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Diffusive shock acceleration (DSA) of particles at collisionless shocks is the major accepted paradigm about the origin of cosmic rays (CRs). As a theory it was developed during the late 1970s in the so-called test-particle case. If one…

High Energy Astrophysical Phenomena · Physics 2023-10-03 Bojan Arbutina

The radiative transfer equation (RTE) arises in many different areas of science and engineering. In this paper, we propose and investigate a discrete-ordinate discontinuous-streamline diffusion (DODSD) method for solving the RTE, which is a…

Numerical Analysis · Mathematics 2016-11-23 Cheng Wang , Qiwei Sheng , Weimin Han

Particle acceleration is an ubiquitous phenomenon in astrophysical and space plasma. Diffusive shock acceleration (DSA) and stochastic turbulent acceleration are known to be the possible mechanisms for producing very high energetic…

High Energy Astrophysical Phenomena · Physics 2021-11-17 Sayan Kundu , Bhargav Vaidya , Andrea Mignone

The research interest in specialized hardware accelerators for deep neural networks (DNN) spikes recently owing to their superior performance and efficiency. However, today's DNN accelerators primarily focus on accelerating specific…

Distributed, Parallel, and Cluster Computing · Computer Science 2020-06-11 Cong Guo , Yangjie Zhou , Jingwen Leng , Yuhao Zhu , Zidong Du , Quan Chen , Chao Li , Bin Yao , Minyi Guo

In this paper a methodology is described to estimate multigroup neutron source distributions which must be added into a subcritical system to drive it to a steady state prescribed power distribution. This work has been motivated by the…

Nuclear Theory · Physics 2021-06-26 Leonardo , R. C. Moraes , Hermes Alves Filho , Ricardo C. Barros

The multigroup neutron transport criticality calculations using modern supercomputers have been widely employed in a nuclear reactor analysis for studying whether or not a system is self-sustaining. However, the design and development of…

Numerical Analysis · Mathematics 2020-02-19 Fande Kong

In this work, we first consider distributed convex constrained optimization problems where the objective function is encoded by multiple local and possibly nonsmooth objectives privately held by a group of agents, and propose a distributed…

Optimization and Control · Mathematics 2020-02-20 Changxin Liu , Huiping Li , Yang Shi

Dynamic spectrum access (DSA) is regarded as an effective and efficient technology to share radio spectrum among different networks. As a secondary user (SU), a DSA device will face two critical problems: avoiding causing harmful…

Machine Learning · Computer Science 2018-10-30 Hao-Hsuan Chang , Hao Song , Yang Yi , Jianzhong Zhang , Haibo He , Lingjia Liu

In Diffusion Transformer (DiT) models, particularly for video generation, attention latency is a major bottleneck due to the long sequence length and the quadratic complexity. We find that attention weights can be separated into two parts:…

For a number of applications like low-source reactor start-up or neutron coincidence counting it is necessary to take into account the stochastic nature of neutron transport and go beyond the average neutron density, which is solution of a…

Computational Physics · Physics 2024-12-04 Philippe Humbert

Over the last few years, Neural Processes have become a useful modelling tool in many application areas, such as healthcare and climate sciences, in which data are scarce and prediction uncertainty estimates are indispensable. However, the…

Machine Learning · Computer Science 2023-11-17 Lorenzo Bonito , James Requeima , Aliaksandra Shysheya , Richard E. Turner

In this work, a new numerical method for the transport of Delayed Neutron Precursors (DNPs) is applied to the Aircraft Reactor Experiment (ARE). The pathline method is based on the Method of Characteristics (MOC) and leverages the pathlines…

Computational Physics · Physics 2025-02-25 Mathis Caprais , Nathan Greiner , André Bergeron

A collision-based hybrid algorithm for the discrete ordinates approximation of the neutron transport equation is extended to the multigroup setting. The algorithm uses discrete energy and angle grids at two different resolutions and…

Computational Physics · Physics 2022-12-05 Ben Whewell , Ryan G. McClarren , Cory D. Hauck , Minwoo Shin

Recent advances in Deep Neural Networks (DNNs) have led to active development of specialized DNN accelerators, many of which feature a large number of processing elements laid out spatially, together with a multi-level memory hierarchy and…

Machine Learning · Computer Science 2021-05-06 Qijing Huang , Minwoo Kang , Grace Dinh , Thomas Norell , Aravind Kalaiah , James Demmel , John Wawrzynek , Yakun Sophia Shao

Diffusion models have achieved remarkable success in generative tasks but suffer from high computational costs due to their iterative sampling process and quadratic attention costs. Existing training-free acceleration strategies that reduce…

Machine Learning · Computer Science 2025-07-24 Ting Jiang , Yixiao Wang , Hancheng Ye , Zishan Shao , Jingwei Sun , Jingyang Zhang , Zekai Chen , Jianyi Zhang , Yiran Chen , Hai Li

Continuous-space video generation has advanced rapidly, while discrete approaches lag behind due to error accumulation and long-context inconsistency. In this work, we revisit discrete generative modeling and present Uniform discRete…

Computer Vision and Pattern Recognition · Computer Science 2025-10-29 Haoge Deng , Ting Pan , Fan Zhang , Yang Liu , Zhuoyan Luo , Yufeng Cui , Wenxuan Wang , Chunhua Shen , Shiguang Shan , Zhaoxiang Zhang , Xinlong Wang

We present results from a fully relativistic Monte Carlo simulation of diffusive shock acceleration (DSA) in unmodified (i.e., test-particle) shocks. The computer code uses a single algorithmic sequence to smoothly span the range from…

Astrophysics · Physics 2007-05-23 Donald C. Ellison

We present a new code aimed at the simulation of diffusive shock acceleration (DSA), and discuss various test cases which demonstrate its ability to study DSA in its full time-dependent and non-linear developments. We present the numerical…

Astrophysics · Physics 2009-11-13 Gilles Ferrand , Turlough Downes , Alexandre Marcowith

The task of learning a diffusion-based neural sampler for drawing samples from an unnormalized target distribution can be viewed as a stochastic optimal control problem on path measures. However, the training of neural samplers can be…

Machine Learning · Computer Science 2026-05-20 Wei Guo , Jaemoo Choi , Yuchen Zhu , Molei Tao , Yongxin Chen

Lesion segmentation requires both speed and accuracy. In this paper, we propose a simple yet efficient network DSNet, which consists of a encoder based on Transformer and a convolutional neural network(CNN)-based distinct pyramid decoder…

Image and Video Processing · Electrical Eng. & Systems 2022-12-15 Yunxiao Liu