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The SD-SPIDER method for the characterization of ultrashort laser pulses requires the solution of a nonlinear integral equation of autoconvolution type with a device-based kernel function. Taking into account the analytical background of a…

Numerical Analysis · Mathematics 2016-03-23 Stephan W. Anzengruber , Steven Buerger , Bernd Hofmann , Guenter Steinmeyer

In this paper, we consider the nonlinear ill-posed inverse problem with noisy data in the statistical learning setting. The Tikhonov regularization scheme in Hilbert scales is considered to reconstruct the estimator from the random noisy…

Statistics Theory · Mathematics 2024-04-09 Abhishake Rastogi

We study regularization of ill-posed equations involving multiplication operators when the multiplier function is positive almost everywhere and zero is an accumulation point of the range of this function. Such equations naturally arise…

Statistics Theory · Mathematics 2019-08-19 Peter Mathé , M. Thamban Nair , Bernd Hofmann

The recently developed data-driven eigenmatrix method shows very promising reconstruction accuracy in sparse recovery for a wide range of kernel functions and random sample locations. However, its current implementation can lead to…

Numerical Analysis · Mathematics 2024-05-15 Koung Hee Leem , Jun Liu , George Pelekanos

The problem of numerical differentiation can be thought of as an inverse problem by considering it as solving a Volterra equation. It is well known that such inverse integral problems are ill-posed and one requires regularization methods to…

Numerical Analysis · Mathematics 2020-04-15 Abinash Nayak

We consider the ill-posed inverse problem of identifying a nonlinearity in a time-dependent PDE model. The nonlinearity is approximated by a neural network, and needs to be determined alongside other unknown physical parameters and the…

Numerical Analysis · Mathematics 2022-11-23 Barbara Kaltenbacher , Tram Thi Ngoc Nguyen

Despite a variety of available techniques the issue of the proper regularization parameter choice for inverse problems still remains one of the biggest challenges. The main difficulty lies in constructing a rule, allowing to compute the…

Numerical Analysis · Mathematics 2017-10-13 Ernesto De Vito , Massimo Fornasier , Valeriya Naumova

This paper is concerned with a novel regularisation technique for solving linear ill-posed operator equations in Hilbert spaces from data that is corrupted by white noise. We combine convex penalty functionals with extreme-value statistics…

Statistics Theory · Mathematics 2012-04-03 Klaus Frick , Philipp Marnitz , Axel Munk

We study the linear ill-posed inverse problem with noisy data in the statistical learning setting. Approximate reconstructions from random noisy data are sought with general regularization schemes in Hilbert scale. We discuss the rates of…

Statistics Theory · Mathematics 2024-04-09 Abhishake Rastogi , Peter Mathé

In this paper, we study the inverse problem for a class of abstract ultraparabolic equations which is well-known to be ill-posed. We employ some elementary results of semi-group theory to present the formula of solution, then show the…

Analysis of PDEs · Mathematics 2015-12-10 Vo Anh Khoa , Le Trong Lan , Nguyen Huy Tuan , Tran The Hung

Inverse problems and regularization theory is a central theme in contemporary signal processing, where the goal is to reconstruct an unknown signal from partial indirect, and possibly noisy, measurements of it. A now standard method for…

Optimization and Control · Mathematics 2014-12-09 Samuel Vaiter , Gabriel Peyré , Jalal M. Fadili

Regularization plays a pivotal role in ill-posed machine learning and inverse problems. However, the fundamental comparative analysis of various regularization norms remains open. We establish a small noise analysis framework to assess the…

Machine Learning · Statistics 2024-09-05 Quanjun Lang , Fei Lu

In this work, we study the well-posedness of certain sparse regularized linear regression problems, i.e., the existence, uniqueness and continuity of the solution map with respect to the data. We focus on regularization functions that are…

Statistics Theory · Mathematics 2024-09-06 Jasper Marijn Everink , Yiqiu Dong , Martin Skovgaard Andersen

Tikhonov regularization is one of the most commonly used methods of regularization of ill-posed problems. In the setting of finite element solutions of elliptic partial differential control problems, Tikhonov regularization amounts to…

Numerical Analysis · Mathematics 2016-09-19 Erik Burman , Peter Hansbo , Mats Larson

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

We propose an image deconvolution algorithm when the data is contaminated by Poisson noise. The image to restore is assumed to be sparsely represented in a dictionary of waveforms such as the wavelet or curvelet transforms. Our key…

Applications · Statistics 2009-11-13 François-Xavier Dupé , Jalal Fadili , Jean Luc Starck

In this paper, we investigate regularization of linear inverse problems with irregular noise. In particular, we consider the case that the noise can be preprocessed by certain adjoint embedding operators. By introducing the consequent…

Numerical Analysis · Mathematics 2024-01-30 Xinyan Li , Simon Hubmer , Shuai Lu , Ronny Ramlau

Implicit inverse problems, in which noisy observations of a physical quantity are used to infer a nonlinear functional applied to an associated function, are inherently ill posed and often exhibit non uniqueness of solutions. Such problems…

Numerical Analysis · Mathematics 2025-05-27 Davide Parodi , Federico Benvenuto , Sara Garbarino , Michele Piana

Accurate determination of the regularization parameter in inverse problems still represents an analytical challenge, owing mainly to the considerable difficulty to separate the unknown noise from the signal. We present a new approach for…

Numerical Analysis · Mathematics 2019-07-24 Eitan Levin , Alexander Y. Meltzer

This paper proposes a new approach for solving ill-posed nonlinear inverse problems. For ease of explanation of the proposed approach, we use the example of lung electrical impedance tomography (EIT), which is known to be a nonlinear and…

Numerical Analysis · Mathematics 2019-08-01 Jin Keun Seo , Kang Cheol Kim , Ariungerel Jargal , Kyounghun Lee , Bastian Harrach
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