Full waveform inversion (FWI) is an effective and efficient data-fitting technique that has been widely used to produce accurate estimation of model parameters in Geophysics. The efficiency and accuracy of FWI are determined by the three main components: numerical solution for forward problem, gradient calculation and model update which usually involves the optimization method. The success of t...

Full Waveform Inversion (FWI) applications classically rely on efficient first-order optimization schemes, as the steepest descent or the nonlinear conjugate gradient optimization. However, second-order information provided by the Hessian matrix is proven to give a useful help in the scaling of the FWI problem and in the speed-up of the optimization. In this study, we propose an efficient matri...

M imaging methods are slowly but surely trending toward the solution of an inverse problem, not only for the velocity-estimation phase but also for the migration step. The general direction is toward the conventional imaging twostep process of velocity estimation followed by migration being superseded by the single full-waveform inversion (FWI) process. However, today, advanced imaging workflow...

Invasive fungal wound infection (FWI) after burn injury, while uncommon, is associated with significant morbidity and mortality. There are numerous risk factors for FWI, including large size incomplete excision of wounds. FWI can be challenging to diagnose. Close attention changes in the physical examination and, particular, appearance wounds leads team suspicious FWI. Once suspected, histopath...

Full waveform inversion (FWI) and distributed acoustic sensing (DAS) are powerful tools with potential to improve how seismic site characterization is performed. FWI able provide true 2D or 3D images of the subsurface by inverting stress wave recordings collected over a wide variety scales. DAS can be used efficiently collect high-resolution from long complex fiber optic arrays well-suited for ...

OBJECTIVES The first purpose of this study was to compare the psychosocial working conditions and mental health of our sample of maritime engine officers with a sample of British shore-based professional engineers. The second purpose was to analyse the relationship between the psychosocial working conditions onboard and mental strain for the Swedish maritime engine officers. MATERIAL AND METH...

Full waveform inversion (FWI) infers the subsurface structure information from seismic data by solving a non-convex optimization problem. Data-driven FWI has been increasingly studied with various neural network architectures to improve accuracy and computational efficiency. Nevertheless, applicability of pre-trained networks is severely restricted potential discrepancies between source functio...

Corrosion is a major safety and economic concern to various industries. In this paper, a novel ultrasonic guided wave tomography (GWT) system based on self-designed piezoelectric sensors is presented for on-line corrosion monitoring of large plate-like structures. Accurate thickness reconstruction of corrosion damages is achieved by using the dispersive regimes of selected guided waves and a re...

We present a method for recovering time-lapse velocity changes using full waveform inversion (FWI). In a preprocessing step we invert for a single intermediate model by simultaneously minimizing the data misfit in the baseline and the monitor surveys. We record the individual FWI gradients corresponding to the baseline and the monitor datasets at each iteration of the inversion. Regions where t...