires the.scattered nodes instead of meshing the domain of the problem. Some examples, such as the propagation of single soliton and the interaction of two solitary waves, are given to show the effectiveness of the meshless method. 展开更多
关键词 generalized regularized long wave equation meshless method moving least-squares approximation CONVERGENCE
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Non-Rigid Image Registration Algorithm Based on B-Splines Approximation
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作者 张红颖 张加万 +1 位作者 孙济洲 孙毅刚 《Transactions of Tianjin University》 EI CAS 2007年第6期447-451,共5页
An intensity-based non-rigid registration algorithm is discussed, which uses Gaussian smoothing to constrain the transformation to be smooth, and thus preserves the topology of images. In view of the insufficiency of ... An intensity-based non-rigid registration algorithm is discussed, which uses Gaussian smoothing to constrain the transformation to be smooth, and thus preserves the topology of images. In view of the insufficiency of the uniform Gaussian filtering of the deformation field, an automatic and accurate non-rigid image registration method based on B-splines approximation is proposed. The regularization strategy is adopted by using multi-level B-splines approximation to regularize the displacement fields in a coarse-to-fine manner. Moreover, it assigns the different weights to the estimated displacements according to their reliabilities. In this way, the level of regularity can be adapted locally. Experiments were performed on both synthetic and real medical images of brain, and the results show that the proposed method improves the registration accuracy and robustness. 展开更多
关键词 non-rigid image registration B-splines approximation regularIZATION
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Measuring System Regularity Using Fuzzy Similarity-based Approximate Entropy
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作者 陈伟婷 王志中 王刚 《Journal of Shanghai Jiaotong university(Science)》 EI 2007年第5期623-627,共5页
Approximate entropy (ApEn), a measure quantifying regularity and complexity, is believed to be an effective analyzing method of diverse settings that include both deterministic chaotic and stochastic processes, partic... Approximate entropy (ApEn), a measure quantifying regularity and complexity, is believed to be an effective analyzing method of diverse settings that include both deterministic chaotic and stochastic processes, particularly operative in the analysis of physiological signals that involve relatively small amount of data. However, the similarity definition of vectors based on Heaviside function, of which the boundary is discontinuous and hard, may cause some problems in the validity and accuracy of ApEn. To overcome these problems, a modified ApEn based on fuzzy similarity (mApEn) was proposed. The performance on the MIX stochastic model, as well as those on the Logistic map and the Hennon map with noise, shows that the fuzzy similarity-based ApEn gets more satisfying results than the standard ApEn when characterizing systems with different regularities. 展开更多
关键词 regularITY approximate entropy (ApEn) fuzzy similarity physiological signal
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COMMON FIXED POINTS WITH APPLICATIONS TO BEST SIMULTANEOUS APPROXIMATIONS
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作者 Sumit Chandok T.D.Narang 《Analysis in Theory and Applications》 2012年第1期1-12,共12页
For a subset K of a metric space(X,d)and x∈X,Px(x)={y∈K:d(x,y)=d(x,K)≡inf{d(x,k):k∈K}}is called the set of best K-approximant to x.An element go E K is said to be a best simulta-neous approximation of the pair y1,... For a subset K of a metric space(X,d)and x∈X,Px(x)={y∈K:d(x,y)=d(x,K)≡inf{d(x,k):k∈K}}is called the set of best K-approximant to x.An element go E K is said to be a best simulta-neous approximation of the pair y1,y2 E∈if max{d(y1,go),d(y2,go)}=inf g∈K max{d(y1,g),d(y2,g)}.In this paper,some results on the existence of common fixed points for Banach operator pairs in the framework of convex metric spaces have been proved.For self mappings T and S on K,results are proved on both T-and S-invariant points for a set of best simultaneous approximation.Some results on best K-approximant are also deduced.The results proved generalize and extend some results of I.Beg and M.Abbas^[1],S.Chandok and T.D.Narang^[2],T.D.Narang and S.Chandok^[11],S.A.Sahab,M.S.Khan and S.Sessa^[14],P.Vijayaraju^[20]and P.Vijayaraju and M.Marudai^[21]. 展开更多
关键词 Banach operator pair best approximation demicompact fixed point STAR-SHAPED NONEXPANSIVE asymptotically nonexpansive and uniformly asymptot-ically regular maps
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A Regularization Method for Approximating the Inverse Laplace Transform
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作者 A. Al-Shuaibi (King Fahd University of Petroleum and Minerals, Saudi Arabia.) 《Analysis in Theory and Applications》 1997年第1期58-65,共8页
A new method for approximating the inerse Laplace transform is presented. We first change our Laplace transform equation into a convolution type integral equation, where Tikhonov regularization techniques and the Four... A new method for approximating the inerse Laplace transform is presented. We first change our Laplace transform equation into a convolution type integral equation, where Tikhonov regularization techniques and the Fourier transformation are easily applied. We finally obtain a regularized approximation to the inverse Laplace transform as finite sum 展开更多
关键词 A regularization Method for approximating the Inverse Laplace Transform
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PARTIAL REGULARITY FOR WEAK SOLUTIONS OF STATIONARY NAVIER-STOKES SYSTEMS 被引量:6
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作者 陈淑红 潭忠 《Acta Mathematica Scientia》 SCIE CSCD 2008年第4期877-894,共18页
This article is concerned with the partial regularity for the weak solutions of stationary Navier-Stokes system under the controllable growth condition.By A-harmonic approximation technique,the optimal regularity is o... This article is concerned with the partial regularity for the weak solutions of stationary Navier-Stokes system under the controllable growth condition.By A-harmonic approximation technique,the optimal regularity is obtained. 展开更多
关键词 Navier-Stokes system A-harmonic approximation regularITY
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OPTIMAL INTERIOR PARTIAL REGULARITY FOR NONLINEAR ELLIPTIC SYSTEMS WITH DINI CONTINUOUS COEFFICIENTS 被引量:3
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作者 邱亚林 谭忠 《Acta Mathematica Scientia》 SCIE CSCD 2010年第5期1541-1554,共14页
In this article, we consider nonlinear elliptic systems of divergence type with Dini continuous coefficients. The authors use a new method introduced by Duzaar and Grotowski, to prove partial regularity for weak solut... In this article, we consider nonlinear elliptic systems of divergence type with Dini continuous coefficients. The authors use a new method introduced by Duzaar and Grotowski, to prove partial regularity for weak solutions, based on a generalization of the technique of harmonic approximation and directly establish the optimal HSlder exponent for the derivative of a weak solution on its regular set. 展开更多
关键词 nonlinear elliptic systems the natural growth condition optimal partial regularity A-harmonic approximation technique
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PARTIAL REGULARITY OF STATIONARY NAVIER-STOKES SYSTEMS UNDER NATURAL GROWTH CONDITION 被引量:1
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作者 Lianhua HE Zhong TAN 《Acta Mathematica Scientia》 SCIE CSCD 2019年第1期94-110,共17页
In this article, we consider the partial regularity of stationary Navier-Stokes system under the natural growth condition. Applying the method of A-harmonic approximation,we obtain some results about the partial regul... In this article, we consider the partial regularity of stationary Navier-Stokes system under the natural growth condition. Applying the method of A-harmonic approximation,we obtain some results about the partial regularity and establish the optimal Holder exponent for the derivative of a weak solution on its regular set. 展开更多
关键词 PARTIAL regularITY Navier-Stoke systems natural growth condition A-harmonic approximation
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New Regularization Algorithms for Solving the Deconvolution Problem in Well Test Data Interpretation 被引量:1
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作者 Vladimir Vasin Georgy Skorik +1 位作者 Evgeny Pimonov Fikri Kuchuk 《Applied Mathematics》 2010年第5期387-399,共13页
Two new regularization algorithms for solving the first-kind Volterra integral equation, which describes the pressure-rate deconvolution problem in well test data interpretation, are developed in this paper. The main ... Two new regularization algorithms for solving the first-kind Volterra integral equation, which describes the pressure-rate deconvolution problem in well test data interpretation, are developed in this paper. The main features of the problem are the strong nonuniform scale of the solution and large errors (up to 15%) in the input data. In both algorithms, the solution is represented as decomposition on special basic functions, which satisfy given a priori information on solution, and this idea allow us significantly to improve the quality of approximate solution and simplify solving the minimization problem. The theoretical details of the algorithms, as well as the results of numerical experiments for proving robustness of the algorithms, are presented. 展开更多
关键词 DECONVOLUTION PROBLEM VOLTERRA Equations Well Test regularIZATION Algorithm Quasi-Solutions Method Tikhonov regularIZATION A Priori Information Discrete approximation Non-Quadratic Stabilizing Functional Special Basis
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Approximate Inertial Manifold for a Class of the Kirchhoff Wave Equations with Nonlinear Strongly Damped Terms 被引量:2
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作者 Chengfei Ai Huixian Zhu Guoguang Lin 《International Journal of Modern Nonlinear Theory and Application》 2016年第4期218-234,共17页
This paper is devoted to the long time behavior of the solution to the initial boundary value problems for a class of the Kirchhoff wave equations with nonlinear strongly damped terms: . Firstly, in order to prove the... This paper is devoted to the long time behavior of the solution to the initial boundary value problems for a class of the Kirchhoff wave equations with nonlinear strongly damped terms: . Firstly, in order to prove the smoothing effect of the solution, we make efficient use of the analytic property of the semigroup generated by the principal operator of the equation in the phase space. Then we obtain the regularity of the global attractor and construct the approximate inertial manifold of the equation. Finally, we prove that arbitrary trajectory of the Kirchhoff wave equations goes into a small neighbourhood of the approximate inertial manifold after large time. 展开更多
关键词 Kirchhoff Wave Equation Global Attractor The Smoothing Effect The regularity approximate Inertial Manifold
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REGULARITY FOR NONLINEAR ELLIPTIC SYSTEMS WITH DINI COEFFICIENTS UNDER NATURAL GROWTH CONDITION FOR THE CASE:1
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作者 邱亚林 《Acta Mathematica Scientia》 SCIE CSCD 2012年第5期1937-1958,共22页
In this article,we consider interior regularity for weak solutions to nonlinear elliptic systems of divergence type with Dini continuous coefficients under natural growth condition for the case 1〈m〈 2.All estimates ... In this article,we consider interior regularity for weak solutions to nonlinear elliptic systems of divergence type with Dini continuous coefficients under natural growth condition for the case 1〈m〈 2.All estimates in the case of m≥2 is no longer suitable,and we can’t obtain the Caccioppoli’s second inequality by using these techniques developed in the case of m≥2.But the Caccioppoli’s second inequality is the key to use A-harmonic approximation method.Thus,we adopt another technique introduced by Acerbi and Fcsco to overcome the difficulty and we also overcome those difficulties due to Dini condition.And then we apply the A-harmonic approximation method to prove partial regularity of weak solutions. 展开更多
关键词 nonlinear elliptic systems natural growth condition partial regularity Aharmonic approximation technique
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Hyperbolic Conservation Laws,Integral Balance Laws and Regularity of Fluxes
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作者 Matania Ben-Artzi Jiequan Li 《Communications on Applied Mathematics and Computation》 2024年第4期2048-2063,共16页
Hyperbolic conservation laws arise in the context of continuum physics,and are mathematically presented in differential form and understood in the distributional(weak)sense.The formal application of the Gauss-Green th... Hyperbolic conservation laws arise in the context of continuum physics,and are mathematically presented in differential form and understood in the distributional(weak)sense.The formal application of the Gauss-Green theorem results in integral balance laws,in which the concept of flux plays a central role.This paper addresses the spacetime viewpoint of the flux regularity,providing a rigorous treatment of integral balance laws.The established Lipschitz regularity of fluxes(over time intervals)leads to a consistent flux approximation.Thus,fully discrete finite volume schemes of high order may be consistently justified with reference to the spacetime integral balance laws. 展开更多
关键词 Balance laws Hyperbolic conservation laws Finite volume approximations Flux regularity CONSISTENCY
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Two-direction refinable functions and twodirection wavelets with high approximation order and regularity 被引量:8
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作者 Shou-zhi YANG You-fa LI 《Science China Mathematics》 SCIE 2007年第12期1687-1704,共18页
The concept of two-direction refinable functions and two-direction wavelets is introduced.We investigate the existence of distributional(or L2-stable) solutions of the two-direction refinement equation: φ(x)=∑p+kφ(... The concept of two-direction refinable functions and two-direction wavelets is introduced.We investigate the existence of distributional(or L2-stable) solutions of the two-direction refinement equation: φ(x)=∑p+kφ(mx-k)+∑p-kφ(k-mx) where m ≥ 2 is an integer. Based on the positive mask {pk+} and negative mask {p-k}, the conditions that guarantee the above equation has compactly distributional solutions or L2-stable solutions are established. Furthermore, the condition that the L2-stable solution of the above equation can generate a two-direction MRA is given. The support interval of φ(x) is discussed amply. The definition of orthogonal two-direction refinable function and orthogonal two-direction wavelets is presented, and the orthogonality criteria for two-direction refinable functions are established. An algorithm for constructing orthogonal two-direction refinable functions and their two-direction wavelets is presented. Another construction algorithm for two-direction L2-refinable functions, which have nonnegative symbol masks and possess high approximation order and regularity, is presented. Finally, two construction examples are given. 展开更多
关键词 two-direction reflnable functions two-direction wavelets ORTHOGONALITY approximation order regularITY
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Approximate Inertial Manifolds to the Generalized Symmetric Regularized Long Wave Equations with Damping Term 被引量:11
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作者 Bo-ling Guo, Ya-dong ShangInstitute of Applied Physics and Computational Mathematics, P.O. Box 8009, Beijing 100088, China 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2003年第2期191-204,共14页
Abstract In the present paper, we construct two approximate inertial manifolds for the generalized symmetric regularized long wave equations with damping term. The orders of approximations of these manifolds to the gl... Abstract In the present paper, we construct two approximate inertial manifolds for the generalized symmetric regularized long wave equations with damping term. The orders of approximations of these manifolds to the global attractor are derived. 展开更多
关键词 Keywords Symmetric regularized long wave equation periodic initial value problem long time behavior approximate inertial manifolds damping term
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