نتایج جستجو برای: fourier power spectrum

تعداد نتایج: 740695  

Journal: :Journal of Nondestructive Evaluation 2018

2012
Md. Sadek Ali Md. Shariful Islam Md. Alamgir Hossain

In this paper, a system, developed for speech encoding, analysis, synthesis and gender identification is presented. A typical gender recognition system can be divided into front-end system and back-end system. The task of the front-end system is to extract the gender related information from a speech signal and represents it by a set of vectors called feature. Features like power spectrum densi...

2010

Fourier Wavefront Reconstruction Over a Rectangular Pupil The iterative and boundary methods developed here for circular and elliptical pupils are based on a method to reconstruct the wavefront over the rectangular pupil. To fully understand this development, it is necessary to first summarize the approach used by Freischlad and Koliopoulos to derive an inverse spatial filter to reconstruct a w...

2005
M. D. TRIFUNAC

This paper describes the physical relationships that exist between the Fourier transform and the response spectrum of a strong-motion accelerogram. By developing the new concept of the "Damped Fourier Spectrum" (D.F.S.), we show that the velocity and displacement of the damped oscillator can be represented by a linear combination of the real and imaginary parts of the D.F.S. and by the initial ...

Journal: :IEEE Trans. Information Theory 1965
Morris J. Levin

The power spectrum of a zero-mean stationary Gaussian random process is assumed to be known except for one or more parameters which are to be estimated from an observation of the process during a finite time interval. The approximation is introduced that the coefficients of the Fourier series expansion of a realization of long-time duration are uncorrelated. Based on this approximation maximum ...

2014
Yung-Hsiang Chou Jean-Fu Kiang

A proper set of models are carefully selected from the literatures to form a wholistic perspective in simulating the wave propagation in evaporation ducts, under a close-to-realistic environment. The split-step Fourier (SSF) propagation algorithm is applied to analyze the propagation properties in evaporation ducts above a rough sea surface, with turbulence in the ducts. The scattering effect o...

1996
Mitchell G. A. Thomson David H. Foster

Several studies of natural-image statistics have concluded that the majority of structural image information is represented in the Fourier domain not by the power spectrum, which can be modeled with a power function of spatial frequency, but by the phase spectrum. Psychophysical experiments are described in which human observers were required to discriminate between visual stimuli differing onl...

2004
Will J. Percival Daniel Burkey Alan Heavens Andy Taylor Shaun Cole John A. Peacock Carlton M. Baugh Joss Bland-Hawthorn Terry Bridges Matthew Colless Chris Collins Warrick Couch Gavin Dalton Roberto De Propris Simon P. Driver George Efstathiou Richard S. Ellis Carlos S. Frenk Karl Glazebrook Carole Jackson Ofer Lahav Ian Lewis Stuart Lumsden Steve Maddox Peder Norberg Bruce A. Peterson

We present the result of a decomposition of the 2dFGRS galaxy overdensity field into an orthonormal basis of spherical harmonics and spherical Bessel functions. Galaxies are expected to directly follow the bulk motion of the density field on large scales, so the absolute amplitude of the observed large-scale redshift-space distortions caused by this motion is expected to be independent of galax...

2014
Abdesselem DAKHLI Chokri BEN AMAR

Genomic sequences allow to classify organisms into different categories and classes which have significant biological knowledge and can justify the evolution and identification of unknown organisms. Also they study mutual relations between organisms. The purpose of this classification is to study living organisms. Our system consists in three phases. The first phase is called transformation wic...

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