Digital twins are virtual representations of physical systems or infrastructure facilities connected to their physical counterparts through sensors providing data on their condition and/or performance in real time, which allows optimizing the management or the operational performance of these systems.  The use of digital replicas of physical systems started in the aerospace and systems engineering in the 1960s, but the concept of a digital twin was not introduced until the early 2000’s, while the term “digital twin” was coined in 2010.