in exploration seismology quality factor is widely used as a seismic attribute to identify anomalies related to attenuation, especially those caused by hydrocarbon. previous studies have indicated that seismic energy loss known as attenuation is greater for high frequency components of seismic data compared to the low frequency components. here the continuous wavelet transform is used to study ...

into the second category of estimators which exploit OFDM sigThis work considers the problem of jointly estimating symbol frame boundaries and camer frequency offsets for orthogonal frequency division multiplexed (OFDM) communications in frequency selective fading environments. Orthogonality between the modulated and virtual carriers over an interference free window of the received signal is us...

The stress wave propagation in a generalized thermoelastic polygonal plate of inner and outer cross sections is studied using the Fourier expansion collocation method. The wave equation of motion based on two-dimensional theory of elasticity is applied under the plane strain assumption of generalized thermoelastic plate of polygonal shape, composed of homogeneous isotropic material.  The freque...

In the present study, the analysis of nonlinear vibration for a simply-supported flexible beam with a constant velocity carrying a moving mass is studied. The amplitude of vibration assumed high and its deformation rate is assumed slow. Due to the high amplitude of vibrations, stretching is created in mid-plane, resulting in, the nonlinear strain-displacement relations is obtained, Thus, Nonlin...

We analyze the solutions of the Schrödinger equation with the low frequency initial data and a time-dependent weakly random potential. We prove a homogenization result for the low frequency component of the wave field. We also show that the dynamics generates a non-trivial energy in the high frequencies, which do not homogenize – the high frequency component of the wave field remains random and...

The accurate solution of quasi-Helmholtz decomposed electric field integral equations (EFIEs) in the presence arbitrary excitations is addressed: Depending on specific excitation, components induced current density do not have same asymptotic scaling frequency, and thus, are solved for with, general, different relative accuracies. In order to ensure scaling, we propose a frequency normalization...

Base on the integral representations of solution being derived via Fokas' transform method, high-frequency asymptotics for Helmholtz equation, in a half-plane and subject to Neumann condition is discussed. For case piecewise constant boundary data, full asymptotic expansions are obtained by using Watson's lemma method steepest descents definite integrals.