Deadlock Prevention Policy In Shipping Traffic System Based On Petri Net

As a typical discrete event system with parallel and conflict, determining how to assign the sea-routes logically and avoid the jams of the sea-routes is one of the main objectives of the management of the shipping traffic. As a perfect modeling tool, Petri nets are an effective way to model, analyze shipping traffic systems.Deadlock prevention policy focuses on controlling every emptied siphon in the original net system such that no siphons can be emptied. However, the number of siphons grows in general exponentially with respect to the size of the Petri net, resulting in that the final net system is much more structurally complicated. Using the elementary siphon theory, the structure of the net system will be much simpler.In this thesis, Petri nets are used to model, analyze the deadlock problems, which are prevented by adding control places. Based on elementary siphon theory, the deadlock prevention method can solve the deadlock problems in shipping traffic systems theoretically. Then a deadlock-free shipping traffic system can be obtained.