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In the reconstruction process of unknown multiple scattering objects in inverse medium scattering problems, the first important step is to effectively locate some approximate domains that contain all inhomogeneous media. Without such an…

Numerical Analysis · Mathematics 2015-06-12 Keji Liu , Jun Zou

This paper reviews recent results on hybrid inverse problems, which are also called coupled-physics inverse problems of multi-wave inverse problems. Inverse problems tend to be most useful in, e.g., medical and geophysical imaging, when…

Analysis of PDEs · Mathematics 2011-10-24 Guillaume Bal

We describe an implicit general relativistic hydrodynamics code. The evolution equations are formulated in comoving coordinates. A conservative finite differencing of the Einstein equations is outlined, and artificial viscosity and…

Astrophysics · Physics 2010-05-12 Matthias Liebendoerfer , Stephan Rosswog , Friedrich-Karl Thielemann

Coordinate-transformation approaches to invisibility cloaking rely on the design of an anisotropic, spatially inhomogeneous "transformation medium" capable of suitably re-routing the energy flux around the region to conceal without causing…

Optics · Physics 2015-05-13 Giuseppe Castaldi , Ilaria Gallina , Vincenzo Galdi

This paper aims to devise an adaptive neural network basis method for numerically solving a second-order semilinear partial differential equation (PDE) with low-regular solutions in two/three dimensions. The method is obtained by combining…

Numerical Analysis · Mathematics 2024-11-05 Jianguo Huang , Haohao Wu , Tao Zhou

The spectral transformation Lanczos method for the sparse symmetric definite generalized eigenvalue problem for matrices $A$ and $B$ is an iterative method that addresses the case of semidefinite or ill conditioned $B$ using a shifted and…

Numerical Analysis · Mathematics 2024-11-07 Michael Stewart

Hyperspectral anomaly detection (HAD), a crucial approach for many civilian and military applications, seeks to identify pixels with spectral signatures that are anomalous relative to a preponderance of background signatures. Significant…

Computer Vision and Pattern Recognition · Computer Science 2025-10-02 Abu Hasnat Mohammad Rubaiyat , Jordan Vincent , Colin Olson

In this article we study the inverse problem of thermoacoustic tomography (TAT) on a medium with attenuation represented by a time- convolution (or memory) term, and whose consideration is motivated by the modeling of ultrasound waves in…

Analysis of PDEs · Mathematics 2017-03-29 Sebastian Acosta , Benjamin Palacios

In this paper, we employ asymptotic analysis to determine information about small volume defects in a known anisotropic scattering medium from far field scattering data. The location of the defects is reconstructed via the MUSIC algorithm…

Analysis of PDEs · Mathematics 2017-02-21 Fioralba Cakoni , Isaac Harris , Shari Moskow

A recently designed hyperspectral imaging device enables multiplexed acquisition of an entire data volume in a single snapshot thanks to monolithically-integrated spectral filters. Such an agile imaging technique comes at the cost of a…

Computer Vision and Pattern Recognition · Computer Science 2015-02-09 K. Degraux , V. Cambareri , L. Jacques , B. Geelen , C. Blanch , G. Lafruit

We present a new method to achieve high-contrast images using segmented and/or on-axis telescopes. Our approach relies on using two sequential Deformable Mirrors to compensate for the large amplitude excursions in the telescope aperture due…

Instrumentation and Methods for Astrophysics · Physics 2015-06-12 Laurent Pueyo , Colin Norman

Lie symmetry analysis is applied to study the nonlinear rotating shallow water equations. The 9-dimensional Lie algebra of point symmetries admitted by the model is found. It is shown that the rotating shallow water equations are related…

Analysis of PDEs · Mathematics 2016-02-08 Alexander Chesnokov

This paper analyzes inverse scattering for the one-dimensional Helmholtz equation in the case where the wave speed is piecewise constant. Scattering data recorded for an arbitrarily small interval of frequencies is shown to determine the…

Analysis of PDEs · Mathematics 2020-08-26 Sophia Bugarija , Peter C. Gibson , Guanghui Hu , Peijun Li , Yue Zhao

We introduce a novel approach to learn geometries such as depth and surface normal from images while incorporating geometric context. The difficulty of reliably capturing geometric context in existing methods impedes their ability to…

Computer Vision and Pattern Recognition · Computer Science 2024-04-02 Xiaoxiao Long , Yuhang Zheng , Yupeng Zheng , Beiwen Tian , Cheng Lin , Lingjie Liu , Hao Zhao , Guyue Zhou , Wenping Wang

An inverse problem of wave propagation into a weakly laterally inhomogeneous medium occupying a half-space is considered in the acoustic approximation. The half-space consists of an upper layer and a semi-infinite bottom separated with an…

Mathematical Physics · Physics 2007-05-23 A. S. Blagovestchenskii , Y. Kurylev , V. Zalipaev

We develop techniques to solve ill-posed inverse problems on the sphere by sparse regularisation, exploiting sparsity in both axisymmetric and directional scale-discretised wavelet space. Denoising, inpainting, and deconvolution problems,…

Information Theory · Computer Science 2017-08-17 Christopher G. R. Wallis , Yves Wiaux , Jason D. McEwen

In this paper, we address the inverse problem of fast, stable, and high-quality wavefront reconstruction from pyramid wavefront sensor data for Adaptive Optics systems on Extremely Large Telescopes. For solving the indicated problem we…

Instrumentation and Methods for Astrophysics · Physics 2019-05-01 Victoria Hutterer , Ronny Ramlau , Iuliia Shatokhina

The recent development of spectral method has been praised for its high-order convergence in simulating complex physical problems. The combination of embedded boundary method and spectral method becomes a mainstream way to tackle…

Numerical Analysis · Mathematics 2018-03-08 Po-Yi Wu , Cheng-Hong Robert Kao , Tony Wen-Hann Sheu

We develop the effective non-Hermitian Hamiltonian approach for open systems with Neumann boundary conditions. The approach can be used for calculating the scattering matrix and the scattering function in open resonator-waveguide systems.…

Quantum Physics · Physics 2015-04-14 Dmitrii N. Maksimov , Almas F. Sadreev , Alina A. Lyapina , Artem S. Pilipchuk

Interstellar medium widely exists in the universe at multi-scales. In this study, we introduce the {\it Multi-scale Decomposition Reconstruction} method, an equation-based model designed to derive width maps of interstellar medium…

Astrophysics of Galaxies · Physics 2025-12-23 Mengke Zhao , Guang-Xing Li , Duo Xu , Keping Qiu
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