System-level simulation

System-level simulation (SLS) is a collection of practical methods used in the field of systems engineering, in order to simulate, with a computer, the global behavior of large cyber-physical systems.

Cyber-physical systems (CPS) are systems composed of physical entities regulated by computational elements (e.g. electronic controllers).

System-level simulation is mainly characterized by:

• a level of detail adapted to the practical simulation of large and complex cyber-physical systems (e.g. plants, aircraft, industrial facilities)
• the possibility to use the simulation even if the system is not fully specified, i.e. simulation does not necessarily require a detailed knowledge of each part of the system. This makes it possible to use the simulation for conception or study phases, even at an early stage in this process

These two characteristics have several implications in terms of modeling choices (see further).

System-level simulation has some other characteristics, that it shares with CPS simulation in general:

• SLS involves multi-physics models (thermo-fluidic, mechanical, electrical, etc.)
• SLS is frequently cross-disciplinary,^[1] i.e. it is frequently the result of a collaboration between people with different expertises
• SLS is generally built upon a hierarchy of models; an organized modeling is usually necessary to make the whole model envisagable; the conceptual decomposition of the system into sub-systems is related to the notion of system of systems

SLS is mainly about computing the evolution over time of the physical quantities that characterize the system of interest, but other aspects can be added like failure modeling or requirement verification.