Ventana software support forum

This announcement is addressed to all who are using one or more published texts to teach System Dynamics. W The field of System Dynamics has seen the publication recently of new texts joining a handful of classics for use in teaching SD to students at different levels of age and experience. It is ap...

geoff coyle wrote: > Yes, its very true but, as far as I am aware, SD is the only operaional > resarch technique that even mentions dimensions. > I am surprised by Geoffs remark. In our introductory course in OR (mostly linear programming) in a business school, we always mention the importance of ch...

There is at least one representation theorem used in fuzzy control theory that says, in effect, that an arbitrary non-linear function of one variable can be approximated by a fuzzy relationship combined with a de-fuzzification procedure. Thus, in some sense, all TABLE functions can be thought of as ...

Not to sow more confusion but it is possible to develop a discrete-event model of an SD model. A Master`s student of mine and I did so for a small Commodity Cycle model about 10 years ago. The time behaviours don`t look very similar but the autocorrelation structures are quite similar. On the other ...

Michael Evans wrote: It IS tricky because you have to integrate a stochastic process (essentially a sequence of delta functions with random arguments) and there are different ways to do this, none of which are equivalent to the Euler or Runge-Kutta methods implemented in most SD packages. Look for l...

Bob Eberlein wrote: > > None of this is very difinitive, but I think there is a nice research > challenge out there around the nature or delays. Any delay can be > represented as a probability distribution of the time it will take an > atom entering a level to leave that level. As we go from first t...