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We formulate a data independent latent space regularisation constraint for general unsupervised autoencoders. The regularisation rests on sampling the autoencoder Jacobian in Legendre nodes, being the centre of the Gauss-Legendre…

This short note considerably simplifies a reconstruction method by the author (Comm. PDE, 45(9):1118--1133, 2020), for reconstructing piecewise constant layered conductivities (PCLC) from partial boundary measurements in electrical…

Analysis of PDEs · Mathematics 2022-08-24 Henrik Garde

Industry standards require medical device manufacturers to perform implant-induced artefact testing in phantoms at a pre-clinical stage to define the extent of artefacts that can be expected during MRI. Once a device is commercially…

Medical Physics · Physics 2023-06-19 Guy Fierens , Joris Walraevens , Ronald Peeters , Christ Glorieux , Nicolas Verhaert

Image corruption by motion artifacts is an ingrained problem in Magnetic Resonance Imaging (MRI). In this work, we propose a neural network-based regularization term to enhance Autofocusing, a classic optimization-based method to remove…

Image and Video Processing · Electrical Eng. & Systems 2022-11-15 Ekaterina Kuzmina , Artem Razumov , Oleg Y. Rogov , Elfar Adalsteinsson , Jacob White , Dmitry V. Dylov

The influence-matrix formalism provides an alternative route to the classical simulation of quantum dynamics. Because influence matrices retain information only about the effective bath seen by local observables, they are expected to be…

Quantum Physics · Physics 2026-05-14 Cathy Li , Bruno Bertini , Katja Klobas , Tianci Zhou

Battery short-term electrical impedance behavior varies between linear, linear time-varying, or nonlinear at different operating conditions. Data-based electrical impedance modeling techniques often model the battery as a linear…

Systems and Control · Computer Science 2018-05-17 Rishi Relan , Koen Tiels , Jean-Marc Timmermans , Johan Schoukens

Reconstructing the structure of the soil using non-invasive techniques is a very relevant problem in many scientific fields, like geophysics and archaeology. This can be done, for instance, with the aid of Frequency Domain Electromagnetic…

Numerical Analysis · Mathematics 2022-01-05 Alessandro Buccini , Patricia Díaz de Alba

Autoencoders are a type of unsupervised neural networks, which can be used to solve various tasks, e.g., dimensionality reduction, image compression, and image denoising. An AE has two goals: (i) compress the original input to a…

Computer Vision and Pattern Recognition · Computer Science 2022-11-24 Firas Laakom , Jenni Raitoharju , Alexandros Iosifidis , Moncef Gabbouj

Detecting inhomogeneities in the electrical conductivity is a special case of the inverse problem in electrical impedance tomography, that leads to fast direct reconstruction methods. One such method can, under reasonable assumptions,…

Numerical Analysis · Mathematics 2018-08-16 Henrik Garde

Classical methods for X-ray computed tomography are based on the assumption that the X-ray source intensity is known, but in practice, the intensity is measured and hence uncertain. Under normal operating conditions, when the exposure time…

Numerical Analysis · Mathematics 2017-07-17 Hari Om Aggrawal , Martin Skovgaard Andersen , Sean Rose , Emil Y. Sidky

Avoiding overfitting is a central challenge in machine learning, yet many large neural networks readily achieve zero training loss. This puzzling contradiction necessitates new approaches to the study of overfitting. Here we quantify…

Information Theory · Computer Science 2022-10-13 Vudtiwat Ngampruetikorn , David J. Schwab

Optimization problems with set submodular objective functions have many real-world applications. In discrete scenarios, where the same item can be selected more than once, the domain is generalized from a 2-element set to a bounded integer…

Data Structures and Algorithms · Computer Science 2021-11-22 Alberto Schiabel , Vyacheslav Kungurtsev , Jakub Marecek

Reconstructing cardiac electrical activity from body surface electric potential measurements results in the severely ill-posed inverse problem in electrocardiography. Many different regularization approaches have been proposed to improve…

Numerical Analysis · Mathematics 2025-11-04 Manuel Haas , Thomas Grandits , Thomas Pinetz , Thomas Beiert , Simone Pezzuto , Alexander Effland

We develop an interpolation-based modeling framework for parameter-dependent partial differential equations arising in control, inverse problems, and uncertainty quantification. The solution is discretized in the physical domain using…

Numerical Analysis · Mathematics 2026-04-20 Erik Burman , Mats G. Larson , Karl Larsson , Jonatan Vallin

We give an algorithm to compute a one-dimensional shape-constrained function that best fits given data in weighted-$L_{\infty}$ norm. We give a single algorithm that works for a variety of commonly studied shape constraints including…

Data Structures and Algorithms · Computer Science 2019-05-30 David Durfee , Yu Gao , Anup B. Rao , Sebastian Wild

We propose a refined iterative likelihood-maximization algorithm for reconstructing a quantum state from a set of tomographic measurements. The algorithm is characterized by a very high convergence rate and features a simple adaptive…

Quantum Physics · Physics 2009-11-13 Jaroslav Rehacek , Zdenek Hradil , E. Knill , A. I. Lvovsky

Favorably scaling numerical time-dependent many-electron techniques such as time-dependent density functional theory (TDDFT) with adiabatic exchange-correlation potentials typically fail in capturing highly correlated electron dynamics. We…

Atomic Physics · Physics 2013-11-25 M. Brics , D. Bauer

Magnetic particle imaging is a tracer based imaging technique to determine the spatial distribution of superparamagnetic iron oxide nanoparticles with a high spatial and temporal resolution. Due to physiological constraints, the imaging…

Medical Physics · Physics 2022-05-03 Nadine Gdaniec , Marija Boberg , Martin Möddel , Patryk Szwargulski , Tobias Knopp

In this paper we investigate the problem of recovering the source term in an elliptic system from a measurement of the state on a part of the boundary. For the particular interest in reconstructing probably discontinuous sources, we use the…

Numerical Analysis · Mathematics 2020-01-08 Michael Hinze , Tran Nhan Tam Quyen

Tuning the regularization hyperparameter $\alpha$ in inverse problems has been a longstanding problem. This is particularly true in the case of fetal brain magnetic resonance imaging, where an isotropic high-resolution volume is…

Image and Video Processing · Electrical Eng. & Systems 2023-04-06 Priscille de Dumast , Thomas Sanchez , Hélène Lajous , Meritxell Bach Cuadra
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