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In non-destructive evaluation guided wave inspections, the elastic structure to be inspected is often embedded within other elastic media and the ensuing leaky waves are complex and non-trivial to compute; we consider the canonical example…

Numerical Analysis · Mathematics 2024-07-04 Evripides Georgiades , Michael J. S. Lowe , Richard V. Craster

This paper presents an application of time-frequency methods to characterize the dispersion of acoustic waves travelling in a one-dimensional periodic or disordered lattice made up of Helmholtz resonators connected to a cylindrical tube.…

Classical Physics · Physics 2009-07-10 Olivier Richoux , Claude Depollier , Jean Hardy

This work is a follow-up to our previous work "A numerical approach related to defect-type theories for some weakly random problems in homogenization" (preprint available on this archive). It extends and complements, both theoretically and…

Analysis of PDEs · Mathematics 2010-05-24 Arnaud Anantharaman , Claude Le Bris

In this paper we are concerned with restricted additive Schwarz with local impedance transformation conditions for a family of Helmholtz problems in two dimensions. These problems are discretized by the finite element method with conforming…

Numerical Analysis · Mathematics 2024-02-13 Qiya Hu , Ziyi Li

Power spectral density measurements of any sampled signal are typically restricted by both acquisition rate and frequency response limitations of instruments, which can be particularly prohibitive for video-based measurements. We have…

Biological Physics · Physics 2009-02-10 Wesley Philip Wong , Ken Halvorsen

Hybrid imaging techniques utilize couplings of physical modalities -- they are called hybrid, because, typically, the excitation and measurement quantities belong to different modalities. Recently there has been an enormous research…

Medical Physics · Physics 2015-06-03 T. Widlak , O. Scherzer

We use the Landweber method for numerical simulations for the multiwave tomography problem with a reflecting boundary and compare it with the averaged time reversal method. We also analyze the rate of convergence and the dependence on the…

Analysis of PDEs · Mathematics 2016-04-21 Plamen Stefanov , Yang Yang

Multiplicative noise models are often used instead of additive noise models in cases in which the noise variance depends on the state. Furthermore, when Poisson distributions with relatively small counts are approximated with normal…

Optimization and Control · Mathematics 2018-06-08 Ruanui Nicholson , Jari P. Kaipio

Interferometric gravitational wave detectors are devoted to pick up the effect induced on masses by gravitational waves. The variations of the length dividing two mirrors is measured through a laser interferometric technique. The Brownian…

Classical Physics · Physics 2009-10-31 Giseppe Curci , Erika D'Ambrosio

Solving time-harmonic wave propagation problems in the frequency domain within heterogeneous media poses significant mathematical and computational challenges, particularly in the high-frequency regime. Among the available numerical…

Numerical Analysis · Mathematics 2025-09-03 Victorita Dolean , Mark Fry , Matthias Langer , Emile Parolin , Pierre-Henri Tournier

In this paper we investigate the problem of identifying conductivity in electrical impedance tomography from one boundary measurement. A variational method with total variation regularization is here proposed to tackle this problem. We…

Analysis of PDEs · Mathematics 2017-09-26 Michael Hinze , Barbara Kaltenbacher , Tran Nhan Tam Quyen

We investigate non-Hermitian degeneracies, also known as exceptional points, in continous elastic media, and their potential application to the detection of mass and stiffness perturbations. Degenerate states are induced by enforcing…

Applied Physics · Physics 2021-02-24 M. I. N. Rosa , M. Mazzotti , M. Ruzzene

When a plane electromagnetic wave impinges upon a diffraction grating or other periodic structures, reflected and transmitted waves propagate away from the structure in different radiation channels. A diffraction anomaly occurs when the…

Computational Physics · Physics 2022-10-05 Zitao Mai , Ya Yan Lu

Electrical Impedance Tomography (EIT) is a powerful imaging technique with diverse applications, e.g., medical diagnosis, industrial monitoring, and environmental studies. The EIT inverse problem is about inferring the internal conductivity…

Machine Learning · Computer Science 2023-10-31 Derick Nganyu Tanyu , Jianfeng Ning , Andreas Hauptmann , Bangti Jin , Peter Maass

Correlation spectroscopy has been proposed as a spectroscopic technique for measuring the coherence between the ground states in electromagnetically induced transparency (EIT). While in time domain the steep dispersion in EIT condition…

Atomic Physics · Physics 2016-07-13 H. M. Florez , C. González , M. Martinelli

In this article, we consider elliptic diffusion problems on random domains with non-smooth diffusion coefficients. We start by illustrating the problems that arise from a non-smooth diffusion coefficient by recapitulating the corresponding…

Numerical Analysis · Mathematics 2019-05-15 M. D. Multerer

Exploiting the similarities between the Helmholtz wave equation and the Klein-Gordon equation, the former is linearized using the Feschbach-Villars procedure used for linearizing the Klein-Gordon equation. Then the Foldy-Wouthuysen…

Optics · Physics 2010-02-23 Sameen Ahmed Khan

Unitary transformations are an essential tool for the theoretical understanding of many systems by mapping them to simpler effective models. A systematically controlled variant to perform such a mapping is a perturbative continuous unitary…

Strongly Correlated Electrons · Physics 2015-03-20 H. Krull , N. A. Drescher , G. S. Uhrig

A novel approach to improving the performances of confocal scanning imaging is proposed. We experimentally demonstrate its feasibility using acoustic waves. It relies on a new way to encode spatial information using the temporal dimension.…

For problems of time-harmonic scattering by polygonal obstacles, embedding formulae provide a useful means of computing the far-field coefficient induced by any incident plane wave, given the far-field coefficient of a relatively small set…

Numerical Analysis · Mathematics 2018-05-24 Andrew Gibbs , Stephen Langdon , Andrea Moiola