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We consider the inverse scattering problem associated with any number of interacting modes in one-dimensional structures. The coupling between the modes is contradirectional in addition to codirectional, and may be distributed continuously…

Mathematical Physics · Physics 2011-11-10 Ole Henrik Waagaard , Johannes Skaar

Time fractional advection-dispersion equations arise as generalizations of classical integer order advection-dispersion equations and are increasingly used to model fluid flow problems through porous media. In this paper we develop an…

Numerical Analysis · Mathematics 2019-05-16 Carlos E. Mejía , Alejandro Piedrahita

Contrast is subject to dramatic changes across the visual field, depending on the source of light and scene configurations. Hence, the human visual system has evolved to be more sensitive to contrast than absolute luminance. This feature is…

Computer Vision and Pattern Recognition · Computer Science 2019-02-13 Arash Akbarinia , Karl R. Gegenfurtner

Texture is the term used to characterize the surface of a given object or phenomenon and is an important feature used in image processing and pattern recognition. Our aim is to compare various Texture analyzing methods and compare the…

Computer Vision and Pattern Recognition · Computer Science 2012-10-30 Pooja Maknikar

In this work we develop and analyze an adaptive finite element method for efficiently solving electrical impedance tomography -- a severely ill-posed nonlinear inverse problem for recovering the conductivity from boundary voltage…

Numerical Analysis · Mathematics 2019-05-16 Bangti Jin , Yifeng Xu , Jun Zou

We propose and implement a broadband, compact, and low-cost wavefront sensing scheme by simply placing a thin diffuser in the close vicinity of a camera. The local wavefront gradient is determined from the local translation of the speckle…

Optics · Physics 2018-01-23 Pascal Berto , Hervé Rigneault , Marc Guillon

We discuss the spontaneous emission from a coherently prepared and microwave driven doublet of potentially closely spaced excited states to a common ground level. Multiple interference mechanisms are identified which may lead to…

Quantum Physics · Physics 2009-10-31 E. Paspalakis , C. H. Keitel , P. L. Knight

We are concerned with the inverse scattering problem of recovering an inhomogeneous medium by the associated acoustic wave measurement. We prove that under certain assumptions, a single far-field pattern determines the values of a…

Analysis of PDEs · Mathematics 2020-05-05 Emilia Blåsten , Hongyu Liu

Due to its highly oscillating solution, the Helmholtz equation is numerically challenging to solve. To obtain a reasonable solution, a mesh size that is much smaller than the reciprocal of the wavenumber is typically required (known as the…

Numerical Analysis · Mathematics 2023-02-21 Qiwei Feng , Bin Han , Michelle Michelle

A theory for wave mechanical systems with local inversion and translation symmetries is developed employing the two-dimensional solution space of the stationary Schr\"odinger equation. The local symmetries of the potential are encoded into…

The interaction between charged particles and the vacuum fluctuations of the electromagnetic field induces decoherence, and therefore affects the contrast of fringes in an interference experiment. In this article we show that if a double…

Quantum Physics · Physics 2009-11-13 Ezequiel Alvarez , Francisco D. Mazzitelli

In this study we present an interferometric technique based on multiple wavelengths to capture the transient free surface contour of nanoliter drops spreading on a wettable surface, in particular close to the three-phase contact line.…

Fluid Dynamics · Physics 2024-12-24 Timo Richter , Mathis Fricke , Peter Stephan , Cameron Tropea , Jeanette Hussong

We propose a scheme to detect the diffusive cloak proposed by Schittny et al [Science 345, 427 (2014)]. We exploit the fact that diffusion of light is an approximation that disregards wave interference. The long-range contribution to…

Optics · Physics 2016-08-11 Milan Koirala , Alexey Yamilov

We develop a stable finite difference method for the elastic wave equation in bounded media, where the material properties can be discontinuous at curved interfaces. The governing equation is discretized in second order form by a fourth or…

Numerical Analysis · Mathematics 2022-01-25 Lu Zhang , Siyang Wang

A new construction of a directional continuous wavelet analysis on the sphere is derived herein. We adopt the harmonic scaling idea for the spherical dilation operator recently proposed by Sanz et al. but extend the analysis to a more…

Astrophysics · Physics 2011-10-28 J. D. McEwen , M. P. Hobson , A. N. Lasenby

We present an algorithm for construction step wavelets on local fields of positive characteristic.

Functional Analysis · Mathematics 2017-02-07 Gleb Berdnikov , Iuliia Kruss , Sergey Lukomskii

The underlying mathematics of the wavelet formalism is a representation of the inhomogeneous Lorentz group or the affine group. Within the framework of wavelets, it is possible to define the ``window'' which allows us to introduce a…

Quantum Physics · Physics 2007-05-23 Y. S. Kim

We consider the elastic wave scattering problem involving rigid obstacles. This work addresses the inverse problem of reconstructing the position and shape of such obstacles using far-field measurements. A novel monotonicity-based approach…

Analysis of PDEs · Mathematics 2025-06-06 Mengjiao Bai , Huaian Diao , Weisheng Zhou

Wavelet Transforms are a widely used technique for decomposing a signal into coefficient vectors that correspond to distinct frequency/scale bands while retaining time localization. This property enables an adaptive analysis of signals at…

Applications · Statistics 2025-11-05 Jack Kissell , Vijini Lakmini , Brani Vidakovic

The empirical wavelet transform is a data-driven time-scale representation consisting of an adaptive filter bank. Its robustness to data has made it the subject of intense developments and an increasing number of applications in the last…

Image and Video Processing · Electrical Eng. & Systems 2024-12-12 Charles-Gérard Lucas , Jérôme Gilles