In theoretical computer science, DEVS is closed under coupling [Zeigper84] [ZPK00].
In other words, given a coupled DEVS model
, its behavior is described as an atomic DEVS model
For a given coupled DEVS
, once we have an equivalent atomic DEVS
can be referred to behavior of atomic DEVS which is based on Timed Event System.
Similar to behavior of atomic DEVS, behavior of the Coupled DEVS class is described depending on definition of the total state set and its handling as follows.
Given a coupled DEVS model
{\displaystyle N=
, its behavior is described as an atomic DEVS model
{\displaystyle M=
Given the partial state
denote the set of imminent components.
The firing component
which triggers the internal state transition and an output event is determined by where Given a coupled DEVS model
{\displaystyle N=
, its behavior is described as an atomic DEVS model
{\displaystyle M=
Given the partial state
{\displaystyle IMM(s)=\{i\in D|t_{si}-t_{ei}=ta(s)\}}
denote the set of imminent components.
which triggers the internal state transition and an output event is determined by where Since in a coupled DEVS model with non-empty sub-components, i.e.,
, the number of clocks which trace their elapsed times are multiple, so time passage of the model is noticeable.
Given a total state
If unit event segment
is the null event segment, i.e.
, the state trajectory in terms of Timed Event System is Given a total state
If unit event segment
is the null event segment, i.e.
, the state trajectory in terms of Timed Event System is