These "extra" models are included in the sub-directory sample\extra.
A model about populations aging using aging cohorts.
A similar model to age.mdl but using chained stocks to achieve the aging.
This model simulates a bouncing ball as it impacts the ground and uses two different time steps depending on its position.
This is a worker burnout model written by Jack Homer and published in The System Dynamics Review Volume 1, Number 1, 1985, Pages 42-62.
This model shows the effect of caffeine on the central nervous system through effects on drowsiness.
A model of the Hog market commodities trading, based on the real market originally created by Denis Meadows.
A simple price/inventory stock model.
Model of a system cooling (cup of coffee).
Jay Forrester's simple implementation of a corporate growth model. As featured in Principles of Systems, by Jay Forrester (Pegasus).
Easter Island tree decimation by the inhabitants of Easter Island hundreds of years ago. Extremely simple model.
The classic Bass diffusion model of the spread of an epidemic.
Gravitational attraction of two massive bodies.
This is a model of a rats kidney. It demonstrates some fast/slow dynamics and uses FIND ZERO function to solve simultaneous equations describing them. It is based on the work of Erik Mosekilde.
The same model using the SIMULTANEOUS function as an alternative.
This is a simple population model configured to be used in gaming. It is essentially the same as the model developed in Chapter 6 of the User’s Guide.
This model features a large subscripted base of ages in a population.
This is a simple model of the procrastination process. It is closely related to the project models discussed in Chapter 3.
This is a simple project model and is very nearly the same as that developed in Introduction to System Dynamics Modeling with DYNAMO, by G.P. Richardson and A.L. Pugh (The MIT Press, Cambridge, MA, 1981) available from Pegasus Communications.
The rabbit model extended to a predator/prey system with foxes.
Simple exponential growth in a snowball.
Simple goal seeking with negative feedback to attain a particular speed.
This is a simple model of water flow that demonstrates a number of useful subscripting tricks.
This is the model presented in World Dynamics by Jay W. Forrester (The MIT Press, Cambridge, MA, 1971; second edition, 1973).