Simulation Using Orchestration

The real world is inherently concurrent and temporal. For simulating physical phenomena of the real world, one prefers frameworks which easily express concurrency and account for the passage of time. We propose Orc, a structured concurrent calculus, as a framework for writing simulations. Orc provides constructs to orchestrate the concurrent invocation of services while managing time-outs, priorities, and failures of services or communication. Orc's treatment of time is of particular interest in simulation. We propose an abstract notion of time and show its utility in coding simulations. We also show how Orc's structure allows us to compute statistics from a simulation.