User:Mmehrabian/sandbox

The orchestration of physical and cyber components in CyberPhysical Systems (CPS) poses new challenges that make the system behavior complex to characterize and hard to verify. In order to guarantee the reliability, verify the performance, and approve correctness, temporal constraints on the system behavior must be met. This work organizes and classifies the timing constraints that are observed in CPS. We find that there are two main kinds of timing constraints, ones based on signal values, e.g., a signal s should be more a particular value for 5 seconds, and ones based on signal events, e.g., 3 milliseconds after a signal s1 rises, signal s2 should also rise. Signal Temporal Logic (STL) has been used to expresses value-based timing constraints, but cannot express event-based timing constraints. Timestamp Temporal Logic (TTL) supports the specification of temporal requirements in CPS in both event-based and signal value-based constraints while simplifying constraint monitoring of distributed, heterogeneous systems based on a global reference time. Additionally, a systematic methodology is presented based on TTL to enable the testing of temporal constraints in CPS applications using commercially available platforms.