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Many natural phenomena involve processes that happen simultaneously at different characteristic length- and timescales. Typically, the region where the process of interest happens is affected by fluctuations in its surroundings. Modeling…

Materials Science · Physics 2026-04-24 Hari Haran Sudhakar , Alessandra Serva , Rocio Semino

KHARMA (an acronym for "Kokkos-based High-Accuracy Relativistic Magnetohydrodynamics with Adaptive mesh refinement") is a new open-source code for conducting general-relativistic magnetohydrodynamic simulations in stationary spacetimes,…

High Energy Astrophysical Phenomena · Physics 2024-08-05 Ben S. Prather

We propose a Neural Hidden Markov Model (HMM) with Adaptive Granularity Attention (AGA) for high-frequency order flow modeling. The model addresses the challenge of capturing multi-scale temporal dynamics in financial markets, where…

Statistical Finance · Quantitative Finance 2026-03-24 Tianzuo Hu

(Abridged) We describe a new algorithm for solving the coupled frequency-integrated transfer equation and the equations of magnetohydrodynamics when the light-crossing time is only marginally shorter than dynamical timescales. The transfer…

Instrumentation and Methods for Astrophysics · Physics 2014-06-24 Yan-Fei Jiang , James M. Stone , Shane W. Davis

Reaction-diffusion systems are used to represent many biological and physical phenomena. They model the random motion of particles (diffusion) and interactions between them (reactions). Such systems can be modelled at multiple scales with…

Quantitative Methods · Quantitative Biology 2018-06-08 Cameron A. Smith , Christian A. Yates

We propose a time-adaptive predictor/multi-corrector method to solve hyperbolic partial differential equations, based on the generalized-$\alpha$ scheme that provides user-control on the numerical dissipation and second-order accuracy in…

Numerical Analysis · Mathematics 2022-10-11 Nicolas A. Labanda , Pouria Behnoudfar , Victor M. Calo

In solar physics, a severe numerical challenge for modern simulations is properly representing a transition region between the million-degree hot corona and a much cooler plasma of about 10000 K (e.g., the upper chromosphere or a…

Solar and Stellar Astrophysics · Physics 2021-04-07 Yu-Hao Zhou , Wen-Zhi Ruan , Chun Xia , Rony Keppens

Modelling the interaction between ionizing photons emitted from massive stars and their environment is essential to further our understanding of galactic ecosystems. We present a hybrid Radiation-Hydrodynamics (RHD) scheme that couples an…

Instrumentation and Methods for Astrophysics · Physics 2024-04-29 Cheryl S. C. Lau , Maya A. Petkova , Ian A. Bonnell

Mixed-frame formulations of radiation-hydrodynamics (RHD), where the radiation quantities are computed in an inertial frame but matter quantities are in a comoving frame, are advantageous because they admit algorithms that conserve energy…

Astrophysics of Galaxies · Physics 2024-11-25 Chong-Chong He , Benjamin D. Wibking , Mark R. Krumholz

We introduce AREPO-RT, a novel radiation hydrodynamic (RHD) solver for the unstructured moving-mesh code AREPO. Our method solves the moment-based radiative transfer equations using the M1 closure relation. We achieve second order…

Instrumentation and Methods for Astrophysics · Physics 2019-02-13 Rahul Kannan , Mark Vogelsberger , Federico Marinacci , Ryan McKinnon , Rüdiger Pakmor , Volker Springel

We have developed a new computer code, RAM, to solve the conservative equations of special relativistic hydrodynamics (SRHD) using adaptive mesh refinement (AMR) on parallel computers. We have implemented a characteristic-wise, finite…

Astrophysics · Physics 2009-11-11 Weiqun Zhang , Andrew I. MacFadyen

Magnetohydrodynamics (MHD) describes the interaction between electrically conducting fluids and electromagnetic fields. We propose and analyze a symplectic, second-order algorithm for the evolutionary MHD system in Els\"asser variables. We…

Numerical Analysis · Mathematics 2025-07-18 Zhen Yao , Catalin Trenchea , Wenlong Pei

We present an adaptive multiresolution method for the numerical simulation of ideal magnetohydrodynamics in two space dimensions. The discretization uses a finite volume scheme based on a Cartesian mesh and an explicit compact Rung-Kutta…

The design and implementation of a new framework for adaptive mesh refinement (AMR) calculations is described. It is intended primarily for applications in astrophysical fluid dynamics, but its flexible and modular design enables its use…

Instrumentation and Methods for Astrophysics · Physics 2020-07-08 James M. Stone , Kengo Tomida , Christopher J. White , Kyle G. Felker

High dynamic range (HDR) imaging under extreme illumination remains challenging for conventional cameras due to overexposure. Event cameras provide microsecond temporal resolution and high dynamic range, while spatially varying exposure…

Computer Vision and Pattern Recognition · Computer Science 2026-03-03 Pengju Sun , Banglei Guan , Jing Tao , Zhenbao Yu , Xuanyu Bai , Yang Shang , Qifeng Yu

State-space models (SSMs) offer efficient alternatives to attention with linear-time recurrence. Mamba2, a recent SSM-based language model, uses selective input gating and a multi-head structure, enabling parallel computation and strong…

Machine Learning · Computer Science 2026-03-25 Yehjin Shin , Seojin Kim , Noseong Park

We describe a novel adaptive ray tracing scheme to solve the equation of radiative transfer around point sources in hydrodynamical simulations. The angular resolution adapts to the local hydrodynamical resolution and hence is of use for…

Astrophysics · Physics 2009-11-07 Tom Abel , Benjamin D. Wandelt

This paper investigates the generation of realistic full-body human motion using a single head-mounted device with an outward-facing color camera and the ability to perform visual SLAM. To address the ambiguity of this setup, we present…

Computer Vision and Pattern Recognition · Computer Science 2025-03-04 Vladimir Guzov , Yifeng Jiang , Fangzhou Hong , Gerard Pons-Moll , Richard Newcombe , C. Karen Liu , Yuting Ye , Lingni Ma

We present Variable Eddington Tensor-closed Transport on Adaptive Meshes (\texttt{VETTAM}), a new algorithm to solve the equations of radiation hydrodynamics (RHD) with support for adaptive mesh refinement (AMR) in a frequency-integrated,…

Instrumentation and Methods for Astrophysics · Physics 2022-03-02 Shyam H. Menon , Christoph Federrath , Mark R. Krumholz , Rolf Kuiper , Benjamin D. Wibking , Manuel Jung

Purpose: Magnetic resonance fingerprinting (MRF) methods typically rely on dictio-nary matching to map the temporal MRF signals to quantitative tissue parameters. Such approaches suffer from inherent discretization errors, as well as high…

Image and Video Processing · Electrical Eng. & Systems 2021-03-11 Pingfan Song , Yonina C. Eldar , Gal Mazor , Miguel Rodrigues