Just to gather new tools to help me in my M. Sc. thesis, I'm taking a course on Discrete Event Simulation. This course in fact is not as general as its name may suggest. It focuses mainly on modelling with a formalism called DEVS (which stands for Discrete Event System Specification), created by Bernard Zeigler.

The choice of the DEVS formalism instead of other tools (like Petri nets or Finite State Automata, for example) was in part because the professors and teaching assistants have been doing research with it for years, but also because there are transformations from almost all the other formalisms' models to DEVS models. Moreover, there are no transformations from DEVS models to a number of those formalisms' models, which is a good indicator of the robustness of DEVS.

So, let's see what a DEVS atomic model looks like:

M = < S, X, Y, internal-delta, external-delta, lambda, ta >

We relate this functions and sets as follows (I'll mix some semantics explanations to give you a taste of the way we think about DEVS models):

In the next post, I'll try to put all this together in a tiny model, to see it "alive".