scholarly journals An Energy Regularization for Cauchy Problems of Laplace Equation in Annulus Domain

2011 ◽  
Vol 9 (4) ◽  
pp. 878-896 ◽  
Author(s):  
Houde Han ◽  
Leevan Ling ◽  
Tomoya Takeuchi
Keyword(s):  
Cauchy Problem ◽  
Laplace Equation ◽  
Regularization Method ◽  
Boundary Data ◽  
Outer Boundary ◽  
Cauchy Problems ◽  
Electrical Field ◽  
Numerical Examples ◽  
The Cauchy Problem ◽  
Ill Posed

AbstractDetecting corrosion by electrical field can be modeled by a Cauchy problem of Laplace equation in annulus domain under the assumption that the thickness of the pipe is relatively small compared with the radius of the pipe. The interior surface of the pipe is inaccessible and the nondestructive detection is solely based on measurements from the outer layer. The Cauchy problem for an elliptic equation is a typical ill-posed problem whose solution does not depend continuously on the boundary data. In this work, we assume that the measurements are available on the whole outer boundary on an annulus domain. By imposing reasonable assumptions, the theoretical goal here is to derive the stabilities of the Cauchy solutions and an energy regularization method. Relationship between the proposed energy regularization method and the Tikhonov regularization with Morozov principle is also given. A novel numerical algorithm is proposed and numerical examples are given.

scholarly journals A modified Tikhonov regularization method based on Hermite expansion for solving the Cauchy problem of the Laplace equation

2020 ◽  
Vol 18 (1) ◽  
pp. 1685-1697
Author(s):  
Zhenyu Zhao ◽  
Lei You ◽  
Zehong Meng
Keyword(s):  
Cauchy Problem ◽  
Laplace Equation ◽  
Tikhonov Regularization ◽  
Regularization Method ◽  
Regularization Parameter ◽  
Solution Process ◽  
Tikhonov Regularization Method ◽  
Hermite Expansion ◽  
The Cauchy Problem ◽  
Ill Posed

Abstract In this paper, a Cauchy problem for the Laplace equation is considered. We develop a modified Tikhonov regularization method based on Hermite expansion to deal with the ill posed-ness of the problem. The regularization parameter is determined by a discrepancy principle. For various smoothness conditions, the solution process of the method is uniform and the convergence rate can be obtained self-adaptively. Numerical tests are also carried out to verify the effectiveness of the method.

scholarly journals Regularization and Error Estimate for the Poisson Equation with Discrete Data

Mathematics ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 422
Author(s):  
Nguyen Anh Triet ◽  
Nguyen Duc Phuong ◽  
Van Thinh Nguyen ◽  
Can Nguyen-Huu
Keyword(s):  
Cauchy Problem ◽  
Initial Data ◽  
Poisson Equation ◽  
Regularization Method ◽  
Random Noise ◽  
Two Dimensional ◽  
The Poisson Equation ◽  
The Cauchy Problem ◽  
Ill Posed ◽  
Dimensional Domain

In this work, we focus on the Cauchy problem for the Poisson equation in the two dimensional domain, where the initial data is disturbed by random noise. In general, the problem is severely ill-posed in the sense of Hadamard, i.e., the solution does not depend continuously on the data. To regularize the instable solution of the problem, we have applied a nonparametric regression associated with the truncation method. Eventually, a numerical example has been carried out, the result shows that our regularization method is converged; and the error has been enhanced once the number of observation points is increased.

scholarly journals Fourier Truncation Regularization Method for a Three-Dimensional Cauchy Problem of the Modified Helmholtz Equation with Perturbed Wave Number

Mathematics ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 705 ◽  
Author(s):  
Fan Yang ◽  
Ping Fan ◽  
Xiao-Xiao Li
Keyword(s):  
Cauchy Problem ◽  
Exact Solution ◽  
Helmholtz Equation ◽  
Regularization Method ◽  
Three Dimensional ◽  
Wave Number ◽  
Modified Helmholtz Equation ◽  
The Cauchy Problem ◽  
Ill Posed ◽  
Regularized Solution

In this paper, the Cauchy problem of the modified Helmholtz equation (CPMHE) with perturbed wave number is considered. In the sense of Hadamard, this problem is severely ill-posed. The Fourier truncation regularization method is used to solve this Cauchy problem. Meanwhile, the corresponding error estimate between the exact solution and the regularized solution is obtained. A numerical example is presented to illustrate the validity and effectiveness of our methods.

scholarly journals An optimal quasi solution for the Cauchy problem for Laplace equation in the framework of inverse ECG

2019 ◽  
Vol 14 (2) ◽  
pp. 204
Author(s):  
Eduardo Hernandez-Montero ◽  
Andres Fraguela-Collar ◽  
Jacques Henry
Keyword(s):  
Inverse Problem ◽  
Cauchy Problem ◽  
Laplace Equation ◽  
Boundary Data ◽  
A Priori ◽  
Normal Derivative ◽  
Cauchy Data ◽  
Dirichlet Data ◽  
Data Completion ◽  
The Cauchy Problem

The inverse ECG problem is set as a boundary data completion for the Laplace equation: at each time the potential is measured on the torso and its normal derivative is null. One aims at reconstructing the potential on the heart. A new regularization scheme is applied to obtain an optimal regularization strategy for the boundary data completion problem. We consider the ℝn+1domain Ω. The piecewise regular boundary of Ω is defined as the union∂Ω = Γ1∪ Γ0∪ Σ, where Γ1and Γ0are disjoint, regular, andn-dimensional surfaces. Cauchy boundary data is given in Γ0, and null Dirichlet data in Σ, while no data is given in Γ1. This scheme is based on two concepts: admissible output data for an ill-posed inverse problem, and the conditionally well-posed approach of an inverse problem. An admissible data is the Cauchy data in Γ0corresponding to an harmonic function inC2(Ω) ∩H1(Ω). The methodology roughly consists of first characterizing the admissible Cauchy data, then finding the minimum distance projection in theL2-norm from the measured Cauchy data to the subset of admissible data characterized by givena prioriinformation, and finally solving the Cauchy problem with the aforementioned projection instead of the original measurement.

AN ILL-POSED PROBLEM FOR THE HEAT EQUATION

2009 ◽  
Vol 19 (09) ◽  
pp. 1631-1641 ◽  
Author(s):  
L. E. PAYNE ◽  
G. A. PHILIPPIN
Keyword(s):  
Cauchy Problem ◽  
Boundary Conditions ◽  
Heat Equation ◽  
Outer Boundary ◽  
Slight Modification ◽  
Cauchy Data ◽  
The Cauchy Problem ◽  
Ill Posed

The Cauchy problem for the heat equation in which Cauchy data are prescribed on the outer boundary of a domain with cavity and no data are given on the inner boundary is known to be ill-posed. By a slight modification of the boundary conditions a new problem is introduced whose solution depends continuously on the data in L2.

scholarly journals Identical Approximation Operator and Regularization Method for the Cauchy problem of 2D Heat Conduction Equation

2020 ◽  
Author(s):  
Shangqin He ◽  
Xiufang Feng
Keyword(s):  
Cauchy Problem ◽  
Heat Conduction ◽  
Regularization Method ◽  
Heat Conduction Equation ◽  
Convergence Rates ◽  
Regularization Parameter ◽  
Numerical Results ◽  
Conduction Equation ◽  
The Cauchy Problem ◽  
Ill Posed

In this paper, an identical approximate regularization method is extended to the Cauchy problem of two-dimensional heat conduction equation, this kind of problem is severely ill-posed. The convergence rates are obtained under a priori regularization parameter choice rule. Numerical results are presented for two examples with smooth and continuous but not smooth boundaries, and compared the identical approximate regularization solutions which are displayed in paper. The numerical results show that our method is effective, accurate and stable to solve the ill-posed Cauchy problems.

scholarly journals The Cauchy Problem for the Laplace Equation and Application to Image Inpainting

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Lamia Jaafar Belaid ◽  
Amel Ben Abda ◽  
Nawal Al Malki
Keyword(s):  
Cauchy Problem ◽  
Laplace Equation ◽  
Crack Detection ◽  
Image Inpainting ◽  
Cauchy Problems ◽  
Stopping Criterion ◽  
The Cauchy Problem ◽  
Noise Data ◽  
Moment Approach ◽  
The Moment

The moment approach to solve the Cauchy problems is investigated. First, we consider the Cauchy problem for the Laplace equation, and we present a moment method for solving it in the case of a flat boundary. Second, we consider the reciprocity gap concept used to solve the problem of crack detection, as a stopping criterion and we study the case of noise data. Finally, we propose an application to the Cauchy problem for the Laplace equation, for the inpainting problem. Some numerical results showing the efficiency of the method proposed are also given.

scholarly journals On quasi-reversibility solutions to the Cauchy problem for the Laplace equation: regularity and error estimates

2020 ◽  
Vol 54 (2) ◽  
pp. 493-529
Author(s):  
Laurent Bourgeois ◽  
Lucas Chesnel
Keyword(s):  
Cauchy Problem ◽  
Finite Elements ◽  
Small Parameter ◽  
Laplace Equation ◽  
Limit Problem ◽  
The Cauchy Problem ◽  
Ill Posed ◽  
Finite Elements Methods ◽  
Regularity Results ◽  
Well Posed

We are interested in the classical ill-posed Cauchy problem for the Laplace equation. One method to approximate the solution associated with compatible data consists in considering a family of regularized well-posed problems depending on a small parameter ε > 0. In this context, in order to prove convergence of finite elements methods, it is necessary to get regularity results of the solutions to these regularized problems which hold uniformly in ε. In the present work, we obtain these results in smooth domains and in 2D polygonal geometries. In presence of corners, due to the particular structure of the regularized problems, classical techniques à la Grisvard do not work and instead, we apply the Kondratiev approach. We describe the procedure in detail to keep track of the dependence in ε in all the estimates. The main originality of this study lies in the fact that the limit problem is ill-posed in any framework.

scholarly journals A robust data completion method for two dimensional Cauchy problems associated with the Laplace equation

2011 ◽  
pp. 309-340
Author(s):  
Franck Delvare ◽  
Alain Cimetière
Keyword(s):  
Laplace Equation ◽  
Regularization Method ◽  
Noisy Data ◽  
Cauchy Problems ◽  
The Finite Element Method ◽  
Data Completion ◽  
The Cauchy Problem ◽  
Completion Problems ◽  
Fading Effect ◽  
Derivatives Of

Our aim is to propose an improved regularization method for data completion problems. This method is presented on the Cauchy problem for the Laplace equation in 2D situations. This method is an iterative one, uses a regularization with fading effect and penalization terms which take into account the fact that, under some regularity assumptions, the partial derivatives of a harmonic function is also harmonic. Many numerical simulations using the finite element method highlight the efficiency, accuracy, stability when data are noisy and the ability of the method to take into account and deblur noisy data.

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