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We investigate the use of neural networks (NNs) for the estimation of hidden model parameters and uncertainty quantification from noisy observational data for inverse parameter estimation problems. We formulate the parameter estimation as a…

Numerical Analysis · Mathematics 2025-10-17 German Villalobos , Johann Rudi , Andreas Mang

Ultrasound imaging is an incontestable vital tool for diagnosis, it provides in non-invasive manner the internal structure of the body to detect eventually diseases or abnormalities tissues. Unfortunately, the presence of speckle noise in…

Computer Vision and Pattern Recognition · Computer Science 2013-05-08 Faouzi Benzarti , Hamid Amiri

We consider the inverse problem of recovering both an unknown electric current and the surrounding electromagnetic parameters of a medium from boundary measurements. This inverse problem arises in brain imaging. We show that under generic…

Analysis of PDEs · Mathematics 2017-10-25 Youjun Deng , Hongyu Liu , Gunther Uhlmann

Emerging sonography techniques often require increasing the number of transducer elements involved in the imaging process. Consequently, larger amounts of data must be acquired and processed. The significant growth in the amounts of data…

Information Theory · Computer Science 2015-06-04 Noam Wagner , Yonina C. Eldar , Zvi Friedman

Nonlinear metasurfaces incorporate many of the functionalities of their linear counterparts such as wavefront shaping but simultaneously they perform nonlinear optical transformations. This dual functionality leads to a rather unintuitive…

This work intends to prove that strong instabilities may appear for high order geometric optics expansions of weakly stable quasilinear hyperbolic boundary value problems, when the forcing boundary term is perturbed by a small amplitude…

Analysis of PDEs · Mathematics 2022-06-30 Corentin Kilque

Ultrasound is an important imaging modality for biological systems. High-frequency ultrasound can also (e.g., via acoustical nonlinearities) be used to provide deeply penetrating and high-resolution imaging of vascular structure via…

Optics · Physics 2015-09-08 Ivan S. Maksymov , Andrew D. Greentree

Fast camera imaging is used to study ion acoustic waves propagating azimuthally in a magnetized plasma column. The high speed image sequences are analyzed using Proper Orthogonal Decomposition and 2D Fourier Transform, allowing to evaluate…

Plasma Physics · Physics 2023-02-01 Simon Vincent , Vincent Dolique , Nicolas Plihon

This paper is concerned with backward problem for nonlinear space fractional diffusion with additive noise on the right-hand side and the final value. To regularize the instable solution, we develop some new regularized method for solving…

Analysis of PDEs · Mathematics 2016-12-19 Erkan Nane , Nguyen Huy Tuan

In this article we develop an effective theory of pulse propagation in a nonlinear and disordered medium. The theory is formulated in terms of a nonlinear diffusion equation. Despite its apparent simplicity this equation describes novel…

Mesoscale and Nanoscale Physics · Physics 2013-05-29 G. Schwiete , A. M. Finkel'stein

Nonlinear effects are crucial in order to compute the cosmological matter power spectrum to the accuracy required by future generation surveys. Here, a new approach is presented, in which the power spectrum, the bispectrum and higher order…

Astrophysics · Physics 2009-11-13 Massimo Pietroni

This paper provides a mathematical analysis of ultrafast ultrasound imaging. This newly emerging modality for biomedical imaging uses plane waves instead of focused waves in order to achieve very high frame rates. We derive the point spread…

Numerical Analysis · Mathematics 2017-01-09 Giovanni S. Alberti , Habib Ammari , Francisco Romero , Timothée Wintz

The theory of nonlinear magnetoacoustic wave in the past has strictly been focused on purely compressive features of the mode. We show that a complete set of nonlinear equations necessarily includes both compressional and shear components…

Plasma Physics · Physics 2013-08-19 J. Vranjes , B. P. Pandey

This paper presents an application of time-frequency methods to characterize the dispersion of acoustic waves travelling in a one-dimensional periodic or disordered lattice made up of Helmholtz resonators connected to a cylindrical tube.…

Classical Physics · Physics 2009-07-10 Olivier Richoux , Claude Depollier , Jean Hardy

The forward problems of pattern formation have been greatly empowered by extensive theoretical studies and simulations, however, the inverse problem is less well understood. It remains unclear how accurately one can use images of pattern…

Computational Physics · Physics 2021-04-07 Hongbo Zhao , Richard D. Braatz , Martin Z. Bazant

The diffusion of electronic wave packets in one-dimensional systems with on-site, binary disorder is numerically investigated within the framework of a single-band tight-binding model. Fractal properties are incorporated by assuming that…

Disordered Systems and Neural Networks · Physics 2008-07-07 P. R. Wells , J. d'Albuquerque e Castro , S. L. A. de Queiroz

In the case of multi-parameter full-waveform inversion, the computation of the additional Hessian terms that contain derivatives with respect to more than one type of parameter is necessary. If a simple gradient-based minimization is used,…

Geophysics · Physics 2018-04-05 Pawan Bharadwaj , Wim Mulder , Guy Drijkoningen

Ultrasound (US) imaging is better suited for intraoperative settings because it is real-time and more portable than other imaging techniques, such as mammography. However, US images are characterized by lower spatial resolution noise-like…

Image and Video Processing · Electrical Eng. & Systems 2023-08-11 Sahar Almahfouz Nasser , Ashutosh Sharma , Anmol Saraf , Amruta Mahendra Parulekar , Purvi Haria , Amit Sethi

The analysis of nonlinear spectroscopy, widely used to study the dynamics and structures of condensed-phase matter, typically employs a perturbative approach noticing the weak interaction between the laser and the matter of interest.…

Optics · Physics 2022-06-23 Xue Zhang , Hui Dong

We investigate the interaction of a plane, linearly polarized, Alfvenic pulse with a one-dimensional, perpendicular to the magnetic field, plasma density inhomogeneity in the strongly nonlinear regime. Our numerical study of the full MHD…

Astrophysics · Physics 2009-11-07 D. Tsiklauri , V. M. Nakariakov , T. D. Arber
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