Results 51 to 60 of about 1,649 (181)
Breaking Barriers in High‐Order Spectral Methods: The Intrinsic Matrix Approach
International Journal for Numerical Methods in Engineering, Volume 127, Issue 5, 15 March 2026.ABSTRACT This paper introduces a unified framework in Hilbert spaces for applying high‐order differential operators in bounded domains using Chebyshev, Legendre, and Fourier spectral methods. By exploiting the banded structure of differentiation matrices and embedding boundary conditions directly into the operator through a scaling law relating ...
Osvaldo Guimarães, José R. C. Piqueira
wiley +1 more source
Polynomial sequences generated by infinite Hessenberg matrices
Special Matrices, 2017 We show that an infinite lower Hessenberg matrix generates polynomial sequences that correspond to the rows of infinite lower triangular invertible matrices. Orthogonal polynomial sequences are obtained when the Hessenberg matrix is tridiagonal. We study
Verde-Star Luis
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Toeplitz versus Hankel: semibounded operators [PDF]
Opuscula Mathematica, 2018 Our goal is to compare various results for Toeplitz \(T\) and Hankel \(H\) operators. We consider semibounded operators and find necessary and sufficient conditions for their quadratic forms to be closable. This property allows one to define \(T\) and \(
Dmitri R. Yafaev
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Analytical solutions to some generalized and polynomial eigenvalue problems
Special Matrices, 2021 It is well-known that the finite difference discretization of the Laplacian eigenvalue problem −Δu = λu leads to a matrix eigenvalue problem (EVP) Ax =λx where the matrix A is Toeplitz-plus-Hankel.
Deng Quanling
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Magnetic Resonance in Medicine, Volume 95, Issue 3, Page 1513-1527, March 2026.ABSTRACT Purpose Pediatric craniofacial imaging may involve examination of both the skull and brain tissues via CT and MRI, respectively. DREAMER (Dual Repetition and Echo Acquisition with Multi‐contrast Encoding and Reconstruction) simultaneously acquires solid‐ and soft‐tissue images, potentially providing a rapid, high‐resolution, and radiation‐free
Brian‐Tinh Duc Vu +8 more
wiley +1 more source
Trace of the Positive Integer Powers (n-1)-Tridiagonal Toeplitz Matrix n×n
JTAM (Jurnal Teori dan Aplikasi Matematika)The trace of a matrix is obtained by summing the elements along the main diagonal of a square matrix. The matrix used in this study is a Toeplitz (n-1)-tridiagonal matrix of order n×n.
Fitri Aryani +3 more
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Stability and Instability of Time‐Domain Boundary Element Methods for the Acoustic Neumann Problem
Proceedings in Applied Mathematics and Mechanics, Volume 26, Issue 1, March 2026.ABSTRACT This work presents a stable time‐domain boundary element method for the acoustic wave equation in three‐dimensional unbounded domains. Other formulations of time‐domain boundary element methods based on retarded potential operators are known to exhibit stability issues, which often hinder their use in industrial contexts.
Simon Schneider +4 more
wiley +1 more source
Multiple-Toeplitz Matrices Reconstruction Algorithm for DOA Estimation of Coherent Signals
IEEE Access, 2019 In this paper, a new direction-of-arrival (DOA) estimation method based on multiple Toeplitz matrices reconstruction is proposed for coherent narrowband signals with a uniform linear array (ULA).
Wei Zhang +3 more
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International Journal of Dermatology, Volume 65, Issue 3, Page 526-534, March 2026.ABSTRACT Background Patients with alopecia areata (AA) in ALLEGRO‐2b/3 (NCT03732807) had clinically significant hair regrowth and patient‐reported improvements with ritlecitinib versus placebo, but patient‐reported improvements in AA Patient Priority Outcomes (AAPPO) emotional symptoms (ES) or activity limitations (AL) were not observed during the 24 ...
Ernest H. Law +8 more
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Nonnegative Matrix Factorization with Toeplitz Penalty
Journal of Informatics and Mathematical Sciences, 2018 Nonnegative Matrix Factorization (NMF) is an unsupervised learning algorithm that produces a linear, parts-based approximation of a data matrix. NMF constructs a nonnegative low rank basis matrix and a nonnegative low rank matrix of weights which, when multiplied together, approximate the data matrix of interest using some cost function.
Corsetti, Matthew, Fokoué, Ernest
openaire +3 more sources