Search found 23 matches

by "George Backus"
Sun Feb 01, 2004 11:41 am
Forum: SD Mailing List Archive
Topic: Using Statistics in Dynamics Models
Replies: 28
Views: 20828

Using Statistics in Dynamics Models

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...
by "George Backus"
Sat Jan 17, 2004 10:09 am
Forum: SD Mailing List Archive
Topic: Can SD models be validated without being run?
Replies: 38
Views: 27359

Can SD models be validated without being run?

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...
by "George Backus"
Thu Jan 15, 2004 3:42 pm
Forum: SD Mailing List Archive
Topic: Can SD models be validated without being run?
Replies: 38
Views: 27359

Can SD models be validated without being run?

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...
by "George Backus"
Thu Jan 08, 2004 1:01 pm
Forum: SD Mailing List Archive
Topic: Can SD models be validated without being run?
Replies: 38
Views: 27359

Can SD models be validated without being run?

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...
by "George Backus"
Sat Apr 19, 2003 6:27 pm
Forum: SD Mailing List Archive
Topic: Can system dynamics models "learn"
Replies: 46
Views: 33408

Can system dynamics models "learn"

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...
by "George Backus"
Fri Feb 21, 2003 1:42 pm
Forum: SD Mailing List Archive
Topic: attractivenss multiplier
Replies: 6
Views: 13182

attractivenss multiplier

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...
by "George Backus"
Sat Feb 15, 2003 10:42 am
Forum: SD Mailing List Archive
Topic: Models for Electric Deregulation
Replies: 4
Views: 8271

Models for Electric Deregulation

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...
by "George Backus"
Mon Nov 18, 2002 7:31 am
Forum: SD Mailing List Archive
Topic: Ecological Footprint of Humanity
Replies: 10
Views: 12941

Ecological Footprint of Humanity

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 ...
by "George Backus"
Sun Nov 17, 2002 8:56 am
Forum: SD Mailing List Archive
Topic: Ecological Footprint of Humanity
Replies: 10
Views: 12941

Ecological Footprint of Humanity

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. ...
by "George Backus"
Tue Nov 20, 2001 9:42 am
Forum: SD Mailing List Archive
Topic: A causes B
Replies: 14
Views: 27511

A causes B

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...
by "George Backus"
Sun Nov 11, 2001 1:57 pm
Forum: SD Mailing List Archive
Topic: Economic Dynamics / Teaching Economics
Replies: 2
Views: 6962

Economic Dynamics / Teaching Economics

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."...
by "George Backus"
Sun Nov 11, 2001 12:41 pm
Forum: SD Mailing List Archive
Topic: Attractiveness Multiplier
Replies: 12
Views: 32674

Attractiveness Multiplier

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...
by "George Backus"
Thu Oct 25, 2001 11:59 am
Forum: SD Mailing List Archive
Topic: Anti-terrorist dynamics
Replies: 0
Views: 5071

Anti-terrorist dynamics

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...
by "George Backus"
Wed Oct 17, 2001 10:32 am
Forum: SD Mailing List Archive
Topic: Unwarranted Criticism
Replies: 16
Views: 21409

Unwarranted Criticism

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...
by "George Backus"
Wed Oct 17, 2001 7:53 am
Forum: SD Mailing List Archive
Topic: Leveraging the list-serve
Replies: 5
Views: 8917

Leveraging the list-serve

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 ...
by "George Backus"
Tue Oct 16, 2001 7:11 am
Forum: SD Mailing List Archive
Topic: Unwarranted Criticism
Replies: 16
Views: 21409

unwarranted criticism

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 ...
by "George Backus"
Mon Oct 15, 2001 1:57 pm
Forum: SD Mailing List Archive
Topic: Leveraging the list-serve
Replies: 5
Views: 8917

Leveraging the list-serve

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...
by "George Backus"
Wed Oct 10, 2001 4:01 pm
Forum: SD Mailing List Archive
Topic: Unwarranted Criticism
Replies: 16
Views: 21409

Unwarranted Criticism

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...
by "George Backus"
Mon Aug 06, 2001 12:03 pm
Forum: SD Mailing List Archive
Topic: Preventing the next boom and bust
Replies: 12
Views: 17027

preventing the next boom and bust

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...
by "George Backus"
Sun Jul 22, 2001 2:16 pm
Forum: SD Mailing List Archive
Topic: Human Behavior in System Dynamics Models
Replies: 9
Views: 11101

Human Behavior in System Dynamics Models

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...
by "George Backus"
Tue Jul 10, 2001 8:30 pm
Forum: SD Mailing List Archive
Topic: Electricity Regulation/Deregulation
Replies: 7
Views: 11132

Electricity Regulation/Deregulation

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...
by "George Backus"
Fri Mar 31, 2000 10:39 am
Forum: SD Mailing List Archive
Topic: Human Behavior in System Dynamics Models
Replies: 9
Views: 11101

Human Behavior in System Dynamics Models

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...
by "George Backus"
Fri Feb 11, 2000 11:45 am
Forum: SD Mailing List Archive
Topic: SD: Simply another tool for public policy development?
Replies: 14
Views: 8654

SD: Simply another tool for public policy development?

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...