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Quasi-Newton (QN) methods provide an efficient alternative to second-order methods for minimizing smooth unconstrained problems. While QN methods generally compose a Hessian estimate based on one secant interpolation per iteration,…

Optimization and Control · Mathematics 2025-04-11 Mokhwa Lee , Yifan Sun

Electron tomography (ET) has become a standard technique for 3D characterization of materials at the nano-scale. Traditional reconstruction algorithms such as weighted back projection suffer from disruptive artifacts with insufficient…

Computer Vision and Pattern Recognition · Computer Science 2019-04-05 Yi Jiang , Elliot Padgett , Robert Hovden , David A. Muller

We demonstrate a novel approach to the reconstruction of scanning probe x-ray diffraction tomography data with anisotropic poly crystalline samples. The method involves reconstructing a voxel map containing an orientation distribution…

Scalable characterization of quantum processors is crucial for mitigating noise and imperfections. While randomized measurement protocols enable efficient access to local observables, inferring a globally consistent description of…

Quantum Physics · Physics 2026-03-10 Zidu Liu , Dominik S. Wild

We present a dual-guided framework for reconstructing unsteady incompressible flow fields using sparse observations. The approach combines optimized sensor placement with a physics-informed guided generative model. Sensor locations are…

Fluid Dynamics · Physics 2025-06-18 Sajad Salavatidezfouli , Henrik Karstoft , Alexandros Iosifidis , Mahdi Abkar

Tomography is an imaging technique that works by reconstructing a scene from acquired data in the form of line integrals of the imaging domain. A fundamental underlying assumption in the reconstruction procedure is the precise alignment of…

Numerical Analysis · Mathematics 2018-07-13 Toby Sanders

We propose a compressive sensing algorithm that exploits geometric properties of images to recover images of high quality from few measurements. The image reconstruction is done by iterating the two following steps: 1) estimation of normal…

Computer Vision and Pattern Recognition · Computer Science 2015-06-11 Virginia Estellers , Jean-Philippe Thiran , Xavier Bresson

We propose Regularized Overestimated Newton (RON), a Newton-type method with low per-iteration cost and strong global and local convergence guarantees for smooth convex optimization. RON interpolates between gradient descent and globally…

Optimization and Control · Mathematics 2025-10-02 Danny Duan , Hanbaek Lyu

In x-ray computed tomography (CT) it is generally acknowledged that reconstruction methods exploiting image sparsity allow reconstruction from a significantly reduced number of projections. The use of such reconstruction methods is…

Numerical Analysis · Mathematics 2014-08-05 Jakob S. Jørgensen , Emil Y. Sidky , Per Christian Hansen , Xiaochuan Pan

The MARS scanner is designed for the x-ray spectroscopic study of samples with the aid of computer tomography methods. Computer tomography allows the reconstruction of slices of an investigated sample using a set of shadow projections…

A stochastic second-order trust region method is proposed, which can be viewed as a second-order extension of the trust-region-ish (TRish) algorithm proposed by Curtis et al. (INFORMS J. Optim. 1(3) 200-220, 2019). In each iteration, a…

Optimization and Control · Mathematics 2019-11-19 Frank E. Curtis , Rui Shi

Recently, tensor data (or multidimensional array) have been generated in many modern applications, such as functional magnetic resonance imaging (fMRI) in neuroscience and videos in video analysis. Many efforts are made in recent years to…

Machine Learning · Computer Science 2023-08-10 Jiaqi Zhang , Yinghao Cai , Zhaoyang Wang , Beilun Wang

In many applications of tomography, the acquired projections are either limited in number or contain a significant amount of noise. In these cases, standard reconstruction methods tend to produce artifacts that can make further analysis…

Numerical Analysis · Mathematics 2016-04-11 D. M. Pelt , K. J. Batenburg

We present a sequential hierarchical least-squares programming solver with trust-region and hierarchical step-filter with application to prioritized discrete non-linear optimal control. It is based on a hierarchical step-filter which…

Optimization and Control · Mathematics 2024-03-13 Kai Pfeiffer , Abderrahmane Kheddar

Non-asymptotic convergence analysis of quasi-Newton methods has gained attention with a landmark result establishing an explicit local superlinear rate of O$((1/\sqrt{t})^t)$. The methods that obtain this rate, however, exhibit a well-known…

Optimization and Control · Mathematics 2023-10-19 Zhan Gao , Aryan Mokhtari , Alec Koppel

High-dimensional nonlinear systems pose considerable challenges for modeling and control across many domains, from fluid mechanics to advanced robotics. Such systems are typically approximated with reduced-order models, which often rely on…

Systems and Control · Electrical Eng. & Systems 2025-09-05 Hugo Buurmeijer , Luis A. Pabon , John Irvin Alora , Roshan S. Kaundinya , George Haller , Marco Pavone

In this paper, we study structured quasi-Newton methods for optimization problems with orthogonality constraints. Note that the Riemannian Hessian of the objective function requires both the Euclidean Hessian and the Euclidean gradient. In…

Optimization and Control · Mathematics 2018-09-05 Jiang Hu , Bo Jiang , Lin Lin , Zaiwen Wen , Yaxiang Yuan

Track reconstruction algorithms are critical for polarization measurements. In addition to traditional moment-based track reconstruction approaches, convolutional neural networks (CNN) are a promising alternative. However, hexagonal grid…

Instrumentation and Methods for Astrophysics · Physics 2023-11-15 Ya-Nan Li , Jia-Huan Zhu , Huai-Zhong Gao , Hong Li , Ji-Rong Cang , Zhi Zeng , Hua Feng , Ming Zeng

Semi-supervised clustering problems focus on clustering data with labels. In this paper,we consider the semi-supervised hypergraph problems. We use the hypergraph related tensor to construct an orthogonal constrained optimization model. The…

Optimization and Control · Mathematics 2023-06-21 Jingya Chang , Dongdong Liu , Min Xi

Recent contributions in the field of quantum state tomography have shown that, despite the exponential growth of Hilbert space with the number of subsystems, tomography of one-dimensional quantum systems may still be performed efficiently…

Quantum Physics · Physics 2013-07-19 Tillmann Baumgratz , David Gross , Marcus Cramer , Martin B. Plenio