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Model-free deep reinforcement learning (RL) algorithms have been widely used for a range of complex control tasks. However, slow convergence and sample inefficiency remain challenging problems in RL, especially when handling continuous and…

Machine Learning · Computer Science 2021-12-07 Wenjie Shi , Shiji Song , Hui Wu , Ya-Chu Hsu , Cheng Wu , Gao Huang

Stochastic Approximation (SA) is a popular approach for solving fixed-point equations where the information is corrupted by noise. In this paper, we consider an SA involving a contraction mapping with respect to an arbitrary norm, and show…

Machine Learning · Computer Science 2021-07-01 Zaiwei Chen , Siva Theja Maguluri , Sanjay Shakkottai , Karthikeyan Shanmugam

Elastodynamic Green's functions are an essential ingredient in seismology as they form the connection between direct observations of seismic waves and the earthquake source. They are also fundamental to various seismological techniques…

Geophysics · Physics 2025-02-06 John M. Rekoske , Dave A. May , Alice-Agnes Gabriel

In this paper, a fast synthetic iterative scheme is developed to accelerate convergence for the implicit DOM based on the stationary phonon BTE. The key innovative point of the present scheme is the introduction of the macroscopic synthetic…

Computational Physics · Physics 2018-12-18 Chuang Zhang , Songze Chen , Zhaoli Guo , Lei Wu

In aircraft design, structural optimization and uncertainty quantification concerning transonic aeroelastic issues are computationally impractical, because the iterative process requires great number of aeroelastic analysis. Emerging…

Fluid Dynamics · Physics 2018-08-15 Ziyi Wang , Weiwei Zhang , Xiaojing Wu , Kongjin Chen

In this paper, we review the key figures of merit to assess the performance of advanced random access (RA) schemes exploiting physical layer coding, repetitions and collision resolution techniques. We then investigate RA modeling aspects…

Information Theory · Computer Science 2018-01-22 Alberto Mengali , Riccardo De Gaudenzi , Cedomir Stefanovic

The Discrete Ordinates Method (DOM) is the most widely used velocity discretization method for simulating the radiative transport equation. However, the ray effect is a long-standing drawback of DOM. In benchmark tests that exhibit the ray…

Dynamical Systems · Mathematics 2025-10-07 Lei Li , Min Tang , Yuqi Yang

Sparse autoencoders (SAEs) decompose language model representations into a sparse set of linear latent vectors. Recent works have improved SAEs using language model gradients, but these techniques require many expensive backward passes…

Machine Learning · Computer Science 2025-05-28 Matthew Chen , Joshua Engels , Max Tegmark

Low-Rank Adaptation (LoRA) fine-tunes large models by learning low-rank updates on top of frozen weights, dramatically reducing trainable parameters and memory. In this work, we address the gap between training with full steps with low-rank…

Estimating weights in the synthetic control method, typically resulting in sparse weights where only a few control units have non-zero weights, involves an optimization procedure that selects and combines control units to closely match the…

Econometrics · Economics 2026-02-03 Rong J. B. Zhu

Real-world image super-resolution aims to recover high-quality images from complex and unknown real-world degradations. However, existing generative Real-ISR methods largely inherit the dense latent representations and quadratic-cost global…

Computer Vision and Pattern Recognition · Computer Science 2026-05-25 Bingtian Qiao , Yue Shi , Yingjie Zhou , Yong Guo , Guangtao Zhai , Jiezhang Cao

Reinforcement learning (RL) is a promising, upcoming topic in automatic control applications. Where classical control approaches require a priori system knowledge, data-driven control approaches like RL allow a model-free controller design…

Systems and Control · Electrical Eng. & Systems 2022-02-01 Daniel Weber , Maximilian Schenke , Oliver Wallscheid

The promising potential of Deep Learning for Automatic Target Recognition (ATR) on Synthetic Aperture Radar (SAR) images vanishes when considering the complexity of collecting training datasets measurements. Simulation can overcome this…

Computer Vision and Pattern Recognition · Computer Science 2022-06-16 Benjamin Camus , Corentin Le Barbu , Eric Monteux

A space-time-parameters structure of parametric parabolic PDEs motivates the application of tensor methods to define reduced order models (ROMs). Within a tensor-based ROM framework, the matrix SVD - a traditional dimension reduction…

Numerical Analysis · Mathematics 2024-08-22 Alexander V. Mamonov , Maxim A. Olshanskii

The recent advancement of foundation models (FMs) has brought about a paradigm shift, revolutionizing various sectors worldwide. The popular optimizers used to train these models are stochastic gradient descent-based algorithms, which face…

Machine Learning · Computer Science 2026-01-06 Shenglong Zhou , Ouya Wang , Ziyan Luo , Yongxu Zhu , Geoffrey Ye Li

Using synthetic data for training neural networks that achieve good performance on real-world data is an important task as it can reduce the need for costly data annotation. Yet, synthetic and real world data have a domain gap. Reducing…

Computer Vision and Pattern Recognition · Computer Science 2022-08-12 Shahaf Ettedgui , Shady Abu-Hussein , Raja Giryes

Deterministic models for radiation transport describe the density of radiation particles moving through a background material. In radiation therapy applications, the phase space of this density is composed of energy, spatial position and…

Numerical Analysis · Mathematics 2021-11-16 Jonas Kusch , Pia Stammer

In this paper, we are concerned with the study of the Isotropic Diffusion Source Approximation (IDSA) (Baxter et al., Phys. Rev. E 73, 046118, 2006) of radiative transfer. After having recalled well-known limits of the radiative transfer…

Numerical Analysis · Mathematics 2016-06-14 Jérôme Michaud

Diffusion-based image super-resolution (SR) models have attracted substantial interest due to their powerful image restoration capabilities. However, prevailing diffusion models often struggle to strike an optimal balance between efficiency…

Computer Vision and Pattern Recognition · Computer Science 2024-12-12 Qinpeng Cui , Yixuan Liu , Xinyi Zhang , Qiqi Bao , Qingmin Liao , Li Wang , Tian Lu , Zicheng Liu , Zhongdao Wang , Emad Barsoum

In this paper, we develop an asymptotic expansion-regularization (AER) method for inverse source problems in two-dimensional nonlinear and nonstationary singularly perturbed partial differential equations (PDEs). The key idea of this…

Numerical Analysis · Mathematics 2022-10-14 Dmitrii Chaikovskii , Aleksei Liubavin , Ye Zhang