Feature extraction

1.

Data Features
Domain
Type
Dimensions
Reference
Time
3
Time
3
(Sun et al. 2010)
(Bao & Intille 2004)
(Sun et al. 2010)
(Bao & Intille 2004)
Time
3
(Godfrey et al. 2008)
Time
3
(Ermes et al. 2008)
Time
3
(Bao & Intille 2004)
Time
3
(Mase 2002)
Zero Crossing Rate
C = x (xi > 0 ∧ xi−1 < 0 ∨ (xi < 0 ∧ xi−1 > 0)}
ZCR = count(C)
C = x (xi > xത ∧ xi−1 < xത ∨ (xi < xത ∧ xi−1 > xത )}
MCR = count(C)
Time
3
Mean Crossing Rate
(Mase 2002)
(Altini et al. 2012)
Time
1
(Kwapisz et al. 2011)
Time
1
(Khan et al. 2010)
σN
i=2 x i − x i−1
N
Time
3
(Kwapisz et al. 2011)
σN
i=1 x i
n
Time
3
(Kwapisz 2010)
Time
3
(Staudenmayer et al.
2009)
Factor
Mean
Variance
Skewness
Equation
σN
i=1 x i
n
N
2
σi=1 xi − σN
i=1 x i
var x =
N
nM3
skewness g1 =
3
xത =
or
M22
Kurtosis
kurtosis g 2 =
N
Covariance
2
cov x, y =
nM4
−3
M22
1
෍ xi − xത ∗ (yi − yത )
N−1
i=1
Average Resultant
Acceleration
Magnitude
Average Absolute
Difference
Average Absolute Value
Root Mean Square
FFT Transformation
Dominant frequency
Energy
Entropy
ARA =
xi2 + yi2 + zi2 =
magnitude =
AAD =
AAV =