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We perform a comparison between two radiative transfer algorithms commonly employed in hydrodynamical calculations of star formation: grey flux limited diffusion and the hybrid scheme, in addition we compare these algorithms to results from…

Solar and Stellar Astrophysics · Physics 2015-06-11 James E. Owen , Barbara Ercolano , Cathie J. Clarke

Context: Thermal conductivity provides important contributions to the energy evolution of the upper solar atmosphere, behaving as a non-linear concentration-dependent diffusion equation. Recently, different methods have been offered as…

Solar and Stellar Astrophysics · Physics 2024-12-11 George Cherry , Boris Gudiksen , Mikolaj Szydlarski

The dominant image-to-image translation methods are based on fully convolutional networks, which extract and translate an image's features and then reconstruct the image. However, they have unacceptable computational costs when working with…

Computer Vision and Pattern Recognition · Computer Science 2022-07-12 Yuda Song , Hui Qian , Xin Du

This paper newly introduces multi-modality loss function for GAN-based super-resolution that can maintain image structure and intensity on unpaired training dataset of clinical CT and micro CT volumes. Precise non-invasive diagnosis of lung…

Image and Video Processing · Electrical Eng. & Systems 2020-04-08 Tong Zheng , Hirohisa Oda , Takayasu Moriya , Shota Nakamura , Masahiro Oda , Masaki Mori , Horitsugu Takabatake , Hiroshi Natori , Kensaku Mori

The development of radiation hydrodynamical methods that are able to follow gas dynamics and radiative transfer self-consistently is key to the solution of many problems in numerical astrophysics. Such fluid flows are highly complex, rarely…

The interpretation of the intensity and polarization of the spectral line radiation produced in the atmosphere of the Sun and of other stars requires solving a radiative transfer problem that can be very complex, especially when the main…

Solar and Stellar Astrophysics · Physics 2015-06-16 Jiri Stepan , Javier Trujillo Bueno

We present Arepo-MCRT, a novel Monte Carlo radiative transfer (MCRT) radiation-hydrodynamics (RHD) solver for the unstructured moving-mesh code Arepo. Our method is designed for general multiple scattering problems in both optically thin…

Astrophysics of Galaxies · Physics 2020-12-16 Aaron Smith , Rahul Kannan , Benny T. -H. Tsang , Mark Vogelsberger , Ruediger Pakmor

The idea of media-based modulation (MBM) is to embed information in the channel states via intentional perturbations of the transmission media. This article covers a broad range of topics regarding MBM, expanding on its benefits and…

Information Theory · Computer Science 2022-11-15 Ehsan Seifi , Amir K. Khandani , Mehran Atamanesh

In this work, we prove rigorous error estimates for a hybrid method introduced in [15] for solving the time-dependent radiation transport equation (RTE). The method relies on a splitting of the kinetic distribution function for the…

Numerical Analysis · Mathematics 2023-06-09 Andrés Galindo-Olarte , Victor P. DeCaria , Cory D. Hauck

To improve the computational efficiencies of the real-space orbital-free density functional theory, this work develops a new single-grid solver by directly providing the closed-form solution to the inner iteration and using an improved…

Computational Physics · Physics 2023-05-16 Ling-Ze Bu , Wei Wang

We present an algorithm for solving the radiative transfer problem on massively parallel computers using adaptive mesh refinement and domain decomposition. The solver is based on the method of characteristics which requires an adaptive…

Astrophysics of Galaxies · Physics 2015-08-13 Lars Buntemeyer , Robi Banerjee , Thomas Peters , Mikhail Klassen , Ralph E. Pudritz

Radiative transfer (RT) modelling is a necessary tool in the interpretation of observations of the thermal emission of interstellar dust. It is also often part of multi-physics modelling. In this context, the efficiency of radiative…

Instrumentation and Methods for Astrophysics · Physics 2024-08-27 Mika Juvela

We discuss an implementation of our 3D radiative transfer (3DRT) framework with the OpenCL paradigm for general GPU computing. We implement the kernel for solving the 3DRT problem in Cartesian coordinates with periodic boundary conditions…

Instrumentation and Methods for Astrophysics · Physics 2011-08-01 Peter H. Hauschildt , E. Baron

In Computational Fluid Dynamics (CFD), coarse mesh simulations offer computational efficiency but often lack precision. Applying conventional super-resolution to these simulations poses a significant challenge due to the fundamental…

We developed a three-dimensional radiative transfer code for an ultra-relativistic background flow-field by using the Monte Carlo (MC) method in the context of gamma-ray burst (GRB) emission. For obtaining reliable simulation results in the…

High Energy Astrophysical Phenomena · Physics 2017-09-13 Ayako Ishii , Naofumi Ohnishi , Hiroki Nagakura , Hirotaka Ito , Shoichi Yamada

We develop a numerical code to calculate the neutrino transfer with multi-energy and multi-angle in three dimensions (3D) for the study of core-collapse supernovae. The numerical code solves the Boltzmann equations for neutrino…

High Energy Astrophysical Phenomena · Physics 2012-03-26 Kohsuke Sumiyoshi , Shoichi Yamada

The MHD version of the adaptive mesh refinement (AMR) code, MG, has been employed to study the interaction of thermal instability, magnetic fields and gravity through 3D simulations of the formation of collapsing cold clumps on the scale of…

Astrophysics of Galaxies · Physics 2020-11-11 C. J. Wareing , J. M. Pittard , S. A. E. G. Falle

Context: The solution of the nonlocal thermodynamical equilibrium (non-LTE) radiative transfer equation usually relies on stationary iterative methods, which may falsely converge in some cases. Furthermore, these methods are often unable to…

Solar and Stellar Astrophysics · Physics 2015-07-29 Julien Lambert , Eric Josselin , Nils Ryde , Alexandre Faure

Cooperative transmission is an emerging communication technique that takes advantage of the broadcast nature of wireless channels. However, due to low spectral efficiency and the requirement of orthogonal channels, its potential for use in…

Information Theory · Computer Science 2016-11-17 Zhu Han , Xin Zhang , H. Vincent Poor

We have developed a three-dimensional radiative transfer method designed specifically for use with parallel adaptive mesh refinement hydrodynamics codes. This new algorithm, which we call hybrid characteristics, introduces a novel form of…

Astrophysics · Physics 2009-11-11 Erik-Jan Rijkhorst , Tomasz Plewa , Anshu Dubey , Garrelt Mellema