An autocorrelation function method for estimation of parameters of autoregressive models

1994 ◽  
Vol 8 (1) ◽  
pp. 33-55 ◽  
Author(s):  
Wang Guang-Te ◽  
V. P. Singh
Keyword(s):  
Autocorrelation Function ◽  
Function Method ◽  
Autoregressive Models ◽  
Estimation Of Parameters

Stochastic and chaotic evaluation of parameters of lectroencephalogram

2015 ◽  
Vol 4 (1) ◽  
pp. 54-59 ◽  
Author(s):  
Горбунов ◽  
D. Gorbunov ◽  
Вохмина ◽  
Yu. Vokhmina ◽  
Еськов ◽  
...  
Keyword(s):  
Phase Space ◽  
Autocorrelation Function ◽  
Compartmental Model ◽  
Mental States ◽  
Rate Of Change ◽  
Pairwise Comparisons ◽  
Estimation Of Parameters ◽  
Brain Potentials ◽  
The Matrix ◽  
Evaluation Of Parameters

Traditionally parameters of amplitude-frequency characteristics of recorded biopotentials are used in EEG. In this paper we show that they are still chaotic, which takes place for the autocorrelation function A(t). It is proposed the two new approaches for estimation of parameters of electroencephalograms. The first is based on the construction of the matrix of pairwise comparisons of recorded samples of brain potentials in subjects in different physiological (mental) states. The second method is based on calculating the parameters of quasi-attractors, which are built on the plane in the coordinates x1=U(t) – a function that changes due to registration of biopotential in cur-rent point and x2=dx1/dt - rate of change of x1. It is possible to construct a three-compartmental model quasi-attractor in the phase space of states, which is also discussed

Acoustic Sounder Observations of Atmospheric Turbulence Parameters in a Convective Boundary Layer

1993 ◽  
Vol 32 (8) ◽  
pp. 1433-1440 ◽  
Author(s):  
Frank Quintarelli
Keyword(s):  
Boundary Layer ◽  
Atmospheric Turbulence ◽  
Autocorrelation Function ◽  
Dissipation Rate ◽  
Function Method ◽  
Convective Conditions ◽  
Convective Boundary ◽  
Pulse Volume ◽  
Spectral Variance ◽  
Turbulence Parameters

Abstract Acoustic sounder observations of atmospheric turbulence parameters presented in this paper include estimates of the dissipation rate ε, estimates of turbulent scale lengths λ, and uncertainties in measurements of the variance of the vertical wind σ2w caused by pulse volume filtering. The calculations are mainly restricted to periods when the convective regime is well established. Two techniques are used to determine ε and λ. Structure functions and the spectral variance of the echo are used to determine ε. The spectrum of vertical velocities are used to calculate λm and the autocorrelation function is used to calculate λe. Estimates of ε obtained from the spectral variance of the echo compare favorably with estimates from the structure function during convective regimes but the agreement is poor in other regimes. The autocorrelation function method for obtaining length scales yields results more reliably than the spectral method. The ratio λm/λe compares favorably with values reported in the literature except at low heights where it is markedly lower. The effects of pulse volume filtering on measurements of σ2w were found to be significant. In convective conditions, σ2w deduced from the Doppler shift of the echo can be underestimated by up to 25% and by greater amounts in other conditions.

Autocorrelation-function method of measuring film thicknesses

1986 ◽  
Vol 29 (5) ◽  
pp. 391-393 ◽  
Author(s):  
V. K. Grigor'ev ◽  
N. N. Solov'ev ◽  
O. I. Shvedova
Keyword(s):  
Autocorrelation Function ◽  
Function Method
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