Risk Prediction of Coal and Gas Outburst Based on Abnormal Gas Concentration in Blasting Driving Face
Table 1
Time-domain features of abnormal gas concentration sequence.
Number
Features
Meaning
Calculation formula
1
Peak value
Maximum gas concentration value in
2
Average value
General level and central trend of gas concentration value in
3
Root mean square value
Dispersion degree of gas concentration value in
4
Variance
Deviation between and its average value
5
Standard deviation
Dispersion degree of gas concentration value in
6
Coefficient of variation
Relative statistics of the dispersion degree of
7
Peak-to-average ratio
Extreme degree of in
8
Skewness
Skew direction and degree of distribution, digital feature of the asymmetric degree of data distribution
9
Kurtosis
The sharpness of the peak of the gas concentration curve
10
Integral of a discrete sequence
The amount of gas emission during the period When the wind speed is constant
11
Peak width
Width of the wave crest in
12
Peak prominence
Prominence of the wave crest in
Note, and are, respectively, the number of gas concentration values within and min; is the sampling interval time; is the sampling start time; and is the total sampling time.
