1. Welfare Engineering in PracticeESAW 2004 Welfare Engineering in Practice: On the Variety of Multiagent Resource Allocation Problems Yann Chevaleyre 1, Ulle Endriss 2, Sylvia Estivie 1 and Nicolas Maudet 1 (1)LAMSADE, Univ. Paris IX-Dauphine (2)Dept. of Computing, Imperial College London

2. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet2 Introduction Recurring problems like E-auctions, patrol … –Similarities between these problems ? Not exploited yet… –Formalize this similarities for a category of problem : Resource allocation problem Why??? –A lot of theoretical result for resource allocation –Possibility to develop a platform

3. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet3 Talk Overview Welfare Engineering Designer scope Resource Allocation Framework Example Applications Criteria Conclusion

4. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet4 Welfare Engineering Social welfare ordering (quality of the solution) Social interaction mechanism (to arrive at a solution) Behaviour profiles (interaction mechanism) How we can make agents negotiate socially optimal outcomes? Socially optimal allocation of resources

5. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet5 Talk Overview Welfare Engineering Designer scope Resource Allocation Framework Example Applications Criteria Conclusion

6. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet6 The Problem of the Designer Scope [Wurman et al 02] Agent scope Mechanism scope System scope Proprietor role End-user role Agent Which agent does designer control?

7. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet7 Talk Overview Welfare Engineering Designer scope Resource Allocation Framework Example Applications Criteria Conclusion

8. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet8 Finite set of agents A and finite set of discrete resources R An allocation A is a partitioning of R amongst the agents in A Every agent i A has a utility function u i (A) Resource Allocation by Negotiation R A A u 1 (A) u 2 (A) u 3 (A) u 4 (A) 1 2 3 4

9. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet9 Social Welfare Social welfare is tied to the welfare of a society’s weakest member Envy-freeness social welfare Egalitarian social welfare Utilitarian social welfare Anything that increases average utility is taken to be socially beneficial Majoring the well being of a society There is zero probability of having an agent envying somebody else Research issue : the impact of individual utility on social welfare

10. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet10 Our framework (1/2) Monetary payments –Deal couple with monetary side payment –Payment function Limited money Approximating flows –Representation of continuous resources (water, energy, …)

11. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet11 Our framework (2/2) Roles –Sellers –Buyers –… Protocol restrictions –Restrictions on the negotiation protocol

12. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet12 Talk Overview Welfare Engineering Designer scope Resource Allocation Framework Example Applications Criteria Conclusion

13. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet13 Examples of Applications (1/3) Multiagent Patrolling (1/2) –The multiagent patrolling problem: how should agents move around an area such that every part of the area is visited the most often ? –Goal : find strategies which minimize the time between 2 visit on each node ??

14. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet14 Examples of Applications (1/3) Multiagent Patrolling (2/2) –Multiagent patrolling applies to: Multi-robot applications (intrusion detection, cleaning team of robots, delivery) Video-games (in warcraft-like games, doom-like, …) Military application (surveillance, tracking intruders) Internet applications –Resources : each node –Utility of each agent : how well it patrols over the node it owns –Resource allocation : agent can exchange nodes in order to maximize his patrolling performance

15. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet15 Examples of Applications (2/3) Allocation of satellite resources [Lemaitre et al 03] Agents send observation request Resources initially held by the virtual proprietor

16. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet16 Examples of Applications (3/3) E-Auctions –Different kinds of e-auction B2C (Business to Consumer) : antique dealer C2C (Consumer to Consumer) : eBay like B2B (Business to Business) : FCC, fairmarket… –Similarities and differences : but all could be represented with a model of resource allocation. –Roles : sellers and buyers

17. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet17 Talk Overview Welfare Engineering Designer scope Resource Allocation Framework Example Applications Criteria Conclusion

18. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet18 Criteria for a Social Welfare Selection (1/2) Proprietor gain –Utility-dependent Example : tax on gain Example of application uses it : Multiagent Patrolling –Transaction-dependent Example : tax on each transaction Example of application uses it : e-auctions –Membership-dependent Example : Entrance fees Example of application uses it : Satellite allocation, e-auctions

19. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet19 Criteria for a Social Welfare Selection (2/2) Application dynamics Between a run Possibility for an application to run several times –Yes : Satellite application, C2C e-auctions –No : FCC e-auctions If yes, whether and how the characteristics could be modified between runs? –C2C e-auctions : users may be different

20. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet20 Conclusion Multiagent resource allocation : A powerful paradigm The first idea of social welfare choice in not necessarily the better. [Guttman, Maes 99] Toward a test platform

21. Welfare Engineering in PracticeESAW 2004 Y. Chevaleyre, U. Endriss, S. Estivie, N. Maudet21 References  [Guttman, Maes 99] R.H. Guttman and P. Maes. Agent Mediated integrative negotiation for retail electronic commerce. In Agent Mediated Electronic Commerce, 1999.  [Lemaitre et al 03] M. Lemaitre, G. Verfaillie, H. Fargier, J. Lang, N. Bataille and J.M. Lachiver. Equitable allocation of earth observing satellites resources. In Proc of the 5th ONERA-DLR Aerospace Symposium (ODAS’03), 2003.  [Wurman et al 02] P.R. Wurman, M.P. Wellman, and W.E. Walsh. Specifing rules for electronic auctions. AI Magazine, 23(3):15-23, 2002.