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We consider the problem of joint reconstruction of both attenuation $a$ and source density $f$ in emission tomography in two dimensions. This is sometimes called the Single Photon Emission Computed Tomography (SPECT) identification problem,…

Analysis of PDEs · Mathematics 2020-01-14 Sean Holman , Philip Richardson

We study an inverse problem where an unknown radiating source is observed with collimated detectors along a single line and the medium has a known attenuation. The research is motivated by applications in SPECT and beam hardening. If…

Functional Analysis · Mathematics 2020-11-10 Tommi Brander , Joonas Ilmavirta , Petteri Piiroinen , Teemu Tyni

We show that under a certain non-cancellation condition the attenuated Radon transform uniquely determines piecewise constant attenuation $a$ and piecewise $C^2$ source density $f$ with jumps over real analytic boundaries possibly having…

Analysis of PDEs · Mathematics 2022-06-22 Sean Holman , Philip Richardson

In the plane, we study the transform $R_\gamma f$ of integrating a unknown function $f$ over circles centered at a given curve $\gamma$. This is a simplified model of SAR, when the radar is not directed but has other applications, like…

Analysis of PDEs · Mathematics 2012-05-07 Plamen Stefanov , Gunther Uhlmann

We consider the inverse problem of identification of degenerate diffusion coefficient of the form $x^\alpha a(x)$ in a one dimensional parabolic equation by some extra data. We first prove by energy methods the uniqueness and Lipschitz…

Analysis of PDEs · Mathematics 2021-12-15 Piermarco Cannarsa , Anna Doubova , Masahiro Yamamoto

In order to understand the linearization problem around a leaf of a singular foliation, we extend the familiar holonomy map from the case of regular foliations to the case of singular foliations. To this aim we introduce the notion of…

Differential Geometry · Mathematics 2014-09-12 Iakovos Androulidakis , Marco Zambon

We study the problem of recovery the source $a(t,x)F(x)$ in the wave equation in anisotropic medium with $a$ known so that $a(0,x)\not=0$ with a single measurement. We use Carleman estimates combined with geometric arguments and give sharp…

Analysis of PDEs · Mathematics 2011-03-08 Plamen Stefanov , Gunther Uhlmann

In this paper we consider the unique determination of inhomogeneities together with possible buried obstacles by scattering measurements. Under the assumption that the buried obstacles have only planar contacts with the inhomogeneities, we…

Analysis of PDEs · Mathematics 2008-04-08 Hongyu Liu

We propose an abstract approach to prove local uniqueness and conditional H\"older stability to non-linear inverse problems by linearization. The main condition is that, in addition to the injectivity of the linearization $A$, we need a…

Functional Analysis · Mathematics 2008-09-02 Plamen Stefanov , Gunther Uhlmann

It is by now well-known that one can recover a potential in the wave equation from the knowledge of the initial waves, the boundary data and the flux on a part of the boundary satisfying the Gamma-conditions of J.-L. Lions. We are…

Analysis of PDEs · Mathematics 2011-10-21 Lucie Baudouin , Sylvain Ervedoza

This paper considers the inverse problem of recovering both the unknown, spatially-dependent conductivity $a(x)$ and the nonlinear reaction term $f(u)$ in a reaction-diffusion equation from overposed data. These measurements can consist of:…

Analysis of PDEs · Mathematics 2021-01-19 Barbara Kaltenbacher , William Rundell

This paper provides an analysis of the linearized inverse problem in multifrequency electrical impedance tomography. We consider an isotropic conductivity distribution with a finite number of unknown inclusions with different frequency…

Numerical Analysis · Mathematics 2016-10-06 Giovanni S. Alberti , Habib Ammari , Bangti Jin , Jin-Keun Seo , Wenlong Zhang

We investigate a singular perturbation for Hamilton-Jacobi equations in an open subset of two dimensional Euclidean space, where the set is determined through a Hamiltonian function and the Hamilton-Jacobi equations are the dynamic…

Analysis of PDEs · Mathematics 2017-08-31 Taiga Kumagai

We study the inverse problem of recovery a compactly supported non-linearity in the semilinear wave equation $u_{tt}-\Delta u+ \alpha(x) |u|^2u=0$, in two and three dimensions. We probe the medium with complex-valued harmonic waves of…

Analysis of PDEs · Mathematics 2022-02-22 Antônio Sá Barreto , Plamen Stefanov

We introduce a novel primal-dual flow for affine constrained convex optimization problems. As a modification of the standard saddle-point system, our primal-dual flow is proved to possess the exponential decay property, in terms of a…

Optimization and Control · Mathematics 2022-03-22 Hao Luo

Hamiltonians are 2-by-2 positive semidefinite real symmetric matrix-valued functions satisfying certain conditions. In this paper, we solve the inverse problem for which recovers a Hamiltonian from the solution of a first-order system…

Functional Analysis · Mathematics 2023-01-02 Masatoshi Suzuki

We investigate the inverse problem of recovering an initial source for the wave equation with fractional attenuation, motivated by photoacoustic tomography (PAT). The attenuation is modeled by a Caputo fractional derivative of order…

Analysis of PDEs · Mathematics 2025-10-10 Sebastian Acosta , Benjamin Palacios

In this article we study the linearized anisotropic Calderon problem. In a compact manifold with boundary, this problem amounts to showing that products of harmonic functions form a complete set. Assuming that the manifold is transversally…

Analysis of PDEs · Mathematics 2018-10-29 David Dos Santos Ferreira , Yaroslav Kurylev , Matti Lassas , Tony Liimatainen , Mikko Salo

In this paper, we study time-harmonic electromagnetic scattering in two scenarios, where the anomalous scatterer is either a pair of electromagnetic sources or an inhomogeneous medium, both with compact supports. We are mainly concerned…

Analysis of PDEs · Mathematics 2022-04-07 Huaian Diao , Xiaoxu Fei , Hongyu Liu , Ke Yang

We consider the determination of an unknown potential $q(x)$ form a fractional diffusion equation subject to overposed lateral boundary data. We show that this data allows recovery of two spectral sequences for the associated inverse…

Mathematical Physics · Physics 2018-11-15 William Rundell , Masahiro Yamamoto
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