Ventana software support forum

People have brought up many threads in this discussion. I will just focus on, what I think are some key aspects of the issues that Jim raises. This will not be a politically correct, balanced perspective. (I have full sympathy for L.L Laubles entry.) To start, there are no first principles in social...

Paul Konnersman writes: "Even if the statement is reconfigured into a Ptolemaic v. Copernican issue, it seems to me unwarranted to say or think that an earth-centric model is false or invalid. It may not be as /useful/ for many purposes to think in terms of an earth-centric solar system, but it...

Jim Hines argues that idea generators do not need validation (where I think we all agree that by validation we mean "valid" confidence rather than perfect and absolute "truth."). The exercise of a positive loop just tells how generic parameters affect the output of a system of eq...

Kim appears certain that there must be some way to validate a model without running it. He notes that SDers have the nasty penchant of always wanting causal feedback in their models -- spiced with a bit of real-world non-linearity. Like most of us, I start with a simple conceptual (one or two loop m...

Our neurons are accumulators. (They are simply levels.) Therefore, definitionally, it is possible to design a system dynamics model that learns like (and describes the learning process of) humans. In John Stermans Business Dynamics, there is a section 13.2.12. It is titled "On Hill Climbing Opt...

Daniel inquired about utility functions to define choices: I maintain a fetish for the Qualitative Choice Theory (QCT) of Daniel McFadden.(Won the Nobel Prize in 2000 for this work). It seems completely compatible with good SD in that it accepts perceptions, includes uncertainty, is statistically ri...

Rafael, Andy Ford, Jeff Amlin, and I have been performing electric utility sector (and other energy) analyses for over 25 years each. (Talk about being in a rut!) Much of the recent work has actively focused on deregulation. We see that all countries and regions to-date have repetitively made the sa...

While we all may have a "sense" that Lomborg is surely wrong, it is important to note that ALL the critiques I have read (and I have read many) are big on emotive reaction and short on factual substance. They are rampant with "if we assume," "surely, " "it must be ...

In responding to Bill Harris: Lomborg argues that most of the reports excess "ecological footprint" is energy. The energy intensity is declining robustly in industrial nations. Substitution can allow renewable energy forms as markets allow it and as service economies become more dominant. ...

The scientific method informs us that the only way to test a theory is through data. The data do not have to represent accurate physical entities but do need to reflect measurable (quantifiable) conditions. Perceptions and emotions can be sampled and ranked. as long as a unique and reproducible meth...

One of the great problems in economic practice is the utility of equilibrium analysis. Although computationally intensives, the approach is easy to apply and logically easy to defend: "This is the most efficient solution and, therefore, it is the way clever humans will make the world work."...

It is often difficult to separate philosophy from science. It is usually very easy to use intuition or "feelings" to form an opinion about what is "good" or "bad." Different value-laden world views produce different perspectives on how the world works. The reality is th...

There is a news article (October 23) : "Pentagon Fishes for Good Ideas to Thwart Terror" at the link below. http://www.reuters.com/news_article.jhtml;jsessionid=Z312HFV3DCBW2CRBAE0CFFAKEEATGIWD?type=topnews&StoryID=320615# The actual RFP is at: http://www.defenselink.mil/news/Oct2001/b...

Bill Harris perspectives are always insightful. His assessment appears solid. I think it can be extended, however. The disciplines of engineering are already a respected. People have trust in the fields. The certification allows a client to also have more trust in the person providing the engineerin...

Geoff McDonnell noted Barry Richmonds article. John Swanson brought us the unwarranted criticism statement. I would have missed both of these, if left to my own juggling of time priorities. It would seem that the community is well served by participants routinely notifying the listserve of articles ...

Johns points are well taken, but.... one does not see OR much outside of the OR journals. If one talks about regression versus econometrics (as in economics), one does not see econometrics much outside selected economic journals. Discrete event simulation has a narrow journalistic audience, yet its ...

The recent discussions indicate that the list-serve has much to offer the SD (and possibly a larger) community. It can be used to organize and promote working panels on key issues plus provide support to the SD Society as needed. For example, if we did want to develop standards for external consumpt...

I am unsure deciding that econometrics is wrong, SD is right, and paradigms are insurmountable, buys the SD community anything. In our collective, possibly biased view, we all believe SD (causality and feedback) has much to offer the world -- many problems could be avoided, many a crisis could be ci...

I think John brings up a good point that the issues of the ".com" are hundred (or thousand) year old issues having to do with basic human limitations -- issues for which system dynamics is well qualified to address but where human nature may long continue to have the power to resist simple...

Jack Ring wrote "The "implicit" part is the problem because the causal factors at the people relationship level are not subject to validation nor calibration." The only important issue for policy is the outcome of decisions. What people think or feel is not relevant to the physic...

I finally have some time to respond to this thread. System Dynamics was in the forefront of the California deregulation analysis. We used ENERGY 2020 (a SD model) with essentially all the significant players in the market: SCE, San Diego Gas & Electric, Pacific Gas & Electric, Enron, Norther...

ads.com> Subject: REPLY Human Behavior in System Dynamics Models (SD3337) Date: Tue, 24 Jul 2001 15:01:40 -0600 Organization: gabackus@home MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Mic...

In response to Bruce Campbell: Irrationality is usually pretty "rational;" it consistently serves some self-interest. The SD communitys concept of rationality simply implies a more reasoned and inclusive approach to serving that self-interest. Nonetheless, in all cases the decision is simp...