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Sample Projects available for Download

Revision as of 16:02, 7 July 2010 by Judyvdouglas.verizon.net (Talk | contribs) (Square Lattice Example)

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Sample Projects Available For Download

The STEM home page ([[1]]) contains several example projects users can import and run with STEM. STEM is designed to allow collaboration and sharing of work by simply importing and exporting projects from your workspace. For information on how to import a project please see: Importing and Exporting Projects

The Square Lattice demo described below requires STEM version dated July 1, 2010 or later The SuperContinentExample project requires GlobalGeography to exist in the STEM workspace before it any of the examples can run.

Some of the example projects you can download are very large as they contain continents or even groups of continents. Before you try to run any of these large scenarios you must make sure you allocate enough system memory for STEM. If you don't do this the application may hang or crash with a "Heap Space" error. To allocate enough memory in Windows, create a shortcut for launching STEM. You may place this anywhere (e.g., on your desktop or on the quicklaunch bar).

Right click on the shortcut. Select "Properties" You should see a field in the Properties Dialogue labeled Target: to the right in the text field you will see something like

C:\stem_builds\stem\STEM.exe -vmargs -Xms812M -Xmx812M

To launch STEM with more memory you must add "virtual machine arguments" to the target line. For example, Target:

C:\stem_builds\stem\STEM.exe -vmargs -Xms896M -Xmx896M

Should work for the demo projects available.

On MAC OS X, using the finder, navigate to where the STEM application is located, right click and select "Show Package Content". Navigate to Contents->MacOS and open the STEM.ini file in an editor. Change the -Xms and the -Xmx lines to increase the memory, e.g. -Xms896M -Xmx 896M or more depending on how much memory is available.



Square Lattice Example

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Figure 1. Square Lattice Example

Description of model and composition goes here

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Figures 2a-c. Spread of the Human Population by Migration Edges

The figures above show the spread of the population itself by migration edges. The population is seeded in the center (10x10) and in a node just left of center. The center population is much larger than the smaller seed to the left (the intensity is saturated). Only the population to the left is infected initially. Open the infector and the population initializer in the property editor to see the initial values. As the infected population on the left spreads, it eventually makes contact with and infects the main population spreading from the center.

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Figures 3a-c. Spread of the Disease

The figures above show the same simulation but display the fraction of people infected as a function of time. Note that the intensity does not reflect the NUMBER of infections (only the fraction). When the infected population on the left reaches the much larger fully susceptible (but not yet infected) population spreading from the right, the intensity actually goes down as the fraction of people infected drops (initially) at the point of contact (see the middle image above). Eventually (right) the main population also becomes infected.

Mexico/USA H1N1 Scenario

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Global Geographic Models Only

The Global Geographic Models project contains no runnable scenarios. Rather, is contains a set of pre-composed models for large regions of the world intended to be built upon in developing your own scenarios. These models, shown int he figure below, include a model for global air transportation, and a set of continent and super-continent models for geographic regions and people. After you download them, please expand them to see the inner components.

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Super-Continent Examples

The Super-Continent Scenarios provide an examples of how to construct scenarios using the Global Model examples described above. These scenarios show how to model large regions such as the Americas, Europe+Africa, and Europe+Asia. The figure below expands the Eur-Africa Scenario. Note that the Inner Eur-Africa Model contains a model for Europe, a model for Africa, together with the connection between Spain and Morocco.


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