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We propose to formulate MRI image reconstruction as an optimization problem and model the optimization trajectory as a dynamic process using ordinary differential equations (ODEs). We model the dynamics in ODE with a neural network and…

Image and Video Processing · Electrical Eng. & Systems 2020-09-16 Eric Z. Chen , Terrence Chen , Shanhui Sun

Mean Deviation (MD) is a critical metric for assessing visual field loss in ophthalmology. While previous work has focused solely on predicting MD from Optical Coherence Tomography (OCT), it is intuitive to assume that combining OCT with…

Computer Vision and Pattern Recognition · Computer Science 2026-05-27 Haojie Yin , Chengcheng Feng , Tianyi Liu , Tianqi Zhang , Kaizhu Huang

In this effort we propose a data-driven learning framework for reduced order modeling of fluid dynamics. Designing accurate and efficient reduced order models for nonlinear fluid dynamic problems is challenging for many practical…

Computational Physics · Physics 2018-12-05 Xuping Xie , Guannan Zhang , Clayton G. Webster

The recent emergence of diffusion models has significantly advanced the precision of learnable priors, presenting innovative avenues for addressing inverse problems. Since inverse problems inherently entail maximum a posteriori estimation,…

Machine Learning · Computer Science 2025-01-22 Jiawei Zhang , Jiaxin Zhuang , Cheng Jin , Gen Li , Yuantao Gu

Deep learning methods for accelerated MRI achieve state-of-the-art results but largely ignore additional speedups possible with noncartesian sampling trajectories. To address this gap, we created a generative diffusion model-based…

Artificial Intelligence · Computer Science 2024-10-02 Trevor J. Chan , Chamith S. Rajapakse

This study employs physics-informed neural networks (PINNs) to reconstruct multiple flow fields in a transient natural convection system solely based on instantaneous temperature data at an arbitrary moment. Transient convection problems…

Fluid Dynamics · Physics 2024-10-11 Nagahiro Ohashi , Nam Phuong Nguyen , Leslie K. Hwang , Beomjin Kwon

Direct optimization of interpolated features on multi-resolution voxel grids has emerged as a more efficient alternative to MLP-like modules. However, this approach is constrained by higher memory expenses and limited representation…

Computer Vision and Pattern Recognition · Computer Science 2023-04-14 Xiangyu Xu , Lichang Chen , Changjiang Cai , Huangying Zhan , Qingan Yan , Pan Ji , Junsong Yuan , Heng Huang , Yi Xu

Continuous optimization is an important problem in many areas of AI, including vision, robotics, probabilistic inference, and machine learning. Unfortunately, most real-world optimization problems are nonconvex, causing standard convex…

Artificial Intelligence · Computer Science 2016-11-10 Abram L. Friesen , Pedro Domingos

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

Multiscale Proper Orthogonal Decomposition (mPOD) decomposes fluid flows into energy-optimal modes within prescribed frequency bands by combining Proper Orthogonal Decomposition with a multiresolution analysis (MRA). In its classical…

Fluid Dynamics · Physics 2026-04-15 Marek Belda , Lorenzo Schena , Romain Poletti , Martin Isoz , Tomáš Hyhlík , Miguel A. Mendez

A novel interface reconstruction strategy for volume of fluid (VOF) methods is introduced that represents the liquid-gas interface as two planes that co-exist within a single computational cell. In comparison to the piecewise linear…

Fluid Dynamics · Physics 2024-03-19 Austin Han , Robert Chiodi , Olivier Desjardins

This paper proposes a new data assimilation method for recovering high fidelity turbulent flow field around airfoil at high Reynolds numbers based on experimental data, which is called Proper Orthogonal Decomposition Inversion…

Fluid Dynamics · Physics 2020-07-14 Yilang Liu , Weiwei Zhang

Optimizing shapes and topology of physical devices is crucial for both scientific and technological advancements, given its wide-ranging implications across numerous industries and research areas. Innovations in shape and topology…

Computational Physics · Physics 2023-10-02 Alexander Luce , Rasoul Alaee , Fabian Knorr , Florian Marquardt

Generally, reduced order models of fluid flows are obtained by projecting the Navier-Stokes equations onto a reduced subspace spanned by vector functions that carry the meaningful information of the dynamics. A common method to generate…

Fluid Dynamics · Physics 2023-09-22 M. Oulghelou , A. Ammar , R. Ayoub

This paper describes the numerical implementation in a high-performance computing environment of an open-source library for model order reduction in fluid dynamics. This library, called pyLOM, contains the algorithms of proper orthogonal…

In this paper, we present a dimension reduction method to reduce the dimension of parameter space and state space and efficiently solve inverse problems. To this end, proper orthogonal decomposition (POD) and radial basis function (RBF) are…

Numerical Analysis · Mathematics 2016-10-18 Fuchen Chen , Lijian Jiang , Guanghui Zheng

A pre-trained unconditional diffusion model, combined with posterior sampling or maximum a posteriori (MAP) estimation techniques, can solve arbitrary inverse problems without task-specific training or fine-tuning. However, existing…

Machine Learning · Computer Science 2026-02-09 Sai Bharath Chandra Gutha , Ricardo Vinuesa , Hossein Azizpour

A numerical algorithm for solving mantle convection problems with strongly variable viscosity is presented. Equations for conservation of mass and momentum for highly viscous and incompressible fluids are solved iteratively by a multigrid…

Geophysics · Physics 2009-11-10 Masanori Kameyama , Akira Kageyama , Tetsuya Sato

The fully implicit method is the most commonly used approach to solve black-oil problems in reservoir simulation. The method requires repeated linearization of large nonlinear systems and produces ill-condi\-tioned linear systems. We…

Numerical Analysis · Mathematics 2020-01-07 Øystein S. Klemetsdal , Atgeirr F. Rasmussen , Olav Møyner , Knut-Andreas Lie

This paper studies the problem of estimating origin-destination (OD) flows from link flows. As the number of link flows is typically much less than that of OD flows, the inverse problem is severely ill-posed and hence prior information is…

Computational Engineering, Finance, and Science · Computer Science 2018-10-16 Jingyuan Xia , Wei Dai , John Polak , Michel Bierlaire