Object-oriented Petri nets with changeable structure (OPNs-CS): analysis on conflicts and deadlocks

Object-oriented Petri nets with changeable structure (OPNs-CS) is capable of modeling a system with uncertainty and subject to change. Prevention of occurrence of conflicts and deadlock in a system controlled based on an OPNs-CS model is essential to ensure that the system functions. Formal descriptions of three conflicts in OPNs-CS and the algorithms for identifying the changes to conflicts are presented, which is important for automatic OPNs-CS model building and conflict resolution. In addition, there is given an algorithm for deadlock detection that is based on O-graph of the equivalent OPNs-CS (EOPNs-CS) model rather than that of OPNs-CS model. The substitution of EOPNs-CS for OPNs-CS dramatically reduces the size and complexity of O-graph and makes the detection much simplified.