Ventana software support forum

re: SD0089 from Gene Bellinger <CrbnBlu@aol.com> > Could you elaborate on this piece a bit. Im not sure I quite get the > implication. System can be dynamic (being time variant) or static. Both system dynamics and discrete-event modelling approaches are designed to simulate the characteristics of a ...

In response to several previous messages related to system simulation: The word "system" is a double use word. It can be used to mean a real system within the pre-defined boundary. It can also be used to represent an abstract system (as the approximation of a real system) within the bounda...

Dear all > > ... This does not mean that one should only build models > > when there is good data, but . . . > What counts is "behavior patterns". Data only give the past, and if one has a > forecastable change in behavior pattern, all past data become useless ... I would like to provide m...

> (snip from SD214) Lets drag it back a bit toward fewer > messages with a higher density, news, scholarship, and deep thoughts. One possibility is to split up this current list into two lists. This one (called Mod) is still a moderated to suit the above criteria but another (called Unm) is preferab...

It is generally recognised that Feedback is fundamentally crucial in SD. However, what is an operational definition of "Feedback" in SD? Both your qualitative and quantitative (cf. feedforward?) statements are welcome. Is Feedback mainly a thinking perspective or a concept/ construct? Or i...

QUOTE Gene Bellinger (SD151): " Wheres the real leverage point?" Scholl Greg (SD153): "In my opinion, it is very difficult to develop strong modeling skills and ..." UNQUOTE IMO, the hardly-unified and loosely-structured stock-and-flow modelling grammar as well as its underlying ...

re: previous messages on "Semantics" and "SD is not differntial equations" IMO, SD is a methodology. It consists of a. the stock-and-flow modelling grammar, and b. the simulation based on discrete-time of fixed-interval with deterministic difference-equation approach (approach M)...

As part of my PhD program, I would like to study more about the topic of optimisation in the system dyanmics context. It seems that this topic can be branched out into three issues: 1. whether optimisation is part of the "conventional" SD methodologies? 2. what is the meaning of optimisati...