1. Object Oriented Design

2. Goals  Discussion Pacman Project  Project X: OOA & D meets AI u Collaborating objects u Objects approaching / or pretending to have complexity of human beings

3. Pacman reflections  Specification in UML u How hard was it? u How complete was the specification? Could somebody else implement it?

4. How to implement Ghost.move ? the big question

5. Object interaction complexity  1970s u Frogger: simple causality: truck hits frog u Space Invaders: indirect causality: Defender shoots laser, laser hits spaceship  1980s u Pacman: early AI: tracking, avoiding, of objects. E.g., ghosts track the pacman  1990/2000s u Simulation of human intentions, goals, emotions, communication, … name that game

6. Homework 6  Design and implement in AgentSheets  Individual projects  Due: Oct. 22

7. Diffusion and Hill Climbing  The presence of an agent can be diffused through space allowing other agents to track agent via hill climbing  The landscape can be shaped to provide navigation clues

8. Solution: combine hill climbing with diffusion  Powerful idea: u applicable to a huge number of OO design problems u A cognitive tool to think about complex problems  Origins u Hill climbing: Artificial Intelligence u Diffusion: Physics  Combination => Distributed Artificial Intelligence

9. How to spread continuous values: Diffusion  Value := (value[left] + value[right] + value[up] + value[down]) / 4  Examples u Temperature u voltage u Presence

10. Examples of Diffusion  Bridge Builder  Avalanche / mudslide  Electric Diffusion  Electric Ink  Heat Diffusion

11. Example

12. Asymmetric Diffusion  Diffusion coefficients representing asymmetric diffusion can be introduced to model... u Water flow (El Nîno) u Wind (Sustainopolis)  Value := 1/n ∑u i * value i

13. Example 1: fire sim

14. Homework 6  Design and implement in AgentSheets  Individual projects  Due: Oct. 22

15. Background  Created in 2000 by Will Wright at Maxis, an Electronic Arts company  Grew out of series of simulation games including: SimCity (also created by Will in 1989), SimAnt, SimTower, SimEarth, …  Info: http://www.thesims.com/http://www.thesims.com/

16. Description

17. Turn in  Project u Sims living in house or outside  At least 2 kinds of diffusions u Objects to satisfy basic needs  Hunger  Thirst  Sleep u Objects / people to satisfy secondary needs  Entertainment  Comfort  Documentation  Same naming conventions and guidelines as usual

18. … and use “4448” as part of your email subject line!!