Statistical Estimation of Changes in the Dominant Frequencies of Structures in Long Noisy Series of Monitoring Data
Figure 3
SNHT results for synthetic data set 1 with noise level Hz (4% of the frequency). Upper line: time series with no shift (shift = 0 Hz) and shifts equal to 0.02, 0.04, 0.08 Hz, that is, lower and higher of the noise standard deviation. A red line indicates the frequency shift. Lower line: the test variable . A dotted horizontal line indicates the 95% level of statistical significance. Vertical dashed lines indicate the position of the real shift (always at point number 30) while a horizontal dashed line indicates the position of the maximum . A gray area indicates the distance between the position of the maximum and the position of the real shift.
