• Journal of the Korea Society for Simulation
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• v.15 no.1
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• pp.1-10
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• 2006

The Flexible Management System (FMS) consists of parallel and concurrent machines, pieces of equipment, and carrying systems classified as buffers, tools, and routers, respectively. The concurrent flow of multiple productions in a system is competed with one another for resources and this resulting competition can cause a deadlock in FMS. Since a deadlock is a condition in which the excessive demand for the resources being used by others causes activities to stop, it is very important to detect and prevent a deadlock. Herein a new algorithm has been studied in order to detect and prevent deadlocks, after defining a relationship between the general places and resource share places in Petri nets like as DAPN: Deadlock Avoidance Petri Net. For presenting the results, the suggested algorithms were also adapted to the models that demonstrated FMS features.

• Journal of the Korea Society for Simulation
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• v.18 no.1
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• pp.9-16
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• 2009

Since a deadlock is a condition in which the excessive demand for the resources being used by others causes activities to stop, it is very important to detect and prevent a deadlock. About the deadlock detection analysis methods are may divide like as Siphon, DAPN and transitive matrix, but it's very difficult to evaluate the performance. Since DES (Discrete Event Systems) is NP-hard, and these detection and avoidance methods used various factors in each technique, it's made difficult to compare with each other's. In this paper, we are benchmarked these deadlock detection analyze methods based on the complexity, the detection time and the understanding after approached to one example.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.751-754
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• 2007

본 연구에서는 유연생산시스템에서의 교착상태 확인 및 회피 알고리즘을 추이적 행렬을 이용하여 제안한다. 추이적행렬은 플레이스와 플레이스간의 관계를 표현함으로 마킹의 흐름을 플레이스와 트랜지션간의 관계형에서 상태와 상태간의 관계를 표현함으로 상태의 변화 검증에 편리하다. 교착상태 확인 및 회피 알고리즘을 제시하고, 기존에 발표되어진 siphon과 DAPN알고리즘간의 비료 검토를 통하여 제안한 알고리즘의 유용성을 검증하였다.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.3
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• pp.213-220
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• 2008

The object of this paper is to propose a method to deal with the problem of modeling user specifications in approaches based on supervisory control and Petri nets. However, most of Petri Net approaches are based on forbidden states specifications, and these specifications are suitable the use of tool such as the reachability graph. But these methods were not able to show the user specification easily and these formalisms are generally limited by the combinatorial explosion that occurs when attempting to model complex systems. Herein, we propose a new efficient method using FSSTP (Forbidden Sequences of State-Transitions Problem) and theory of region. Also, to detect and avoid the deadlock problem in control process, we use DAPN method (Deadlock Avoidance Petri nets) for solving this problem in control model.