Table 1:

Summary of Different Perspectives on the Digital Twin

Reference	Definition	Viewpoint	Fidelity	Temporal Integration
GE [5]	Software representation	Product, Process	Complete	Offline
Siemens [6]	Virtual representation	Product, Process	Complete	Offline
Shao and Kibira [7]	Integrated model	Process, System	Partial or Complete	Real-time
Tao and Zhang [8]	Reference model	Product	Complete	Offline
Coronado et al. [9]	Digital model	System	Complete	Near real-time or Offline
Ahuett-Garza and Kurfess [10]	Cyber-physical system	System	Partial	Real-time
Negri et al. [11], Kritzinger et al. [12]	Virtual or computerized counterpart	System	Partial	Real-time
Garetti et al. [13]	Virtual representation	System	Partial	Real-time
Haag and Anderl [14]	Digital representation	Product	Complete	Offline
Boschert and Rosen [15]	Data and model	Product, Process, System	Partial	Real-time or Offline