Complex Reactive Real Time Systems and the Safety Case

Stone, G.R.

Complex reactive real time systems are systems of systems that interact with the external world to perform selections of tasks in real time. They may be required to carry out selected tasks when some components of the system cannot be considered acceptably safe. They may be required to operate continuously. The requirements of a safety case for such systems can be considered by use of a 'response to tasking model' based on a representative system. Consideration of the response to tasking model indicates that what we are used to considering as a safety case for more straightforward systems may be inadequate for such systems. The application of safety cases to existing complex reactive real time systems may benefit from review. As semi-autonomous and autonomous systems become more prevalent, there will be more urgency for safety cases to take account of a sophisticated, automated decisionmaking process that is flexible, responsive to changing circumstances and intelligent. This may require reevaluation of the format, content and presentation of safety cases. A navy warship is used as an example complex reactive real time system to illustrate the issues in demonstrating achievement of acceptable safety. .

Cite as: Stone, G.R. (2004). Complex Reactive Real Time Systems and the Safety Case. In Proc. Ninth Australian Workshop on Safety-Related Programmable Systems (SCS 2004), Brisbane, Australia. CRPIT, 47. Cant, T., Ed. ACS. 23-32.

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