A denotational semantics for RTPA

Real-time process algebra (RTPA) is designed to deal with a rich set of fundamental real-time processes such as timing, interrupt, concurrency, and event/time-driven. Some of the RTPA processes cannot be described adequately in conventional denotational semantics paradigms. This paper develops a new framework for modeling time and processes in order to represent RTPA in denotational semantics. Within this framework, time is modeled by elapse of process execution. The process environment encompasses states of all variables, represented as mathematical maps, which project variables to their corresponding values. Duration is introduced as a pair of time interval and the environment to represent the process environment change during a time interval. Temporal ordered durations and operations on them are used to denote process executions. With all these means, the semantics of RTPA processes of timing, interrupt, concurrency, event/time-driven, and traditional sequential processes can be formally expressed.