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Related papers: Numerical non-LTE 3D radiative transfer using a mu…

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The emergence of three-dimensional magneto-hydrodynamic (MHD) simulations of stellar atmospheres has sparked a need for efficient radiative transfer codes to calculate detailed synthetic spectra. We present RH 1.5D, a massively parallel…

Solar and Stellar Astrophysics · Physics 2015-01-21 Tiago M. D. Pereira , Han Uitenbroek

This study concentrates on advancing mathematical and computational methodology for radar tomography imaging in which the unknown volumetric velocity distribution of a wave within a bounded domain is to be reconstructed. Our goal is to…

Instrumentation and Methods for Astrophysics · Physics 2018-04-04 Mika Takala , Defne Us , Sampsa Pursiainen

We present a ray-tracing technique for radiative transfer modeling of complex three-dimensional (3D) structures which include dense regions of high optical depth like in dense molecular clouds, circumstellar disks, envelopes of evolved…

Astrophysics · Physics 2009-11-11 J. Steinacker , A. Bacmann , Th. Henning

We consider the radiation transfer problem in the discrete-ordinate, plane-parallel approach. We introduce two benchmark problems with exact known solutions and show that for strongly non-homogeneous media the homogeneous layers…

Computational Physics · Physics 2007-05-23 M. -P. Zorzano , A. M. Mancho , L. Vazquez

This paper compares the performance of seven different element agglomeration algorithms on unstructured triangular/tetrahedral meshes when used as part of a geometric multigrid. Five of these algorithms come from the literature on AMGe…

Numerical Analysis · Mathematics 2020-05-20 S. Dargaville , A. G. Buchan , R. P. Smedley-Stevenson , P. N. Smith , C. C. Pain

Multipath communication not only allows improved throughput but can also be used to leverage different path characteristics to best fulfill each application's objective. In particular, certain delay-sensitive applications, such as real time…

Networking and Internet Architecture · Computer Science 2017-07-06 Laurent Chuat , Adrian Perrig , Yih-Chun Hu

We describe a code designed for hot media {(T $\ge$} a few 10$^4$ K), optically thick to Compton scattering. It computes the structure of a plane-parallel slab of gas in thermal and ionization equilibrium, illuminated on one side or on both…

Astrophysics · Physics 2009-09-25 Anne-Marie Dumont , Suzy Collin

In this paper, we propose and analyze a new semi-implicit stochastic multiscale method for the radiative heat transfer problem with additive noise fluctuation in composite materials. In the proposed method, the strong nonlinearity term…

Numerical Analysis · Mathematics 2026-05-12 Shan Zhang , Yajun Wang , Xiaofei Guan

We consider distributed Luby transform (DLT) codes for efficient packet transmission in a multi-way relay network, where the links are modeled as erasure channels. Density evolution is applied for asymptotic performance analysis, and…

Information Theory · Computer Science 2014-10-02 Iqbal Hussain , Ming Xiao , Lars K. Rasmussen

We describe the implementation of a module for the Athena magnetohydrodynamics (MHD) code which solves the time-independent, multi-frequency radiative transfer (RT) equation on multidimensional Cartesian simulation domains, including…

Instrumentation and Methods for Astrophysics · Physics 2015-06-03 Shane W. Davis , James M. Stone , Yan-Fei Jiang

Neural radiance fields (NeRF) have demonstrated the potential of coordinate-based neural representation (neural fields or implicit neural representation) in neural rendering. However, using a multi-layer perceptron (MLP) to represent a 3D…

Computer Vision and Pattern Recognition · Computer Science 2023-03-22 Daniel Rho , Byeonghyeon Lee , Seungtae Nam , Joo Chan Lee , Jong Hwan Ko , Eunbyung Park

Obeying constraints imposed by classical physics, we give optimal fine-grained algorithms for matrix multiplication and problems involving graphs and mazes, where all calculations are done in 3-dimensional space. We assume that whatever the…

Data Structures and Algorithms · Computer Science 2024-12-20 Quentin F. Stout

With the rising imaging resolution of handheld devices, existing multi-exposure image fusion algorithms struggle to generate a high dynamic range image with ultra-high resolution in real-time. Apart from that, there is a trend to design a…

Computer Vision and Pattern Recognition · Computer Science 2024-12-19 Xin Su , Zhuoran Zheng

We present a new numerical model called "Pakal" intended to solve the radiative transfer equation in a three-dimensional (3D) geometry, using the approximation for a locally plane-parallel atmosphere. Pakal uses pre-calculated radial…

Solar and Stellar Astrophysics · Physics 2011-06-14 Victor De la Luz , Alejandro Lara , J. E. Mendoza-Torres , Caius L. Selhorst

Algebraic multigrid (AMG) is often an effective solver for symmetric positive definite (SPD) linear systems resulting from the discretization of general elliptic PDEs, or the spatial discretization of parabolic PDEs. However, convergence…

Numerical Analysis · Mathematics 2019-09-10 Thomas A. Manteuffel , Steffen Munzenmaier , John Ruge , Ben S. Southworth

Lidars are depth measuring sensors widely used in autonomous driving and augmented reality. However, the large volume of data produced by lidars can lead to high costs in data storage and transmission. While lidar data can be represented as…

Image and Video Processing · Electrical Eng. & Systems 2022-06-07 Xuanyu Zhou , Charles R. Qi , Yin Zhou , Dragomir Anguelov

Driven by the appealing properties of neural fields for storing and communicating 3D data, the problem of directly processing them to address tasks such as classification and part segmentation has emerged and has been investigated in recent…

Computer Vision and Pattern Recognition · Computer Science 2024-01-31 Adriano Cardace , Pierluigi Zama Ramirez , Francesco Ballerini , Allan Zhou , Samuele Salti , Luigi Di Stefano

The computational cost of fast non-LTE synthesis is one of the challenges that limits the development of 2D and 3D inversion codes. It also makes the interpretation of observations of lines formed in the chromosphere and transition region a…

Solar and Stellar Astrophysics · Physics 2022-02-03 A. Vicente Arévalo , A. Asensio Ramos , S. Esteban Pozuelo

In recent advances in solving the problem of transmission network expansion planning, the use of robust optimization techniques has been put forward, as an alternative to stochastic mathematical programming methods, to make the problem…

Computational Engineering, Finance, and Science · Computer Science 2016-09-28 Roberto Minguez , Raquel Garcia-Bertrand

The multigrid methodology is reviewed. By integrating numerical processes at all scales of a problem, it seeks to perform various computational tasks at a cost that rises as slowly as possible as a function of $n$, the number of degrees of…

High Energy Physics - Lattice · Physics 2009-10-22 Achi Brandt
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