A Model for the Structural, Functional, and Deontic Specification of Organizations in Multiagent Systems (the oise+ model) M Jomi Fred Hübner, Jaime Simão Sichman, and Olivier Boissier USP/LTI & ENSM.SE/SMA SBIA'2002, Porto de Galinhas, Brazil Context A MAS has two properties which seems controversial: • ? a global purpose ? autonomous agents While the autonomy of the agents is essential for the MAS, it may also cause the looseness of the global congruence/coherence. The organization of a MAS is used solve this conflict • constraining the agents behavior towards its global purpose. Example: when an agent adopts a role, it indeed adopts a • set of behavioral constraints that collaborates for the global purpose. Introduction — Context 2 Problem The MAS organization may become inefficient in case the • environment changes. Reorganization is mandatory. • However, before tackling this problem, it is necessary to • precisely define what is an organization. Introduction — Problem 3 Organizational points of view agents unable to represent their organization ant colony agent centered observer key: organizational description built by observation Introduction — Organizational points of view 4 Organizational points of view agents unable to represent agents able to represent their organization their organization ant colony social reasoning agent centered observer key: organizational description built by observation observer Introduction — Organizational points of view 5 Organizational points of view agents unable to represent agents able to represent their organization their organization ant colony social reasoning agent centered observer key: organizational description built by observation observer DPS organization centered observer organizational specification key: organizational specification obtained by copy key: behavioral constraint Introduction — Organizational points of view 6 Organizational points of view agents unable to represent agents able to represent their organization their organization ant colony social reasoning agent centered observer key: organizational description built by observation observer DPS MOISE/AGR (our interest) organization centered observer organizational specification observer key: organizational specification obtained by copy organizational key: behavioral constraint specification Introduction — Organizational points of view 7 How to describe/specify an organization? In the case of an organizational centered point of view, there are three dimensions to describe an organization: by its structure (roles and groups, e.g. AGR • [Ferber and Gutknecht, 1998]), by its functioning (global plans and tasks, e.g. TÆMS • [Decker and Lesser, 1994], STEAM [Tambe, 1997]), or by deontic relations (agents' obligations, norms, . ) • Addressing these three dimensions is a prolific approach when one wants to design or describe a MAS organization. The problem is to define these aspects in such a way that they can be both assembled in a single coherent specification. Introduction — How to describe/specify an organization? 8 The MOISE model A first attempt to join roles with plans is the MOISE (Model of Organization for multI-agent SystEms) [Hannoun et al., 2000]. The MOISE is structured along three levels: i) the behaviors that an agent is responsible for when it adopts a role (individual level), ii) the interconnections between roles (social level), and iii) the aggregation of roles in large structures (collective level). MOISE main shortcomings (concerning reorganization) are the lack of the concept of an explicit global plan and • the strong dependence among the structure and the • functioning. Introduction — The MOISE model 9 Objective A model that assembles the three dimensions in a • coherent MAS organizational description suitable for the reorganization process (independence among dimensions) Introduction — Objective 10 General view of the oise+ model M environment global purpose E P S organizational F organizational structure functioning agents' behavior space groups, links, roles permissions global goals, plans, compatibilities, cardinalities obligations missions, schemes, preferences Moise+ OISE+ — General view of the OISE+ model 11 M M Structural dimension Individual level • ? organizational roles and ? role inheritance Social level • ? role links (authority, communication, . ) ? representing the social role's relational aspect Collective level • ? groups and sub-groups ? well-formation rules (roles' cardinalities and compatibilities) OISE+ — Structural dimension 12 M Organizational Entity soc (structure 3-5-2) Marcos goalkeeper coach player Lucio 1..2 Edmilson back Roque Jr. middle back Cafu leader 5..5 3..3 attacker Gilberto Silva middle leader 2..2 goalkeeper 0..1 Juninho 0..1 1..1 1..1 Ronaldinho attack Roberto Carlos 1..1 Ronaldo attacker defense 1..1 team Rivaldo 1..1 Structure links intra-group inter-group inheritance: min..max acq Key composition: com sub-groups scope: role aut group Abs Role compat OISE+ — Structural dimension 13 M Functional dimension Describes how the global goals are decomposed by plans and distributed to the agents by missions Collective level • ? schemes: represents a global plan decomposition Individual level • ? missions: a set of scheme's global goals that an agent may be committed to OISE+ — Functional dimension 14 M m1, m2, m3 score a goal m1 m3 get the ball shot at the opponent's goal m1 m2 go towards the opponent field kick the ball to the goal area m2 m2 be placed in the middle field go to the opponent back line m1 m3 kick the ball to (agent committed to m2) be placed in the opponent goal area Key Organizational Entity Scheme Lucio m1 missions goal Cafu m2 success rate sequence choice parallelism Rivaldo m3 OISE+ — Functional dimension 15 M Deontic dimension This dimension relates the structure and the functioning dimensions describing the permissions and obligations from roles to missions • representing the social role's normative aspect • role deontic relation mission time constraint back per m1 Any middle obl m2 Any attacker obl m3 Any OISE+ — Deontic dimension 16 M Conclusions The oise+ model allows us to specify a MAS • M organization along the structural, functional, and deontic dimension, which are usually expressed separately in MAS organization models. The main contribution of this model for the reorganization • process is the independence design of each one of these dimensions. We have used the oise+ model to specify the three • M dimensions of a MAS organization in ? a soccer domain and ? a B2B (business to business) domain An implementation is available at • http://www.lti.pcs.usp.br/moise OISE+ — Conclusions 17 M Future work grant to the MAS a kind of autonomy regarding its • organization: reorganization. The agents must obey their organization, but they can change it. OISE+ — Future work 18 M References [Decker and Lesser, 1994] Decker, K. and Lesser, V. (1994). Task environment centered design of organizations. In Proceedings of the AAAI Spring Symposium on Computational Organization Design. [Ferber and Gutknecht, 1998] Ferber, J. and Gutknecht, O. (1998). A meta-model for the analysis and design of organizations in multi-agents systems. In Demazeau, Y., editor, Proceedings of the 3rd International Conference on Multi-Agent Systems (ICMAS’98), pages 128–135. IEEE Press. [Hannoun et al., 2000] Hannoun, M., Boissier, O., Sichman, J. S., and Sayettat, C. (2000). Moise: An organizational model for multi-agent systems. In Monard, M. C. and Sichman, J. S., editors, Proceedings of the International Joint Conference, 7th Ibero-American Conference on AI, 15th Brazilian Symposium on AI (IBERAMIA/SBIA’2000), Atibaia, SP, Brazil, November 2000, LNAI 1952, pages 152–161, Berlin. Springer. [Tambe, 1997] Tambe, M. (1997). Towards flexible teamwork. Journal of Artificial Intelligence Reseearch, 7:8–124. OISE+ — References 19 M Organizational Specification and Entity structural functional groups deontic schemas roles missions specification organizational grType scType group schema instances instances role mission player player agRole agMis entity organizational agents purpose OISE+ — Organizational Specification and Entity 20 M.