• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.441-444
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• 1988

This paper presents a methodology for developing the graphic simulator for a robotic workcell. The Petri Net model is applied to described the system state and the workcell simulation is performed by the event scheduling approach of the model. For the graphic display of simulation process, the information of the workcell resources are stored in hierachically-structured data_babe, and the geometry of the resources is described by robot modelling, component modelling, and world modelling.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.4
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• pp.414-427
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• 1990

This paper presents the development of the graphic simulator for an assembly workcell. The assembly workcell consists of two PUMA 560 manipulators, a conveyor belt system, a work table, and a vision sensor. In this study, the Petri Net theory is applied to model the assembly workcell and to construct the simulator. The event scheduling approach is used to simulate the cell. In order to show the graphic display of the simulation process, robot modelling, component modelling, and world modelling are included. The developed simulator is used to display the transition of the system state during the simulation. It is also used as a tool in selection the best resource states by studying the performance of the system as the resource states are changed.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05b
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• pp.815-818
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• 2003

EMFG는 동시성과 병렬성의 표현이 뛰어난 그래프 이론으로서 마크의 변화를 통해 모델링된 시스템의 동작을 확인할 수 있으나, 박스의 마크 변화를 시각적으로 관측하기가 어렵다. 따라서 본 연구에서는 EMFG 구성을 관리하게 하고, 마크 변화를 시각적으로 쉽게 관측할 수 있을 뿐 아니라 EMFG의 동작도 시뮬레이션 할 수 있는 EMFG 시뮬레이터를 설계하고 구현한다. 그리고 EMFG 시뮬레이터와 기존의 Petri Net 시뮬레이터를 비교한다.

• Proceedings of the Korea Society for Simulation Conference
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• 2002.05a
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• pp.169-173
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• 2002

반도체 공정은 복잡하고 다양한 물리, 화학작용을 수반하며, 폭넓은 데이터 발생 및 관리에도 불구하고 공정진행시 내부 특성의 복잡함 때문에 효율적인 모델링이 어려웠다. 또한 원하는 출력을 얻기 위한 제어입력의 선정도 용이하지 않으므로 현재의 최적공정운영은 전문가의 경험에 의존하여 많은 시행 착오를 거쳐 수행되고 있다. 본 논문에서는 반도체 공정의 최적운영을 위해 다음 세 단계로 나누어 연구를 수행하였다. 첫째, 반도체 공정을 설비를 기반으로 컬러드 페트리 넷을 이용하여 모델링하고 둘째, Run-to-Run control에 기반한 최적공정운영 관리모델을 실험하고 셋째, 지식기반 데이터베이스를 기반으로 하는 지능적인 적응형 공정관리모델(Adaptive Process Control model)의 프레임 웍을 제안한다.

• Journal of the Korea Society for Simulation
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• v.4 no.1
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• pp.13-24
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• 1995

In general, simulation and analytic method are used for real system analysis. However, or date, there has been only the theoretical works on each approach. Therefore it is required that we study on the relationship between each approaches to obtain more reliable and correct system analysis results. In this paper, using SPN(Stochasitc Petri Net) formalism, we propose the method of output prediction of the DEVS(Discrete Event system Specification) simulation. For this we suggest a transformation algorithm which transform SPN form DEVS formalism based on the event scheduling world view and a verification algorithm for it. We then show an example to apply it to the real system, such that the Grocery Store System.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.10
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• pp.48-60
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• 1996

This paper focuses on the necessities of interworking and dervation of the requirements of interworking system for interworking between 64 Kbps based N-ISDN (narrowband ISDN) and B-ISDN(broadband ISDN). Furthermore, the design and the implementation of IWF (interworking function) are presentd. We analyze two ISDN signalling systems, and propose the architecture of interworking system. And then we make the baisc call procedure model between N-ISDN and B-ISDN, and verify the dynamic behaviors through the reachability tree of petri net. IWF is designed and implemented for transforming the differences between the two signalling systems. The operational confirmity of th eimplemented program was confirmed by the local test method. The performance of IWF was evaluated throguh the simulation language SLAM-II. As the result of evaluation shows, we confirm that the processing delay is maintained within 3 ms under the utilization 0.9.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.13-16
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• 1999

The terrestrial/satellite hybrid network may replace or supply the terrestrial network in some areas or certain application. Futhermore, it can play an important role in the development of B-ISDN due to their features of flexible wide coverage, independent of ground distances and geographical constraints, multiple access and multipoint broadcast. Also, satellite have the capability to supply terrestrial ATM and B-ISDN with flexible links for access networks as well as trunk networks. This paper describes the design and verification of the interworking protocol between terrestrial B-ISDN and satellite network. For the verification, the designed interworking protocol is modeled by Petri-net and analyzed by reachability tree.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.6
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• pp.811-821
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• 1998

A new scheduling algorithm for large scale semiconductor processes is addressed. The difficulties of scheduling for semiconductor fabrication processes are mainly due from repeating production of wafers that experience reentrant flows. Sequence branch algorithm (SBA) is proposed for large real scheduling problems when all processing times are deterministic. The SBA is based on the reachability graph of Petri net of which the several defects such as memory consumption and system deadlock are complemented. Though the SBA shows the solution deviating a little from the optimal solution of mixed integer programming, it is adjustable for large size scheduling problems. Especially, it shows a potential that is capable of handling commercial size problems that are intractable with mathematical programming.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.1
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• pp.87-95
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• 2004

We proposed the division algorithm that was aimed at dividing system models. It used a transitive matrix to express the relation between place and transition. And the division algorithm was applied to the scheduling problem, with the division-scheduling algorithm. The division-scheduling algorithm was able to calculate the divided subnet table. And it is able to reduce the analysis complexity. In this study, we applied the proposed division algorithm and division-scheduling algorithm to flexible manufacturing system models. We compared the efficiency and performance of the division-scheduling algorithm with the Hillion algorithm, Korbaa algorithm, and Unfolding algorithm proposed in previous researches.

• Asia pacific journal of information systems
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• v.14 no.4
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• pp.49-70
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• 2004

Multi-agent technology is being regarded as one of the promising technologies for today's supply chain management because of its desirable features such as autonomy, intelligence, and collaboration. This paper suggests a multi-agent system architecture with which companies can improve the efficiency of their supply chains by collaborative operation. Reflecting the practical difficulties of collaboration in complex supply chains, the architecture allows agent systems to share information with only neighboring companies for the coordinated operation. The suggested architecture is elaborated with a collaboration model based on Petri-net, conversation models for communication, and internal behavior models of each agent. A simulation experiment was performed for the evaluation of the suggested architecture. The result implies that when the estimation of market demand is higher than a certain level, the suggested architecture can be beneficial.