Table 7.

Classification of Industry 4.0 technologies based on obtained keywords’ co-occurrences.

A: Intelligent Sensors
Sensor/Actuator	Kumar et al. [102], Lao et al. [111], Park et al. [112], Peng et al. [113], Peng and Tsan [98], Tarashioon et al. [115], Tsao et al. [116]
Automation	Musselman and Djurdjanovic [104]
B: Cloud-related Technologies
Cloud	Kiangala and Wang [94], Uhlmann et al. [117], Vlasov et al. [119]
Cloud/edge computing	Barbieri et al. [99], Yan et al. [120], Zhang et al. [122]
Big Data	Barbieri et al. [99], Kozlowski et al. [110], Chien and Chen [109], Villalobos et al. [118], Yan et al. [120], Zhang et al. [122]
RFID	Goodall et al. [92], Sadiki et al. [105], Vlasov et al. [119], Zhang et al. [122]
PLC	Al-Jlibawi et al. [107], Barbieri et al. [99], Kiangala and Wang [94]
C: Internet of Things Technologies
Internet of Things	Farooq et al. [38], Li et al. [96], Lin et al. [103], Sadiki et al. [105], Shan et al. [114], Uhlmann et al. [117], Vlasov et al. [119]
CPS system	Farooq et al. [38]
SCADA	Farooq et al. [38], Al-Jlibawi et al. [107], Kiangala and Wang [94]
Machine learning	Zhang et al. [121]
Artificial Intelligence	Bekar et al. [108]