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 ...

The present paper is aimed at introducing a new algorithm for image encryption using chaotic tent maps and the desired key image. This algorithm consists of two parts, the first of which works in the frequency domain and the second, in the time domain. In the frequency domain, a desired key image is used, and a random number is generated, using the chaotic tent map, in order to change the phase...

A simple but efficient method to improve readability of discrete pseudo time-frequency representations (TFRs) of nonstationary signals by the reassignment of the representations in discrete frequency dimension is presented. The method does not rely on the nonzero time derivative of the window function employed in the estimation of pseudo TFR. This property of the reassignment method is advantag...

The output data from a structure is the building block for output-only modal analysis. The structure response in the output data, however, is usually contaminated with noise. Naturally, the success of output-only methods in determining the modal parameters of a structure depends on noise level. In this paper, the possibility and accuracy of identifying the modal parameters of a simply supported...

given the sensitivity of current ground-based gravitational wave (gw) detectors, any continuous-wave signal we can realistically expect will be at a level or below the background noise. hence, any data analysis of detector data will need to rely on statistical techniques to separate the signal from the noise. while with the current sensitivity of our detectors we do not expect to detect any tru...

This paper presents a new time-frequency based EEG seizure detection method. This method uses the distribution of interspike intervals as a criterion for discriminating between seizure and nonseizure activities. To detect spikes in the EEG, the signal is mapped into the time-frequency domain. The high instantaneous energy of spikes is reflected as a localized energy in time-frequency domain. Hi...

harmonics have become an important issue in modern power systems. the widespread penetration of non-linear loads to emerging power systems has turned power quality analysis into an important operation issue under both steady state and transient conditions. this paper employs an extended harmonic domain (ehd) based framework for dynamic analysis of long term analysis over voltages during the tra...