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In this paper, we introduce a novel two-point gradient method for solving the ill-posed problems in Banach spaces and study its convergence analysis. The method is based on the well known iteratively regularized Landweber iteration method…

Numerical Analysis · Mathematics 2022-05-12 Gaurav Mittal , Ankik Kumar Giri

In this paper, we discuss the construction, analysis and implementation of a novel iterative regularization scheme with general convex penalty term for nonlinear inverse problems in Banach spaces based on the homotopy perturbation…

Numerical Analysis · Mathematics 2018-01-10 Jing Wang , Wei Wang , Bo Han

In this work we discuss a method to adapt sequential subspace optimization (SESOP), which has so far been developed for linear inverse problems in Hilbert and Banach spaces, to the case of nonlinear inverse problems. We start by revising…

Numerical Analysis · Mathematics 2016-02-23 Anne Wald , Thomas Schuster

In this paper, we propose and analyze a two-point gradient method for solving inverse problems in Banach spaces which is based on the Landweber iteration and an extrapolation strategy. The method allows to use non-smooth penalty terms,…

Numerical Analysis · Mathematics 2018-12-31 Min Zhong , Wei Wang , Qinian Jin

In recent years Landweber(-Kaczmarz) method has been proposed for solving nonlinear ill-posed inverse problems in Banach spaces using general convex penalty functions. The implementation of this method involves solving a (nonsmooth) convex…

Numerical Analysis · Mathematics 2016-08-24 Qinian Jin

In this paper, the local convergence of Iteratively regularized Landweber iteration method is investigated for solving non-linear inverse problems in Banach spaces. Our analysis mainly relies on the assumption that the inverse mapping…

Numerical Analysis · Mathematics 2020-11-17 Gaurav Mittal , Ankik Kumar Giri

In this paper we propose an extension of the iteratively regularized Gauss--Newton method to the Banach space setting by defining the iterates via convex optimization problems. We consider some a posteriori stopping rules to terminate the…

Numerical Analysis · Mathematics 2013-06-11 Qinian Jin , Min Zhong

We consider parameter identification problems in parametrized partial differential equations (PDE). This leads to nonlinear ill-posed inverse problems. One way to solve them are iterative regularization methods, which typically require…

Numerical Analysis · Mathematics 2018-05-07 Dominik Garmatter , Bernard Haasdonk , Bastian Harrach

The choice of a suitable regularization parameter is an important part of most regularization methods for inverse problems. In the absence of reliable estimates of the noise level, heuristic parameter choice rules can be used to accomplish…

Numerical Analysis · Mathematics 2022-05-23 Simon Hubmer , Ekaterina Sherina , Stefan Kindermann , Kemal Raik

In this paper, we propose and analyze a fast two-point gradient algorithm for solving nonlinear ill-posed problems, which is based on the sequential subspace optimization method. A complete convergence analysis is provided under the…

Analysis of PDEs · Mathematics 2019-11-06 Guangyu Gao , Bo Han , Shanshan Tong

An efficient nonlinear contrast source inversion scheme for electromagnetic imaging of sparse two-dimensional investigation domains is proposed. To avoid generating a sequence of linear sparse optimization problems, the non-linearity is…

Signal Processing · Electrical Eng. & Systems 2021-04-13 Ali I. Sandhu , Abdulla Desmal , Hakan Bagci

Stochastic gradient descent (SGD) and its variants are widely used and highly effective optimization methods in machine learning, especially for neural network training. By using a single datum or a small subset of the data, selected…

Numerical Analysis · Mathematics 2026-01-21 Bangti Jin , Zeljko Kereta , Yuxin Xia

We investigate the ill-posed inverse problem of recovering unknown spatially dependent parameters in nonlinear evolution PDEs. We propose a bi-level Landweber scheme, where the upper-level parameter reconstruction embeds a lower-level state…

Numerical Analysis · Mathematics 2024-03-07 Tram Thi Ngoc Nguyen

This article introduces an innovative mathematical framework designed to tackle non-linear convex variational problems in reflexive Banach spaces. Our approach employs a versatile technique that can handle a broad range of variational…

Numerical Analysis · Mathematics 2023-09-13 Pablo M. Berná , Antonio Falcó

Regularisation theory in Banach spaces, and non--norm-squared regularisation even in finite dimensions, generally relies upon Bregman divergences to replace norm convergence. This is comparable to the extension of first-order optimisation…

Optimization and Control · Mathematics 2021-03-19 Tuomo Valkonen

We consider a class of inverse problems defined by a nonlinear map from parameter or model functions to the data. We assume that solutions exist. The space of model functions is a Banach space which is smooth and uniformly convex; however,…

Functional Analysis · Mathematics 2015-05-30 Maarten V. de Hoop , Lingyun Qiu , Otmar Scherzer

We consider nonlinear inverse problems described by operator equations in Banach spaces. Assuming conditional stability of the inverse problem, that is, assuming that stability holds on a closed, convex subset of the domain of the operator,…

Numerical Analysis · Mathematics 2012-06-19 Maarten V. de Hoop , Lingyun Qiu , Otmar Scherzer

We derive and analyse a new variant of the iteratively regularized Landweber iteration, for solving linear and nonlinear ill-posed inverse problems. The method takes into account training data, which are used to estimate the interior of a…

Numerical Analysis · Mathematics 2020-03-19 Andrea Aspri , Sebastian Banert , Ozan Öktem , Otmar Scherzer

Consider linear ill-posed problems governed by the system $A_i x = y_i$ for $i =1, \cdots, p$, where each $A_i$ is a bounded linear operator from a Banach space $X$ to a Hilbert space $Y_i$. In case $p$ is huge, solving the problem by an…

Numerical Analysis · Mathematics 2023-05-17 Qinian Jin , Xiliang Lu , Liuying Zhang

We introduce and investigate an iterative scheme for approximating common fixed point of a family of Bregman relatively-nonexpansive mappings in real reflexive Banach spaces. We prove strong convergence theorem of the sequence generated by…

Functional Analysis · Mathematics 2017-07-27 Oladipo Abiodun Timoye , Enyinnaya Ekuma-Okereke
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