Monday, January 25, 2010

Simple Population Models

In a Master's course last semester I built a model to compare simple population cohort models using System Dynamics and Agent Based Modeling. Someone also asked in the System Dynamics forum if it was possible to embed models in a blog, so I thought I' try it out here. The model below simulates people moving through an aging chain, where at the age group of fecund, they influence the birth rate. Both models produce similar dynamics, but the representations offer a few unique insights on problem formulations. The System Dynamics model is quite a bit easier to build and calibrate, producing good fits to the UN data. The agent model is more complicated and is prone to stochastic effects (which could be smoothed with more agents), but it also more easily allows for additional individual attributes such as gender and wealth. Use the navigation buttons to explore the different implementations and run the model to 2050 to have more time and glimpse of where we might be headed (the population scale is per million people). Note, you'll need to have Java and increase the amount of applet memory available to at least 400M. See this page for a good explanation on how to do this.

<applet code="world_population_aging_chain/Simulation$Applet.class" archive="http://mysite.verizon.net/bruceskarin/models/com.xj.anylogic.engine.jar,http://mysite.verizon.net/bruceskarin/models/world_population_aging_chain.jar" width="902" height="718"> </applet>

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