Necessary and sufficient conditions for deadlock in manufacturing systems

Scheduling resources to avoid deadlock in a manufacturing system has been studied extensively over the past decade. Previous work developed sufficient conditions to avoid deadlocked states. What distinguishes the different approaches is the number of nondeadlocked states that are allowed by the application of the method. This is an important consideration since in all the methods these non-deadlocked states are those with high resource allocation. This paper presents both sufficient and necessary conditions to determine deadlocked states in a manufacturing system. Several examples showing the applications of the theory are presented and are compared with other methods