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This paper investigates inverse source problems for time-dependent electromagnetic waves governed by Maxwell's equations. After applying the Fourier transform with respect to time, the problem leads to a frequency-domain electromagnetic…

Numerical Analysis · Mathematics 2026-03-11 Fenglin Sun , Hongxia Guo

Magnetic particle imaging (MPI) is a medical imaging modality of recent origin, and it exploits the nonlinear magnetization phenomenon to recover the spatially dependent concentration of the nanoparticles. Currently, image reconstruction in…

Numerical Analysis · Mathematics 2019-04-23 Tobias Kluth , Bangti Jin

Metasurfaces are subwavelength-structured artificial media that can shape and localize electromagnetic waves in unique ways. The inverse design of these devices is a non-convex optimization problem in a high dimensional space, making global…

Computational Physics · Physics 2019-11-22 Jiaqi Jiang , Jonathan A. Fan

By using a computer keyboard as a finger recording device, we construct the largest existing dataset for gesture recognition via surface electromyography (sEMG), and use deep learning to achieve over 90% character-level accuracy on…

Human-Computer Interaction · Computer Science 2021-09-30 Michael S. Crouch , Mingde Zheng , Michael S. Eggleston

A central goal of modern magnetic resonance imaging (MRI) is to reduce the time required to produce high-quality images. Efforts have included hardware and software innovations such as parallel imaging, compressed sensing, and deep…

Medical Physics · Physics 2023-03-27 Yihong Xu , Chad W. Farris , Stephan W. Anderson , Xin Zhang , Keith A. Brown

Magnetic induction tomography (MIT) is an efficient solution for long-term brain disease monitoring, which focuses on reconstructing bio-impedance distribution inside the human brain using non-intrusive electromagnetic fields. However,…

Computer Vision and Pattern Recognition · Computer Science 2021-02-17 Zuohui Chen , Qing Yuan , Xujie Song , Cheng Chen , Dan Zhang , Yun Xiang , Ruigang Liu , Qi Xuan

We propose an application of online hard sample mining for efficient training of Neural Radiance Fields (NeRF). NeRF models produce state-of-the-art quality for many 3D reconstruction and rendering tasks but require substantial…

Computer Vision and Pattern Recognition · Computer Science 2024-08-07 Juuso Korhonen , Goutham Rangu , Hamed R. Tavakoli , Juho Kannala

Inversion of electromagnetic data finds applications in many areas of geophysics. The inverse problem is commonly solved with either deterministic optimization methods (such as the nonlinear conjugate gradient or Gauss-Newton) which are…

Geophysics · Physics 2019-12-03 Vladimir Puzyrev , Andrei Swidinsky

Electroencephalography (EEG) is a tool that allows us to analyze brain activity with high temporal resolution. These measures, combined with deep learning and digital signal processing, are widely used in neurological disorder detection and…

Signal Processing · Electrical Eng. & Systems 2024-11-20 Isaac Ariza , Lorenzo J. Tardon , Ana M. Barbancho , Irene De-Torres , Isabel Barbancho

This paper is concerned with the electromagnetic inverse scattering problem that aims to determine the location and shape of anisotropic scatterers from far field data (at a fixed frequency). We study the orthogonality sampling method which…

Analysis of PDEs · Mathematics 2019-11-05 Isaac Harris , Dinh-Liem Nguyen

Magnetoencephalography (MEG) has a high temporal resolution well-suited for studying perceptual learning. However, to identify where learning happens in the brain, one needs to ap- ply source localization techniques to project MEG sensor…

Applications · Statistics 2015-12-04 Ying Yang , Michael J. Tarr , Robert E. Kass

Inspired by recent work on extended image volumes that lays the ground for randomized probing of extremely large seismic wavefield matrices, we present a memory frugal and computationally efficient inversion methodology that uses techniques…

Geophysics · Physics 2021-04-05 Mathias Louboutin , Felix J. Herrmann

The following electromagnetism (EM) inverse problem is addressed. It consists in estimating local radioelectric properties of materials recovering an object from the global EM scattering measurement, at various incidences and wave…

Applications · Statistics 2015-06-11 François Giraud , Pierre Minvielle , Marc Sancandi , Pierre Del Moral

We study source localization from high dimensional M/EEG data by extending a multiscale method based on Entropic inference devised to increase the spatial resolution of inverse problems. This method is used to construct informative prior…

Quantitative Methods · Quantitative Biology 2015-02-13 Leonardo S. Barbosa , Nestor Caticha

This article presents a novel undersampled magnetic resonance imaging (MRI) technique that leverages the concept of Neural Radiance Field (NeRF). With radial undersampling, the corresponding imaging problem can be reformulated into an image…

Image and Video Processing · Electrical Eng. & Systems 2024-03-05 Tae Jun Jang , Chang Min Hyun

Magnetic Resonance Imaging (MRI) plays a vital role in diagnosis, management and monitoring of many diseases. However, it is an inherently slow imaging technique. Over the last 20 years, parallel imaging, temporal encoding and compressed…

High temporal resolution measurements of human brain activity can be performed by recording the electric potentials on the scalp surface (electroencephalography, EEG), or by recording the magnetic fields near the surface of the head…

Data Analysis, Statistics and Probability · Physics 2015-01-22 Kevin H. Knuth

Detecting where and when brain regions activate in a cognitive task or in a given clinical condition is the promise of non-invasive techniques like magnetoencephalography (MEG) or electroencephalography (EEG). This problem, referred to as…

Machine Learning · Statistics 2020-11-26 Jérôme-Alexis Chevalier , Alexandre Gramfort , Joseph Salmon , Bertrand Thirion

We consider the inverse problem of determining the geometry of penetrable objects from scattering data generated by one incident wave at a fixed frequency. We first study an orthogonality sampling type method which is fast, simple to…

Numerical Analysis · Mathematics 2022-07-21 Thu Le , Dinh-Liem Nguyen , Vu Nguyen , Trung Truong

Travel time tomography for the velocity structure of a medium is a highly non-linear and non-unique inverse problem. Monte Carlo methods are becoming increasingly common choices to provide probabilistic solutions to tomographic problems but…

Computational Physics · Physics 2020-05-08 Stephanie Earp , Andrew Curtis