The Sample Models
The Sample models will normally install into the sample subdirectory of the models subdirectory of Vensim.
We give a very brief description of what the models are and when appropriate an indication of how they relate to the Vensim documentation. The list is arranged alphabetically by directory.
intro.mdl
This is the only model in the sample directory itself. It is closely related to the workforce inventory model described in Tutorial 2. In this model there is a fixed workforce and a loop through overtime, morale and productivity that causes the model to oscillate.
bpr
The bpr subdirectories contains several models related to business process engineering.
BPR0.vmfThis is a simple word an arrow description of a business process. This model cannot be simulated. There is no feedback in this model.
BPR1.vmf This model presents programming style flow diagram that outlines a business process. The model cannot be simulated but demonstrates the flexibility of sketches built in Vensim.
BPR2.vmf This is a mechanical simulation model of a business process. This model has only limited feedback in the form of stopping processing when there is no work to do. It is very similar to the first project model developed in Tutorial 3.
BPR3.vmf
This model has the same basic physics as bpr2.vmf but uses feedback policies to manage the capacity allocations throughout. It can generate oscillatory behavior just like the workforce inventory model of Tutorial 2.
finance
This is a financial model that is attached to a emerging market model. It is closely related to the example used in the financial modeling discussion.
kalman
This is a version of the workforce inventory model developed in Tutorial 2 that has been modified to demonstrate the use of Kaman Filtering.
maint1
This is a version of the workforce inventory model developed in Tutorial 2 that has been modified to demonstrate the use of Kaman Filtering.
market
This is a model of market growth in a market for which sales representatives are fundamental to achieving this growth.
mproject
This is a multistage model of projects. It is related to the project modelsand also the multistage project models discussed in Tutorial 17 (Subscripts).
urban
This is the model of urban development and decay presented in Urban Dynamics by J.W. Forrester (The MIT Press, Cambridge, MA, 1969) available from Pegasus Communications.
wrld3-03
This is an updated version of the model that was used for the book The Limits to Growth by D.H. Meadows et al (Universe Books, New York, 1972). The model was updated for Beyond the Limits: confronting global collapse, envisioning a sustainable future by D.H. Meadows et al (Chelsea Green Publishing Company, Post Mills, VT, 1992) and then again for Limits to Growth – the 30-Year Update, by Donella H. Meadows, Jogern Randers and Dennis L. Meadows (Chelsea Green Publishing Company, White River Junction, VT, 2004)
In addition to wrld3-03.vmf there is a model Word3_03_Scenarios.vmf that has a constant named scenario which can be used to recreate the scenarios described in the latest book. Set it to 1 for Scenario 1, 2 for Scenario 2 and so on up to 10. To accommodate this some changes to structure were necessary but these have been isolated into a single view. The model also includes some documentation on the different scenarios and suggestions for your own exploration.
