Ventana software support forum

Danas "Global Citizen" columns were carried by several Vermont newspapers and widely cited in policy discussions here. The an editorial about her can be seen at www.burlingtonfreepress.com/editorial/thursday/1000h.htm It appeared Thursday, along with a cheery photo of her that doesnt appea...

Jack raises a good, tough question--one that has the power to surface unquestioned assumptions. I hope serious debate will be triggered about new concepts and opportunities for action. Here at the beginning of that discussion, Id like to understand more clearly one point. Jack wrote: > Initially, ou...

One needs to distinguish between the types of models being solved. In many dynamic systems (those involving a time variable), it is posited that the state of the system evolves in accordance with a system of differential equations. In such systems of equations, typically, the partial derivatives of ...

Someone comes up with an idea that costs depart- > ment A $10 per unit, and saves the department B $50 per unit, re- > ducing the companys overall cost $40 per unit. As manager wont > agree, because that would raise As costs and make the manager > look bad. > ----------------------------------------...

> Khalid Saeed wrote: > > > Perhaps we should discuss an accreditation process for the teaching > > programs rather than for the individuals. Could list readers tell us what accreditations SD programs have to begin with? Many are housed in business or engineering departments that presumably have the...

<snip> > 3) In the formulation of model equations where there are issues > requiring allocation or another type of choice. In this settings Linear > Programs will often be used to run an optimization at each time a Im not quite sure whether this is a fourth application of optimisation or a restateme...

Its not clear from your message what your modeling problem is. Empirical data from each of the situations you describe can be analyzed using standard survival statistics methods to either estimate the parameters of the survival distribution (or a non-parametric survival distribution estimate) or to ...

Does the term "perennial" in your question simply relate to the fact that being a tree, cocoa is biologically a perennial, or do you have in mind a model for sustainable yield, or is there something else intended? Bill Steinhurst From: "William Steinhurst" <wsteinhu@psd.state.vt....

Robert Glitz wrote: > I think it would be kind of neat if they could build a management flight > simulator of potential conflict and use it to convince lawmakers of > systemic approaches to policy. This is exactly the correct approach. Modeling and model use seem to work best when there is a specifi...

Lets remember that there are situations where the global behavior of a system is qualitatively altered by small shifts in the value of a parameter. Aside from transitions to chaos, there are qualitative differences that can be of great significance in some settings between, for instance, a damped sy...

<snip>
It is not like word processing -- one can not
> just buy the software and read a few pages of the manual and begin to
> compose.

Absolutely. Owning a copy of AutoCad does not make one an architect.

Bill Steinhurst
wsteinhu@psd.state.vt.us

Jay Forrester wrote:

<snip>
> Differential equations are difficult, confusing, weak, and
> unrealistic.

Difficult and confusing, certainly. Unrealistic, often. But weak?
Could you clarify?

Bill Steinhurst
wsteinhu@psd.state.vt.us

The list looks like a very good way to focus thinking, and the purpose of opening the discussion with an audience works, but I dont feel that the ranking can be so fixed. For instance, the time scale of intervention will make a difference as to the effectiveness of the "levers." This shoul...

George Richardson <gr383@cnsvax.albany.edu> wrote: > We need a term for the circularities that are so crucial to an > endogenous view of a systems dynamics. Forrester wrote "<snip> A feedback control systems exists > whenever the environment causes a decision which in turn affects the > origina...

Sounds like a natural for SD modeling. Anyone out there modeled this system already? How about developing some reference modes this summer in Cambridge? ------- Forwarded Message Follows ------- From: Hans William Kramer <lucidity@leland.Stanford.EDU> im theorizing as to the design of a compost-heat...

Jim Hines wrote: > As David Lane suggested, molecules seem to refer to a class of generic structures slightly below his > Abstracted Micro Structures. Abstracted Microstructures are intended to generate a mode of behavior. > Behavior is not really the central point for molecules, structural represen...

D.C.Lane wrote: > However, in Boston, as part of my presentation, I will also be launching > an attempt to record and document the known generic structures I enjoyed your presentation at the Conference and hope the menagerie is rapidly collected, carefully labeled and skillfully presented to the pub...

Check out "The Dynamics of U.S. Electric Utility Deregulation,"
George Backus and Susan Baylis, US DOE, Office of Utility Technology.

Also, Systematic Solutions Inc., of Ohio has an electric industry
deregulation simulation game thats a lot of fun.

Bill Steinhurst
wsteinhu@psd.state.vt.us

> models > which deal with criminal behaviour in society or other such sociological > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The Multnomah County (Oregon) Criminal Justice Department did a lot of work in that area in the early to mid-70s. I think they mostly used stochastic queing mod...

ON Wed, 15 May 1996 11:58:04 -0400 (EDT) George Richardson <gr383@cnsvax.albany.edu> said: > One can find definitions of feedback loops and the feedback perspective > in various system dynamics writings, notably the early writings of > Forrester. Youll also find much discussion of this in Feedback >...

Thomas Fiddaman wrote: > > To replace 1990 oil consumption with horses, youd need about 6 billion of them: > snip of course, as the Romans understood, the fuel efficiency of a horse and human laborer are not that different, so much of the work done by fossil fuels (e.g., moving people or packages sh...