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Inference by means of mathematical modeling from a collection of observations remains a crucial tool for scientific discovery and is ubiquitous in application areas such as signal compression, imaging restoration, and supervised machine…

Numerical Analysis · Mathematics 2022-07-19 Matthias Chung , Rosemary Renaut

Tikhonov regularization is a popular approach to obtain a meaningful solution for ill-conditioned linear least squares problems. A relatively simple way of choosing a good regularization parameter is given by Morozov's discrepancy…

Numerical Analysis · Mathematics 2020-06-24 Jeffrey Cornelis , Nick Schenkels , Wim Vanroose

The study of solving inverse singular value problems for nonnegative matrices has been around for decades. It is clear that an inverse singular problem is trivial if the desirable matrix is not restricted to a certain structure. Provided…

Numerical Analysis · Mathematics 2013-12-11 Sheng-Jhih Wu , Matthew M. Lin

From the viewpoint of inverse problem, the optimization of drug release based on the multi-laminated drug controlled release devices has been regarded as the solution problem of the diffusion equation initial value inverse problem. In view…

Numerical Analysis · Mathematics 2019-04-15 Xinming Zhang , Ling Ma

We deal with the shape reconstruction of inclusions in elastic bodies. For solving this inverse problem in practice, data fitting functionals are used. Those work better than the rigorous monotonicity methods from [5], but have no…

Numerical Analysis · Mathematics 2022-12-13 Sarah Eberle , Bastian Harrach

In image denoising (IDN) processing, the low-rank property is usually considered as an important image prior. As a convex relaxation approximation of low rank, nuclear norm based algorithms and their variants have attracted significant…

Image and Video Processing · Electrical Eng. & Systems 2020-04-03 Yanwei Zhao , Ping Yang , Qiu Guan , Jianwei Zheng , Wanliang Wang

We consider the efficient numerical minimization of Tikhonov functionals with nonlinear operators and non-smooth and non-convex penalty terms, which appear for example in variational regularization. For this, we consider a new class of SCD…

Numerical Analysis · Mathematics 2024-10-18 Helmut Gfrerer , Simon Hubmer , Ronny Ramlau

From linear classifiers to neural networks, image classification has been a widely explored topic in mathematics, and many algorithms have proven to be effective classifiers. However, the most accurate classifiers typically have…

Machine Learning · Statistics 2017-06-30 Elizabeth Newman , Misha Kilmer , Lior Horesh

This paper is concerned with the inverse scattering problem which aims to determine the spatially distributed dielectric constant coefficient of the 2D Helmholtz equation from multifrequency backscatter data associated with a single…

Numerical Analysis · Mathematics 2020-02-25 Trung Truong , Dinh-Liem Nguyen , Michael Klibanov

This paper presents a novel hybrid algorithm for minimizing the sum of a continuously differentiable loss function and a nonsmooth, possibly nonconvex, sparse regularization function. The proposed method alternates between solving a…

Optimization and Control · Mathematics 2025-04-01 Hao Wang , Xiangyu Yang , Yichen Zhu

We introduce in this document a direct method allowing to solve numerically inverse type problems for linear parabolic equations. We consider the reconstruction of the full solution of the parabolic equation posed in $\Omega\times (0,T)$ -…

Optimization and Control · Mathematics 2024-02-11 Arnaud Munch , Diego Souza

This paper deals with Tikhonov regularization for linear and nonlinear ill-posed operator equations with wavelet Besov norm penalties. We show order optimal rates of convergence for finitely smoothing operators and for the backwards heat…

Numerical Analysis · Mathematics 2019-04-03 Frederic Weidling , Benjamin Sprung , Thorsten Hohage

We present a generalized formulation for reweighted least squares approximations. The goal of this article is twofold: firstly, to prove that the solution of such problem can be expressed as a convex combination of certain interpolants when…

Ill-posed inverse problems are common in astronomy, and their solutions are unstable with respect to noise in the data. Solutions of such problems are typically found using two classes of methods: parametrization and fitting the data…

Instrumentation and Methods for Astrophysics · Physics 2021-12-17 Damir Gasymov , Ivan Katkov

Conditional stability estimates require additional regularization for obtaining stable approximate solutions if the validity area of such estimates is not completely known. In this context, we consider ill-posed nonlinear inverse problems…

Numerical Analysis · Mathematics 2020-01-29 Frank Werner , Bernd Hofmann

One of the fundamental problems of interest for discrete-time linear systems is whether its input sequence may be recovered given its output sequence, a.k.a. the left inversion problem. Many conditions on the state space geometry, dynamics,…

Optimization and Control · Mathematics 2024-04-01 Kyle Poe , Enrique Mallada , Rene Vidal

This is a survey, which is a continuation of the previous survey of the author about applications of Carleman estimates to Inverse Problems, J. Inverse and Ill-Posed Problems, 21, 477-560, 2013. It is shown here that Tikhonov functionals…

Mathematical Physics · Physics 2014-10-29 Michael V. Klibanov

We consider the inverse problem of reconstructing the interior boundary curve of a doubly connected domain from the knowledge of the temperature and the thermal flux on the exterior boundary curve. The use of the Laguerre transform in time…

Numerical Analysis · Mathematics 2024-02-23 Roman Chapko , Leonidas Mindrinos

We consider a statistical inverse learning problem, where the task is to estimate a function $f$ based on noisy point evaluations of $Af$, where $A$ is a linear operator. The function $Af$ is evaluated at i.i.d. random design points $u_n$,…

Machine Learning · Statistics 2021-11-02 Tatiana A. Bubba , Martin Burger , Tapio Helin , Luca Ratti

We consider the problem of efficiently solving large-scale linear least squares problems that have one or more linear constraints that must be satisfied exactly. Whilst some classical approaches are theoretically well founded, they can face…

Numerical Analysis · Mathematics 2021-12-24 Jennifer Scott , Miroslav Tuma