Weighted Petri nets are common tools for modeling and validating discrete event systems involving resource allocation, such as flexible manufacturing systems (FMSs). A subclass of weighted Petri nets called a system of sequential systems with shared resources (S4R) has the power for modeling complex FMSs where the execution of an operation may require multiple resource types and multiple units of some resource types. Deadlock resolution is a crucial issue for the operation of an FMS. A direct and efficient policy is developed in this paper for detecting deadlock markings by extracting a weighted resource flow graph (WRFG) from an S4R and recovering them by synthesizing a recovery-transition...