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Most users ever online was 52 on Tue Aug 04, 2009 12:44 pm

SD as risk analysis tool

12253 — 2010-03-16T14:08:43-04:00

Hi!

I am currently writing on a paper about SD and wanted to ask, if anyone of you has got a practical example where SD was used as a risk analysis tool?

In my paper I am concentrating on financial risks - but this needn´t to be the case in the example.

I´m looking forward to getting answers from you.

Regards

Statistics : Posted by Thomas Hafner • on Tue Mar 16, 2010 1:08 pm • Replies 0 • Views 3

Re: Why simulation?

5452 — 2010-03-15T14:59:24-04:00

Not sure I understand this question.

Cory, are you saying that there are only a handful of real applications of SD that have been useful in a practical sense? That there are few examples available for inspection? Or that SD applications have not been shown to be clearly better than possible alternatives?

I read some articles in SDR and elsewhere about what I assume are real world applications. I have assumed that there are many more, but that unlike academics (who have to publish) businesses tend not to publish, especially when the subject concerns an intractable problem they have been having. There should be 'closet' examples floating around. In addition to these and published articles there are those examples 'exposed' by the System Dynamics Applications Award. The presentation about the Fluor Corp., for example mentioned that the SD approach developed has been used at over 100 large projects.

Am I missing something in the question? Or is it just that 'we' feel ther...

Statistics : Posted by Richard Dudley • on Thu Feb 04, 2010 2:16 pm • Replies 9 • Views 225

New Book Honors Barry Richmond

7283 — 2010-03-12T12:14:01-05:00

isee systems and The Creative Learning Exchange have published a new book titledTracing Connections: Voices of Systems Thinkers . In tribute to their colleague and friend Barry Richmond, twelve contributing authors share their stories about applying systems thinking and system dynamics to their work.

With a foreword by Jay W. Forrester, the book includes chapters by the following authors:

Tracy Benson, Waters Foundation Systems Thinking in SchoolsProject
Frank Draper, Catalina Foothills SchoolDistrict
James Doyle, Worcester PolytechnicInstitute
Diana Fisher, Wilson HighSchool
Ali Mashayekhi, Sharif University of Technology,Tehran
John Morecroft, London BusinessSchool
John Newman, The WorldBank
Corey Peck, Lexidyne,LLC
Steve Peterson, Lexidyne,LLC

...

Statistics : Posted by Joanne Egner • on Sat Jan 10, 2009 12:54 pm • Replies 8 • Views 859

www.wired.com article about Whirlwind Computer

3581 — 2010-03-08T11:18:22-05:00

An article about the Whirlwind Computer, along with a photo including Jay Forrester is featured in the section "This Day in Tech" on the website http://www.wired.com/thisdayintech. The title of the article is "March 8, 1955: The Mother of All Operating Systems."

Statistics : Posted by Roberta Spencer • on Sat Jan 10, 2009 1:03 pm • Replies 8 • Views 1024

CfP: Special session on Modelling Societal Transitions

6112 — 2010-03-08T10:40:29-05:00

Dear all,
We are aiming to put together a special session on 'Modelling Societal Transitions' in the 3rd World Congress on Social Simulation, and invite contributions that focus on methods and/or applications of simulation models in the context of societal transitions.

Applications could range from case-specific models of a certain transition to more general – thought experiment-like – simulations.
Methods should preferably involve novel approaches, like the use of ontologies, data-mining techniques, workbenches and exploratory modelling. These contributions can range from sample implementations of these novel approaches to thorough methodological discussions.

We intend to work towards a special issue in JASSS (Journal of Artificial Societies and Social Simulation) on this subject and this call for papers can therefore be considered a first step thereto.

Further details can be found in the attached call for papers.

We are looking forward to your contributions and your presence...

Statistics : Posted by Gonenc Yucel • on Sat Jan 10, 2009 12:59 pm • Replies 10 • Views 1401

Re: Tools/Tecniques to nudge people fill in blanks

5058 — 2010-03-05T10:22:26-05:00

There are three words that I found important in this phrase. Starting, distant and miss.

I believe that it is illusionary to put everything that affects reality especially at the beginning of the modeling effort, whether salient or distant or important or not. I even believe that one can at a first stage and even when a model is ‘finished’ not include important aspects of reality, the objective of modeling being usefulness.

My priority is always understandability before completion. Some people may think differently. A model is never complete and it is better to realize it as soon as possible. If something is missing it may always be found later on and there is always something missing. It is too difficult to decide whether something is salient or not, one of the objective of modeling being to discover it later on, as one works on the model. Putting too much pressure on people to find what is important or not is counterproductive to my opinion and I adhere to the opinion of Jim...

Statistics : Posted by Jean-Jacques Lauble • on Tue Mar 02, 2010 5:19 pm • Replies 3 • Views 89

Re: SD Curriculum?

11006 — 2010-03-01T08:37:53-05:00

Hi Jens,

Gene Bellinger has put together a set of learning resources at his Systems Wiki.

"http://systemswiki.org/index.php?title=Main_Page"

The site has some very good material on it and a great list of references to other sources.

-Scott

Statistics : Posted by Scott Fortmann-Roe • on Fri Feb 26, 2010 1:35 pm • Replies 3 • Views 89

Re: Carbon neutral: including offsetting fees in registration

5515 — 2010-02-25T18:03:33-05:00

To assert that offsets don't work whether they're real or fake strikes me as an overstatement. Obviously there are lots of potential problems with offsets that are not "additional" or are outright fraudulent. But to the extent that these are avoided, and offset is just a way to trade money for reduced emissions somewhere else. I don't see how that's different from trading money for reduced emissions at home. The problem with offsets is not that they're intrinsically a gimmick, but that they have a lot of enforcement and transparency problems, especially when the price of emissions in the rest of the world is 0.

That aside, I think it's legitimate to question the conference venue. My guess is that transport would be the dominant share of emissions, that meals and lighting hardly matter, and thus we should focus on things like location and provisions for teleparticipation.

Statistics : Posted by Thomas Fiddaman • on Sun Nov 29, 2009 12:42 pm • Replies 12 • Views 1526

SBP10

9137 — 2010-02-24T17:41:20-05:00

REMINDER TO REGISTER FOR SBP10!
2010 International Conference on Social Computing, Behavioral Modeling, and Prediction (SBP10) Held on the main campus of the National Institutes of Health, Bethesda, Maryland March 29 – April 1.

Don’t forget to reserve your hotel room at the SBP10 conference rate! There are a limited number of rooms still available at the Hyatt Regency Bethesda Hotel. Please be sure to book your room at the hotel to ensure you receive the negotiated conference rate. To make a reservation, please call the hotel directly at 301-657-1234 or 888-421-1442 (specify the "Hyatt Regency Bethesda") and request the SBP 10 group rate or visithttps://resweb.passkey.com/go/SBPX

Attendance at the conference, tutorials, and workshop is free! But space is limited and registration is required. The main conference and tutorial #4 are still...

Statistics : Posted by Patricia Mabry • on Sat Jan 10, 2009 12:51 pm • Replies 22 • Views 2008

Re: Forum Organization

2010-02-20T16:21:12-05:00

Robert Eberlein wrote:Comments on the forum organization can be posted here.

Statistics : Posted by Anonymous • on Tue Aug 04, 2009 7:02 am • Replies 1 • Views 854

Post doc position in healthcare modelling at Imperial Colleg

2258 — 2010-02-18T09:39:46-05:00

I would like to inform you of a vacancy for a post doc position at Imperial College BusinessSchool.

Research Associate – Healthcare Modelling

The research associate will develop simulation techniques to assess the impact of innovations in care services (including their implications for infrastructural requirements) which are enabled by new healthcare technologies or organisational changes. These techniques will be employed in a number of contexts such as telecare or care for patients suffering from specific conditions such as stroke.

The successful candidate will have a good first degree and a relevant research degree (preferably a completed PhD), e.g. in management science or operations research. They will have expertise in simulation modelling, ideally knowledge both of system dynamics and discrete event simulation (alternatively, expertise in one approach and willingness to acquire knowledge in the other). Experience in interviewing in a range of public...

Statistics : Posted by Steffen Bayer • on Sat Jan 10, 2009 1:01 pm • Replies 13 • Views 6888

Re: Writing a good SD conference paper

5515 — 2010-02-16T21:45:28-05:00

Since the conference paper submission deadline is almost here (March 22 - see http://systemdynamics.org/conferences/current/index.htm), I thought I'd bump this post up. There are some useful additional comments on my original post at http://blog.metasd.com/2009/04/writing-an-sd-conference-paper/. Also, some good presentation ideas in this thread http://systemdynamics.org/forum/viewtopic.php?f=4&t=101#p419.

Statistics : Posted by Thomas Fiddaman • on Mon Apr 27, 2009 4:02 pm • Replies 5 • Views 646

Re: About practical use of Model Analysis

5058 — 2010-02-16T10:08:35-05:00

Hi Jim
To my opinion, the first problem with model analysis whether formal or not (what does really formal means ?) is: is there a market for analysis alone? It looks to me that people spend so much time building and verifying models that they have no more time to analyze them.
The fact that analyzing a model takes much more time than building it, reinforces that situation.
The same situation occurs with business people meeting. A report of the meeting is rarely produced and the next meeting, nobody has read the report.
One of the solutions is to build models that can be easily analyzed, or even that are analyzed automatically. This is why I like reality checks that are built in the model and verify the coherence of its results with some aspects of reality. It alleviates the burden of model analysis.
The problem with reality checks is that it needs practice and doubles the time to build a model if done seriously. It too necessitates a strict top down model building, starting from...

Statistics : Posted by Jean-Jacques Lauble • on Thu Jan 21, 2010 10:01 am • Replies 2 • Views 115

Re: SD blogroll

5515 — 2010-02-15T18:10:16-05:00

For what it's worth, I'm collecting these suggestions at
http://delicious.com/tomfid/SystemDynamics+blog

Statistics : Posted by Thomas Fiddaman • on Thu Jan 21, 2010 9:56 pm • Replies 10 • Views 179

Re: Limits to Growth

5993 — 2010-02-14T10:01:32-05:00

Not to echo exactly what I said in the infamous "Colbert Report" thread, but these are some of the issues I raised. I mentioned that several things have to happen for things to proceed well. The globe has to admit it's in Overshoot - a dynamic that can only have so many outcomes - most of them bad. This is, I believe, part of the point Dennis Meadows was getting at. We must acknowledge that at this point "worse before better" is probably the best scenario. That is very harsh medicine for people, many of whom, don't even acknowledge that there is a problem at all.

A smooth S-curve to some global equilibrium of sustainability is indeed a total fantasy, and in fact, for reasons which should be familiar to this audience, the globe actually must run a fair number of percentage points under the theoretical carrying capacity to be robust in the very long-term in the face of any short term shocks. Say that, and people will most likely look at you like you have thre...

Statistics : Posted by Michael Fletcher • on Mon Jan 25, 2010 3:52 pm • Replies 7 • Views 148

Facilitated modelling in OR stream: EURO XXI, Lisbon

3351 — 2010-02-10T05:30:56-05:00

***APOLOGIES IF YOU RECEIVED THIS MESSAGE MORE THAN ONCE***

EURO XXIV Conference
Lisbon 11-14 July 2010

CALL FOR PAPERS:

Stream: Facilitated Modelling in OR
Co-organisers: Alberto Franco (Warwick) and Gilberto Montibeller (LSE)

We would like to invite you to submit a title/abstract or propose a session for consideration in the Facilitated Modelling in OR Stream at EURO XXIV, Lisbon 11-14 July 2010. The stream welcomes contributions from researchers and practitioners engaged in the development and/or use of facilitated modelling approaches to organisational intervention. We define Facilitated Modelling as an approach to modelling where the operational researcher works both as an analyst and as a facilitator throughout the intervention, from helping the client to structure and define the nature of the problem situation of interest, to supporting the evaluation of priorities and development of plans for subsequent implementation. Presentations of particular interest may include...

Statistics : Posted by Etiënne Rouwette • on Wed Feb 10, 2010 5:30 am • Replies 0 • Views 39

Re: Proposal for SDR Editorial Classification

5939 — 2010-02-09T13:00:47-05:00

Thanks Brian,

It sounds like the current classifications do cover some of the ideas Bill suggested. I actually never noticed the tags, before, but looking back over the last few years it appears that there are a few cases where Notes & Insights, Reviews, and Citations appear with Research Articles. I'm guessing the issues without any tags are all research? I did not see research problems at all. Perhaps there is room for one of the classifications suggested instead? Case-studies, perhaps?

I also like the idea of asking associate editors to pursue different topic areas. This seems like another way to have a range of content without explicit categorization. If that were to be encouraged again, the SD forum could be good resource for soliciting papers.

On that note, out of curiosity, how much soliciting is even needed currently? That is, have there been many cases where the review was short on papers, or is there always more than enough?

One final thought is that it might be a go...

Statistics : Posted by Bruce Skarin • on Sat Jan 30, 2010 10:33 am • Replies 3 • Views 98

Re: Higher Education Management and announcement

2267 — 2010-02-08T08:23:03-05:00

If you talk to any academic working in education about what characterises their job, the chances are that he or she will mention increased workloads, an ever changing education environment and a sharpening focus on teaching quality, student learning experiences and assessment practice. Making best use of scarce resources coupled with strategic and operational planning in an uncertain world are, of course, fundamental to the work of many OR workers and there is now a growing literature on the application of OR to education management and planning. Furthermore, how we teach and assess students studying OR and related courses in Schools, Colleges and Universities has evolved considerably as academics have encompassed developing technologies and teaching paradigms, and responded to the academic profiles of incoming students and the requirements of employers. This stream will address all of these issues from classroom practice to university strategic planning. Any papers relating OR to...

Statistics : Posted by Gary Bell • on Wed Mar 04, 2009 7:13 am • Replies 5 • Views 837

[ANN] Simgua 3.6 Released

11006 — 2010-02-07T15:11:03-05:00

I am pleased to announce that we have released version 3.6 of Simgua a cross-platform and extensible System Dynamics simulation software.

Based on feedback on this message board, the following features were added in this release:

Unit Checking : Simgua now includes the ability to specify units for the different stocks, flows and other primitives in your models. Units will be automatically checked to ensure that they areconsistent.
Unit Conversion : A robust unit conversion system has been added to Simgua that lets you specify a primitive as having one set of units and then automatically convert them into another set. So, for instance, you can multiple 2 meters by 1 hectare and get the results in liters. A wide range of units are supported by Simgua and new, custom units may be definedeasily.
Model Verification : In addition to unit checking, a number of

...

Statistics : Posted by Scott Fortmann-Roe • on Sun Feb 07, 2010 3:11 pm • Replies 0 • Views 39

Re: Equations for Acceleration and Deceleration

2456 — 2010-02-05T17:22:50-05:00

Thank you, Jim, will follow-up.

Bill

Statistics : Posted by Bill Braun • on Tue Feb 02, 2010 3:24 pm • Replies 2 • Views 92

Forum Software Update

5463 — 2010-01-31T10:29:05-05:00

I have updated phpBB to the latest version. I don't know if there will be any visible changes (the wiki software has also been updated to the latest version).

I have also updated the email digest add in - let me know if you run into any trouble. (bob@vensim.com).

Statistics : Posted by Robert Eberlein • on Sat Jan 10, 2009 1:36 pm • Replies 10 • Views 1017

Re: Is the forum moribund?

2030 — 2010-01-29T19:06:17-05:00

Has anyone noticed what Gene Bellinger is doing over on his Systems Thinking World site on LinkedIn?

"http://www.linkedin.com/groupAnswers?viewQuestions=&gid=2639211&forumID=3&sik=1264809815024"

A different audience, but quite a bit more traffic.

Though I didn't respond to the poll I will say that the inability to respond via email to the digest is a hindrance for me ... just one more stumbling block.

Steve

Statistics : Posted by Stephen Wehrenberg • on Tue Jan 12, 2010 5:08 pm • Replies 18 • Views 236

Re: System Dynamics and the Airline Industry?

5454 — 2010-01-24T17:30:03-05:00

Thanks Jean-Jacques and Bob,

Two very useful pointers.

A couple of related links:

"http://en.wikipedia.org/wiki/Peoplexpress_Airlines"
"http://www.businessweek.com/magazine/content/07_11/b4025055.htm"
"http://web.mit.edu/jsterman/www/SDG/MFS/PE.html"

and

"http://www.airliners.net/aviation-articles/read.main?id=68"

"PEOPLExpress burgeoned out of less than nothing, seemed bound for instant greatness, and then perished almost as quickly. Take a visit, now, to the origins of the low-fare airline of the 80s, and the politics of big business in the deregulation era..."

regar...

Statistics : Posted by Jim Duggan • on Wed Jan 13, 2010 5:23 pm • Replies 3 • Views 69

Re: Vensim model on Colbert Report?

5993 — 2010-01-23T10:18:18-05:00

I largely agree Tom, but I would counter one point by saying that while there are indeed many Market Growth Models, the Forrester Market Growth Model was the core template for many of the models that followed.

In regards to your other points:

Denial is the rejection of an obvious reality. Or as my wife says, "denial, it's not just a river in Egypt." People are so desperate to avoid the realities that they attempt to obscure things by just about any means necessary. The economic arguments are, in my mind, so specious. "Economic Impact?" Are these people kidding? It doesn't take a SD model to know that the short term pain now is nothing compared to what the world will see if the 'business as usual' scenario runs it's course to 2100.

Unfortunately we designed an industrial society whose structure makes overshooting the worlds carrying capacity almost inevitable. First we must acknowledge our mistake and acknowledge we are in an Overshoot situation and acce...

Statistics : Posted by Michael Fletcher • on Fri Dec 11, 2009 10:13 pm • Replies 11 • Views 379

Re: [ANN] Simgua 3.0 Released

11279 — 2010-01-21T12:30:08-05:00

The only worry I would have in automatically converting units is that I have found that it is often not until a unit error is discovered that people realize they are using different units in the first place! -- what I would love to be able to do is specify all the unit conversions in one place and have them "hidden" in the overall model so it isn't cluttered up by unit converters. The only big worry I would have is that people would start using unit converters to disappear entire stock-flow structures.

Eg; a simple coffee-shop revenue model would look like

coffee/day (brewing) --> coffee --> coffee/day (sold)

(often times this is where an error for beginning modelers creep in as they want coffee sold/day to flow directly into some money stock. of course we have to have another stock/flow structure)

money/day --> money

and a multiplier (money/coffee) that joins the coffee sold outflow with the money made inflow

coffee/day * money/coffee = money/day
--

so I wou...

Statistics : Posted by Eric Stiens • on Tue Aug 18, 2009 9:57 am • Replies 18 • Views 639

Re: SD Archive: Age of Material in a Stock

5515 — 2010-01-15T13:35:12-05:00

Nice one!

It's also possible to view the discussion in the email list archive at http://www.ventanasystems.co.uk/forum/viewthread.php?tid=3173

Tom

Statistics : Posted by Thomas Fiddaman • on Fri Jan 15, 2010 3:20 am • Replies 1 • Views 58

Re: Great Ecological and Wildlife Management Articles

11006 — 2010-01-14T08:57:40-05:00

I received two private replies to my post referring me to:

* Allyson Beall, Len Zeoli. "Participatory modeling of endangered wildlife systems: Simulating the sage-grouse and land use in Central Washington". Ecological Economics. 2008.

* Allyson Beall, Andrew Ford, "Reports from the Field: Assessing the art and science of participatory environmental modeling" The International Journal of Information Systems and Social Change. 2009.

* The articles in the Summer 2004 special edition of the System Dynamics Review: "http://www3.interscience.wiley.com/journal/109086592/issue"

Maybe people would be willing to add replies to this thread listing additional articles...

Statistics : Posted by Scott Fortmann-Roe • on Tue Oct 27, 2009 2:37 pm • Replies 2 • Views 119

Re: India Chapter Constitution

11374 — 2010-01-08T23:25:45-05:00

Constitution is simple and a good one to start off....

Extend my support for the new chapter.

Karan, Shall email you the scanned letter.

warm regards,

Nithin Naik

Statistics : Posted by Nithin Naik • on Sat Jan 02, 2010 2:00 am • Replies 7 • Views 149

Integrative Graduate Education and Research Traineeship

5452 — 2009-12-26T09:01:29-05:00

A number of US universities are now offering IGERT (Integrative Graduate Education and Research Traineeship) funding. Some of these may be of interest to doctoral students with interested in applying SD. Funding for these trusteeships is from the US National Science Foundation and is, unfortunately, only available to US citizens at this time.

Two of these programs, of which I am aware, include an SD component as an integrative tool to give students from a variety of disciplines a cross disciplinary perception on the problem /research realm. Note, these are not SD programs as such, but programs that use SD as an integrative tool.

These programs are:

Cornell University: Food Systems and Poverty Reduction (seehttp://igert.ciifad.cornell.edu/ )

Washington State University: Nitrogen Systems: Policy-oriented Integrated Research and Education(http://igert.nspire.wsu.edu/ ) (thanks to Andy Ford for...

Statistics : Posted by Richard Dudley • on Sat Dec 26, 2009 9:01 am • Replies 0 • Views 83

Re: Number of System Dynamics Practitioners

8781 — 2009-12-18T17:08:46-05:00

Hello,

I would call me a practical system (dynamics) thinker, dealing with complex dynamic problems in organizations (such as implementing Lean Management in a sustainable way).

There is always a definition gap between SD practioners (1) and SD practioners (2)

(1) reprensenting, consultants and acedemics highly focusing on the tools and simulations itself, using that for supporting their work

(2) representing practioners working in complex work and organizational environments with some background on systems thinking, system dynamics and applying that knowledge into the organization at present stage. Not as an expert but as one of them. Some of these even don't know the English words around system dynamics such as loops, causal loops, feedback but rather only know the German aquivalent. So they are often unheard, even though they are dealing with system dynamics.

IMHO, it needs more general education at universities (pretty much what Jay W. Forrester has done with Road Maps in th...

Statistics : Posted by Ralf Lippold • on Wed Nov 18, 2009 11:25 pm • Replies 3 • Views 206

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