Conception de modèles pour la simulation

1. Conception de modèles pour la simulation Exercices de familiarisation

2. How does one program a Mas?

3. Methodology • Internal structure of the agents • Communication • Control

4. Communication • Questions • Who communicate with whom? • What language?

5. Coordination and control • Questions • Who does what ? • How are the actions scheduled ? • How are the conflicts resolved ?

6. Without communication • Planes coordinate without communication. B: conflict with C B: I go up C: conflict with B C: I stabilize the level A: Conflict with B A: I turn right B Conflict with A B: I turn right

7. With communication A: I go to Montpellier B: Do I go up? B I go to Chiang Mai C: I go to Djakarta A: No you go left , I go up B: ok

8. Without communication • Agent structure Sensors Environmental change Plan generator Models of the world Possible plans Execution Model assesment Controler

9. With communication Planes Communication Sensors Environmental change Plan generator Models of the world Possible plans Execution Model assesment Controler

10. Three main issues for reactive agents • Representation of space and environment • Actions and perceptions • Decision between perception and action

11. Environment • A space and a medium for interactions • The perception of an agent is the result of the actions of other agents (externalities)

12. Interactions • Interactions through a field of forces • Interactions through the use of marks • Interactions through actions with neighbors

13. A field of forces • Reynolds Boids • Fish shoal (Mesle) • Planes (Zeghal)

14. The use of marks • The relation with environment is linked to the perception of marks, • The action is the use of marks • Examples • Foraging robots • Foraging ants

15. Without cooperation • Explore : randomly • Find : if I perceive a mine, then I take • Carry: go back to the base • Base : drop what I am carrying

16. With marks • Robots use marks • Follow Mark : If not carrying and perceive mark then follow marks

17. Result

18. With explicit cooperation • Help: if perceive agent carrying then propose help • Exchange : If help proposed then give the resource

19. Action on the neighbors • Assess the state of the neighbors and the pressure • Analyze the state and pressure and choose the best action • Move and put pressure on the neighbours

20. Cognitive agents • A cognitive agent • has memory • has beliefs and skills • has goals • can communicate • Some parts of knowledge are facts. Other parts are models of the world.

21. Three main questions for a cognitive MAS • Decision • Organization • Communication

22. Decision • Choices • Knowledge and beliefs • Objectives • Computation • What are the formalisms?

23. Organization • Who can do the task ? • Who has access to resources ? • Who can communicate ?

24. Communication • Agents communicate • to inform themselves • to distribute the tasks • to resolve the conflicts • to learn • The problem of languages

25. From goals to intentions (commitment) • Blinded : Until the agent believes it has accomplished its intention • Single-minded : As long as it thinks it is possible • Open minded : As soon as it has the goal

26. Some strategies for negotiation • Always concede • Be competitive • Be cooperative : look for a mutually acceptable solution • Inaction • Break

27. From individual to collective with cognitive agents. • Reactive agents often coordinate through the environment • Two approaches for cognitive agents • define mutual beliefs, joint desires and joint intentions • define norms and conventions.