A COLOURED PETRI NET APPROACH FOR THE MANAGEMENT OF OPERATING MODES IN DISCRETE EVENT SYSTEMS

This paper addresses the problem of operating mode management in Discrete Event Systems, which is studied within the general framework of dependable systems for which robustness is a key requirement. Specification of system behaviour is ensured through the use of Coloured Petri nets (CP nets) on the basis of a multi-model design. Particular transitions are specified as switching events that allow the system to switch to a different operating mode, when exceptional events occur, such a failure, loss of a resource, or failed resource recovery. The adopted methodology considers the aspects of mode activation/deactivation, starting state and handling of resource states common to multiple operating modes. An algorithm is provided to generate a global CP net permitting easy implementation of existing methods and tools.