Coordination operators and their composition under the actor-role-coordinator (ARC) model

Abstract

For large open and distributed real-time applications, coordination constraints among concurrent, spatially distributed and autonomous entities can be complex. The Actor-Role-Coordinator (ARC) model we developed earlier [1] introduced the concept of roles which are abstractions of behaviors that are to be coordinated. Each role's behaviors may be shared by many concurrent entities, or played by many actors . Based on the role concept, coordination activities in large systems are partitioned into inter-role and intra-role coordinations to mitigate the coordination complexity. This paper focuses on coordination primitives and the composition of these primitives in forming more complex intra-role and inter-role coordination constraints. In particular, we define two primitive coordination operators, i.e., precede (≺ t ) and select (⊵ p ), and use them to express temporal and spacial (with respect to actor system's behavioral space) coordination constraints among concurrent and autonomous actors. We further provide an operational semantics for these operators under the ARC model and provide case studies to illustrate their expressiveness in specifying complex coordination constraints.