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We describe a novel framework for estimating subsurface properties, such as rock permeability and porosity, from time-lapse observed seismic data by coupling full-waveform inversion, subsurface flow processes, and rock physics models. For…

Geophysics · Physics 2020-05-06 Dongzhuo Li , Kailai Xu , Jerry M. Harris , Eric Darve

Light Detection and Ranging (LiDAR) are fast emerging sensors in the field of Earth Observation. It is a remote sensing technology that utilizes laser beams to measure distances and create detailed three-dimensional representations of…

Signal Processing · Electrical Eng. & Systems 2025-04-15 Saad Ahmed Jamal

Ideal MHD provides an accurate description of low-frequency Alfv\'en waves in fully ionized plasmas. However, higher frequency waves in many plasmas of the solar atmosphere cannot be correctly described by ideal MHD and a more accurate…

Solar and Stellar Astrophysics · Physics 2016-12-07 David Martínez-Gómez , Roberto Soler , Jaume Terradas

Here we use synthetic data to explore the performance of forward models and inverse methods for helioseismic holography. Specifically, this work presents the first comprehensive test of inverse modeling for flows using lateral-vantage…

Solar and Stellar Astrophysics · Physics 2018-08-15 K. DeGrave , D. C. Braun , A. C. Birch , A. D. Crouch , B. Javornik

In order to meet the theoretically achievable imaging performance, calibration of modern radio interferometers is a mandatory challenge, especially at low frequencies. In this perspective, we propose a novel parallel iterative…

Instrumentation and Methods for Astrophysics · Physics 2016-09-09 Martin Brossard , Mohammed Nabil El Korso , Marius Pesavento , Rémy Boyer , Pascal Larzabal , Stefan J. Wijnholds

Plasmon and polariton modes are derived for an ideal semi-infinite (half-space) plasma and an ideal plasma slab by using a general, unifying procedure, based on equations of motion, Maxwell's equations and suitable boundary conditions.…

Optics · Physics 2015-05-13 M. Apostol , G. Vaman

Inverse electromagnetic design has emerged as a way of efficiently designing active and passive electromagnetic devices. This maturing strategy involves optimizing the shape or topology of a device in order to improve a figure of merit--a…

Optics · Physics 2018-12-05 Andrew Michaels , Eli Yablonovitch

We demonstrated the accurate prediction of a quasibound spectrum of a negative ion using a novel high-precision theoretical approach. We used La$^-$ as a test case due to a recent experiment that measured energies of 11 resonances in its…

Atomic Physics · Physics 2021-02-24 M. S. Safronova , C. Cheung , M. G. Kozlov , S. E. Spielman , N. D. Gibson , C. W. Walter

Deep learning is having a profound impact in many fields, especially those that involve some form of image processing. Deep neural networks excel in turning an input image into a set of high-level features. On the other hand, tomography…

Machine Learning · Statistics 2017-01-03 Francisco A. Matos , Diogo R. Ferreira , Pedro J. Carvalho , JET Contributors

I introduce an algorithm for estimating parameters from multidimensional data based on forward modelling. In contrast to many machine learning approaches it avoids fitting an inverse model and the problems associated with this. The…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 C. A. L. Bailer-Jones

In this paper, we present an efficient algorithm for the long time behavior of plasma simulations. We will focus on 4D drift-kinetic model, where the plasma's motion occurs in the plane perpendicular to the magnetic field and can be…

Numerical Analysis · Mathematics 2014-10-01 Francis Filbet , Chang Yang

In this paper, we study the convergence properties of an iterative algorithm for fast nonlinear model predictive control of quasi-linear parameter-varying systems without inequality constraints. Compared to previous works considering this…

Optimization and Control · Mathematics 2023-09-15 Christian Hespe , Herbert Werner

Here we present a new non-parametric approach to density estimation and classification derived from theory in Radon transforms and image reconstruction. We start by constructing a "forward problem" in which the unknown density is mapped to…

Numerical Analysis · Mathematics 2024-12-20 James Webber , Erika Hussey , Eric Miller , Shuchin Aeron

In this paper, we develop a computational multiscale to solve the parabolic wave approximation with heterogeneous and variable media. Parabolic wave approximation is a technique to approximate the full wave equation. One benefit of the…

Numerical Analysis · Mathematics 2021-04-07 Eric Chung , Yalchin Efendiev , Sai-Mang Pun , Zecheng Zhang

This contribution, built on the companion paper [1], is focused on the different mathematical approaches available for the analysis of the quasilinear approximation in plasma physics.

Analysis of PDEs · Mathematics 2020-11-17 Claude Bardos , Nicolas Besse

Diffusion probabilistic models (DPMs) are a key component in modern generative models. DPM-solvers have achieved reduced latency and enhanced quality significantly, but have posed challenges to find the exact inverse (i.e., finding the…

Computer Vision and Pattern Recognition · Computer Science 2023-12-01 Seongmin Hong , Kyeonghyun Lee , Suh Yoon Jeon , Hyewon Bae , Se Young Chun

Full-waveform inversion (FWI) is a powerful geophysical imaging technique that infers high-resolution subsurface physical parameters by solving a non-convex optimization problem. However, due to limitations in observation, e.g., limited…

Numerical Analysis · Mathematics 2023-11-09 Xiong-Bin Yan , Keke Wu , Zhi-Qin John Xu , Zheng Ma

Geophysical models usually contain both sharp interfaces and smooth variations, and it is difficult to accurately account for both of these two types of medium parameter variations using conventional full-waveform inversion methods. In…

Geophysics · Physics 2019-05-22 Kai Gao , Lianjie Huang

We report the realization of a new iterative Fourier-transform algorithm for creating holograms that can diffract light into an arbitrary two-dimensional intensity profile. We show that the predicted intensity distributions are smooth with…

Atomic Physics · Physics 2009-11-13 M. Pasienski , B. DeMarco

Seismic waves are the most sensitive probe of the Earth's interior we have. With the dense data sets available in exploration, images of subsurface structures can be obtained through processes such as migration. Unfortunately, relating…

Geophysics · Physics 2009-05-05 R. B. Schlottmann