# Ants - Scalable Game Design wiki by yurtgc548

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```									Computational Representation
of Ant Foraging
Clayton Lewis
June 26, 2010
Simulation
• from the scalable game design home
page,
– click “Summer Institute 2010”
– then “STEM Simulations”
– then “Ants”
Project
Explore
• Run the complete simulation, and see what
features of the behavior of the simulated ants
you can identify.
• At this stage, don’t examine the rules, or
modify simulation properties.
• Run the simulation fairly slowly at first so as
to be able follow the behavior of individual
ants.
• Think about the brown markings as trails, not
tunnels.
Discussion
• How do these behaviors of the
simulated ants compare to those of real
ants?
Ants
• How do they find their way back to the
nest?
• Why could it be useful for the trail
pheromone to evaporate?
Exploring Variations
• The simulation property “ticks”
measures how quickly the ants have
exhausted the food.
• The simulation property “turning”
controls how often ants turn when
foraging
• Let’s use these properties to explore
what value of turning works best
Exploring Turning
• We’ll create a simple food layout
• Use the arrow tool and move the nest to the
middle of the worksheet
• Erase the food
• Place 4 lollipops a little way NE,SE,SW, and
NW of the nest
• Erase the ants and put 4 in next to the nest,
E,S,W,N
• SAVE the worksheet
Exploring Turning (Cont.)
• We’ll assign values of “turning” by
counting off: 10,50,90
• Set the value of turning to your value in
the Simulation Properties Window
• Run the simulation
• Report the value of ticks when all the
food is gone
What is the best turning
value?
Exploring Turning (Cont.)
• Let’s change food layout
• Use the arrow tool and move the food near
the corners of the worksheet
• SAVE

• Check that your simulation properties window
shows your value of turning, and ticks 0
• Run the simulation again with your value of
turning
What is the best turning
value?
More Explorations
What is the effect of pheromone life?
Does it depend on the amount of food at
a food site?
Does this effect depend on number of
foragers?
Does the optimal turning value depend on
the number of foragers?
Actual Ant Turning is Density
Dependent (Gordon, 1999)
• The program uses several
computational thinking patterns:
– collision (ant and food)
– diffusion (distance to nest)
– hillclimbing (to find nest)
– polling (to control ticks)
• These and many others are described
on the Wiki
Extending/Changing the
Program
• What if there is no pheromone trail?
– (Try it… first find the rule that places the trail… a
little tricky!)
• The ants don’t follow the trail perfectly… can
you (or your students) improve this?
• Some real ants don’t begin to search until
they have moved some distance straight from
the nest…(why?) … could you add this
feature?
Ant Tournament
• Students can be challenged to produce
improved ants that forage more quickly
• …and to research how their
improvements relate to real ant foraging
Final Words
• Real ant researchers use simulations to
understand ant behavior…
• … and some computer scientists study
ants to understand new ways of
searching for information.
• More ant materials are on the Wiki

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