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We study an example of exact parametric resonance in a extended system ruled by nonlinear partial differential equations of nonlinear Schr\"odinger type. It is also conjectured how related models not exactly solvable should behave in the…

patt-sol · Physics 2009-10-10 J. J. Garcia-Ripoll , V. M. Perez-Garcia , P. Torres

We present a new nonlinear optimization approach for the sparse reconstruction of single-photon absorption and two-photon absorption coefficients in photoacoustic tomography (PAT). This framework comprises of minimizing an objective…

Optimization and Control · Mathematics 2020-06-30 Madhu Gupta , Rohit Kumar Mishra , Souvik Roy

In this paper we the formulation of inverse problems as constrained minimization problems and their iterative solution by gradient or Newton type. We carry out a convergence analysis in the sense of regularization methods and discuss…

Numerical Analysis · Mathematics 2021-01-15 Barbara Kaltenbacher , Kha Van Huynh

Previous papers have shown the impact of partial convergence of discretized PDE on the accuracy of tangent and adjoint linearizations. A series of papers suggested linearization of the fixed point iteration used in the solution process as a…

Numerical Analysis · Mathematics 2022-02-24 Emmett Padway , Dimitri Mavriplis

The problem of state reconstruction is considered for uncertain linear time-invariant systems with overparameterization, arbitrary state-space matrices and unknown additive perturbation described by an exosystem. A novel adaptive observer…

Systems and Control · Electrical Eng. & Systems 2024-03-14 Anton Glushchenko , Konstantin Lastochkin

We introduce and discuss shape-based models for finding the best interpolation data in the compression of images with noise. The aim is to reconstruct missing regions by means of minimizing a data fitting term in the $L^2$-norm between the…

Numerical Analysis · Mathematics 2022-02-23 Zakaria Belhachmi , Thomas Jacumin

We consider a class of uncertain linear time-invariant overparametrized systems affected by bounded disturbances, which are described by a known exosystem with unknown initial conditions. For such systems an exponentially stable extended…

Systems and Control · Electrical Eng. & Systems 2024-02-14 Anton Glushchenko , Konstantin Lastochkin

Physics-based models often involve large systems of parametrized partial differential equations, where design parameters control various properties. However, high-fidelity simulations of such systems on large domains or with high grid…

Computational Physics · Physics 2025-05-15 Diba Behnoudfar

We introduce and discuss shape based models for finding the best interpolation data in compression of images with noise. The aim is to reconstruct missing regions by means of minimizing data fitting term in the $L^2$-norm between the images…

Numerical Analysis · Mathematics 2020-11-05 Zakaria Belhachmi , Thomas Jacumin

Motivated by the maneuvering target tracking with sensors such as radar and sonar, this paper considers the joint and recursive estimation of the dynamic state and the time-varying process noise covariance in nonlinear state space models.…

Systems and Control · Electrical Eng. & Systems 2023-05-09 Hua Lan , Jinjie Hu , Zengfu Wang , Qiang Cheng

In this work, we propose a telegraph coupled partial differential equation (TCPDE) based model for image restoration. New framework interpolates between a couple of non-linear telegraph equation and a parabolic equation. Proposed strategy…

Analysis of PDEs · Mathematics 2019-09-12 Sudeb Majee , Subit K. Jain , Rajendra K. Ray , Ananta K. Majee

In this study, we present several improvements of the non-relativistic Friedrichs-Lee model with multiple discrete and continuous states and still retain its solvability. Our findings establish a solid theoretical basis for the exploration…

High Energy Physics - Phenomenology · Physics 2025-04-17 Zhiguang Xiao , Zhi-Yong Zhou

Entanglement has been proposed as a means to improve the sensitivity of sensing weak signals. While the degree of this quantum advantage is well understood in noiseless settings, the situation is more complex under realistic conditions,…

Quantum Physics · Physics 2026-05-07 Noah Kaufmann , Kasper H. Nielsen , Eva M. González-Ruiz , Anders S. Sørensen

We describe an efficient domain decomposition-based framework for nonlinear multiscale PDE problems. The framework is inspired by manifold learning techniques and exploits the tangent spaces spanned by the nearest neighbors to compress…

Numerical Analysis · Mathematics 2021-11-10 Shi Chen , Qin Li , Jianfeng Lu , Stephen J. Wright

We study the effects of time and space correlations of an external additive colored noise on the steady-state behavior of a Time-Dependent Ginzburg-Landau model. Simulations show the existence of nonequilibrium phase transitions controlled…

Condensed Matter · Physics 2009-10-22 Jordi Garcia-Ojalvo , Jose M. Sancho

In many scientific settings, acquiring complete observations of PDE coefficients and solutions can be expensive, hazardous, or impossible. Recent diffusion-based methods can reconstruct fields given partial observations, but require…

Artificial Intelligence · Computer Science 2026-02-17 Harris Abdul Majid , Giannis Daras , Francesco Tudisco , Steven McDonagh

In the present paper we consider the problem of Laplace deconvolution with noisy discrete observations. The study is motivated by Dynamic Contrast Enhanced imaging using a bolus of contrast agent, a procedure which allows considerable…

Statistics Theory · Mathematics 2012-07-12 Fabienne Comte , Charles-André Cuénod , Marianna Pensky , Yves Rozenholc

Hybrid inverse problems are based on the interplay of two types of waves, in order to allow for imaging with both high resolution and high contrast. The inversion procedure often consists of two steps: first, internal measurements involving…

Analysis of PDEs · Mathematics 2022-10-14 Giovanni S. Alberti

Exponentially stable extended adaptive observer is proposed for a class of linear time-invariant systems with unknown parameters and overparameterization. It allows one to reconstruct unmeasured states and bounded external disturbance…

Systems and Control · Electrical Eng. & Systems 2023-01-19 Anton Glushchenko , Konstantin Lastochkin

This paper proposes a new extended-state observer-based framework for adaptive nonlinear regulator design of a class of nonlinear systems, in the general nonequilibrium theory. By augmenting an extended-state observer with an internal…

Systems and Control · Electrical Eng. & Systems 2024-12-20 Lei Wang , Christopher M. Kellett