Agent-based modeling and simulation - Modeling and Simulation of Complex Systems - page 14

As already mentioned, there is no such thing as the one model.
Instead, each simulation model exists in at least three stages (concep-
tual model, formal model, executable model). In colloquial speech the
term model is often used synonymously with executable model and
one has to be aware of the subtle differences.
2.1.4 Simulation
The term simulation is frequently used with two slightly different
meanings. The first interpretation of simulation refers to the meth-
odology of using simulation techniques for solving a specific problem.
This covers the whole process of analyzing the problem, developing
a simulation model (consisting of a conceptual model, formal model,
and executable model), executing experiments and interpreting the
results (see Figure 2.1).
The second interpretation refers to simulation as the act of actually
executing an executable simulation model. Therefore, a simulation
takes an executable model (and data) as input and applies a number
of computational steps to transform a model from an initial state into
a final state.
In the following, the term simulation refers to the second interpret-
ation:
Definition 2 (Simulation) The term simulation refers to the exe-
cution of a specific executable simulation model.
Although it is possible to simulate manually, almost always an appro-
priate simulation engine is used.
Definition 3 (Simulation engine) A simulation engine is a soft-
ware application that executes the simulation of a model.
A simulation engine may internally use any kind of data structures
and execution control as long as the simulation is executed correctly.
Within this thesis, the term simulation engine refers to a piece of
software and not to the execution control mechanism or any other