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This paper studies the problem of parameter estimation in resonant, acoustic fluid-structure interaction problems over a wide frequency range. Problems with multiple resonances are known to be subjected to local minima, which represents a…

Computational Physics · Physics 2019-03-06 Peter Göransson , Jacques Cuenca , Timo Lähivaara

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

The inverse medium problem for a circular cylindrical domain is studied using low-frequency acoustic waves as the probe radiation. It is shown that to second order in $k_{0}a$ ($k_{0}$ the wavenumber in the host medium, $a$ the radius of…

Classical Physics · Physics 2009-11-10 Thierry Scotti , Armand Wirgin

Seismic coda waves, once regarded as noise, are now recognized as key indicators of wave scattering in seismograms. Aki (1969) first proposed that these waves result from small-scale heterogeneities in the Earth's interior, spurring…

Geophysics · Physics 2025-07-11 Ning Liu , Wen-Tao Hu

Horizontal line arrays are often employed in underwater environments to estimate the direction of arrival (DOA) of a weak signal. Conventional beamforming (CB) is robust but has wide beamwidths and high-level sidelobes. High-resolution…

Signal Processing · Electrical Eng. & Systems 2020-12-09 Qi Zhang , Jiang Zhu , Yuantao Gu , Zhiwei Xu

The angular spectrum approach (ASA)---a fast, frequency domain method for calculation of the acoustic field---enables passive source localization and modeling forward propagation in homogeneous media with high computational efficiency. Here…

Signal Processing · Electrical Eng. & Systems 2020-12-02 Scott Schoen , Costas D. Arvanitis

Local helioseismology has so far relied on semi-analytical methods to compute the spatial sensitivity of wave travel times to perturbations in the solar interior. These methods are cumbersome and lack flexibility. Here we propose a…

Seismic data are commonly modeled by a high-frequency single scattering approximation. This amounts to a linearization in the medium coefficient about a smooth background. The discontinuities are contained in the medium perturbation. The…

Analysis of PDEs · Mathematics 2009-09-25 Christiaan C. Stolk , Maarten V. de Hoop

This paper is concerned with the numerical solution to a 3D coefficient inverse problem for buried objects with multi-frequency experimental data. The measured data, which are associated with a single direction of an incident plane wave,…

Numerical Analysis · Mathematics 2017-05-04 Dinh-Liem Nguyen , Michael V. Klibanov , Loc H. Nguyen , Michael A. Fiddy

With the rapid advancement of technology, the recognition of underwater acoustic signals in complex environments has become increasingly crucial. Currently, mainstream underwater acoustic signal recognition relies primarily on…

Sound · Computer Science 2024-01-08 Minghao Chen

Underwater acoustic environment estimation is a challenging but important task for remote sensing scenarios. Current estimation methods require high signal strength and a solution to the fragile echo labeling problem to be effective. In…

The motivation of this work is an inverse problem for the acoustic wave equation, where an array of sensors probes an unknown medium with pulses and measures the scattered waves. The goal of the inversion is to determine from these…

Numerical Analysis · Mathematics 2018-06-18 Liliana Borcea , Vladimir Druskin , Alexander V. Mamonov , Mikhail Zaslavsky

In these last years, many studies have focalized on the design of reliable underwater acoustic communication systems. However, the ocean acoustic communication channel exhibits strong amplitude and phase fluctuations and the phenomena of…

Signal Processing · Electrical Eng. & Systems 2019-07-16 Yasin Yousif Al-Aboosi , Hussein A. Abdulnabi

Time-lapse electrical resistivity tomography (ERT) is a popular geophysical method to estimate three-dimensional (3D) permeability fields from electrical potential difference measurements. Traditional inversion and data assimilation methods…

Geophysics · Physics 2022-08-10 M. K. Mudunuru , E. L. D. Cromwell , H. Wang , X. Chen

Real time acquisition of accurate underwater sound velocity profile (SSP) is crucial for tracking the propagation trajectory of underwater acoustic signals, making it play a key role in ocean communication positioning. SSPs can be directly…

Sound · Computer Science 2025-09-09 Wei Huang , Jiajun Lu , Hao Zhang , Tianhe Xu

Mapping the seafloor with underwater imaging cameras is of significant importance for various applications including marine engineering, geology, geomorphology, archaeology and biology. For shallow waters, among the underwater imaging…

Computer Vision and Pattern Recognition · Computer Science 2022-12-21 Panagiotis Agrafiotis , Konstantinos Karantzalos , Andreas Georgopoulos

Based on the normal mode and ray theory, this article discusses the characteristics of surface sound source and reception at the surface layer, and explores depth estimation methods based on normal modes and rays, and proposes a depth…

The spatial-temporal distribution of underwater sound velocity affects the propagation mode of underwater acoustic signals. Therefore, rapid estimation and prediction of underwater sound velocity distribution is crucial for providing…

Sound · Computer Science 2025-03-31 Jiajun Lu , Hao Zhang , Pengfei Wu , Sijia Li , Wei Huang

Uncertainty quantification of groundwater (GW) aquifer parameters is critical for efficient management and sustainable extraction of GW resources. These uncertainties are introduced by the data, model, and prior information on the…

Geophysics · Physics 2021-12-08 Amal Alghamdi , Marc Hesse , Jingyi Chen , Umberto Villa , Omar Ghattas

Accurate prediction and synthesis of seismic waveforms are crucial for seismic-hazard assessment and earthquake-resistant infrastructure design. Existing prediction methods, such as ground-motion models and physics-based wave-field…

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