• Journal of the Korean Society for Precision Engineering
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• v.12 no.10
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• pp.166-174
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• 1995

Flelxible Manufacturing Systems(FMS), which consist of various machine groups, can produce machine parts in different physical dimensions and lot sizes. In this paper, a novel method which utilizes Colored and Timed Petri Net is proposed to model a FMS. Each machine group of FMS is modulized and modeled using expanded Petri Nets. Colored and Timed Petri Nets are defined, and the flexible manufacturing systems's design algorithm based on this definition is developed and verified in a real FMS plant by computer simulations.

• International Journal of Control, Automation, and Systems
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• v.5 no.4
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• pp.463-470
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• 2007

Colored Petri net model which is a model of discrete event systems is considered in this work. A supervisory controller which enforces reversibility and liveness simultaneously is presented. Furthermore, the algorithms, written by pseudo-code, are presented for the supervisory controller design. A program is developed to implement these algorithms.

• Journal of Mechanical Science and Technology
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• v.20 no.10
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• pp.1527-1533
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• 2006

Workflow systems have benefited the enterprise and customer in many aspects. But with the increasing complexity of the system, workflow design becomes a complicated and time-consuming process. In this paper, we model the system based on the Hierarchical Colored Petri Nets (HCPN) to avoid the complexity of the system, and the super nets of the model are abstracted as independent components to increase the flexibility, acceptability and maintainability of the system. Another important characteristic of this model is its convenience for reuse and workflow mining. The development process of the overhead traveling crane was given to demonstrate the proposed method.

• Journal of KIISE:Software and Applications
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• v.27 no.3
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• pp.210-216
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• 2000

Place/Transition(P/T) nets has been used in protocol verification and concurrent system verification since it is suitable for describing concurrency and provides several well-established verification techniques. And it has been used as a base formalism for such high-level Petri nets as colored Petri nets, object-oriented Petri nets and etc. However, when analyzing complex models using P/T nets and P/T nets-based high-level Petri nets, there may be state explosion in reachability analysis due to improper handling of concurrency. In this paper, we define a structural concurrency in P/T nets, propose a partitioning algorithm based on the detected structural concurrency, and provide analysis techniques for such properties as boundedness of places and liveness of transitions, which are performed on compositional reachability graphs. The analysis techniques based on Petri net slices can be used in efficiently analyzing P/T nets-based high-level Petri net models as well as P/T net models.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.05a
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• pp.137-142
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• 2006

상황은 단일 사건에 의해 결정되는 경우도 있지만, 많은 경우 일련의 사건이 특정 시간 제약을 만족하면서 발생할 때 상황이 결정된다. 따라서 상황에 대한 추론은 시간 제약 조건 만족 여부와 함께 사건의 발생을 순서를 확인하는 방법으로 수행될 수 있다. 한편, 어떤 상황은 분명하게 정의되는 것이 아니라 애매한 개념을 사용하여 기술되기 때문에, 퍼지 개념을 이용한 상황 기술과 이에 대한 추론이 필요하다. 한편, 유비쿼터스 환경에서와 같이 여러 대상에 대한 상황을 유추하여 서비스를 제공해야 하는 경우에, 대상 간에 동일한 상황이 발생할 수 있기 때문에 이에 대한 고려가 필요하다. 이러한 상황 추론을 위해서 이 논문에서는 Fuzzy Colored Timed Petri net 모델이라는 상황 추론 모델에 대해서 제안한다. 제안한 모델은 Timed Petri net 성질을 이용하여 일련의 사건 발생을 모델링하고, Colored Petri net의 성질을 이용하여 다수 대상에 대한 상황 추론을 허용하며, fuzzy 토큰 개념을 이용하여 애매한 개념을 사용하여 정의된 상황에 대한 추론을 가능하게 한다.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.1099-1104
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• 1993

The real time control system for FMS(Flexible Manufacturing System) is implemented at this paper. To achieve this goal, the Colored and Timed Petri-Net model is constructed and used to simulate the real time operation of FMS. Using the Colored and Timed Petri-Net model, evaluating any kind of FMS plant is possible. On-line shceduler, intelligent dispatcher, real time monitor and the simulation model of shop floor are contructed using LAN communication, relational database system in this paper. Finally, this real time control system is applied to the FMS/CIM center at Seoul National University.

• Journal of The Korean Association of Information Education
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• v.13 no.1
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• pp.96-104
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• 2009

We want to achieve the reliable information system such as e learning system in the internet environments. The difficulty of the program reliability estimation comes from faults that occurred from program and data files are distributed among several servers. This paper is focus on a modeling approach based on Colored Petri Nets to estimate the program reliability in an internet environment. The procedure of analyzing the reliability is as follows. At first, we propose an internet program model. This model is transformed into a Colored Petri net, and the reliability is estimated. We adapt this model to the analyzing the reliability in the internet environment. This method is very simple, and is very helpful to develope program

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.3
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• pp.291-296
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• 2006

In context-aware computing environment, some context is characterized by a single event, but many other contexts are determined by a sequence of events which happen with some timing constraints. Therefore context inference could be conducted by monitoring the sequence of event occurrence along with checking their conformance with timing constraints. Some context could be described with fuzzy concepts instead of concrete concepts. Multiple entities may interact with a service system in the context-aware environments, and thus the context inference mechanism should be equipped to handle multiple entities in the same situation. This paper proposes a context inference model which is based on the so-called fuzzy colored timed Petri net. The model represents and handles the sequential occurrence of some events along with involving timing constraints, deals with the multiple entities using the colored Petri net model, and employs the concept of fuzzy tokens to manage the fuzzy concepts.

• 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.

• Journal of KIISE:Software and Applications
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• v.36 no.4
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• pp.283-290
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• 2009

Context-awareness is one of the key features of ubiquitous paradigm. A methodology that is specifying the relationships between the contexts and services needs to be developed to intelligently and sensitively deal with dynamic environment. The existing models on context-aware modeling are difficult to verify the correctness of models with respect to timeliness. In this paper we propose an approach which includes timing constraint in the relations of the context model, and verify its effectiveness using colored Petri-Net. Moreover, a context-modeling toolkit including context-awareness engine and simulator is developed to support agent-based context-aware service. The effectiveness of the proposed methodology is demonstrated using an example of Usilvercare.