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In this paper we present two efficient implementations of the diffusion approximation to be employed in Monte Carlo computations of radiative transfer in dusty media of massive circumstellar disks. The aim is to improve the accuracy of the…

Instrumentation and Methods for Astrophysics · Physics 2009-11-13 M. Min , C. P. Dullemond , C. Dominik , A. de Koter , J. W. Hovenier

Topology optimization enables the automated design of efficient structures by optimally distributing material within a defined domain. However, traditional gradient-based methods often scale poorly with increasing resolution and…

Computational Engineering, Finance, and Science · Computer Science 2025-08-08 Aaron Lutheran , Srijan Das , Alireza Tabarraei

Recently, machine learning has been successfully applied to model-based left ventricle (LV) segmentation. The general framework involves two stages, which starts with LV localization and is followed by boundary delineation. Both are driven…

Computer Vision and Pattern Recognition · Computer Science 2015-07-29 Peng Sun , Haoyin Zhou , Devon Lundine , James K. Min , Guanglei Xiong

Broad emission lines of active galactic nuclei stem from a spatially extended region (broad-line region, BLR) that is composed of discrete clouds and photoionized by the central ionizing continuum. The temporal behaviors of these emission…

Instrumentation and Methods for Astrophysics · Physics 2016-12-07 Yan-Rong Li , Jian-Min Wang , Jin-Ming Bai

We present an implementation of radiative transfer with flux-limited diffusion (FLD) for the moving-mesh code {\small AREPO} and use the method in a physical model for the formation of protostars with non-ideal…

Solar and Stellar Astrophysics · Physics 2025-12-23 Alexander C. Mayer , Rüdiger Pakmor , Thorsten Naab , Oliver Zier , Alexei V. Ivlev , Tommaso Grassi , Paola Caselli , Volker Springel

Permutation testing is a non-parametric method for obtaining the max null distribution used to compute corrected $p$-values that provide strong control of false positives. In neuroimaging, however, the computational burden of running such…

Radiative transfer is a key component in almost all astrophysical and cosmological simulations. We present Magritte: a modern open-source software library for 3D radiative transfer. It uses a deterministic ray-tracer and formal solver, i.e.…

Instrumentation and Methods for Astrophysics · Physics 2020-01-08 Frederik De Ceuster , Ward Homan , Jeremy Yates , Leen Decin , Peter Boyle , James Hetherington

Starting from the observation that the correlation coefficient defined by the scattered field data tested by two adjacent antennas decreases with the noise, it turns out that the imaging performance can be improved by adding non-redundant…

Applied Physics · Physics 2024-01-08 Xinhui Zhang , Naike Du , Jing Wang , Andrea Massa , Xiuzhu Ye

In this work, we propose a general framework for wireless imaging in distributed MIMO wideband communication systems, considering multi-view non-isotropic targets and near-field propagation effects. For indoor scenarios where the objective…

Signal Processing · Electrical Eng. & Systems 2025-08-26 Kangda Zhi , Tianyu Yang , Shuangyang Li , Yi Song , Amir Rezaei , Giuseppe Caire

This letter describes how to improve performance of cellular systems by combining non-equiprobable signaling (shaping) with low-density parity check (LDPC) coding for an orthogonal frequency division multiplexing system. We focus on…

Signal Processing · Electrical Eng. & Systems 2026-02-03 Sandesh Rao Mattu , Nishant Mehrotra , Robert Calderbank

The so-called full non-local thermodynamic equilibrium (FNLTE) radiative transfer problem allows us to take into account not only deviations of the radiation field from the Planckian but also deviations of the densities and velocity…

Solar and Stellar Astrophysics · Physics 2026-05-14 T. Lagache , M. Sampoorna , F. Paletou

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

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

The solar chromosphere is a region where radiation plays a critical role in energy transfer and interacts strongly with the plasma. In this layer, strong spectral lines, such as the Lyman lines, contribute significantly to radiative energy…

Solar and Stellar Astrophysics · Physics 2026-02-10 W. Ruan , D. Przybylski , R. Cameron , S. K. Solanki

In this paper, we present our spectrum sharing algorithm between a multi-input multi-output (MIMO) radar and Long Term Evolution (LTE) cellular system with multiple base stations (BS)s. We analyze the performance of MIMO radars in detecting…

Networking and Internet Architecture · Computer Science 2014-08-29 Haya Shajaiah , Ahmed Abdelhadi , Charles Clancy

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

State-of-the-art ray tracing techniques operate on hierarchical acceleration structures such as BVH trees which wrap objects in a scene into bounding volumes of decreasing sizes. Acceleration structures reduce the amount of ray-scene…

Graphics · Computer Science 2019-10-04 Francois Demoullin , Ayub Gubran , Tor Aamodt

Numerical methods for radiative transfer play a key role in modern-day astrophysics and cosmology, including study of the inhomogeneous reionization process. In this context, ray tracing methods are well-regarded for accuracy but notorious…

Instrumentation and Methods for Astrophysics · Physics 2025-12-16 Nathan X. Marshak , Kathlynn Simotas , Zarija Lukić , Hyunbae Park , James Ahrens , Chris R. Johnson

Spatial Modulation (SM) is a technique that can enhance the capacity of MIMO schemes by exploiting the index of transmit antenna to convey information bits. In this paper, we describe this technique, and present a new MIMO transmission…

Systems and Control · Computer Science 2012-04-09 Rajab M. Legnain , Roshdy H. M. Hafez , Abdelgader M. Legnain

Purpose: To evaluate an algorithm for calibrationless parallel imaging to reconstruct undersampled parallel transmit field maps for the body and brain. Methods: Using synthetic data, body, and brain measurements of relative transmit maps,…

Image and Video Processing · Electrical Eng. & Systems 2020-11-13 Aaron T Hess , Iulius Dragonu , Mark Chiew