Sensors of Smart Devices in the Internet of Everything (IoE) Era: Big Opportunities and Massive Doubts

Table 2

Frequency-domain features.

Feature	Citation
Spectral centroid	[18, 180, 181, 183]
Spectral Std deviation	[180, 183]
Spectral kurtosis	[18, 180, 183]
Spectral skewness	[18, 180, 183]
Spectral crest	[18, 180, 183]
Irregularity-J	[18, 180, 183]
Smoothness	[18, 180, 183]
Flatness	[18, 180, 183]
Roll off	[18, 180, 183]
Entropy	[18, 183]
Brightness	[18, 183]
Roughness	[18, 183]