Modeling and Simulation

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Modeling and Simulation
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Warm-up Activity (1 of 3)

• You will be given a set of nine pennies. Lets
  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?

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Warm-up Activity (1 of 3)
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Warm-up Activity (2 of 3)

• With the same set of nine pennies, lets 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?

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Warm-up Activity (2 of 3)
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Warm-up Activity (3 of 3)

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

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Warm-up Activity (3 of 3)
Possibly heavy
Possibly Light
Possibly heavy
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Modeling and SimulationSwarm Theory
The Wisdom of Crowds
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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 nouns

Animal Collective Noun
Geese Gaggle
Crows Murder
Barracuda Battery
Sharks Shiver
Tilapia Taint
A flock of seagulls.
A school of fish.
An army of ants.
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What is Swarming?

• 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

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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 Surowieckis The Wisdom of
Crowds and write a two page, double spaced paper
that summarizes his thoughts.
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Why is Swarm Theory Important?

• Computers have changed our lives
• Industry Emergencies
• Military Internet
• Management Traffic Control
• Not all problems can be solved with traditional
  hardware and software!!!

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Models for Swarming Behavior
The whole is greater than the sum of each
part. Solve complex problems using simple
agents.

• Ant Colony Optimization (ACO)

• Particle Swarm Optimization (PSO)

• Ants are great at finding the closest source of
  food
• Ants use pheromones to communicate information

• Birds are excellent at finding multiple sources
  of food simultaneously
• Birds broadcast information locally

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Ant Colony Optimization

• Ants Foraging
• Cooperative search using pheromone trails

ACO finds shortest route!!!
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Particle Swarm Optimization

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

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Building Blocks of Swarm Theory

• In nature, all swarms are self-organizing and use
  these principles
• Positive Feedback
• Negative Feedback
• Fluctuation/Randomness
• Multiple Interactions

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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 tomorrows lecture (U1 L2.ppt)