scholarly journals FNS-parameterization of human magnetoencephalograms for the diagnosis of photosensitive epilepsy

2021 ◽  
Vol 2103 (1) ◽  
pp. 012046
Author(s):  
R R Khairullina ◽  
S A Demin ◽  
V A Yunusov ◽  
O Y Panischev
Keyword(s):  
High Frequency ◽  
Phase Synchronization ◽  
Flicker Noise ◽  
Initial Time ◽  
High Frequency Region ◽  
New Methods ◽  
Noise Spectroscopy ◽  
Time Signals ◽  
Photosensitive Epilepsy ◽  
Frequency Phase

Abstract This work presents the results of parameterization of magnetoencephalogram signals from healthy subjects and a patient with photosensitive epilepsy. Diagnostic criteria were established during the extraction of resonant and high-frequency (chaotic) components of the initial time signals. It is shown that an increase in the intensity of the chaotic components of the studied signals in the high-frequency region leads to a violation of cross-correlation relationships and a decrease in the level of manifestation of frequency-phase synchronization. The discovered signs of photosensitive epilepsy will contribute to the development of new methods for the diagnosis and medical control of this disease based on Flicker-Noise Spectroscopy.

scholarly journals Analysis of biomedical signals by flicker-noise spectroscopy: Identification of photosensitive epilepsy using magnetoencephalograms

Laser Physics ◽  
2009 ◽  
Vol 19 (4) ◽  
pp. 836-854 ◽  
Author(s):  
S. F. Timashev ◽  
Yu. S. Polyakov ◽  
R. M. Yulmetyev ◽  
S. A. Demin ◽  
O. Yu. Panischev ◽  
...  
Keyword(s):  
Flicker Noise ◽  
Biomedical Signals ◽  
Noise Spectroscopy ◽  
Photosensitive Epilepsy

scholarly journals An attempt to find precursors in the ULF geomagnetic data by means of flicker noise spectroscopy

2006 ◽  
Vol 13 (3) ◽  
pp. 255-263 ◽  
Author(s):  
M. Hayakawa ◽  
S. F. Timashev
Keyword(s):  
Main Shock ◽  
Flicker Noise ◽  
Low Frequency ◽  
Nonlinear Behavior ◽  
Phenomenological Method ◽  
Frequency Data ◽  
Noise Spectroscopy ◽  
Time Signals ◽  
Geomagnetic Data ◽  
Derivatives Of

Abstract. The flicker noise spectroscopy which is a new phenomenological method for the retrieval of information contained in chaotic time signals, is based on the analysis of recognizable irregularities (pulse, jumps, and discontinuities of derivatives of various order). This method is applied to the ULF (ultra-low-frequency) data observed at Guam in 1992–1994, in order to study the temporal nonlinear behavior of the lithospheric activity prior to the large 1993 Guam earthquake (8 August 1993). We have found that the lithosphere must have exhibited the step-like discontinuous behaviors in the lithosphere 101, 78, 54, 31 and 8 days before the main shock. This kind of nonlinear temporal behavior can be tracked by means of our flicker noise spectroscopy.

scholarly journals The VIT Transform Approach to Discrete-Time Signals and Linear Time-Varying Systems

Eng ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 99-125
Author(s):  
Edward W. Kamen
Keyword(s):  
Discrete Time ◽  
Initial Conditions ◽  
Linear Time ◽  
Order Term ◽  
Initial Time ◽  
Time Varying ◽  
Varying Coefficients ◽  
Time Signals ◽  
Time Varying Systems ◽  
Time Varying Coefficients

A transform approach based on a variable initial time (VIT) formulation is developed for discrete-time signals and linear time-varying discrete-time systems or digital filters. The VIT transform is a formal power series in z−1, which converts functions given by linear time-varying difference equations into left polynomial fractions with variable coefficients, and with initial conditions incorporated into the framework. It is shown that the transform satisfies a number of properties that are analogous to those of the ordinary z-transform, and that it is possible to do scaling of z−i by time functions, which results in left-fraction forms for the transform of a large class of functions including sinusoids with general time-varying amplitudes and frequencies. Using the extended right Euclidean algorithm in a skew polynomial ring with time-varying coefficients, it is shown that a sum of left polynomial fractions can be written as a single fraction, which results in linear time-varying recursions for the inverse transform of the combined fraction. The extraction of a first-order term from a given polynomial fraction is carried out in terms of the evaluation of zi at time functions. In the application to linear time-varying systems, it is proved that the VIT transform of the system output is equal to the product of the VIT transform of the input and the VIT transform of the unit-pulse response function. For systems given by a time-varying moving average or an autoregressive model, the transform framework is used to determine the steady-state output response resulting from various signal inputs such as the step and cosine functions.

Anderson-Stuart Model to Analyze AC and DC Conductivity of Lithium Zinc-Silicate Glass / Glass-Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 919-924
Author(s):  
M.S. Jogad ◽  
V.K. Shrikhande ◽  
A.H. Dyama ◽  
L.A. Udachan ◽  
Govind P. Kothiyal
Keyword(s):  
High Frequency ◽  
Glass Ceramics ◽  
Low Frequency ◽  
Frequency Region ◽  
Dc Conductivity ◽  
Frequency Range ◽  
High Frequency Region ◽  
Dc Conductivities ◽  
Conductivity Variation ◽  
Different Temperatures

AC and DC conductivities have been measured by using the real (e¢) and imaginary (e¢¢) parts of the dielectric constant data of glass and glass-ceramics (GC) at different temperatures in the rage 297-642K and in the frequency range 100 Hz to 10 MHz. Using Anderson –Stuart model, we have calculated the activation energy, which is observed to be lower than that of the DC conductivity. The analysis for glass/glass-ceramics indicates that the conductivity variation with frequency exhibits an initial linear region followed by nonlinear region with a maximum in the high-frequency region. The observed frequency dependence of ionic conductivity has been analyzed within the extended Anderson–Stuart model considering both the electrostatic and elastic strain terms. In glass/glassceramic the calculations based on the Anderson-Stuart model agree with the experimental observations in the low frequency region but at higher frequencies there is departure from measured data.

Channel thermal noise of SOI MOSFET in high-frequency region

2005 ◽  
Vol 20 (2) ◽  
pp. 216-220
Author(s):  
Nirupama Kapoor ◽  
Subhasis Haldar ◽  
Mridula Gupta ◽  
R S Gupta
Keyword(s):  
High Frequency ◽  
Thermal Noise ◽  
Frequency Region ◽  
High Frequency Region ◽  
Soi Mosfet

scholarly journals Identification of earthquake precursors in the hydrogeochemical and geoacoustic data for the Kamchatka peninsula by flicker-noise spectroscopy

2011 ◽  
Vol 11 (2) ◽  
pp. 541-548 ◽  
Author(s):  
G. V. Ryabinin ◽  
Yu. S. Polyakov ◽  
V. A. Gavrilov ◽  
S. F. Timashev
Keyword(s):  
Statistical Physics ◽  
Systems Approach ◽  
Flicker Noise ◽  
Large Earthquake ◽  
Kamchatka Peninsula ◽  
Time Frame ◽  
Underground Water ◽  
Ion Concentration ◽  
Seismic Zone ◽  
Noise Spectroscopy

Abstract. A phenomenological systems approach for identifying potential precursors in multiple signals of different types for the same local seismically active region is proposed based on the assumption that a large earthquake may be preceded by a system reconfiguration (preparation) on different time and space scales. A nonstationarity factor introduced within the framework of flicker-noise spectroscopy, a statistical physics approach to the analysis of time series, is used as the dimensionless criterion for detecting qualitative (precursory) changes within relatively short time intervals in arbitrary signals. Nonstationarity factors for chlorine-ion concentration variations in the underground water of two boreholes on the Kamchatka peninsula and geacoustic emissions in a deep borehole within the same seismic zone are studied together in the time frame around a large earthquake on 8 October 2001. It is shown that nonstationarity factor spikes (potential precursors) take place in the interval from 70 to 50 days before the earthquake for the hydrogeochemical data and at 29 and 6 days in advance for the geoacoustic data.

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