Ventana software support forum

Posted by Bob Eberlein <bob@vensim.com> I am changing the From address on message posted to the list to simply show the send System Dynamics Mailing List. Many of you have been replying to messages with content intended for a poster and not the list. Such replies are simply lost as I do not approve ...

Posted by Bob Eberlein <bob@vensim.com> Hi Everyone, That query was, I am afraid, somewhat confusing and the reposnses were even more confusing. I probably should not have posted the original query, and I have decided not to post the reponses. At the abstract level of variables named S1 and S2 clear...

Posted by Bob Eberlein <bob@vensim.com> Hi Everyone, I have moved the system dynamics mailing list to a new home. The new post to address is: sdmail@lists.systemdynamics.org to manage your subscription or unsubscribe go to: http://www.systemdynamics.org/mailman/listinfo/sdmail This list uses the Mai...

Posted by Bob Eberlein <bob@vensim.com> Hi Everyone, I have moved the system dynamics mailing list to a new home. The new post to address is: sdmail@lists.systemdynamics.org to manage your subscription or unsubscribe go to: http://www.systemdynamics.org/mailman/listinfo/sdmail This list uses the Mai...

Hi Everyone, I have already run into some problems in the way this list is implemented. The best solution I have come up with is to have it appear that all messages are coming from system-dynamics@vensim.com - otherwise every time you post a message you will be bombarded with out of office replies. ...

Hi Everyone, Happy New Year. As many of you have noticed the system dynamics mailing list has not been working very well recently. To make things better I have moved the list to a new server. To post messages to the list send them to sdmail@listserv.albany.edu there is no e on the listserv. To subsc...

Ventana Systems, Inc. builds simulations models of complex situations to help organizations choose the best policies and investments, as judged by the outcomes that define the organization’s success. We concentrate on top-level problems of corporations, government, the economy, and the environment. ...

Hi Everyone, The System Dynamics Society is pleased to announce that the DVD version of the MIT System Dynamics Group Literature Collection, selected by Jay W. Forrester is now available. (A CD version will be available later this year.) This collection includes the scanned D-Memos which are the int...

Forwarded from Susan Soldavin: New Book Offers Real-World Environmental Modeling Solutions Mediated modeling is an innovative new approach that uses the process of building computer models as a tool to help solve complex environmental policy and management problems. Rather than having outside expert...

Hi Everyone, The list has been completely silent for some time. Something about the dynamics of conversation that I do not fully understand. If you are getting this, however, you may rest assured that you are still subscribed. I also want to remind people that the early registration deadline for the...

Hi Everyone, I am pleased to be able to tell you that Tony Kennedy has successfully put the archives from this mailing list up on a searchable discussion board. Posts on a subject have been combined in threads and most of the email headers stripped out so that you can see just the discussion. The ar...

(was Using Statistics in Dynamics Models, Do we need to Simulate to Validate Models?) The discussion of statistics and simulation has been very interesting but I fear perhaps somewhat abstract and theoretical in nature. A number of the points that Jim Hines has raised are fundamentally more practica...

New registration information about the2004 International Conference of the System Dynamics Society, to be held in Oxford, England, July 25-29, has just been posted on the Society website. Please visit http://www.systemdynamics.org and go to the "2004 Conference" page. Under "Conferenc...

Hi Everyone, I have enjoyed this discussion but one very important thing has not been emphasized. Kim asks why we dont simply validate mode relationships by running regressions. As long as there are observations on all model variables that is something that can be done and, if the observations are a...

8 Please find below conference information and the Call for Papers, Presentations, Workshops and Sessions for the 22nd International Conference of the System Dynamics Society. Space is limited at the conference venue and early registration is essential. Registration materials will be available in Ja...

Hi Everyone, For those who have not aleady received this here is the call for papers for next summers system dynamics conference in Oxford England. Bob Eberlein bob@vensim.com Please find below conference information and the Call for Papers, Presentations, Workshops and Sessions for the 22nd Interna...

Hi Rutger, I am the one who runs the system-dynamics mailing list. I have looked into yahoo groups, and I dont like them. They have annoying ads and they archive things for only a month or two. The system dynamics mailing list has archives going back to December of 1994 ( http://www.vensim.com/sdmai...

Hi Ric, The answer depends very much on what you are trying to do by introducing noise as well as the model you are using. If you are looking at steady state statistics then take a look at the textbook meantioned in the other posts. There is a caveat on that, however. If you are dealing with models ...

Hi Everyone, The program for the New York City Conference is starting to take form and I want to bring you up to date on where things are. I encourage you to get your registration in early and look forward to seeing you at the conference. More information on the conference is available from the soci...

Hi Everyone, Just a reminder that the deadline for submissions to the 2003 conference of the System Dynamics Society is next Friday, March 28. We are looking for work related to the theory and application of system dynamics. More details on the the requirements for submissions are available from htt...

Hi Everyone, Just a reminder that the deadline for early review conference submission is this Friday February 14, and the final submission deadline is March 28. Submissions made by the 14th will be reviewed with a decision about placement returned by March 20. Works submitted after the 14th will hav...

Just a quick note to remind you about the deadlines and key dates for the 21st International Conference of the System Dynamics Society to be held in New York City, July 20 - 24, 2003. For complete information and updates, please visit our website: http://www.systemdynamics.org. NEW INFORMATION inclu...

I thought this might be of interest to people. Bob Eberlein bob@vensim.com International Conference on Systems, Development and Self-Organization (ICSDS2002) November 30--December 1, 2002, Beijing, China http://www.icsds.em.tsinghua.edu.cn Important Dates * July 30, 2002: 1-page, 300-word extended a...

A couple of notes on DT and integration. Jim suggests that we use an equation such as: > outflow = if (stock > normally indicated outflow*dt) > then (normally indicated outflow) > else (0) but also says we should not confuse this dt with our solution interval (call it Time Step). If we really treat ...

Jim Hines wrote: > My point is just that dt can now be regarded as being just as rigorous > as any other real (or hyper-real) number -- zero, one, pi, etc. This > means that the Dynamo equations (and Euler integration in concept) are > correct **mathematically**. Of course, digital computers dont al...