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We propose an immersed boundary scheme for the numerical resolution of the Complete Electrode Model in Electrical Impedance Tomography, that we use as a main ingredient in the resolution of inverse problems in medical imaging. Such method…

Numerical Analysis · Mathematics 2023-05-24 Jérémi Dardé , Niami Nasr , Lisl Weynans

In Electrical Impedance Tomography (EIT), the internal conductivity of a body is recovered via current and voltage measurements taken at its surface. The reconstruction task is a highly ill-posed nonlinear inverse problem, which is very…

Numerical Analysis · Mathematics 2018-03-28 Sarah Hamilton , Andreas Hauptmann , Samuli Siltanen

We study iterative finite element approximations for the numerical approximation of semilinear elliptic boundary value problems with monotone nonlinear reactions of subcritical growth. The focus of our contribution is on an optimal a priori…

Numerical Analysis · Mathematics 2025-08-18 Florian Spicher , Thomas P. Wihler

This paper tackles the data completion problem related to the Helmholtz equation. The goal is to identify unknown boundary conditions on parts of the boundary that cannot be accessed directly, by making use of measurements collected from…

Numerical Analysis · Mathematics 2025-10-08 Jamal Daoudi , Chakir Tajani

We consider the problem of positioning a cloud of points in the Euclidean space $\mathbb{R}^d$, using noisy measurements of a subset of pairwise distances. This task has applications in various areas, such as sensor network localization and…

Statistics Theory · Mathematics 2012-11-22 Adel Javanmard , Andrea Montanari

We present a study of the numerical solution of the two dimensional electrical impedance tomography problem, with noisy measurements of the Dirichlet to Neumann map. The inversion uses parametrizations of the conductivity on optimal grids.…

Mathematical Physics · Physics 2015-06-03 Liliana Borcea , Fernando Guevara Vasquez , Alexander V. Mamonov

This paper focuses on prior information for improved sparsity reconstruction in electrical impedance tomography with partial data, i.e. data measured only on subsets of the boundary. Sparsity is enforced using an $\ell_1$ norm of the basis…

Numerical Analysis · Mathematics 2016-01-20 Henrik Garde , Kim Knudsen

We consider the Calder\'on problem with partial data in certain admissible geometries, that is, on compact Riemannian manifolds with boundary which are conformally embedded in a product of the Euclidean line and a simple manifold. We show…

Analysis of PDEs · Mathematics 2016-02-16 Casey Rodriguez

We consider Inverse Electrical Impedance Tomography (EIT) problem on recovering electrical conductivity and potential in the body based on the measurement of the boundary voltages on the $m$ electrodes for a given electrode current. The…

Optimization and Control · Mathematics 2024-12-17 Ugur G. Abdulla , Saleheh Seif

This work proposes a nonlinear finite element method whose nodal values preserve bounds known for the exact solution. The discrete problem involves a nonlinear projection operator mapping arbitrary nodal values into bound-preserving ones…

Numerical Analysis · Mathematics 2023-04-04 Gabriel Barrenechea , Emmanuil Georgoulis , Tristan Pryer , Andreas Veeser

The monotonicity-based approach has become one of the fundamental methods for reconstructing inclusions in the inverse problem of electrical impedance tomography. Thus far the method has not been proven to be able to handle extreme…

Analysis of PDEs · Mathematics 2021-02-05 Valentina Candiani , Jérémi Dardé , Henrik Garde , Nuutti Hyvönen

In this paper we investigate the problem of identifying conductivity in electrical impedance tomography from one boundary measurement. A variational method with total variation regularization is here proposed to tackle this problem. We…

Analysis of PDEs · Mathematics 2017-09-26 Michael Hinze , Barbara Kaltenbacher , Tran Nhan Tam Quyen

We propose a new numerical method for the solution of the problem of the reconstruction of the initial condition of a quasilinear parabolic equation from the measurements of both Dirichlet and Neumann data on the boundary of a bounded…

Analysis of PDEs · Mathematics 2020-09-29 Thuy T. Le , Loc H. Nguyen

This paper deals with a priori pointwise error estimates for the finite element solution of boundary value problems with Neumann boundary conditions in polygonal domains. Due to the corners of the domain, the convergence rate of the…

Numerical Analysis · Mathematics 2018-05-01 Thomas Apel , Johannes Pfefferer , Sergejs Rogovs , Max Winkler

Some linear integro-differential operators have old and classical representations as the Dirichlet-to-Neumann operators for linear elliptic equations, such as the 1/2-Laplacian or the generator of the boundary process of a reflected…

Analysis of PDEs · Mathematics 2017-10-10 Nestor Guillen , Jun Kitagawa , Russell W. Schwab

For numerical approximation the reformulation of a PDE as a residual minimisation problem has the advantages that the resulting linear system is symmetric positive definite, and that the norm of the residual provides an a posteriori error…

Numerical Analysis · Mathematics 2023-05-29 Harald Monsuur , Rob Stevenson , Johannes Storn

Incorporating boundaries of the imaging object as a priori information to imaging algorithms can significantly improve the performance of electromagnetic medical imaging systems. To avoid overly complicating the system by using different…

Computer Vision and Pattern Recognition · Computer Science 2022-03-14 A. Al-Saffar , A. Stancombe , A. Zamani , A. Abbosh

We consider the spectral structure of indefinite second order boundary-value problems on graphs. A variational formulation for such boundary-value problems on graphs is given and we obtain both full and half-range completeness results. This…

Spectral Theory · Mathematics 2017-07-05 Sonja Currie , Bruce Alastair Watson

We consider the problem of numerically approximating the solutions to an elliptic partial differential equation (PDE) for which the boundary conditions are lacking. To alleviate this missing information, we assume to be given measurement…

Numerical Analysis · Mathematics 2024-06-07 Andrea Bonito , Diane Guignard

In this paper, we consider an inverse conductivity problem on a bounded domain $\Omega\subset\mathbb{R}^n$, $n\geq2$, also known as Electrical Impedance Tomography (EIT), for the case where unknown impenetrable obstacles are embedded into…

Analysis of PDEs · Mathematics 2021-04-29 Jiaqing Yang