Modeling and Simulation

Warm-up Activity (1 of 3)

You will be given a set of nine pennies. Let’s assume that one of the pennies is a counterfeit that is slightly heavier than the other pennies. If we had a scale and you could make three measurements, how would you determine which penny is counterfeit?

Warm-up Activity (1 of 3)

Warm-up Activity (2 of 3)

With the same set of nine pennies, let’s now assume that one of the pennies is a counterfeit and that is might be slightly heavier OR lighter than the other pennies. If we had a scale and you could make three measurements, how would you determine which penny is counterfeit AND whether it is heavier or lighter?

Warm-up Activity (2 of 3)

Warm-up Activity (3 of 3)

Can you repeat the previous exercise with 12 coins???

Warm-up Activity (3 of 3)

Possibly Light

Possibly heavy

Possibly heavy

Modeling and Simulation:Swarm Theory

“The Wisdom of Crowds”

What is a Swarm?• A swarm is a collective noun used to describe

a large group of animals, usually in motion (bees, ants, people, etc.).

Other collective nounsAnimal Collective Noun

Geese Gaggle

Crows Murder

Barracuda Battery

Sharks Shiver

Tilapia Taint

“A flock of seagulls.”

“A school of fish.”

“An army of ants.”

• Swarming is a behavior that describes how a group of individual animals/objects move together in the same direction all at once.

Some things most swarms have in common:– No one person is in control (there is no general)– Members only talk to those close to them– The collective behavior is organized/intelligent– The whole group is responsive to minute changes

What is Swarming?

What is Swarm Theory?• Swarm Theory is the modeling and simulation

of the collective behavior of groups of simple agents.

“The wisdom of crowds.”

Extra Credit [ ??? Pts]: Read the first two chapters of James Surowiecki’s “The Wisdom of Crowds” and writea two page, double spaced paper that summarizes his thoughts.

Why is Swarm Theory Important?

Computers have changed our lives:

Industry EmergenciesMilitary InternetManagement Traffic Control

Not all problems can be solved with traditional hardware and software!!!

Models for Swarming Behavior

Ant Colony Optimization (ACO)

• Ants are great at finding the closest source of food

• Ants use pheromones to communicate information

Particle Swarm Optimization (PSO)

• Birds are excellent at finding multiple sources of food simultaneously

• Birds broadcast information locally

“The whole is greater than the sum of each part.”“Solve complex problems using simple agents.”

Ant Colony Optimization

• Ants Foraging– Cooperative search using pheromone trails

ACO finds shortest route!!!

Particle Swarm Optimization

Birds Foraging•Flock searches the entire space•“I found food!!!” is only broadcast locally•Rest of flock continues to search

Building Blocks of Swarm Theory

In nature, all swarms are self-organizing and use these principles:

1.Positive Feedback2.Negative Feedback3.Fluctuation/Randomness4.Multiple Interactions

Swarm Theory

• Homework:– Download U1H1.doc

• Watch the online video clip listed in the document• Answer the questions• Turn in your answers at start of class tomorrow

– Read over tomorrow’s lecture (U1 L2.ppt)