REPLY Hybrid Discrete/Continuous Examples (SD6050)

[Jean-Jacques Laublé jean-jacques.lauble wanadoo.fr]

Posted by  Jean-Jacques Laublé <jean-jacques.lauble at wanadoo.fr>
Hi Francisco

I believe like you that feedbacks are systemic (the notion of system is not
easy to define) but when you consult the web sites of different DES
packages, you will generally not see nay reference to any feed back. (Example 
SIMUL8, Extend etc.)

In Extend it seems that with newer versions, feed backs are considered when
the package is working continuously, but it is not working the same way then
current DS packages do.

I think that there might be two reasons for that.
The first is that DES considers a system as the result of multiple events
and that the study of these individual events is enough to explain how the
whole system works so DES is not so much systemic. DES is then not
interested in feed back loops that take a more holistic approach.

A second reason may be practical: It must no be easy to make feed back loops
work, when only a part of the system changes when an event occurs. Will the
feed back loops work every time a new event is occurring? I think it must
not be easy to implement.
This is why I was interested how practically anylogic is managing this
difficulty.
One other question is the utility of mixing paradigms in the same model.
What is the added value, considering the added complexity. What about using
SD and then DES or AB, successively, if one has different kind of problems?

I think that the problem for SD is not getting more powerful but identifying
better when it can be used with profit, and helping concretely users to
build useful models.
Regards.
Jean-Jacques Laublé 
Posted by  Jean-Jacques Laublé <jean-jacques.lauble at wanadoo.fr>
posting date  Sat, 11 Nov 2006 15:37:19 +0100