نتایج جستجو برای: chebyshev systems
تعداد نتایج: 1187453 فیلتر نتایج به سال:
in this thesis, using concepts of wavelets theory some methods of the solving optimal control problems (ocps). governed by time-delay systems is investigated. this thesis contains two parts. first, the method of obtaining of the ocps in time delay systems by linear legendre multiwavelets is presented. the main advantage of the meth...
We consider the convergence properties of several iterative implementations of linear multiuser receivers, under the assumption of long random spreading sequences. We nd that parallel interference cancellation diverges for systems loads of greater than 17%. Using known results from the theory of iterative solutions for linear systems, we derive optimal or near optimal relaxation parameters for ...
In this paper, the ultraspherical operational matrices of derivatives are constructed. Based on these operational matrices, two numerical algorithms are presented and analyzed for obtaining new approximate spectral solutions of a class of linear and nonlinear Lane-Emden type singular initial value problems. The basic idea behind the suggested algorithms is basically built on transforming the eq...
In this paper we compare Krylov subspace methods with Chebyshev series expansion for approximating the matrix exponential operator on large, sparse, symmetric matrices. Experimental results upon negative-definite matrices with very large size, arising from (2D and 3D) FE and FD spatial discretization of linear parabolic PDEs, demonstrate that the Chebyshev method can be an effective alternative...
In this paper we describe the use of multivariate Chebyshev polynomials in computing spectral derivations and Clenshaw–Curtis type quadratures. The multivariate Chebyshev polynomials give a spectrally accurate approximation of smooth multivariate functions. In particular we investigate polynomials derived from the A2 root system. We provide analytic formulas for the gradient and integral of A2 ...
The Effect of Window Parameter () in Dolph-chebyshev window on the processing of atmospheric signals
The effect of Window Parameter () in Dolph-Chebyshev window on the SNR of radar returns is discussed and proposed an optimum value of “” with which data may be weighed using Dolph-Chebyshev window. It is observed that the Dolph-Chebyshev window can be used with “”corresponding to the minimum of sidelobe attenuation of 50dB to taper the data for spectral analysis. From the results, it may be ...
An O(N(logN)2/ loglogN) algorithm for computing the discrete Legendre transform and its inverse is described. The algorithm combines a recently developed fast transform for converting between Legendre and Chebyshev coefficients with a Taylor series expansion for Chebyshev polynomials about equallyspaced points in the frequency domain. Both components are based on the FFT, and as an intermediate...
Let G be a strict RS-set (resp. an RS-set) in X and let F be a bounded (resp. totally bounded) subset of X satisfying rG(F )> rX(F ), where rG(F ) is the restricted Chebyshev radius of F with respect to G. It is shown that the restricted Chebyshev center of F with respect to G is strongly unique in the case when X is a real Banach space, and that, under some additional convexity assumptions, th...
Moment functions are widely used in image analysis as feature descriptors. Compared to geometric moments, orthogonal moments have become more popular in image analysis for their better representation capabilities. In comparison to continuous orthogonal moments discrete orthogonal moments provide a more accurate description of the image features. This paper compares the performance of discrete o...
In this article, the second kind Chebyshev wavelet method is presented for solving a class of multi-order fractional differential equations (FDEs) with variable coefficients. We first construct the second kind Chebyshev wavelet, prove its convergence and then derive the operational matrix of fractional integration of the second kind Chebyshev wavelet. The operational matrix of fractional integr...
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