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The high resolution and sensitivity provided by proposed Atacama Large Millimeter Array will reveal new small scale structures in many sources, e.g. star forming regions. Such inhomogeneities may not have been considered in the analysis of…

Astrophysics · Physics 2007-05-23 M. Juvela , P. Padoan

Nowadays computational complexity of fast walsh hadamard transform and nonlinearity for Boolean functions and large substitution boxes is a major challenge of modern cryptography research on strengthening encryption schemes against linear…

Cryptography and Security · Computer Science 2020-04-27 Behrooz Khadem , Reza Ghasemi

This paper proposes a mode multigrid (MMG) method, and applies it to accelerate the convergence of the steady state flow on unstructured grids. The dynamic mode decomposition (DMD) technique is used to analyze the convergence process of…

Computational Physics · Physics 2018-02-27 Yilang Liu , Weiwei Zhang , Jiaqing Kou

The multigrid algorithm is an efficient numerical method for solving a variety of elliptic partial differential equations (PDEs). The method damps errors at progressively finer grid scales, resulting in faster convergence compared to…

Numerical Analysis · Mathematics 2021-05-06 Francisco Holguin , GS Sidharth , Gavin Portwood

The massive hot stars play crucial role in the dynamics of galaxies. These stars influence their surroundings through strong winds which are highly structured processes. The theoretical study of the non-symmetric phenomena of the stellar…

Solar and Stellar Astrophysics · Physics 2026-01-30 Jakub Fišák , Jiří Kubát , Nicolas Moens , Brankica Kubátová

Spectral line observations are an indispensable tool to remotely probe the physical and chemical conditions throughout the universe. Modelling their behaviour is a computational challenge that requires dedicated software. In this paper, we…

Instrumentation and Methods for Astrophysics · Physics 2024-11-06 Thomas Ceulemans , Frederik De Ceuster , Leen Decin , Jeremy Yates

We present new methods for radiative transfer on hierarchial grids. We develop a new method for calculating the scattered flux that employs the grid structure to speed up the computation. We describe a novel subiteration algorithm that can…

Instrumentation and Methods for Astrophysics · Physics 2015-06-05 T. Lunttila , M. Juvela

In this paper we discuss numerical methods and algorithms for the solution of NLTE stellar atmosphere problems involving expanding atmospheres, e.g., found in novae, supernovae and stellar winds. We show how a scheme of nested iterations…

Astrophysics · Physics 2011-06-02 P. H. Hauschildt , E. Baron

Context. 3D numerical simulations of radiative transfer are crucial for understanding complex astrophysical objects. For Monte Carlo radiative transfer, the spatial grid design is critical yet complex. Common grids include hierarchical…

Astrophysics of Galaxies · Physics 2024-07-30 Arno Lauwers , Maarten Baes , Peter Camps , Bert Vander Meulen

Trapping lithium with a big number in a simplified experimental setup has difficulties and challenges today. In this paper, we experimentally demonstrate the enhancement of \textsuperscript{6}Li trapping efficiency in a three-dimensional…

Atomic Physics · Physics 2017-08-16 Kai Li , Dongfang Zhang , Tianyou Gao , Shi-Guo Peng , Kaijun Jiang

In complex environments, autonomous robot navigation and environmental perception pose higher requirements for SLAM technology. This paper presents a novel method for semantically enhancing 3D point cloud maps with thermal information. By…

Robotics · Computer Science 2026-01-15 Jiajun Sun , Yangyi Ou , Haoyuan Zheng , Chao yang , Yue Ma

We have developed a set of techniques for performing large scale ab initio calculations using multigrid accelerations and a real-space grid as a basis. The multigrid methods permit efficient calculations on ill-conditioned systems with long…

mtrl-th · Physics 2009-10-28 E. L. Briggs , D. J. Sullivan , J. Bernholc

In this paper we explore the possibility for solving the 3D Maxwell's equations in the presence of nonlinear and/or inhomogeneous material response. We propose using a hybrid approach which combines a bound- ary integral representation with…

Numerical Analysis · Mathematics 2019-08-07 Aihua Lin , Per Kristen Jakobsen

For the practical implementation of massive multiple-input multiple-output (MIMO) systems, the hybrid processing (precoding/combining) structure is promising to reduce the high cost rendered by large number of RF chains of the traditional…

Information Theory · Computer Science 2015-04-16 Weiheng Ni , Xiaodai Dong , Wu-Sheng Lu

To realize low-latency spatial transmission system for immersive telepresence, there are two major problems: capturing dynamic 3D scene densely and processing them in real time. LiDAR sensors capture 3D in real time, but produce sparce…

Computer Vision and Pattern Recognition · Computer Science 2026-01-14 Kazuhiko Murasaki , Shunsuke Konagai , Masakatsu Aoki , Taiga Yoshida , Ryuichi Tanida

We investigate the effects of horizontal radiative transfer (RT) a NLTE on important diagnostic iron lines in a realistic 3-D HD simulation. Using a multi-level atom we compute and compare widely used Fe I line profiles at 3 different…

Solar and Stellar Astrophysics · Physics 2015-06-16 R. Holzreuter , S. K. Solanki

A numerical scheme is proposed for the solution of the three-dimensional radiative transfer equation with variable optical depth. We show that time-dependent ray tracing is an attractive choice for simulations of astrophysical ionization…

Astrophysics · Physics 2009-10-31 Alexei Razoumov , Douglas Scott

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 this paper, a novel multigrid method based on Newton iteration is proposed to solve nonlinear eigenvalue problems. Instead of handling the eigenvalue $\lambda$ and eigenfunction $u$ separately, we treat the eigenpair $(\lambda, u)$ as…

Numerical Analysis · Mathematics 2024-04-30 Fei Xu , Manting Xie , Meiling Yue

This work develops a nonlinear multigrid method for diffusion problems discretized by cell-centered finite volume methods on general unstructured grids. The multigrid hierarchy is constructed algebraically using aggregation of degrees of…

Numerical Analysis · Mathematics 2020-10-29 Chak Shing Lee , François Hamon , Nicola Castelletto , Panayot S. Vassilevski , Joshua White