Jean-Sébastien Bolduc

Meeting Logs

Meeting --- 08/06/05

    •  During the previous meeting we discussed sub-experiments, as an alternative to the more general Extended Time considered before. A sub-experiment is a DEVS model specification that is embedded in an atomic-DEVS variant (the Wrapper). The sub-experiment is performed when a transition occurs in the Wrapper, thus actually creating a time base orthogonal to the upper level's.
    • This setup has been implemented in PyDEVS, with the sub-experiment linked to the wrapper's external-transition.
    • During the present meeting, we concluded that it would be preferable to ling a sub-experiment to the wrapper's internal transition, so that  a stand-alone wrapper (i.e., not coupled to some generator) would be meaningful.
    • Considerations on data access led us to the notion of Experimental Frame, that includes:
      • a Collector, that processes the sub-experiment's trace to produce a value usable by the higher level (the wrapper);
      • a Monitor, that determines when a sub-experiments terminates,
      • an Initializer, that initializes the sub-experiment.
    • Observing that the time-base of a DEVS is not constrained to the real numbers, we came up with a nice idea of a time-base to be tested: DD/MM/YY (isomorphic to the natural numbers).
    • From a reusability point-of-view, this is important as the time scale of an experiment can be seconds, while the time scale of another can be days. We considered how such experiments could be coupled.
    • Short discussion on Variable Structure DEVS ("it's in the eye of the beholder!...")
    • Finally, we reviewed/refreshed the project overview. A detailed outline will follow.


  1. Write a detailed outline of the project;
  2. Implement nested time using internal transition, and formalize the idea;
  3. Implement the time base example.