Search found 88 matches

by "Jim Hines"
Wed Jun 06, 2001 9:28 pm
Forum: SD Mailing List Archive
Topic: System Dynamics Certification
Replies: 12
Views: 9908

System Dynamics Certification

Among Rom Kozial cautions us that certifying academic programs in SD might discourage the spontaneous popping up of courses in SD. That is a serious concern. There is a flip side, though: An accreditation program might actually encourage academic institutions to create explicit programs in system dy...
by "Jim Hines"
Fri Jun 01, 2001 10:08 am
Forum: SD Mailing List Archive
Topic: ST & SD in real life
Replies: 13
Views: 13143

ST & SD in real life

Gordon Kubanek invites interrested folks to discuss SD certification in Atlanta this summer. This comes idea comes up from time to time, and I for one would like to discuss it again in Atlanta. At the moment, anyway, I think I am opposed to it -- although I certainly recognize the allure. I just thi...
by "Jim Hines"
Wed Apr 11, 2001 11:36 am
Forum: SD Mailing List Archive
Topic: Fast Demonstration of Complex Behavior
Replies: 6
Views: 20942

Fast Demonstration of Complex Behavior

The people-moving example is wonderful not only because its simple and cool. Its wonderful because it also highlights a difficulty in agent-based representations of dynamic systems: Analyzing agent-based representations is more difficult than analyzing more traditional SD representations. (The tradi...
by "Jim Hines"
Sat Apr 07, 2001 10:46 am
Forum: SD Mailing List Archive
Topic: Boston area tribute to Dana Meadows
Replies: 0
Views: 2354

Boston area tribute to Dana Meadows

A tribute to Dana Meadows will be held in Cambridge, MA, at the American Academy of Arts and Sciences (136 Irving Street) on April 22nd starting at 1:30PM. The announcement (including directions) appears below. Regards, Jim Hines jhines@mit.edu DONELLA MEADOWS (1941-2001) EARTH DAY MEMORIAL SERVICE ...
by "Jim Hines"
Sat Mar 31, 2001 12:24 pm
Forum: SD Mailing List Archive
Topic: Complex Adaptive System - Friend or Foe?
Replies: 9
Views: 31699

Complex Adaptive System - Friend or Foe?

>... System Dynamics can not compete with the attractiveness of these > high-tech state-of-the-art technologies to draw young people..." Many years ago when doing work in expert systems was incredibly fashionable, I had a friend who happened to be a Swami in the Kashmir Shavism tradition and wh...
by "Jim Hines"
Sat Mar 10, 2001 5:44 pm
Forum: SD Mailing List Archive
Topic: Modelling traditions - flavours of the same thing?
Replies: 7
Views: 6644

Modelling traditions - flavours of the same thing?

Geoff McDonnel asks for pointers to any work combinging CAS(agent-based) modeling with Stock-and-flow type modeling. Weve taken a couple of baby steps in this direction to look at the evolution of policies. See http://web.mit.edu/org-ev/www/. Regards, Jim Hines jhines@mit.edu -----Original Message--...
by "Jim Hines"
Thu Mar 08, 2001 10:58 am
Forum: SD Mailing List Archive
Topic: Modelling traditions - flavours of the same thing?
Replies: 7
Views: 6644

Modelling traditions - flavours of the same thing?

Alexander Lubyansky says he disagrees a bit with point 2. And I think he may be referring to an email of mine where I said, "Second, to say that discrete event modeling and system dynamics are flavors of some larger thing, is as useful as saying that hammers and houses are flavors of the same t...
by "Jim Hines"
Wed Feb 28, 2001 12:21 pm
Forum: SD Mailing List Archive
Topic: Modelling traditions - flavours of the same thing?
Replies: 7
Views: 6644

Modelling traditions - flavours of the same thing?

I liked Roland Shiefers approach of translating models into different formats. And efforts along those lines can help us all to understand how different ways of modeling either are or arent useful **tools** for understanding system dynamics. I think that Rolands main point is that having a single in...
by "Jim Hines"
Fri Feb 23, 2001 11:58 am
Forum: SD Mailing List Archive
Topic: The time scale regarding when to use system dynamics
Replies: 8
Views: 6459

The time scale regarding when to use system dynamics

I like Roland Shiefers idea system dynamics is still developing, but Im afraid I disagree when he writes that different modeling traditions are "only different flavours of the same thing". I think of system dynamics as a viewpoint: A viewpoint that all patterns of behavior are generated by...
by "Jim Hines"
Mon Feb 12, 2001 2:57 pm
Forum: SD Mailing List Archive
Topic: MITs Distance SD Program
Replies: 0
Views: 1968

MITs Distance SD Program

The next semester for MITs Advanced Study Program in System Dynamics will begin the week of March 5th. Four courses will be offered. One of the courses called "Advanced Topics in System Dynamics" is new this semester. This course consists of a number of half-semester "topics" -- ...
by "Jim Hines"
Wed Nov 29, 2000 10:29 am
Forum: SD Mailing List Archive
Topic: SD and Architecture
Replies: 2
Views: 6682

SD and Architecture

Riverside asks about system dynamcis and architecture. Im out of my depth here, but ... If you havent read Christophe Alexander, you might find his books intriguing. __The Timeless Way of Building__ and __A Pattern Language: Towns, Buildings and Construction__ are wondeful. Alexander, oddly enough, ...
by "Jim Hines"
Wed Nov 29, 2000 9:57 am
Forum: SD Mailing List Archive
Topic: Request for system boundary setting guidance
Replies: 3
Views: 8328

Request for system boundary setting guidance

Roy Greenhalgh asks for adivice on setting boundaries for SD models. It depends on what modeling approach you happen to be using. When using an approach that involves an early phase of causal loop diagram, setting the boundary is a no-brainer. When using an approach that goes directly to stock and f...
by "Jim Hines"
Wed Nov 15, 2000 3:00 pm
Forum: SD Mailing List Archive
Topic: course material for adult education
Replies: 4
Views: 26850

course material for adult education

Alfred Bosshard asks
>> if anyone has (or knows about) a system teaching course for adults

MIT has a series of courses offered at a distance. For info see
http://caes.mit.edu/asp/off_campus/syst ... index.html.

Jim Hines
jhines@mit.edu
by "Jim Hines"
Wed Nov 15, 2000 2:55 pm
Forum: SD Mailing List Archive
Topic: Building your own models
Replies: 18
Views: 60249

Building your own models

Niall Palfreyman writes >I guess the equivalent [to software patterns] in the SD world are the systems >architypes, but Ive never seen these all gathered together in one place >in a form which would be directly insertible into an SD model. I think that the SD **molecules** are equivalent to patterns...
by "Jim Hines"
Mon Nov 13, 2000 11:18 am
Forum: SD Mailing List Archive
Topic: Delays in SD modeling!!
Replies: 15
Views: 54852

Delays in SD modeling!!

Geoff Coyles formula N=DEL^2/Vn is very nice and I for one agree that I should have read his book a long time ago. Two comments: I think that its probably good to bear in mind the many injunctions (often from Goeff Coyle) that modeling decisions depend on the problem. Often a modeler only needs the ...
by "Jim Hines"
Mon Nov 13, 2000 10:48 am
Forum: SD Mailing List Archive
Topic: Modelling HRM / Quantifying a model
Replies: 8
Views: 6009

Modelling HRM / Quantifying a model

Geoff --

I like your comment about the desirability of building your own model. What
do you (and others) make of the many queries in this list asking for models
on this or that topic?

Jim Hines
jhines@mit.edu
by "Jim Hines"
Fri Nov 10, 2000 11:44 am
Forum: SD Mailing List Archive
Topic: Delays in SD modeling!!
Replies: 15
Views: 54852

Delays in SD modeling!!

Concerning Ramaswamys desire to put a probability density function into a delay. Some people may not be aware that the traditional delay structures: first- and higher- order smooths and material delays already have a probabilistic interpretation. The interpretation is that the time constant (or the ...
by "Jim Hines"
Fri Nov 10, 2000 10:22 am
Forum: SD Mailing List Archive
Topic: Modelling HRM / Quantifying a model
Replies: 8
Views: 6009

Modelling HRM / Quantifying a model

Rutger Mooy asks how to quantify soft variables like quality of company. One word of advice: Try not to cascade two "soft" lookup functions. So for example try not to go from "salary" to "effect of salary on quality of company" and then from "quality of company&quo...
by "Jim Hines"
Wed Oct 11, 2000 10:14 am
Forum: SD Mailing List Archive
Topic: Stochastic processes in System Dynamics modeling
Replies: 2
Views: 3628

Stochastic processes in System Dynamics modeling

Sharada, Im not sure of your precise interest, but in our organizational evolution work, we use probability distributions to govern learning between managers. This is really a combination of SD with agent-based, genetic algorithms. More info available at http://web.mit.edu/org-ev/www. Regards, Jim H...
by "Jim Hines"
Sun Oct 01, 2000 2:56 pm
Forum: SD Mailing List Archive
Topic: INFORM Note on 2001 System Dynamics Conference-Call for Pape
Replies: 0
Views: 5499

INFORM Note on 2001 System Dynamics Conference-Call for Pape

Roberta Spenser posted the formal Call For Papers for the SD conference in Atlanta. Id just like to briefly and personally encourage everyone on this list to submit something. If you want an opportunity to actually TALK to folks about your work, a **poster session** is for you. To submit for a poste...
by "Jim Hines"
Thu Aug 17, 2000 2:37 pm
Forum: SD Mailing List Archive
Topic: Quantifying soft data
Replies: 16
Views: 15144

Quantifying soft data

The difference between the scene you describe and the system dynamics view lies in the reason for quantifying soft variables. In the scene, the reason for quantifying the literary works is to compare the various works of Shakespeare, Byron, etc. The purpose of quantifying in system dynamics is so th...
by "Jim Hines"
Thu Jun 29, 2000 10:38 am
Forum: SD Mailing List Archive
Topic: The Reality of the Beer Game
Replies: 6
Views: 7118

The Reality of the Beer Game

Just a couple of anecdotes on the reality of beer games. A group of executives at a large chain of supermarkets once played the beer game. At the point in the debrief when folks realized that placing multiple orders for a given inventory shortage was the root of the problem, a woman stood up and sai...
by "Jim Hines"
Sun Mar 19, 2000 6:56 pm
Forum: SD Mailing List Archive
Topic: System Dynamics: Art, Science or Profession
Replies: 19
Views: 13011

System Dynamics: Art, Science or Profession

At the end of an instructive posting, my friend Jack Homer writes: > Indeed, SD practitioners should actively discourage and, at the >least, avoid being a party to hasty action based on incomplete modeling and >analysis. But, all models and analyses incomplete. Right? Seems to me that the question o...
by "Jim Hines"
Thu Mar 16, 2000 11:14 am
Forum: SD Mailing List Archive
Topic: System Dynamics: Art, Science or Profession
Replies: 19
Views: 13011

System Dynamics: Art, Science or Profession

Bruce Cambell asks:
>How does one know which structure is valid, other than to compare
>output behaviour with observed behaviour?

Cant you also compare model structure to observed structure?

Regards,
Jim Hines
MIT
From: "Jim Hines" <jhines@MIT.EDU>
by "Jim Hines"
Wed Feb 23, 2000 3:20 pm
Forum: SD Mailing List Archive
Topic: Causal loop and Stock and Flow Diagramming
Replies: 8
Views: 7627

Causal loop and Stock and Flow Diagramming

Stephen Wehrenberg asks us >> Do YOU ever use CLDs, and if so, under what conditions? Answering for me: Yes. In consulting, I usually start with causal loop diagrams before going on to stock and flows. The exception is when I see immediately a very clear and important stock and flow structure (the i...