Kruger This work aims at evaluating the performance of pattern recognition methods in the identification of different microstructures presented by cast iron, namely, lamellar, vermicular and nodular microstructures, through the statistical fluctuation and fractal analyses of backscattered ultrasonic signals. The signals were obtained with a broad band ultrasonic probe with a central frequency of 5 MHz.
The statistical fluctuations of the ultrasonic signals were analyzed by means of Hurst RSA and detrended-fluctuation analyses DFAand the fractal analyses were carried out by applying the minimal cover and box-counting techniques forexbrothers. net contact the signals.
The results presented correspond to an average taken over randomly chosen sets of events. It is worthwhile pointing out that the microstructure classification was made by using backscattering signals acquired during pulse echo ultrasonic nondestructive testing only.
Therefore, that approach is a promising method for material characterization. View Show abstract A definition of Hurst exponent is an object of numerous researches.
In this paper we apply an approach of small data basis, suggested in work . This algorithm gives forexbrothers.
net contact estimated Hurst exponent Relations for daily volatilities can be rescaled for the N horizon: both variances allows finding a rescaling law for the correlation.