Intra-Role Coordination Using Group Communication: A Preliminary Report

We propose group communication for agent coordination within "active rooms" and other pervasive computing scenarios featuring strict real-time requirements, inherently unreliable communication, and a large but continuously changing set of context-aware autonomous systems. Messages are exchanged over "multicast channels", which may remind of chat rooms in which everybody hears everything being said. The issues that have to be faced (e.g., changing users' preferences and locations; performance constraints; redundancies of sensors and actuators; agents on mobile devices continuously joining and leaving) require the ability of dynamically selecting the "best" agents for providing a service in a given context. Our approach is based on the idea of "implicit organization", which refers to the set of all agents willing to play a given role on a given channel. An implicit organization is a special form of team with no explicit formation phase and a single role involved. No middle agent is required. A set of protocols, designed for unreliable group communication, are used to negotiate a coordination policy, and for team coordination. Preconditions and effects of these protocols are formalized by means of the joint intention theory (JIT)