Health Diagnosis of Roadheader Based on Reference Manifold Learning and Improved K-Means

Table 2

Characteristic parameters.

Time-frequency characteristics	Markup symbols	Energy ratios of wavelet analysis	Markup symbols
Peak-to-peak	pk	Ratio 1	E1
Effective value	st	Ratio 2	E2
Absolute mean	me	Ratio 3	E3
Impulse factor	va	Ratio 4	E4
Kurtosis value	Kr	Ratio 5	E5
Margin factor	L	Ratio 6	E6
Peak factor	C	Ratio 7	E7
Waveform factor	S	Ratio 8	E8