A Model for the Structural, Functional, and Deontic Specification of Organizations in Multiagent Systems (the Moise + model)

Transcription

1 A Model for the Structural, Functional, and Deontic Specification of Organizations in Multiagent Systems (the Moise + model) Jomi Fred Hübner, Jaime Simão Sichman, and Olivier Boissier USP/LTI & ENSM.SE/SMA SBIA'2002, Porto de Galinhas, Brazil

2 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

3 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

4 Organizational points of view ant colony agents unable to represent their organization agent centered observer key: organizational description built by observation Introduction Organizational points of view 4

5 Organizational points of view ant colony agents unable to represent their organization agents able to represent their organization social reasoning agent centered observer key: organizational description built by observation observer Introduction Organizational points of view 5

6 Organizational points of view ant colony agents unable to represent their organization agents able to represent their organization social reasoning agent centered observer DPS key: organizational description built by observation observer organization centered observer organizational specification key: organizational specification obtained by copy key: behavioral constraint Introduction Organizational points of view 6

7 Organizational points of view ant colony agents unable to represent their organization agents able to represent their organization social reasoning agent centered observer DPS key: organizational description built by observation MOISE/AGR observer (our interest) organization centered observer organizational specification key: organizational specification obtained by copy key: behavioral constraint organizational specification observer Introduction Organizational points of view 7

8 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

9 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

10 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

11 General view of the Moise + model environment global purpose E P S organizational structure F agents behavior space organizational functioning Moise+ groups, links, roles compatibilities, cardinalities permissions obligations global goals, plans, missions, schemes, preferences MOISE + General view of the MOISE + model 11

12 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) MOISE + Structural dimension 12

13 soc Organizational Entity (structure 3-5-2) player coach 1..2 Marcos Lucio Edmilson goalkeeper back back goalkeeper 1..1 leader middle defense attacker 2..2 attack 1..1 team Roque Jr. Cafu Gilberto Silva Juninho Ronaldinho Roberto Carlos Ronaldo Rivaldo leader middle attacker Key Structure inheritance: min..max composition: sub-groups scope: role group Abs Role links acq com aut compat intra-group inter-group MOISE + Structural dimension 13

14 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 MOISE + Functional dimension 14

15 score a goal m1, m2, m3 m1 m1 get the ball go towards the opponent field m2 m3 be placed in the middle field be placed in the opponent goal area Key shot at the opponent s goal kick the ball to the goal area go to the opponent back line m2 m3 m2 kick the ball to (agent committed to m2) Organizational Entity m1 Scheme Lucio m1 goal missions success rate sequence choice parallelism Cafu Rivaldo m2 m3 MOISE + Functional dimension 15

16 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 m 1 Any middle obl m 2 Any attacker obl m 3 Any MOISE + Deontic dimension 16

17 Conclusions The Moise + model allows us to specify a MAS 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 Moise + model to specify the three dimensions of a MAS organization in a soccer domain and a B2B (business to business) domain An implementation is available at MOISE + Conclusions 17

18 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. MOISE + Future work 18

19 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 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 , Berlin. Springer. [Tambe, 1997] Tambe, M. (1997). Towards flexible teamwork. Journal of Artificial Intelligence Reseearch, 7: MOISE + References 19

20 Organizational Specification and Entity groups group instances structural grtype roles role player agrole deontic agents functional schemas missions schema instances agmis sctype mission player organizational organizational entity specification purpose MOISE + Organizational Specification and Entity 20