Table 1.

Nine review articles published between 2013 and 2020

S. no.	Citation	Year	Focus area	Keywords	#K*	Period	#CI$
1	Wang et al. (2016a)	2020	Device-free HAR	HAR, gesture recognition, motion detection, Device-free, dense sensing, IoT, RFID, human object interaction	7	2011–2017	212
2	Wang et al. (2020)	2020	Sensor-based HAR	Mobile sensing, human-behaviour, human behaviour inference, cloud-edge computing, activity recognition, context awareness	6	2007–2018	136
3	Demrozi et al. (2019b)	2020	Sensor-based HAR	HAR, DL, ML, available datasets, accelerometer, sensors	6	2015–2019	219
4	Beddiar et al. (2020)	2020	Vision-based	HAR, behaviour understanding, Action representation, action detection, computer vision	4	2010–2019	237
5	Dhiman Chhavi (2019)	2019	Vision-based recognition	Two-dimension anomaly detection, three-dimensional anomaly detection, crowd anomaly, skeleton based fall detection, AAL	5	2006–2018	226
6	Lima et al. (2019)	2019	Sensor-based HAR	HAR, smartphones, feature extraction, inertial sensors	4	2006–2017	149
7	Lara and Labrador (2013)	2018	Sensor-based HAR	AAL, HAR, ADL, activity recognition system (ARS), dataset	6	2003–2017	134
8	Hx et al. (2017)	2017	Sensor-based HAR	DL, activity recognition, pervasive computing, pattern recognition	4	2011–2017	80
9	Ke et al. (2013)	2013	Video-based activity recognition	HAR, segmentation, feature representation, health monitoring, security surveillance, human computer interface	5	2003– 2012	145

^#K keywords, ^$#CI #citations, AAL ambient assistive living, ADL activity of daily living