Rea: Workflows for Cyber-Physical Systems

Cyber-Physical Systems (CPSs) are distributed systems composed of computational and physical processes, often containing human actors. In a CPS setting, the computational processes collect information about their physical environment via sensors and react upon them using actuators in order to realize a change in the physical world. In the approach presented in this paper, a CPS application is described as a hierarchical workflow of loosely-coupled tasks whose execution can be constrained with various conditions. We have designed a framework (P epsilon alpha) of a minimal set of combinators implementing features relevant to CPS programming. The details are revealed through an illustrative example defined in our fully functional implementation embedded into an extended version of the Erlang distributed functional programming language.