**6. References**


URL: people.mech.kuleuven.ac.be/jwyns/phd/order.html

[33] Wyns, J. (1999) Reference architecture for holonic manufacturing systems-the key to support evolution and reconfiguration, Ph.D. thesis, Katholieke Universiteit Leuven.

> © 2012 Pan, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

© 2012 Pan, licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Petri nets (PN)2 have been recognized as one of the most powerful formal methods for modeling FMS. The reason is that they are well suited to represent such FMS characteristics as precedence relations, concurrence, conflict and synchronization. Their analysis methods used for deadlock prevention in FMS include structural analysis and reachability graphs. Deadlock prevention and avoidance schemes have been developed for controlling FMS3-8 by using the former. In particular, deadlock prevention problems are solved using the concept

**A Computationally Improved Optimal Solution** 

**Manufacturing Systems Using Theory of Regions** 

While competing for a finite number of resources in a flexible manufacturing system (FMS), e.g., robots and machines, each part has a particular operational flow that determines the order in which such resources are needed. However, such competition for shared resources by concurrent job processes can lead to a system deadlock. It occurs when parts are blocked waiting for shared resources held by others that will never be granted. Its related blocking phenomena often incur unnecessary overhead cost, e.g., a long downtime and low utilization rate of some critical and expensive resources, possibly leading to a catastrophic outcome in some highly automated FMS. Therefore, an efficient deadlock control policy must be developed to ensure that deadlocks do not occur. Having received considerable attention in literature, deadlock is normally prevented by using an offline computational mechanism to control the resource requests in order to avert deadlocks. Fanti and Zhou1 introduce three fundamental methods (i.e. prevention, detection and avoidance) to solve the deadlock problems. Deadlock prevention aims to impose system constraints to prevent a deadlock. Importantly, deadlock prevention algorithms do not require run-time costs since the problems are solved in system design and planning stages. This study belongs to the

**for Deadlocked Problems of Flexible** 

Additional information is available at the end of the chapter

Yen-Liang Pan

**1. Introduction** 

http://dx.doi.org/10.5772/50873

deadlock prevention field.
