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Many iterative parallel-in-time algorithms have been shown to be highly efficient for diffusion-dominated partial differential equations (PDEs), but are inefficient or even divergent when applied to advection-dominated PDEs. We consider the…

Numerical Analysis · Mathematics 2022-04-26 H. De Sterck , R. D. Falgout , O. A. Krzysik

In numerous applications, surrogate models are used as a replacement for accurate parameter-to-observable mappings when solving large-scale inverse problems governed by partial differential equations (PDEs). The surrogate model may be a…

Optimization and Control · Mathematics 2025-12-08 Ruanui Nicholson , Radoslav Vuchkov , Umberto Villa , Noemi Petra

Image restoration tasks demand a complex balance between spatial details and high-level contextualized information while recovering images. In this paper, we propose a novel synergistic design that can optimally balance these competing…

Computer Vision and Pattern Recognition · Computer Science 2021-03-17 Syed Waqas Zamir , Aditya Arora , Salman Khan , Munawar Hayat , Fahad Shahbaz Khan , Ming-Hsuan Yang , Ling Shao

A new algorithm is developed to tackle the issue of sampling non-Gaussian model parameter posterior probability distributions that arise from solutions to Bayesian inverse problems. The algorithm aims to mitigate some of the hurdles faced…

Machine Learning · Statistics 2019-11-19 Leen Alawieh , Jonathan Goodman , John B. Bell

This work focuses on an efficient stress recovery procedure for laminated composite curved structures, which relies on Isogeometric Analysis (IGA) and equilibrium. Using a single element through the thickness in combination with a…

Numerical Analysis · Mathematics 2020-10-27 Alessia Patton , Pablo Antolin , Josef Kiendl , Alessandro Reali

This paper introduces bootstrap multigrid methods for solving eigenvalue problems arising from the discretization of partial differential equations. Inspired by the full bootstrap algebraic multigrid (BAMG) setup algorithm that includes an…

Numerical Analysis · Mathematics 2023-01-11 James Brannick , Shuhao Cao

A Hamiltonian decomposition of a regular graph is a partition of its edge set into Hamiltonian cycles. The problem of finding edge-disjoint Hamiltonian cycles in a given regular graph has many applications in combinatorial optimization and…

Combinatorics · Mathematics 2022-01-12 Andrey Kostenko , Andrei Nikolaev

Ptychography is a popular imaging technique that combines diffractive imaging with scanning microscopy. The technique consists of a coherent beam that is scanned across an object in a series of overlapping positions, leading to reliable and…

Numerical Analysis · Mathematics 2024-08-08 Ricardo Parada , Samy Wu Fung , Stanley Osher

Ptychography is a well-studied phase imaging method that makes non-invasive imaging possible at a nanometer scale. It has developed into a mainstream technique with various applications across a range of areas such as material science or…

Image and Video Processing · Electrical Eng. & Systems 2022-08-01 Semih Barutcu , Aggelos K. Katsaggelos , Doğa Gürsoy

Accurate sarcopenia diagnosis via ultrasound remains challenging due to subtle imaging cues, limited labeled data, and the absence of clinical context in most models. We propose MedVQA-TREE, a multimodal framework that integrates a…

Image and Video Processing · Electrical Eng. & Systems 2025-08-28 Pardis Moradbeiki , Nasser Ghadiri , Sayed Jalal Zahabi , Uffe Kock Wiil , Kristoffer Kittelmann Brockhattingen , Ali Ebrahimi

This paper considers the phase retrieval problem in which measurements consist of only the magnitude of several linear measurements of the unknown, e.g., spectral components of a time sequence. We develop low-complexity algorithms with…

Information Theory · Computer Science 2016-08-24 Tianyu Qiu , Prabhu Babu , Daniel P. Palomar

Joint camera pose and dense geometry estimation from a set of images or a monocular video remains a challenging problem due to its computational complexity and inherent visual ambiguities. Most dense incremental reconstruction systems…

Computer Vision and Pattern Recognition · Computer Science 2024-04-18 Kirill Mazur , Gwangbin Bae , Andrew J. Davison

Degradation-agnostic image restoration aims to handle diverse corruptions with one unified model, but faces fundamental challenges in balancing efficiency and performance across different degradation types. Existing approaches either…

Computer Vision and Pattern Recognition · Computer Science 2026-03-02 Bin Ren , Yawei Li , Xu Zheng , Yuqian Fu , Danda Pani Paudel , Hong Liu , Ming-Hsuan Yang , Luc Van Gool , Nicu Sebe

Monocular depth estimation (MDE) typically produces depth estimations that are defined up to an unknown scale or shift. When only sparse metric anchors are available, recovering accurate metric depth becomes challenging yet necessary for…

Computer Vision and Pattern Recognition · Computer Science 2026-05-11 Yuanyan Li , Matthias Althoff

Iterative projection algorithms are successfully being used as a substitute of lenses to recombine, numerically rather than optically, light scattered by illuminated objects. Images obtained computationally allow aberration-free…

Optics · Physics 2007-05-23 S. Marchesini

Fourier phase retrieval is a classical problem of restoring a signal only from the measured magnitude of its Fourier transform. Although Fienup-type algorithms, which use prior knowledge in both spatial and Fourier domains, have been widely…

Computer Vision and Pattern Recognition · Computer Science 2020-11-23 Eunju Cha , Chanseok Lee , Mooseok Jang , Jong Chul Ye

We study nonconvex optimization for phase retrieval and the more general problem of semidefinite low-rank matrix sensing; in particular, we focus on the global nonconvex landscape of overparametrized versions of the nonsmooth amplitude…

Optimization and Control · Mathematics 2025-11-25 Andrew D. McRae

Loosely coupled partitioned methods for multiphysics problems treat each subproblem as a separate entity and advance them independently in time. In so doing these methods enable code reuse, increase concurrency and provide a convenient…

Computational Engineering, Finance, and Science · Computer Science 2025-07-31 Pavel Bochev , Justin Owen , Paul Kuberry , Jeffrey Connors

We propose a level-set-based semi-Lagrangian method on graded adaptive Cartesian grids to address the problem of surface reconstruction from point clouds. The goal is to obtain an implicit, high-quality representation of real shapes that…

Numerical Analysis · Mathematics 2026-03-26 Silvia Preda , Matteo Semplice

We study the problem of recovering the phase from magnitude measurements; specifically, we wish to reconstruct a complex-valued signal x of C^n about which we have phaseless samples of the form y_r = |< a_r,x >|^2, r = 1,2,...,m (knowledge…

Information Theory · Computer Science 2016-11-17 Emmanuel Candes , Xiaodong Li , Mahdi Soltanolkotabi