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A solution of the radiative-transfer problem in arbitrary velocity fields introduced in a previous paper, has limitations in its applicability. For large-scale applications, the methods described also require large memory sets that are…

Solar and Stellar Astrophysics · Physics 2009-09-24 S. Knop , P. H. Hauschildt , E. Baron

Higher resolution telescopes as well as 3D numerical simulations will require the development of detailed 3D radiative transfer calculations. Building upon our previous work we extend our method to include both continuum and line transfer.…

Astrophysics · Physics 2009-11-13 E. Baron , Peter H. Hauschildt

The randomized row method is a popular representative of the iterative algorithm because of its efficiency in solving the overdetermined and consistent systems of linear equations. In this paper, we present an extended randomized multiple…

Numerical Analysis · Mathematics 2024-11-06 Nian-Ci Wu , Chengzhi Liu , Yatian Wang , Qian Zuo

We present a proof of concept for solving a 1+1D complex-valued, delay partial differential equation (PDE) that emerges in the study of waveguide quantum electrodynamics (QED) by adapting the finite-difference time-domain (FDTD) method. The…

Mathematical Software · Computer Science 2018-11-19 Yao-Lung L. Fang

Aims. We present MCFOST-art, a new non-local thermodynamic equilibrium radiative transfer solver for multilevel atomic systems. The code is embedded in the 3D radiative transfer code MCFOST and is compatible with most of the MCFOST modules.…

Solar and Stellar Astrophysics · Physics 2021-03-03 B. Tessore , C. Pinte , J. Bouvier , F. Ménard

In [7], a new iterative method for solving linear system of equations was presented which can be considered as a modification of the Gauss-Seidel method. Then in [4] a different approach, say 2D-DSPM, and more effective one was introduced.…

Numerical Analysis · Mathematics 2009-06-10 Davod Khojasteh Salkuyeh

MIMO mobile systems, with a large number of antennas at the base-station side, enable the concurrent transmission of multiple, spatially separated information streams and, therefore, enable improved network throughput and connectivity both…

Information Theory · Computer Science 2021-01-06 Konstantinos Nikitopoulos , Marcin Filo , Chathura Jayawardena , Rahim Tafazolli

Our objective is to stabilise and accelerate the time-domain boundary element method (TDBEM) for the three-dimensional wave equation. To overcome the potential time instability, we considered using the Burton--Miller-type boundary integral…

Numerical Analysis · Mathematics 2022-01-05 Toru Takahashi , Masaki Tanigawa , Naoya Miyazawa

Doublet line emission and absorption is common in astronomical sources (e.g. [OIII], [OII], NaD, MgII). In many cases, complex kinematics in the emitting source can cause the doublet lines to merge, making characterisation of the source…

Instrumentation and Methods for Astrophysics · Physics 2018-09-26 Carolin Villforth , Tom L. Underwood , Mark Tolson , Nikhil Modha

Most of the physical information about astrophysical objects is obtained via the analysis of their electromagnetic spectra. Observed data coupled with radiation transfer models in physical conditions representative of stars, planets,…

Solar and Stellar Astrophysics · Physics 2026-05-29 Maria Bergemann , Richard Hoppe

We investigate the accuracy of the recently proposed nonclassical transport equation. This equation contains an extra independent variable compared to the classical transport equation (the path-length $s$), and models particle transport…

Nuclear Theory · Physics 2016-11-08 Richard Vasques , Kai Krycki , Rachel N. Slaybaugh

We propose a fast inference method for Bayesian nonlinear support vector machines that leverages stochastic variational inference and inducing points. Our experiments show that the proposed method is faster than competing Bayesian…

Machine Learning · Statistics 2018-03-22 Florian Wenzel , Theo Galy-Fajou , Matthaeus Deutsch , Marius Kloft

Multilevel optimization has gained renewed interest in machine learning due to its promise in applications such as hyperparameter tuning and continual learning. However, existing methods struggle with the inherent difficulty of efficiently…

Machine Learning · Computer Science 2024-10-16 Yuntian Gu , Xuzheng Chen

In this paper we propose a modified Lie-type spectral splitting approximation where the external potential is of quadratic type. It is proved that we can approximate the solution to a one-dimensional nonlinear Schroedinger equation by…

Mathematical Physics · Physics 2022-03-17 Andrea Sacchetti

Thermal radiative transfer (TRT) presents significant computational challenges due to the stiff, nonlinear coupling between radiation and material energy, particularly in multigroup, high-fidelity transport models. In this work, we develop…

Numerical Analysis · Mathematics 2026-03-24 Samuel Olivier , James S. Warsa , HyeongKae Park

We present an algorithm for two-dimensional radiative transfer in axisymmetric, circumstellar media. The formal integration of the transfer equation is performed by a generalization of the short characteristics (SC) method to spherical…

Astrophysics · Physics 2007-05-23 C. P. Dullemond , R. Turolla

Radiative transfer modelling is part of many astrophysical simulations and is used to make synthetic observations and to assist analysis of observations. We concentrate on the modelling of the radio lines emitted by the interstellar medium.…

Instrumentation and Methods for Astrophysics · Physics 2021-01-04 M. Juvela

We consider an adaptive multiresolution-based lattice Boltzmann scheme, which we have recently introduced and studied from the perspective of the error control and the theory of the equivalent equations. This numerical strategy leads to…

Numerical Analysis · Mathematics 2022-01-20 Thomas Bellotti , Loïc Gouarin , Benjamin Graille , Marc Massot

In this letter, we address the optimal source and relay matrices design for the multiple-input multiple-output~(MIMO) relaying broadcast channels~(BC) with direct links~(DLs) based on weighted sum-rate criterion.This problem is nonlinear…

Signal Processing · Electrical Eng. & Systems 2020-03-13 Haibin Wan , Wen Chen , Xiaoli Wang

Innovation in the physical layer of communication systems has traditionally been achieved by breaking down the transceivers into sets of processing blocks, each optimized independently based on mathematical models. Conversely, deep learning…

Information Theory · Computer Science 2022-05-04 Mathieu Goutay
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