Human Activity Recognition in AAL Environments Using Random Projections

Table 1

Catalogue of features.

Feature number	Description	Equation (notation)
4–6	Acceleration (-, -, and -axes)
7–9	Gyroscope (-, -, and -axes)
10–15	Moving variance of 100 samples of acceleration and gyroscope data	, here
16-17	Movement intensity of acceleration and gyroscope data
18	Movement intensity of difference between acceleration and gyroscope data
19–21	Moving variance of 100 samples of movement intensity data	, here
22–24	Polar coordinates of acceleration data	,; ,
25–27	Polar coordinates of gyroscope data	,; ,
28–30	Polar coordinates of difference between acceleration and gyroscope data	,; ,
31	Simple moving average of acceleration data
32	Simple moving average of gyroscope data
33	Simple moving average of difference between acceleration and gyroscope data
34	First eigenvalue of moving covariance between acceleration data
35	First eigenvalue of moving covariance between gyroscope data
36	First eigenvalue of moving covariance of difference between acceleration and gyroscope data
37–42	Moving energy of acceleration and gyroscope data	, here
43–48	Difference between moving maximum and moving minimum of acceleration and gyroscope data	, here
49	Moving correlation between - and -axis of acceleration data
50	Moving correlation between -axis and -axis of acceleration data
51	Moving correlation between -axis and -axis of acceleration data
52	Moving correlation between -axis and -axis of gyroscope data
53	Moving correlation between -axis and -axis of gyroscope data
54	Moving correlation between -axis and -axis of gyroscope data
55–57	Projection of gyroscope data onto acceleration data
58	Moving mean of orientation vector of acceleration data	, here
59	Moving variance of orientation vector of acceleration data	,
60	Moving energy of orientation vector of acceleration data	, here
61–63	Moving energy of difference between acceleration and gyroscope data	, here  ,
64	Moving energy of difference between -axis and -axis of acceleration data
65	Moving energy of difference between -axis and -axis of acceleration data
66	Moving energy of difference between -axis and -axis of acceleration data
67	Moving mean of orientation vector of difference between acceleration and gyroscope data	, here
68	Moving variance of orientation vector of difference between acceleration and gyroscope data	,
69	Moving energy of orientation vector of difference between acceleration and gyroscope data	, here
70	Moving mean of orientation vector of gravity data	, here
71	Moving variance of orientation vector of gravity data	,
72	Moving energy of orientation vector of gravity data	, here
73	Moving mean of orientation vector of difference between acceleration and gravity data	,
74	Moving variance of orientation vector of difference between acceleration and gravity data	,
75	Moving energy of orientation vector of difference between acceleration and gravity data	,
76–81	Moving cumulative sum of acceleration and gyroscope data	, here
82	Simple moving average of cumulative sums of acceleration data
83	Simple moving average of cumulative sums of gyroscope data
84	Simple moving average of cumulative sums of difference between accelerometer and gyroscope data
85–90	Moving 2nd-order cumulative sum of acceleration and gyroscope data
91–93	Moving 2nd-order cumulative sum of differences between cumulative sums of acceleration and gyroscope data
94–96	Polar coordinates of moving cumulative sum of acceleration data	,; ,
97–99	Polar coordinates of moving cumulative sum of gyroscope data	,; ,
100–102	Polar coordinates of moving cumulative sum of differences between acceleration and gyroscope data	, ,