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We describe a photon-conserving radiative transfer algorithm, using a spatially-adaptive ray tracing scheme, and its parallel implementation into the adaptive mesh refinement (AMR) cosmological hydrodynamics code, Enzo. By coupling the…

Instrumentation and Methods for Astrophysics · Physics 2015-05-20 John H. Wise , Tom Abel

High-precision time transfer over a long haul of fiber plays a significant role in many fields. The core method, namely cascading relay nodes for the compensation of signal attenuation and dispersion, is however insufficient to deal with…

Optics · Physics 2024-12-25 Yufei Zhang , Ziyang Chen , Bin Luo , Hong Guo

Recent progress in image recognition has stimulated the deployment of vision systems at an unprecedented scale. As a result, visual data are now often consumed not only by humans but also by machines. Existing image processing methods only…

Computer Vision and Pattern Recognition · Computer Science 2022-09-13 Zhuang Liu , Hung-Ju Wang , Tinghui Zhou , Zhiqiang Shen , Bingyi Kang , Evan Shelhamer , Trevor Darrell

Computed Tomography (CT) imaging, while essential for diagnostics, exposes patients to ionizing radiation. To accurately quantify radiation dosage, this study introduces MIDSX, a specialized open-source Monte Carlo (MC) photon transport…

Medical Physics · Physics 2023-11-29 John Meneghini

Super resolution offers a way to harness medium even lowresolution but historically valuable remote sensing image archives. Generative models, especially diffusion models, have recently been applied to remote sensing super resolution…

Computer Vision and Pattern Recognition · Computer Science 2025-10-28 Songxi Yang , Tang Sui , Qunying Huang

We consider imaging of fast moving small objects in space, such as low earth orbit satellites. The imaging system consists of ground based, asynchronous sources of radiation and several passive receivers above the dense atmosphere. We use…

Signal Processing · Electrical Eng. & Systems 2020-03-03 Matan Leibovich , George Papanicolaou , Chrysoula Tsogka

Although Monte Carlo path tracing is a simple and effective algorithm to synthesize photo-realistic images, it is often very slow to converge to noise-free results when involving complex global illumination. One of the most successful…

The current standard for a variety of computer vision tasks using smaller numbers of labelled training examples is to fine-tune from weights pre-trained on a large image classification dataset such as ImageNet. The application of transfer…

Computer Vision and Pattern Recognition · Computer Science 2021-08-31 Jo Plested , Xuyang Shen , Tom Gedeon

Currently, applying diffusion models in pixel space of high resolution images is difficult. Instead, existing approaches focus on diffusion in lower dimensional spaces (latent diffusion), or have multiple super-resolution levels of…

Computer Vision and Pattern Recognition · Computer Science 2023-12-13 Emiel Hoogeboom , Jonathan Heek , Tim Salimans

The electrical network reconfiguration problem aims to minimize losses in a distribution system by adjusting switches while ensuring radial topology. The growing use of renewable energy and the complexity of managing modern power grids make…

Systems and Control · Electrical Eng. & Systems 2025-08-12 Yacine Mokhtari , Patrick Coirault , Emmanuel Moulay , Jérôme Le Ny , Didier Larraillet

Context. Three-dimensional non-local thermodynamical equilibrium (NLTE) radiative transfer calculations are a fundamental tool for a detailed spectral analysis in stellar atmospheres, but require vast amounts of computer power. This…

Solar and Stellar Astrophysics · Physics 2023-07-12 Elias R. Udnæs , Tiago M. D. Pereira

A grid-overlay finite difference method is proposed for the numerical approximation of the fractional Laplacian on arbitrary bounded domains. The method uses an unstructured simplicial mesh and an overlay uniform grid for the underlying…

Numerical Analysis · Mathematics 2024-04-08 Weizhang Huang , Jinye Shen

Previous work has shown that it is possible to train deep neural networks with low precision weights and activations. In the extreme case it is even possible to constrain the network to binary values. The costly floating point…

Neural and Evolutionary Computing · Computer Science 2017-11-30 Sam Leroux , Steven Bohez , Tim Verbelen , Bert Vankeirsbilck , Pieter Simoens , Bart Dhoedt

We propose a numerical method to find the optimal transport map between a measure supported on a lower-dimensional subset of R^d and a finitely supported measure. More precisely, the source measure is assumed to be supported on a simplex…

Computational Geometry · Computer Science 2017-07-06 Quentin Mérigot , Jocelyn Meyron , Boris Thibert

We simulate convection near the solar surface, where the continuum optical depth is of order unity. Hence, to determine the radiative heating and cooling in the energy conservation equation, we must solve the radiative transfer equation…

Astrophysics · Physics 2007-05-23 Robert Stein , Aake Nordlund

This paper presents an efficient parallel radiative transfer-based inverse-problem solver for time-domain optical tomography. The radiative transfer equation provides a physically accurate model for the transport of photons in biological…

Medical Physics · Physics 2022-08-31 E. L. Gaggioli , O. P. Bruno

In this paper, we rethink the low-light image enhancement task and propose a physically explainable and generative diffusion model for low-light image enhancement, termed as Diff-Retinex. We aim to integrate the advantages of the physical…

Computer Vision and Pattern Recognition · Computer Science 2023-08-28 Xunpeng Yi , Han Xu , Hao Zhang , Linfeng Tang , Jiayi Ma

A full symmetry classification is given for models of energy transport in radiant plasma when the mass density is spatially variable and the diffusivity is nonlinear. A systematic search for conservation laws also leads to some potential…

Mathematical Physics · Physics 2015-06-18 P. Broadbridge , N. M. Ivanova

The Transfer Matrix Method is a powerful numerical tool for simulating wave propagation in layered media. It has been widely applied in many fields, although its use is typically restricted to passive media. In this paper, we develop the…

Numerical transfer matrices have been widely used in the study of wave propagation and scattering. These may be viewed as descretizations of a recently introduced fundamental notion of transfer matrix which admits a representation in terms…

Classical Physics · Physics 2023-10-03 Farhang Loran , Ali Mostafazadeh