In this paper we propose a class of 2D circularly-symmetric filter banks based on a 1D IIR Gaussian prototype. We approach two cases, namely dyadic and uniform filter banks. The Gaussian prototype is obtained using an efficient rational approximation, namely the Chebyshev-Padé approximation. Then, using a frequency transformation, the corresponding 2D filters with circular symmetry are derived....

A new complex Jacobi iterative technique adapted for the solution of three-dimensional (3D) wide-angle (WA) beam propagation is presented. The beam propagation equation for analysis of optical propagation in waveguide structures is based on a novel modified Padé(1,1) approximant operator, which gives evanescent waves the desired damping. The resulting approach allows more accurate approximation...

The cluster variation – Padé approximant method is a recently proposed tool, based on the extrapolation of low/high temperature results obtained with the cluster variation method, for the determination of critical parameters in Ising-like models. Here the method is applied to the three-dimensional simple cubic Ising model, and new results, obtained with an 18-site basic cluster, are reported. O...

The equations governing the flow of an electrically conducting, incompressible viscous fluid over an infinite flat plate in the presence of a magnetic field are investigated using the homotopy perturbation method (HPM) with Padé approximants (PA) and 4 order Runge–Kutta method (4RKM). Approximate analytical and numerical solutions for the velocity field and heat transfer are obtained and compar...

We design convergent multipoint Padé interpolation schemes to Cauchy transforms of non-vanishing complex densities with respect to Jacobi-type weights on analytic arcs, under mild smoothness assumptions on the density. We rely on the work [10] for the choice of the interpolation points, and dwell on the Riemann-Hilbert approach to asymptotics of orthogonal polynomials introduced in [33] in the ...

Magnetic resonance spectroscopy is increasingly recognized as one of the key diagnostic modalities in oncology. This type of spectroscopy can detect early radiation damage to biomolecules as a salient feature of malignancy. Notwithstanding such appealing characteristics, progress in magnetic resonance spectroscopy is currently hampered by the lack of mathematically and clinically reliable spect...

Two physical models of the human vocal tract have been successfully developed for producing English /l/ and /r/ and Japanese /r/. The first model was originally designed for the alveolar lateral approximant and the retroflex approximant, while the second model was designed to produce English “bunched /r/.” With these models, we observed that different configurations of the vocal tract can produ...

Are voiceless approximants categorically distinct from voiceless fricatives? We address this question by means of acoustic analysis of voiceless laterals in Icelandic, Welsh, and the endangered variety Estonian Swedish. All three have a voiceless lateral functioning in contrast to a voiced lateral approximant. The analysis focused on duration – including any period of voicing (‘pre-voicing’) ju...

Asymptotic Padé-approximant methods are utilized to estimate the O(α5s) contribution to the H → gg rate and the O(α4s) contribution to the H → bb̄ rate. The former process is of particular interest because of the slow convergence evident from the three known terms of its QCD series, which begins with an O(α2s) leading-order term. The O(α5s) contribution to the H → gg rate is expressed as a degre...

We study the effect of a possible fourth heavy generation of fermions on the Higgs sector of the standard model. We show, from the violation of elastic unitarity, that the scale of strong interactions is well below 1 TeV even with a Higgs mass as low as 500 GeV provided the fourth generation fermion mass is equal or larger than the Higgs mass. The diagonal Pade approximant method is then used t...