Cross-criticality Interfaces for Cyber-physical Systems

Cyber-physical systems (CPS) are typically sys- tems with services of mixed criticality. For different criticali- ties of systems, different progress models and communication types have been developed, depending whether the focus has to be on predictability or resource efficiency. In this paper we present a generic component and communication model for CPS that not only allows the co-existence of computing paradigms of different criticality, but also supports the data exchange between them. Besides the classic trigger mechanisms based on time, i.e., time- triggered, or arrival of messages, i.e., event-triggered, we also introduce a rate-bounded variant of the event-triggered activation. Further, the communication channels are labelled of whether they use event messages or state messages. Based on the trigger model and the message semantics we can derive the appropriate interface types of communication channels between CPS subsystems of different criticality.