Search found 29 matches

by "Ray on EV1"
Wed Oct 14, 2020 7:31 pm
Forum: SD Mailing List Archive
Topic: Limitations of System dynamics?
Replies: 10
Views: 20888

Limitations of System dynamics?

The system dynamics methods are suitable in general. But changing paths in the middle of a project might be more catastrophic than your current situation. You should re-think where you are: Your experienced in UML, your client is not communicating well with your programmers. Communication difficulti...
by "Ray on EV1"
Fri Jan 09, 2004 8:13 pm
Forum: SD Mailing List Archive
Topic: Can SD models be validated without being run?
Replies: 38
Views: 27355

Can SD models be validated without being run?

Kim, I hope we can more clearly understand the semantic difficulties around using the work "validate". From Websters Dictionary, there are two opportunities: 1) To mark with an indication of official sanction. 2) To establish the soundness of Thus, a group of people can agree to the use of...
by "Ray on EV1"
Fri Jan 09, 2004 5:54 pm
Forum: SD Mailing List Archive
Topic: Models for Winning Business
Replies: 7
Views: 9718

Models for Winning Business

Finn, You pointed out some of the considerable pitfalls of using a systematic method to solve generic problems. But there is an up side. It is usually beneficial for us to characterize the systems we work in/with. The selling example is great. We should be aware of the generic components to consider...
by "Ray on EV1"
Sun Nov 30, 2003 9:07 pm
Forum: SD Mailing List Archive
Topic: Manufacturing Control Systems
Replies: 30
Views: 51612

Manufacturing Control Systems

Lets make sure we are talking about the same thing. Below, I see: "Yaman, can you find a single name that works for either discrete-time or continuous-time?" But I believe the discussion was more along the lines of discrete-event systems and continuous-process systems. If we pursue "d...
by "Ray on EV1"
Sat Nov 29, 2003 10:08 am
Forum: SD Mailing List Archive
Topic: Manufacturing Control Systems
Replies: 30
Views: 51612

Manufacturing Control Systems

8 JEAN-JACQUES, I thought it would be fun to address two points of your posting: 1) "One of the problem is to find a sufficiently small period ot time, to order the arrival of events. The order of arrival is always important in discrete simulation. This is generally not a problem unless the dis...
by "Ray on EV1"
Sun Nov 16, 2003 11:45 am
Forum: SD Mailing List Archive
Topic: Manufacturing Control Systems
Replies: 30
Views: 51612

Manufacturing Control Systems

Roland, Texas Instruments worked on such a project through the 90s and then sold everything they had developed to Accenture (www.accenture.com/). The fundamental problem TI had in this endeavor was to define the goal - the objective function for the optimization. The engineering team had concerns fo...
by "Ray on EV1"
Sun Sep 14, 2003 8:48 pm
Forum: SD Mailing List Archive
Topic: System Dynamics Applications in Power Plant Steam Cycles
Replies: 3
Views: 4373

System Dynamics Applications in Power Plant Steam Cycles

David, System Dynamics may help you study a system with dynamics, that is a system with stocks and flows, but your condensers normal mode of operation is more than likely in steady state. As such, all relationships can be dealt with algebraically. While SD tools are great at managing complex relatio...
by "Ray on EV1"
Mon May 12, 2003 7:07 pm
Forum: SD Mailing List Archive
Topic: Number of replications
Replies: 5
Views: 5142

Number of replications

Joel gave a very good summary. For free, try a google search on design of experiment: http://www.google.com/search?as_q=&num=10&hl=en&ie=UTF-8&oe=UTF-8&btnG=Googl e+Search&as_epq=Design+of+experiment&as_oq=&as_eq=&lr=&as_ft=i&as_filetype=& as_qdr=all&a...
by "Ray on EV1"
Tue May 06, 2003 7:33 pm
Forum: SD Mailing List Archive
Topic: Communicating System Dynamics to Others
Replies: 16
Views: 11817

Communicating System Dynamics to Others

There probably is no business looking for SD. Business have problems/opportunities they need solutions to. We can not expect to walk into a business a say "See how good this company did by addressing its problems with SD!" The first thing to do is get to know your potential client; learn t...
by "Ray on EV1"
Mon May 05, 2003 8:42 pm
Forum: SD Mailing List Archive
Topic: Communicating System Dynamics to Others
Replies: 16
Views: 11817

Communicating System Dynamics to Others

J.J. Laublé From: "ALLOCAR SRASBOURG" It seems that this task may take some introspection. What I read from you was that you would not approach them with the topic of SD because you know how they would respond. If you have experienced this behavior from them in the past, it may be due to y...
by "Ray on EV1"
Tue Apr 29, 2003 8:14 pm
Forum: SD Mailing List Archive
Topic: Can system dynamics models "learn"
Replies: 46
Views: 33404

Can system dynamics models "learn"

I have to thank John Sterman for awakening me to the ghosts in my machines. As such, I need a more objective concept of learning. It would be instructive to address an agent subjected to a process which results in learning a behavior. So there is an agent which is to learn a process, a training proc...
by "Ray on EV1"
Sun Apr 27, 2003 7:26 pm
Forum: SD Mailing List Archive
Topic: can system dynamics model learn
Replies: 5
Views: 8913

can system dynamics model learn

I like Richard Hammings commentary on modeling which points out the importance is not in the numbers the model produces but the insight the numbers bring. Our goals are diverse - a good thing. If some wish to design models that learn, we have to opportunity to study learning. If one of our goals to ...
by "Ray on EV1"
Sat Apr 26, 2003 6:39 pm
Forum: SD Mailing List Archive
Topic: Can system dynamics models "learn"
Replies: 46
Views: 33404

Can system dynamics models "learn"

Sorry for the interruption, but I am so focused on this topic that I couldnt let this opportunity lie. Specifically, "if a model that learns/changes could lose its problem focus". If we look at the hill climbing problem, we could find that a given hill climbing routine assigned to climb an...
by "Ray on EV1"
Fri Apr 25, 2003 2:19 pm
Forum: SD Mailing List Archive
Topic: Can system dynamics models "learn"
Replies: 46
Views: 33404

Can system dynamics models "learn"

Marsha, Thank you for the energy and thoughtfulness you put into the message. It has given me a lot to consider and some to comment on. First I would like to ask you not to be too discourage about your finding of the ridged view “we do x when y occurs”. I have run into this for decades. It is not yo...
by "Ray on EV1"
Mon Apr 21, 2003 3:01 pm
Forum: SD Mailing List Archive
Topic: Can system dynamics models "learn"
Replies: 46
Views: 33404

Can system dynamics models "learn"

I like the approach but I am a little lost in the detail of: * the desired state "s" is a changing goal. It describes a learned * response. Is it the intent to describe this optimization process as a learning process? So this should be valid when the end point is fixed (a given state) or c...
by "Ray on EV1"
Fri Apr 18, 2003 9:37 am
Forum: SD Mailing List Archive
Topic: Can system dynamics models "learn"
Replies: 46
Views: 33404

Can system dynamics models "learn"

My favorite approach comes from control systems engineering. It is automatic tuning. An example could be the controller on an elevator. The objective is to locate the correct position to stop the elevator at a floor with an accuracy of 2mm and to do so quickly but not jerky and dont overshoot the en...
by "Ray on EV1"
Fri Mar 28, 2003 10:19 am
Forum: SD Mailing List Archive
Topic: Simulation Model Interchange Language
Replies: 13
Views: 16349

Simulation Model Interchange Language

I have really enjoyed this topic. A little research shows that the Defense Modeling and Simulation Office (https://www.dmso.mil/) has supported the development of an integrating concept labeled High Level Architecture (HLA). More info can be found at: http://www.mitre.org and http://www.omg.org/. Th...
by "Ray on EV1"
Fri Mar 28, 2003 8:20 am
Forum: SD Mailing List Archive
Topic: SD health care system
Replies: 3
Views: 3838

SD health care system

We have seen some very informative links to important issues in the health industry. I would like to add my two meager comments: 1) Consider what your supporters are interested in. 2) Consider what you are interested in. 3) It may not be necessary (or possible) to exercise pertinent models with the ...
by "Ray on EV1"
Tue Mar 18, 2003 9:52 am
Forum: SD Mailing List Archive
Topic: ANNOUNCE System dynamics used in amending UK Government poli
Replies: 0
Views: 2695

ANNOUNCE System dynamics used in amending UK Government poli

The write up by Eric Wolstenholme was very exciting. Hearing politicians address a rational basis at least promising. What would be additionally informative is hearing of the process which was used to develop the model and present the findings. Was there bipartisan review? Data validation? Ray From:...
by "Ray on EV1"
Fri Feb 28, 2003 1:26 pm
Forum: SD Mailing List Archive
Topic: Simulation Model Interchange Language
Replies: 13
Views: 16349

Simulation Model Interchange Language

Yes, as Jim Hines points out, this is extremely valuable. It would be appropriate to set up a list server to address this issue so as not to clog the normal SD channel. There are many examples of specification development and recommended practices development on the web. It would be appropriate to h...
by "Ray on EV1"
Sat Feb 22, 2003 12:39 pm
Forum: SD Mailing List Archive
Topic: SD and the propensity to file long term disability
Replies: 2
Views: 4332

SD and the propensity to file long term disability

I just had to add one more that I have noticed. The number of TV
advertisements by lawyers promoting civil action for LTDs. This may have a
correlation with a lack of other jobs to do.

Ray
From: "Ray on EV1" <rtjoseph@ev1.net>
by "Ray on EV1"
Sat Feb 22, 2003 9:51 am
Forum: SD Mailing List Archive
Topic: Attractiveness Multiplier
Replies: 12
Views: 32655

attractiveness multiplier

The latest issue of The Industrial Physicist had an article on how to apply
the predator-prey model to sales. One of the three parameters of the model
can be viewed as attractiveness.

Ray
From: "Ray on EV1" <rtjoseph@ev1.net>
by "Ray on EV1"
Sun Feb 09, 2003 8:47 pm
Forum: SD Mailing List Archive
Topic: Business simulations - web sites?
Replies: 4
Views: 4554

Business simulations - web sites?

Sheila, You will probably get URLs from numerous others so I will focus on just one issue. It is usually best to define the problem before generating a solution. Although it would be possible and a fun (and impressive) mountain to climb, having different machines for different aspects of a business ...
by "Ray on EV1"
Thu Feb 06, 2003 9:29 am
Forum: SD Mailing List Archive
Topic: Channel Systems
Replies: 5
Views: 5215

Channel Systems

Timothy, It would be advantageous to differential between marketing and sales. Where a marketing strategy can be carried out on the web or at retail (and numerous other forms not addressed), phone is typical a sales campaign form. This is also true if the web action is mass emails. Telemarketing hou...
by "Ray on EV1"
Wed Jan 29, 2003 7:22 am
Forum: SD Mailing List Archive
Topic: Channel Systems
Replies: 5
Views: 5215

Channel Systems

Timothy, Yes. I have often provided the margin calculations differentiating sales channels. Every industry I have worked with does this on a continuing basis. But, they always approach it algebraically. Since youve brought it to this channel, I am guessing that you are interested in the dynamics. Th...