Making Connections - Latest Comments

Re: About

Necmi Tosun — Mon, 02 Jan 2012 11:27:12 -0000

Hi Cambell,

Please let me know your contact details.

Necmi Tosun (ntosun2000@yahoo.com)

Re: Spatial Modeling with isee Spatial Map

Peter Song — Sun, 01 Jan 2012 21:13:50 -0000

Another tip. I used a gif animator to produce a movie. I hope somebody can integrate Spatial Map and a GIF animator to get it in a one step. I tried to upload the animated GIF file but this site does not allow an animated gif...

Re: Spatial Modeling with isee Spatial Map

Peter Song — Fri, 30 Dec 2011 01:54:45 -0000

Finally I got it. I set the Pause Interval at 10 in STELLA's Run Specs and observed the changes by clicking the Run button 24 times at 10, 20,30,..., 80, ...150, 180,... 240. Check out the image below. To have this, I set the colorsetting in Spatial Map as below.

Re: Spatial Modeling with isee Spatial Map

Peter Song — Fri, 30 Dec 2011 01:07:06 -0000

Question: I have to keep pressing the "Run" button to see Spatial Map change. Is there any way to see it changed continuously like in a movie? I am modeling a spread of Foot-Mouth disease and audience will be more pleased to see a movie rather than a series of static images flickering...

Re: Spatial Modeling with isee Spatial Map

Peter Song — Fri, 30 Dec 2011 01:03:54 -0000

Not much discussions going on... Spatial Map is only included in the full license version, not in the Trial version. I had to buy STELLA 9.1.4 to see it running. It is installed in the STELLA folder.

Re: 2011 Barry Richmond Scholarship Award

Joanne Egner — Wed, 28 Dec 2011 11:51:05 -0000

Hi Rahayu,

You may want to connect with the System Dynamics Society (www.systemdynamics.org). The link to their discussion forum is right on the home page. There also are a number of system dynamics practitioners connected via LinkedIn that could be helpful.

Good luck!
Joanne

Re: 2011 Barry Richmond Scholarship Award

Rahayu S Arifin — Mon, 26 Dec 2011 07:45:50 -0000

i would like to participate the system dynamics expert discussion, eventhought I am still far for being understand the system dynamics. I use this methodology for my disertation on water supply system . The case study is Bandung - Indonesia. How to be registered as participant ? Thanks to reply this message.

Re: Spatial Modeling with isee Spatial Map

Peter Song — Fri, 23 Dec 2011 00:00:44 -0000

Where is the Spatial Map? I am a STELLA version 7.x user and wish to upgrade to 9.1.4 for Spatial Map. I downloaded a Trial version but can't find Spatial Map there?

Re: Private: Steady-State Initialization of Conveyors

Mac — Sun, 27 Nov 2011 15:08:16 -0000

Please explain why exponential leakage cannot be 0 (either set to 0 during sensitivity analysis, or set to 0 for initial conditions, or calculated to become 0 as a result of model feedback.

Re: Published Papers that Feature Models

Krish — Wed, 16 Nov 2011 13:50:12 -0000

Hi jeremy

I am a beginner in "system dynamics", and I am trying to implement the given article
regarding supply chain. Can u help me with devoloping graph for the model as it includes summation of model variables.

Saeed, K. (2009). Can trend forecasting improve stability in supply chains? A response to Forrester’s challenge in Appendix L of Industrial Dynamics. System Dynamics Review, 25(1), 63-78

PDF : http://onlinelibrary.wiley.com...

Re: Running Models from the Command Line

isee systems, inc. — Thu, 20 Oct 2011 09:31:26 -0000

Brandi,

Yes, the help file link in the post shows the complete list of command line arguments:
http://www.iseesystems.com/Hel...

After adding the command line option in v9.1 as an experiment, we have been surprised pleased to see how many users take advantage of it. Logging, status and verbose mode switches are definitely features we would like to add in the future. Thank you for the feedback.

Re: Running Models from the Command Line

Brandi — Wed, 19 Oct 2011 12:38:42 -0000

I've seen the list of command line options, but are these the only options available? Is there anyway to output, such as verbose to the command line screen (such a progress indicator, which model run, etc). If a verbose or log option is not available, will it be made available in future versions?

Re: About

isee systems, inc. — Tue, 18 Oct 2011 11:14:31 -0000

This is a bug in the present version of iThink and STELLA. Without Excel installed on your system it makes it more difficult, but not impossible, to import data from CSV files. We are correcting this problem in the upcoming release.

How to Import Without Excel from a CSV File:
The specific import feature that gets adversely affected is the ability to maintain a persistent link to an import data file. As you probably have discovered, if you try to manage the persistent links, you'll get an error that Excel is not found. What you can do are one-time imports of CSV files.

If you go to the Edit menu and select "Import Data", choose the "One Time" import type and select your CSV file, this should work on the subsequent run. You will have to manually set this up again if data changes in the imported CSV file.

Exporting to a CSV file without Excel installed works without any problems.

Re: About

Stanhopkins — Mon, 17 Oct 2011 19:36:31 -0000

It seems the iThink software cannot import data into a model unless Excel is installed on the same system. Booo! I'm using Open Office and don't have it installed. Even a raw .csv file cannot be input unless it is read by Excel and presented to your software. This should not be.

Re: Tip: Setting up imports for 2D Graphical Functions

Sdavie — Thu, 11 Aug 2011 10:36:57 -0000

I am afraid I don't understand your question. Please e-mail support@iseeesystems.com so we can discuss further. Thank you!

Re: Tip: Setting up imports for 2D Graphical Functions

Ch_sawvapark — Thu, 11 Aug 2011 03:53:19 -0000

how can import data to be array(parity) initial if each parity has different value.

Re: “Tracing Connections” book honors Barry Richmond

Systemswiki — Mon, 25 Jul 2011 19:09:10 -0000

Are things getting any closer to offering this book in Kindle format?

Re: What is Delta Time (DT)?

Alejandro — Mon, 18 Jul 2011 16:15:18 -0000

Thank you very much understand it without the translator

Re: What is Delta Time (DT)?

Nat Pierson — Mon, 18 Jul 2011 15:26:10 -0000

Alejandro,

It is possible to switch your model to a DT of 1, but this can be dangerous. A DT of 1 is can be too large, and depending what kind of model it is, this can cause unwanted behavior, such as artifactual delays (see this help article http://www.iseesystems.com/Hel... . I would recommend trying to find a workable common DT that is closer to 0.25 between the two models you are trying to connect.

I hope my answer can be clearly translated for you. If you would like more information, please email support@iseesystems.com.

Re: What is Delta Time (DT)?

Alejandro — Mon, 18 Jul 2011 15:02:14 -0000

Hello, I congratulate you for the article, I wonder if it is possible to transform a model that is by definition DT 0.0625 to DT 1 to do is to connect two models using a different DT. PD: Excuse my English I'm still learning and I'm writing with the help of a translator.

Re: Rethinking ‘Cash for Clunkers’

Justinowell — Thu, 07 Jul 2011 11:51:35 -0000

Great post. Thanks for sharing.

Re: Private: Modeling Customers Switching Between Brands – The General Case

Guest — Thu, 16 Jun 2011 15:48:57 -0000

Great post. I am curious, however, in how you would account for customers reducing spend across all brands? What if a customer is spending $10 on Golden Grahams and $8 on Life Cereal in the first period and $8 on Golden Grahams and $5 on Life Cereal in the second period. You would have overall contraction vs. switching, or do you somehow prorate this?

Re: What is the difference between STELLA and iThink?

Jeremy Merritt — Thu, 16 Jun 2011 09:02:49 -0000

We have attempted to clarify this issue within a couple of other posts:

- Why DT Matters: http://blog.iseesystems.com/mo...
- Integration Methods and DT: http://blog.iseesystems.com/mo...

Hopefully, you and others reading these comments will find these articles useful.

Re: Methods for Using Arrays Effectively, Part 1

Franco_lezcano_91 — Thu, 09 Jun 2011 10:47:22 -0000

Hello. First of all, sorry for my bad english, i am from peru, and I`m working with Stella, doing some proyects for the university. I`d like to know how to get the sum of a flow element in diferent time.
Iam planning to use an array, but the thing is that i dont kwno how to use it, wolud you help whit some basic example

thanks!!

Re: What is the difference between STELLA and iThink?

Bsginc — Mon, 23 May 2011 04:22:27 -0000

Every time I read the discussion of the time function and DT, in iStella and iThink, I cringe. You talk of time frames that are appropriate to business and the social sciences as being 1 to 13 and 0 to 12, respectively.

I cringe because those ranges appear to encompass 13 periods. At least when using language conventionally. That, of course, is really not the case as you are talking time periods that begin at a point and go TO a point, not THRU a point in time. Further, each point is exactly that, a point in time, not a period of time as is represented by the interval between two points.

If you can't wrap your head around this fundamental difference, understanding the description of time periods and the differences in how they are represented in iStella and iThink is a struggle.

Because language is so imprecise, you might consider this point when attempting to explain both products to new users.