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We study an inverse problem for the wave equation where localized wave sources in random scattering media are to be determined from time resolved measurements of the waves at an array of receivers. The sources are far from the array, so the…

Mathematical Physics · Physics 2016-07-18 Liliana Borcea , Ilker Kocyigit

We consider the classical integral equation reformulation of the radiative transport equation (RTE) in a heterogeneous medium, assuming isotropic scattering. We prove an estimate for the norm of the integral operator in this formulation…

Numerical Analysis · Mathematics 2019-03-21 J. C. H. Blake , I. G. Graham , F. Scheben , A. Spence

Several applications in medical imaging and non-destructive material testing lead to inverse elliptic coefficient problems, where an unknown coefficient function in an elliptic PDE is to be determined from partial knowledge of its…

Optimization and Control · Mathematics 2022-12-13 Bastian Harrach

Motivated by applications in quantitative photoacoustic imaging, we study inverse problems to a semilinear radiative transport equation (RTE) where we intend to reconstruct absorption coefficients in the equation from single and multiple…

Analysis of PDEs · Mathematics 2020-07-21 Kui Ren , Yimin Zhong

We consider inverse problems of determining coefficients or time independent factors of source terms in radiative transport equations by means of Carleman estimate. We establish global Lipschitz stability results with an additional…

Analysis of PDEs · Mathematics 2020-09-10 Manabu Machida , Masahiro Yamamoto

Photon transport through a diffusing slab can be described by the radiative transfer equation (RTE). When the slab is highly scattering and weakly absorbing, the RTE simplifies to the diffusion equation. In this paper, an inverse diffusion…

This paper concerns the quantitative step of the medical imaging modality Thermo-acoustic Tomography (TAT). We model the radiation propagation by a system of Maxwell's equations. We show that the index of refraction of light and the…

Analysis of PDEs · Mathematics 2015-06-17 Guillaume Bal , Ting Zhou

We present a numerical code that solves the forward and inverse problem of the polarized radiative transfer equation in geometrical scale under the Zeeman regime. The code is fully parallelized, making it able to easily handle large…

Solar and Stellar Astrophysics · Physics 2019-09-04 A. Pastor Yabar , J. M. Borrero , B. Ruiz Cobo

It is proposed to monitor spatial and temporal spreads of epidemics via solution of a Coefficient Inverse Problem for a system of three coupled nonlinear parabolic equations. To solve this problem numerically, a version of the so-called…

Numerical Analysis · Mathematics 2025-04-08 Michael V. Klibanov , Trung Truong

We study the global convergence of the gradient descent method of the minimization of strictly convex functionals on an open and bounded set of a Hilbert space. Such results are unknown for this type of sets, unlike the case of the entire…

Numerical Analysis · Mathematics 2022-04-08 Thuy T. Le , Loc. H. Nguyen

It is known that the set of all solutions of a commutant lifting and other interpolation problems admits a Redheffer linear-fractional parametrization. The method of unitary coupling identifies solutions of the lifting problem with minimal…

Functional Analysis · Mathematics 2010-04-06 Joseph A. Ball , Alexander Kheifets

We propose a new numerical method to reconstruct the isotropic electrical conductivity from measured restricted Dirichlet-to-Neumann map data in electrical impedance tomography (EIT) model. "Restricted Dirichlet-to-Neumann (DtN) map data"…

Numerical Analysis · Mathematics 2019-02-20 Michael V. Klibanov , Jingzhi Li , Wenlong Zhang

We present a new method for the numerical solution of the radiative-transfer equation (RTE) in multidimensional scenarios commonly encountered in computational astrophysics. The method is based on the direct solution of the Boltzmann…

Computational Physics · Physics 2020-10-06 L. R. Weih , A. Gabbana , D. Simeoni , L. Rezzolla , S. Succi , R. Tripiccione

When solving the time-dependent radiative transport equation (RTE), implicit time discretization is often employed for its robustness and stability. This results in a sequence of steady-state RTEs with identical cross-sections but varying…

Numerical Analysis · Mathematics 2026-04-24 Qinchen Song , Lei Zhang , Min Tang

We present a numerical implementation of radiative transfer based on an explicitly photon-conserving advection scheme, where radiative fluxes over the cell interfaces of a structured or unstructured mesh are calculated with a second-order…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Margarita Petkova , Volker Springel

Radiative transfer in curved spacetimes has become increasingly important to understanding high-energy astrophysical phenomena and testing general relativity in the strong field limit. The equations of radiative transfer are physically…

Astrophysics · Physics 2009-11-13 Avery E. Broderick

We present a new flexible wavefront propagation algorithm for the boundary value problem for sub-Riemannian (SR) geodesics in the roto-translation group $SE(2) = \mathbb{R}^2 \rtimes S^1$ with a metric tensor depending on a smooth external…

Group Theory · Mathematics 2017-01-26 Erik J. Bekkers , Remco Duits , Alexey Mashtakov , Gonzalo R. Sanguinetti

The Riemannian manifold of curves with a Sobolev metric is an important and frequently studied model in the theory of shape spaces. Various numerical approaches have been proposed to compute geodesics, but so far elude a rigorous…

Numerical Analysis · Mathematics 2025-05-16 Sascha Beutler , Florine Hartwig , Martin Rumpf , Benedikt Wirth

A new numerical method for an inverse problem for an elliptic equation with unknown potential is proposed. In this problem the point source is running along a straight line and the source-dependent Dirichlet boundary condition is measured…

Numerical Analysis · Mathematics 2008-09-24 Hua Shan , M. V. Klibanov , Jianzhong Su , Natee Pantong , Hanli Liu

The radiative transfer equation (RTE) is a cornerstone for describing the propagation of electromagnetic radiation in a medium, with applications spanning atmospheric science, astrophysics, remote sensing, and biomedical optics. Despite its…

Optics · Physics 2024-01-19 Vladimir Allaxwerdian , Dmitry V. Naumov