DRILL Answer the following question’s about yesterday’s activity in your notebook: 1.Was the activity an example of ACO or PSO? 2.What was the positive feedback? 3.What was the negative feedback? 4.How did we build in fluctuations?

Swarm Theory: “The Wisdom of Crowds” Creating a Swarm

Swarm Intelligence Swarming is a behavior that describes how a group of individual animals/objects move together in the same direction all at once. Swarm Theory is the modeling and simulation of the collective behavior of groups of simple agents. “A flock of seagulls.”“A school of fish.” “An army of ants.”

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.” Works best for finding discrete solutions Works best for finding continuous solutions How do we choose which to use?

Swarm Theory: Setting it up To solve a problem using swarming techniques you will have to: 1.Define the domain 2.Create an algorithm 3.Write instructions for the agent 4.Define the criteria for completion

Swarm Theory: Setting it up Domain Algorithm Agent Threshold

Defining the Domain Domain – the set of all possible input values to a function. Spatial – a specified region of space Temporal – a period of time Other Combination Problem:Find the nearest, least expensive gas station to Poly. Domain: All gas stations within a 1 mile radius of Poly. What was the domain in yesterday’s activity? Problem:Choose the most reasonable of five homework sets. Domain:The five homework sets.

Creating an Algorithm Algorithm – a step by step procedure for solving a problem, usually iterative 1.Positive Feedback –> 2.Negative Feedback –> 3.Fluctuation –> 4.Multiple Interactions –> Amplifies good solutions Stabilizes the system Mimics nature Iteration “Choose Homework” Dancing Erasing past Random # Iteration

Building the Agent Each agent in a swarm is given a set of simple instructions that require it to search the domain, test its surroundings and communicate results. 1.Explore and look for possible solutions 2.Inspect solution 3.Return and communicate results 4.Wash, rinse, repeat… “Choose Homework”

Swarm Theory Homework: – Read over tomorrow’s lecture (U1 L4.ppt) Pop quiz is possible – Set up a swarm intelligence to solve this problem: A nest of ants are looking for food in a large field that is divided up into a 8x8 grid. In one of the grids are balls representing food. The food can only be “found” if an agent enters a grid space adjacent to the food. What is the shortest route to the food?

Swarm Theory Ants(A) are looking for food(F) in a large field that is divided up into a 8x8 grid. In one of the grids are balls representing food. The food can only be “found” if an agent enters a grid space adjacent to the food. What is the shortest route to the food? F A 1.Define the domain 2.Create an algorithm 3.Write instructions for the agent 4.Define the criteria for completion