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Recovering nonlinearly degraded signal in the presence of noise is a challenging problem. In this work, this problem is tackled by minimizing the sum of a non convex least-squares fit criterion and a penalty term. We assume that the…

Signal Processing · Electrical Eng. & Systems 2019-02-27 Marc Castella , Jean-Christophe Pesquet , Arthur Marmin

A host of problems involve the recovery of structured signals from a dimensionality reduced representation such as a random projection; examples include sparse signals (compressive sensing) and low-rank matrices (matrix completion). Given…

Information Theory · Computer Science 2012-05-22 Shirin Jalali , Arian Maleki , Richard Baraniuk

Many inverse problems include nuisance parameters which, while not of direct interest, are required to recover primary parameters. Structure present in these problems allows efficient optimization strategies - a well known example is…

Numerical Analysis · Mathematics 2015-06-05 Aleksandr Y. Aravkin , Tristan van Leeuwen

Solving inverse problems \(Ax = y\) is central to a variety of practically important fields such as medical imaging, remote sensing, and non-destructive testing. The most successful and theoretically best-understood method is convex…

Numerical Analysis · Mathematics 2025-09-23 Daniel Obmann , Gyeongha Hwang , Markus Haltmeier

Problems in differentiable rendering often involve optimizing scene parameters that cause motion in image space. The gradients for such parameters tend to be sparse, leading to poor convergence. While existing methods address this sparsity…

Graphics · Computer Science 2025-03-31 Ishit Mehta , Manmohan Chandraker , Ravi Ramamoorthi

We study an inverse problem associated with an eddy current model. We first address the ill-posedness of the inverse problem by proving the compactness of the forward map with respect to the conductivity and the non-uniqueness of the…

Analysis of PDEs · Mathematics 2019-08-26 Junqing Chen , Ying Liang , Jun Zou

Robust Optimization has traditionally taken a pessimistic, or worst-case viewpoint of uncertainty which is motivated by a desire to find sets of optimal policies that maintain feasibility under a variety of operating conditions. In this…

Machine Learning · Statistics 2017-11-22 Matthew Norton , Akiko Takeda , Alexander Mafusalov

This note addresses the question of optimally estimating a linear functional of an object acquired through linear observations corrupted by random noise, where optimality pertains to a worst-case setting tied to a symmetric, convex, and…

Statistics Theory · Mathematics 2023-08-01 Simon Foucart , Grigoris Paouris

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 document introduces a strategy to solve linear optimization problems. The strategy is based on the bounding condition each constraint produces on each one of the problem's dimension. The solution of a linear optimization problem is…

Optimization and Control · Mathematics 2018-09-24 Gerardo L. Febres

Both for the theoretical and practical treatment of Inverse Problems, the modeling of the noise is a crucial part. One either models the measurement via a deterministic worst-case error assumption or assumes a certain stochastic behavior of…

Probability · Mathematics 2016-04-26 Daniel Gerth , Andreas Hofinger , Ronny Ramlau

Stochastic optimisation algorithms are the de facto standard for machine learning with large amounts of data. Handling only a subset of available data in each optimisation step dramatically reduces the per-iteration computational costs,…

Numerical Analysis · Mathematics 2024-12-19 Matthias J. Ehrhardt , Zeljko Kereta , Jingwei Liang , Junqi Tang

This paper considers a noisy data structure recovery problem. The goal is to investigate the following question: Given a noisy observation of a permuted data set, according to which permutation was the original data sorted? The focus is on…

Information Theory · Computer Science 2020-11-24 Minoh Jeong , Alex Dytso , Martina Cardone , H. Vincent Poor

In this work, we investigate the optimal map-making technique for the linear system $d=Ax+n$ while carefully taking into account singularities that may come from either the covariance matrix $C = \langle nn^t \rangle$ or the main matrix…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-09 Zirui Zhang , Yiwen Wu , Yang Liu , Siyu Li , Hong Li , Hao Liu

This paper introduces a novel approach to learning sparsity-promoting regularizers for solving linear inverse problems. We develop a bilevel optimization framework to select an optimal synthesis operator, denoted as $B$, which regularizes…

Machine Learning · Statistics 2026-03-03 Giovanni S. Alberti , Ernesto De Vito , Tapio Helin , Matti Lassas , Luca Ratti , Matteo Santacesaria

We propose a nonconvexly regularized convex model for linear regression problems under non-Gaussian noise. The cost function of the proposed model is designed with a possibly non-quadratic data fidelity term and a nonconvex regularizer via…

Optimization and Control · Mathematics 2025-09-04 Wataru Yata , Keita Kume , Isao Yamada

We provide an overview of recent progress in statistical inverse problems with random experimental design, covering both linear and nonlinear inverse problems. Different regularization schemes have been studied to produce robust and stable…

Statistics Theory · Mathematics 2023-12-27 Abhishake , Tapio Helin , Nicole Mücke

Stochastic programs where the uncertainty distribution must be inferred from noisy data samples are considered. The stochastic programs are approximated with distributionally-robust optimizations that minimize the worst-case expected cost…

Optimization and Control · Mathematics 2024-01-04 Farhad Farokhi

In this work, we consider a class of differentiable criteria for sparse image computing problems, where a nonconvex regularization is applied to an arbitrary linear transform of the target image. As special cases, it includes…

Optimization and Control · Mathematics 2013-08-27 Emilie Chouzenoux , Anna Jezierska , Jean-Christophe Pesquet , Hugues Talbot

The Monotonocity Principle (MP), stating a monotonic relationship between a material property and a proper corresponding boundary operator, is attracting great interest in the field of inverse problems, because of its fundamental role in…