1. Biology: foraging Day 6 COLQ 201 Multiagent modeling Harry Howard Tulane University

2. 25-Jan-2010COLQ 201, Prof. Howard, Tulane University2 Course organization  http://www.tulane.edu/~howard/Multiagent/ http://www.tulane.edu/~howard/Multiagent/  Photos?

3. 25-Jan-2010COLQ 201, Prof. Howard, Tulane University3 Photos

4. Ants Models Library > Biology > Ants (updated version of the one on the website)

5. 25-Jan-2010COLQ 201, Prof. Howard, Tulane University5 Overview  Set up the model & turn plotting on.  Look at the splotches that are not in the center. Notice how far they are from the center splotch.  Run the model & stop it when it stops changing.  What is the order in which the splotches (food sources) are consumed?

6. 25-Jan-2010COLQ 201, Prof. Howard, Tulane University6 Ant foraging  How do ants navigate?  Now let us experiment: population = 125, diffusion = 50, evaporation = 10.  Decrease population to 50 & run. What is the difference?  Increase population to 200 & run. What is the difference?  Test diffusion at 25 & 75. What is the difference?  Test evaporation at 5 & 50. What is the difference?

7. AntSystem has several errors

8. Programming NetLogo Models Library > Earth Science > Fire

9. 25-Jan-2010COLQ 201, Prof. Howard, Tulane University9 Intro to Fire  Set up  What do you think the green represents?  What do you think the red represents?  What do you think the black represents?  Run it.  Experiment  Lower density to 55. What % burns?  Raise density to 65. What % burns?  Set density to 59. What % burns?  What are the agents?

10. 25-Jan-2010COLQ 201, Prof. Howard, Tulane University10 Conclusion  This is an example of a common feature of complex systems:  the presence of a non-linear threshold or critical parameter.

11. 25-Jan-2010COLQ 201, Prof. Howard, Tulane University11 How it is programmed  Switch to the Procedures tab.  Click on the Procedures pull-down menu. What procedures do you see?  fade-embers  go  ignite  setup  Find each of these in the code.  What is the relation of setup and go to the interface?

12. 25-Jan-2010COLQ 201, Prof. Howard, Tulane University12 Procedures  What is the layout of a procedure?  What does ;; mean?  What does ask do?  What does if do?  What does set do?

13. 25-Jan-2010COLQ 201, Prof. Howard, Tulane University13 Turtles & patches

14. 25-Jan-2010COLQ 201, Prof. Howard, Tulane University14 Next time  Biology: migration  Scatter, Randomly walking