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Over the last two decades, a great deal of research has been focused on solving deadlock problems in resource allocation systems such as computer communication systems, workflow systems, and flexible manufacturing systems, resulting in a wide variety of approaches. As a well-defined problem in resource allocation systems, deadlock prevention based on a(More)
This paper addresses the deadlock problems in flexible manufacturing systems (FMS) by using a Petri net siphon control method and the theory of regions. The proposed policy consists of two stages. The first one, called siphons control, is to add, for every siphon that we identify, a monitor to the original net model such that it is optimally invariant(More)
This paper develops a two-stage approach to synthesizing liveness-enforcing supervisors for flexible manufacturing systems (FMS) that can be modeled by a class of Petri nets. First, we find siphons that need to be controlled using a mixed integer programming (MIP) method. This way avoids complete siphon enumeration that is more time-consuming for a sizable(More)
Deadlock prevention plays an important role in the modeling and control of flexible manufacturing systems (FMS). This paper presents a novel and computationally efficient method to design optimal control places, and an iteration approach that only computes the reachability graph of a plant Petri net model once in order to obtain a maximally permissive(More)
Transgene copy number is usually determined by means of Southern blot analysis which can be time consuming and laborious. In this study, quantitative real-time PCR was developed to determine transgene copy number in transgenic wheat. A conserved wheat housekeeping gene,puroindoline-b, was used as an internal control to calculate transgene copy number.(More)