Guaranteeing temporal validity with a real-time logic of knowledge

In applications where data needs to be shared among distributed components it is desirable to have overall data consistency at all times. This is crucial for safety-critical systems, where inconsistency can lead to failures. Overall continuous data consistency is, however, rarely possible to achieve. For distributed systems, a relaxed view based on the temporal validity of data can be proven sufficient. If components in a distributed computer-based system have different temporal validity constraints for the same data, then as long as these constraints are satisfied overall system inconsistency is not harmful. We propose the use of a formal analysis technique for guaranteeing temporal validity of shared data. The approach is based on a real-time temporal logic of knowledge suitable for verification through model checking. It allows us to check that the shared data in the system is consistent "enough" and cannot be a source of failure. We illustrate the approach with an open dynamic real-time distributed computer-based system.