• Asia pacific journal of information systems
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• v.6 no.1
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• pp.223-240
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• 1996

The paper proposes an approach, called OPNets, for modeling and validating manufacturing systems that is based on object-oriented high-level Petri nets. In OPNets, modeling components of Petri net are constructed into hierarchical objects that communicate with each other by passing messages. To enhance the reusability and maintainability, OPNets organizes a system into hierarchical objects that inherit attributes and behavioral properties from the object of super class and object-interaction relations are separated from the internal structure of object. The modeling scheme of OPNets tries to resolve the complexity problems of Petri net. To illustrate the modeling schemes of OPNets, a storage/retrieval example has been proposed.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.669-672
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• 2000

This paper deals with cryptography by applying RSA and Petri nets. Firstly, we introduce RSA cryptography and a Petri net based private-key cryptography. Then we propose a new public-key cryptography, Petri Net based Public-Key Cryptography dented as PNPKC, by taking the advantages of these two proposed cryptographys and give an example to show how to apply PNPKC. Finally, we do the comparison between RSA cryptography and PNPKC on security as well as computation order. As the results, the security of PNPKC is as strong as RSA cryptography and further the encryption and decryption of PNPKC are in average 210 times as fast as RSA cryptography from our experimental data.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.353-357
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• 1992

This paper constitutes the simulator of the serial production line using Extended Petri Nets. We analyze each operations and effect of machine down, calculating the performance measures for improving the capability of manufacturing system. The performance measures are system efficiency, average utilization of machines, average buffer level, and so on. We intend to present the information of the operation states and various problem occurring in the systems.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.205-205
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• 2000

In this paper, we are proposed an analysis method of the operation schedule in FMS using Time Petri Nets(TPN) unfolding. TPN's unfolding is one of the analysis methods after changed non-cyclic net from the concurrent net without to expand the state explosion. We are illustrated this proposed to analyze a schedule problem in Ratio-driven FMS modeling.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.4
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• pp.174-181
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• 1994

A FMS is a typical discrete event system exhibiting concurrency, asynchronicity and non-determinism. To represent a FMS with those characteristics, Colored and Timed Petri Nets is defined and the modeling procedure is provided in this paper. To analyze and evaluate the performance of a FMS, a simulation software is developed and applied to SNU FMS/CM Center. This software enables to detect the bottleneck machine and decide the optimal direction in case of the expansion of a FMS.

• Nuclear Engineering and Technology
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• v.44 no.8
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• pp.929-938
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• 2012

The Computerized Procedure System (CPS) is one of the primary operating support systems in the digital Main Control Room. The CPS displays procedure on the computer screen in the form of a flow chart, and displays plant operating information along with procedure instructions. It also supports operator decision making by providing a system decision. A procedure flow should be correct and reliable, as an error would lead to operator misjudgment and inadequate control. In this paper we present a modeling for the CPS that enables formal verification based on Petri nets. The proposed State Token Petri Nets (STPN) also support modeling of a procedure flow that has various interruptions by the operator, according to the plant condition. STPN modeling is compared with Coloured Petri net when they are applied to Emergency Operating Computerized Procedure. A converting program for Computerized Procedure (CP) to STPN has been also developed. The formal verification and validation methods of CP with STPN increase the safety of a nuclear power plant and provide digital quality assurance means that are needed when the role and function of the CPS is increasing.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.12
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• pp.84-94
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• 1996

In this work, a fuzzy petri net model for modeling a general form of fuzzy production system which consists of chaining fuzzy production rules and so requires multistage reasoning process is presented. For the obtained fuzzy petri net model, the net will be transformed into some matrices, and also be systematically led to an algebraic form of a state equation. Since it is fond that the approximate reasoning process in fuzzy systems corresponds to the dynamic behavior of the fuzzy petri net, it is further shown that the multistage reasoning process can be carried out by executing the state equation.

• Journal of the Korea Society for Simulation
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• v.14 no.1
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• pp.19-32
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• 2005

In this study, a distributed simulation of Petri net models under HLA/RTI framework is considered. Throughout our modeling experiences, it is recognized that the proper use of interface specification and time management services are important in order to achieve successful implementation of RTI. The interfacing tokens between Petri net models are distinguished as information entity and physical entity. Both entities are modeled as InteractionClass in order to send and receive messages. For the synchronization of local simulation clocks, a conservative method with NERA service is considered. A cell manufacturing system is modeled and implemented with RTI to illustrate the distributed simulation of Petri net models.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.5
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• pp.9-18
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• 1997

The petri net is a graphic model which is adaptable in modeling a complex concurrent parallel ssystem, and it is widely used in the fields of industrial enginering, computer science, electric engineeringand chemistry. Recently, the net is applied to the communication protocol, and extended to represent complex systems. There are several extended petri nets named as TPN (timed petri net), SPN (stochastic petri net), FPN(fuzzy petri net) and TFPN(timed fuzzy petri net). Accodingly, this SPN (stochastic petri net), FPN (fuzzy petri net) and TFPN(timed fuzzy petri net). Accodingly, this paper proposes an advanced communication protocol modeling method using the fuzzy value of the transition and firing delay time as the arguments of the function. The proposed method can produce clearer firing rules, and it is supposed to be used to design and analyse communication protocols in great effection.

• Journal of Korea Multimedia Society
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• v.5 no.6
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• pp.704-711
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• 2002

Multimedia communication systems are characterized by supporting three different typer of services such as circuit switched services, and packet switched real Lime and non real time services. The wireless channels in a cell ate allocated by calls of these different service classes and the different service requirements have to be met. SRN is an extension of stochastic Petri nets and provides compact Modeling facilities for system analysis. To get the performance index, appropriate reward rates are assigned to its SRN. In this paper, we present a SRN model for performance analysis of channel allocation of multimedia mobile communication systems. The key contribution of this paper constitutes the Petri nets modeling techniques instead of complicate numerical analysis of Markov chains and easy way of performance analysis for channel allocations under SRN rewards concepts.