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We consider the inverse scattering problem for sparse scatterers. An image reconstruction algorithm is proposed that is based on a nonlinear generalization of iterative hard thresholding. The convergence and error of the method was analyzed…

Numerical Analysis · Mathematics 2019-03-27 Anna C. Gilbert , Howard W. Levinson , John C. Schotland

The first globally convergent numerical method for a Coefficient Inverse Problem (CIP) for the Riemannian Radiative Transfer Equation (RRTE) is constructed. This is a version of the so-called \textquotedblleft convexification" method, which…

Numerical Analysis · Mathematics 2023-04-13 Michael V. Klibanov , Jingzhi Li , Loc H. Nguyen , Vladimir G. Romanov , Zhipeng Yang

Precomputed Radiance Transfer (PRT) remains an attractive solution for real-time rendering of complex light transport effects such as glossy global illumination. After precomputation, we can relight the scene with new environment maps while…

Graphics · Computer Science 2023-07-13 Nithin Raghavan , Yan Xiao , Kai-En Lin , Tiancheng Sun , Sai Bi , Zexiang Xu , Tzu-Mao Li , Ravi Ramamoorthi

Thermal Radiative Transfer (TRT) is the dominant energy transfer mechanism in high-energy density physics with applications in inertial confinement fusion and astrophysics. The stiff interactions between the material and radiation fields…

Computational Physics · Physics 2019-05-01 Hans Hammer , HyeongKae Park , Luis Chacon

We propose an explicit-implicit scheme for numerically solving Special Relativistic Radiation Hydrodynamic (RRHD) equations, which ensures a conservation of total energy and momentum (matter and radiation). In our scheme, 0th and 1st moment…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Hiroyuki R. Takahashi , Ken Ohsuga , Yuichiro Sekiguchi , Tsuyoshi Inoue , Kengo Tomida

The phase retrieval problem is found in various areas of applications of engineering and applied physics. It is also a very active field of research in mathematics, signal processing and machine learning. In this paper, we present an…

Optimization and Control · Mathematics 2023-04-26 Rossen Nenov , Dang-Khoa Nguyen , Peter Balazs

In this short paper, the authors report a new computational approach in the context of Density Functional Theory (DFT). It is shown how it is possible to speed up the self-consistent cycle (iteration) characterizing one of the most…

Computational Physics · Physics 2015-05-19 Edoardo Di Napoli , Paolo Bientinesi

Reconstructing the unknown spectrum of a given X-ray source is a common problem in a wide range of X-ray imaging tasks. For high-energy sources, transmission measurements are mostly used to recover the X-ray spectrum, as a solution to an…

Applied Physics · Physics 2023-07-13 Arthur Walker , Alexandre Friou , Kevin Ginsburger

Remarkable mathematical properties of the integrable nonlinear Schr\"odinger equation (NLSE) can offer advanced solutions for the mitigation of nonlinear signal distortions in optical fibre links. Fundamental optical soliton, continuous and…

Exactly Solvable and Integrable Systems · Physics 2017-06-07 L. L. Frumin , A. A. Gelash , S. K. Turitsyn

A new approach to distributed cooperative beamforming in relay networks with frequency selective fading is proposed. It is assumed that all the relay nodes are equipped with finite impulse response (FIR) filters and use a filter-and-forward…

Adaptation and Self-Organizing Systems · Physics 2016-11-15 Haihua Chen , Alex B. Gershman , Shahram Shahbazpanahi

Fast, high-order accurate algorithms for electromagnetic scattering from axisymmetric objects are of great importance when modeling physical phenomena in optics, materials science (e.g. meta-materials), and many other fields of applied…

Numerical Analysis · Mathematics 2019-05-22 Jun Lai , Michael O'Neil

The discussion regarding the numerical integration of the polarized radiative transfer equation is still open and the comparison between the different numerical schemes proposed by different authors in the past is not fully clear. Aiming at…

Solar and Stellar Astrophysics · Physics 2017-09-06 Gioele Janett , Edgar S. Carlin , Oskar Steiner , Luca Belluzzi

Light field (LF) images containing information for multiple views have numerous applications, which can be severely affected by low-light imaging. Recent learning-based methods for low-light enhancement have some disadvantages, such as a…

Computer Vision and Pattern Recognition · Computer Science 2023-08-16 Shansi Zhang , Nan Meng , Edmund Y. Lam

Generative models based on flow matching have attracted significant attention for their simplicity and superior performance in high-resolution image synthesis. By leveraging the instantaneous change-of-variables formula, one can directly…

Computer Vision and Pattern Recognition · Computer Science 2025-01-06 Yasi Zhang , Peiyu Yu , Yaxuan Zhu , Yingshan Chang , Feng Gao , Ying Nian Wu , Oscar Leong

This paper develops and analyzes a general iterative framework for solving parameter-dependent and random convection-diffusion problems. It is inspired by the multi-modes method of [7,8] and the ensemble method of [20] and extends those…

Numerical Analysis · Mathematics 2021-10-22 Xiaobing Feng , Yan Luo , Liet Vo , Zhu Wang

Radio Tomographic Imaging (RTI) is a phaseless imaging approach that can provide shape reconstruction and localization of objects using received signal strength (RSS) measurements. RSS measurements can be straightforwardly obtained from…

Applied Physics · Physics 2023-11-17 Amartansh Dubey , Zan Li , Ross Murch

A recursive algebraic method which allows to obtain the Feynman or Schwinger parametric representation of a generic L-loops and (E+1) external lines diagram, in a scalar $\phi ^{3}\oplus \phi ^{4}$ theory, is presented. The representation…

High Energy Physics - Theory · Physics 2009-11-11 Ivan Gonzalez , Ivan Schmidt

Obtaining the inverse of a large symmetric positive definite matrix $\mathcal{A}\in\mathbb{R}^{p\times p}$ is a continual challenge across many mathematical disciplines. The computational complexity associated with direct methods can be…

Numerical Analysis · Mathematics 2025-09-03 Ann Paterson , Jennifer Pestana , Victorita Dolean

This paper presents approximation methods for time-dependent thermal radiative transfer problems in high energy density physics. It is based on the multilevel quasidiffusion method defined by the high-order radiative transfer equation (RTE)…

Numerical Analysis · Mathematics 2026-03-18 Dmitriy Y. Anistratov , Joseph M. Coale

Interpreting scattered acoustic and electromagnetic wave patterns is a computational task that enables remote imaging in a number of important applications, including medical imaging, geophysical exploration, sonar and radar detection, and…

Computational Physics · Physics 2025-04-03 Owen Melia , Olivia Tsang , Vasileios Charisopoulos , Yuehaw Khoo , Jeremy Hoskins , Rebecca Willett