scholarly journals Semi-orthogonal wavelet frames on positive half-line using the Walsh Fourier transform

2018 ◽  
Vol 2 (6) ◽  
pp. 175-183
Author(s):  
Abdullah Abdullah ◽  
Afroz Afroz
Keyword(s):  
Fourier Transform ◽  
Half Line ◽  
Wavelet Frames ◽  
Orthogonal Wavelet ◽  
Positive Half

scholarly journals Frames associated with shift invariant spaces on positive half line

2021 ◽  
Vol 13 (1) ◽  
pp. 23-44
Author(s):  
Owais Ahmad ◽  
Mobin Ahmad ◽  
Neyaz Ahmad
Keyword(s):  
Sufficient Conditions ◽  
Gabor Frames ◽  
Half Line ◽  
Necessary Condition ◽  
Wavelet Frames ◽  
Invariant Space ◽  
Unified Approach ◽  
Shift Invariant Spaces ◽  
Invariant Spaces ◽  
Positive Half

Abstract In this paper, we introduce the notion of Walsh shift-invariant space and present a unified approach to the study of shift-invariant systems to be frames in L2(ℝ+). We obtain a necessary condition and three sufficient conditions under which the Walsh shift-invariant systems constitute frames for L2(ℝ+). Furthermore, we discuss applications of our main results to obtain some known conclusions about the Gabor frames and wavelet frames on positive half line.

scholarly journals Gabor systems on positive half line via Walsh-Fourier transform

2020 ◽  
Vol 12 (2) ◽  
pp. 468-482
Author(s):  
O. Ahmad ◽  
N.A. Sheikh
Keyword(s):  
Fourier Transform ◽  
Applied Mathematics ◽  
Vital Role ◽  
Complete Characterization ◽  
Half Line ◽  
Tight Frames ◽  
Gabor Systems ◽  
Orthonormal Bases ◽  
Positive Half

Gabor systems play a vital role not only in modern harmonic analysis but also in several fields of applied mathematics, for instances, detection of chirps, or image processing. In this paper, we investigate Gabor systems on positive half line via Walsh-Fourier transform. We provide the complete characterization of orthogonal Gabor systems on positive half line. Furthermore, we provide the characterization of tight frames and orthonormal bases of Gabor systems on positive half line in Fourier domain.

TIGHT WAVELET FRAMES GENERATED BY THE WALSH POLYNOMIALS

2013 ◽  
Vol 11 (06) ◽  
pp. 1350042 ◽  
Author(s):  
FIRDOUS AHMAD SHAH
Keyword(s):  
Explicit Construction ◽  
Half Line ◽  
Wavelet Frame ◽  
Wavelet Frames ◽  
Orthonormal Wavelets ◽  
Extension Principles ◽  
Positive Half

Tight wavelet frames and their promising features in applications have attracted a great deal of interest and effort in recent years. In this paper, we give an explicit construction of tight wavelet frames generated by the Walsh polynomials on positive half-line ℝ+ using the extension principles. Finally, we derive the wavelet frame decomposition and reconstruction formulas which are similar to those of orthonormal wavelets on positive half-line ℝ+.

WAVELET PACKETS ASSOCIATED WITH NONUNIFORM MULTIRESOLUTION ANALYSIS ON POSITIVE HALF LINE

2013 ◽  
Vol 06 (01) ◽  
pp. 1350007 ◽  
Author(s):  
Vikram Sharma ◽  
P. Manchanda
Keyword(s):  
Multiresolution Analysis ◽  
Wavelet Packets ◽  
Half Line ◽  
State University ◽  
Spectral Pairs ◽  
Funct Anal ◽  
Positive Half

Gabardo and Nashed [Nonuniform multiresolution analysis and spectral pairs, J. Funct. Anal.158 (1998) 209–241] introduced the Nonuniform multiresolution analysis (NUMRA) whose translation set is not a group. Farkov [Orthogonal p-wavelets on ℝ+, in Proc. Int. Conf. Wavelets and Splines (St. Petersburg State University, St. Petersburg, 2005), pp. 4–26] studied multiresolution analysis (MRA) on positive half line and constructed associated wavelets. Meenakshi et al. [Wavelets associated with Nonuniform multiresolution analysis on positive half line, Int. J. Wavelets, Multiresolut. Inf. Process.10(2) (2011) 1250018, 27pp.] studied NUMRA on positive half line and proved the analogue of Cohen's condition for the NUMRA on positive half line. We construct the associated wavelet packets for such an MRA and study its properties.

scholarly journals Asymptotic solution of Sturm-Liouville problem with periodic boundary conditions for relativistic finite-difference Schrödinger equation

2020 ◽  
Vol 28 (3) ◽  
pp. 230-251
Author(s):  
Ilkizar V. Amirkhanov ◽  
Irina S. Kolosova ◽  
Sergey A. Vasilyev
Keyword(s):  
Finite Difference ◽  
Boundary Conditions ◽  
Periodic Boundary ◽  
Asymptotic Series ◽  
Periodic Boundary Conditions ◽  
Singularly Perturbed ◽  
Half Line ◽  
Asymptotic Convergence ◽  
Relativistic Particles ◽  
Positive Half

The quasi-potential approach is very famous in modern relativistic particles physics. This approach is based on the so-called covariant single-time formulation of quantum field theory in which the dynamics of fields and particles is described on a space-like three-dimensional hypersurface in the Minkowski space. Special attention in this approach is paid to methods for constructing various quasi-potentials. The quasipotentials allow to describe the characteristics of relativistic particles interactions in quark models such as amplitudes of hadron elastic scatterings, mass spectra, widths of meson decays and cross sections of deep inelastic scatterings of leptons on hadrons. In this paper SturmLiouville problems with periodic boundary conditions on a segment and a positive half-line for the 2m-order truncated relativistic finite-difference Schrdinger equation (LogunovTavkhelidzeKadyshevsky equation, LTKT-equation) with a small parameter are considered. A method for constructing of asymptotic eigenfunctions and eigenvalues in the form of asymptotic series for singularly perturbed SturmLiouville problems with periodic boundary conditions is proposed. It is assumed that eigenfunctions have regular and boundary-layer components. This method is a generalization of asymptotic methods that were proposed in the works of A. N. Tikhonov, A. B. Vasilyeva, and V. F Butuzov. We present proof of theorems that can be used to evaluate the asymptotic convergence for singularly perturbed problems solutions to solutions of degenerate problems when 0 and the asymptotic convergence of truncation equation solutions in the case m. In addition, the SturmLiouville problem on the positive half-line with a periodic boundary conditions for the quantum harmonic oscillator is considered. Eigenfunctions and eigenvalues are constructed for this problem as asymptotic solutions for 4-order LTKT-equation.

Optimization and Simulation of OFDM System Based on Orthogonal Wavelet

2014 ◽  
Vol 548-549 ◽  
pp. 1221-1226
Author(s):  
Zeng You Sun ◽  
Fan Ming Zeng
Keyword(s):  
Fourier Transform ◽  
Discrete Fourier Transform ◽  
Orthogonal Frequency Division Multiplexing ◽  
Modulation Method ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Orthogonal Wavelet ◽  
Optimization And Simulation

In order to reduce the Orthogonal Frequency division Multiplexing (OFDM) Inter-Carrier Interference (ICI), Put forward a kind of modulation method that based on the orthogonal frequency division multiplexing of orthogonal wavelet, Using orthogonal wavelet instead of discrete Fourier transform, optimize the design for OFDM systems, on the premise of without protection interval to reduce the system interference, using MATLAB to simulate the OFDM system, results show that the optimization of the OFDM can reduce the power of the ICI and Inter-symbol Interference (ISI) and improve the comprehensive anti-jamming of the OFDM system.

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