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One of the main tools for solving linear systems arising from the discretization of the Helmholtz equation is the shifted Laplace preconditioner, which results from the discretization of a perturbed Helmholtz problem $-\Delta u - (k^2 + i…

Numerical Analysis · Mathematics 2020-06-18 Luis García Ramos , Reinhard Nabben

We investigate wavefront solutions in a nonlinear system of two coupled reaction-diffusion equations with degenerate diffusivity: \[n_t = n_{xx} - nb, \quad b_t = [D nbb_x]_x + nb,\] where $t\geq0,$ $x\in\mathbb{R}$, and $D$ is a positive…

Analysis of PDEs · Mathematics 2024-07-16 Luisa Malaguti , Elisa Sovrano

We obtain sharp convergence rates, using Dirichlet correctors, for solutions of wave equations in a bounded domain with rapidly oscillating periodic coefficients. The results are used to prove the exact boundary controllability that is…

Analysis of PDEs · Mathematics 2022-05-17 Fanghua Lin , Zhongwei Shen

We obtain discrete characterizations of wave front sets of Fourier-Lebesgue and quasianalytic type. It is shown that the microlocal properties of an ultradistribution can be obtained by sampling the Fourier transforms of its localizations…

Analysis of PDEs · Mathematics 2016-06-14 Andreas Debrouwere , Jasson Vindas

Shearlet theory has become a central tool in analyzing and representing 2D data with anisotropic features. Shearlet systems are systems of functions generated by one single generator with parabolic scaling, shearing, and translation…

Functional Analysis · Mathematics 2010-11-23 Gitta Kutyniok , Jakob Lemvig , Wang-Q Lim

Constrained diffusions in convex polyhedral domains with a general oblique reflection field, and with a diffusion coefficient scaled by a small parameter, are considered. Using an interior Dirichlet heat kernel lower bound estimate for…

Probability · Mathematics 2013-08-19 Amarjit Budhiraja , Zhen-Qing Chen

Despite the remarkable progress, weakly supervised segmentation approaches are still inferior to their fully supervised counterparts. We obverse the performance gap mainly comes from their limitation on learning to produce high-quality…

Computer Vision and Pattern Recognition · Computer Science 2018-05-29 Yunchao Wei , Huaxin Xiao , Honghui Shi , Zequn Jie , Jiashi Feng , Thomas S. Huang

We introduce a global wave front set suitable for the analysis of tempered ultradistributions of quasianalytic Gelfand-Shilov type. We study the transformation properties of the wave front set and use them to give microlocal existence…

Analysis of PDEs · Mathematics 2013-09-18 Marco Cappiello , René Schulz

A rigorous approach for solving canonical circular open-ended dielectric-lined waveguide diffraction problems is presented. This is continuation of our recent paper [1] where a simpler case of uniform dielectric filling has been considered.…

Accelerator Physics · Physics 2022-06-15 Sergey N. Galyamin , Viktor V. Vorobev

The wavelet transform, a family of orthonormal bases, is introduced as a technique for performing multiresolution analysis in statistical mechanics. The wavelet transform is a hierarchical technique designed to separate data sets into sets…

Chemical Physics · Physics 2009-11-07 Ahmed E. Ismail , Gregory C. Rutledge , George Stephanopoulos

In this paper, we study nonhomogeneous wavelet systems which have close relations to the fast wavelet transform and homogeneous wavelet systems. We introduce and characterize a pair of frequency-based nonhomogeneous dual wavelet frames in…

Functional Analysis · Mathematics 2010-02-11 Bin Han

In this paper novel classes of 2-D vector-valued spatial domain wavelets are defined, and their properties given. The wavelets are 2-D generalizations of 1-D analytic wavelets, developed from the Generalized Cauchy-Riemann equations and…

Statistics Theory · Mathematics 2010-05-10 S. C. Olhede , G. Metikas

An elegant and convenient rigorous approach for solving circular open-ended dielectric-loaded waveguide diffraction problems is presented. It uses the solution of corresponding Wiener-Hopf-Fock equation and leads to an infinite linear…

Accelerator Physics · Physics 2021-04-27 Sergey N. Galyamin , Viktor V. Vorobev , Andrey V. Tyukhtin

This report aims to present my research updates on distance function wavelets (DFW) based on the fundamental solutions and the general solutions of the Helmholtz, modified Helmholtz, and convection-diffusion equations, which include the…

Computational Engineering, Finance, and Science · Computer Science 2025-10-20 W. Chen

In this paper, we introduce a new (constructive) characterization of tight wavelet frames on non-flat domains in both continuum setting, i.e. on manifolds, and discrete setting, i.e. on graphs; discuss how fast tight wavelet frame…

Functional Analysis · Mathematics 2015-10-07 Bin Dong

We obtain a convergent power series expansion for the first branch of the dispersion relation for subwavelength plasmonic crystals consisting of plasmonic rods with frequency-dependent dielectric permittivity embedded in a host medium with…

Analysis of PDEs · Mathematics 2015-05-14 Santiago Fortes , Robert Lipton , Stephen Shipman

The wavelet spectra is a common starting point for estimating the Hurst exponent of a self-similar signal using wavelet-based techniques. The decay of the $\log_2$ average energy of the detail wavelet coefficients as a function of the level…

Methodology · Statistics 2025-12-02 Raymond J. Hinton, , Pepa Ramírez Cobo , Brani Vidakovic

Pinning and depinning of wavefronts are ubiquitous features of spatially discrete systems describing a host of phenomena in physics, biology, etc. A large class of discrete systems is described by overdamped chains of nonlinear oscillators…

Materials Science · Physics 2009-11-07 A. Carpio , L. L. Bonilla

We present a unified group-theoretical derivation of the Continuous Wavelet Transform (CWT) on the circle $\mathbb S^1$ and the real line $\mathbb{R}$, following the general formalism of Coherent States (CS) associated to unitary square…

Mathematical Physics · Physics 2007-05-23 Manuel Calixto , Julio Guerrero

We show the relevance of a multifractal-type analysis for pointwise convergence and divergence properties of wavelet series: Depending on the sequence space which the wavelet coefficients sequence belongs to, we obtain deterministic upper…

Functional Analysis · Mathematics 2017-01-12 Céline Esser , Stéphane Jaffard