• Title, Summary, Keyword: timed place petri nets

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Initial requirements to the optimal performance of systems modeled by timed place Petri nets using the synchronic time ratio (Synchronic time ratio를 이용 시간 페트리 네트로 모델링된 시스템의 최적 성능에 필요한 초기 조건 결정)

  • Go, In-Seon;Choi, Juang-Hwan
    • Journal of Institute of Control, Robotics and Systems
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    • v.3 no.1
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    • pp.101-108
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    • 1997
  • The initial token value required to the optimal performance of discrete event systems can be decided by Sum of Delay Time and Synchronic Time ratio, which are new synchronic variables in Timed Place Petri Nets. For the system consisting of two Live-and-Bounded circuits(LB-circuits) fused in common Transition-Transition-Path or common Place-Place-Path, we prove that the Synchronic Time Ratio is the initial token ratio between two LB-circuits to optimally perform system functions. These results are generalized and formulated as a theorem. The initial tokens of a specific place can imply shared resources. Using the theorem, we can decide the minimum number of the shared resources to obtain the optimal performance, and minimize the idling time of resources. As an example, an automated assembly system is modeled by Timed Place Petri Net, and the initial tokens to achieve the optimal system performance are identified. All the values are verified by simulation.

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Performance evaluations of discrete event system using Petri Nets (페트리 네트를 이용한 이산 사건 시스템의 성능 분석)

  • 최정환;고인선
    • 제어로봇시스템학회:학술대회논문집
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    • pp.1241-1244
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    • 1996
  • This paper present a performance evaluation method for Timed Place Petri Nets modeled by Live-and-Bounded Circuits (LB-circuits) through a bottom-up approach. The method can handle the case for the nets having common resources(CR). The target system is divided into the sub-systems by disconnecting the common Transition-Transition-Path(TTP) or Place-Place-Path (PPP) between sub-systems. The common PPP pattern is classified into Parallel Common Resource (PCR) and Sequential Common Resource (SCR) in detail for handling common resources. We evaluate the performance of each divided sub-system, and calculate the sub-systems affect on the performance of the whole system. The facts are generalized as a theorem. The developed theorem are applied into the performance evaluation of an automated assembly system shown in an example. All the results are verified by simulation.

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Synchronic relations with a time constraint

  • Koh, Inseon
    • 제어로봇시스템학회:학술대회논문집
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    • pp.676-680
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    • 1994
  • Three synchronic variables (Deviation Time, Fairness Time, Synchronic Time) are defined for Timed Place Petri Nets (TPPN). These parameters show the dependency between the firing of transition subsets in the time domain by different values. The approaches in this paper can be used to find synchronic relations in Stochastic Petri Nets. This paper presents how to decide the minimum resources required to a Flexible Manufacturing Cell using Synchronic Time concept.

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Design of Incidence Matrix on SE&TPN for Construction of Modular on the Flexible Manufacturing System (유연생산시스템 모듈라 구축을 위한 확장 세이프/시간형 PN 접속행렬 설계)

  • 김만균;함효준
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.21 no.47
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    • pp.193-209
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    • 1998
  • The objective of this paper is to present a methodology for design of the FMS by using a new modeling tool which is called SE&TPN(Safe Extended & Timed Petri Net). A FMS, which consists of various machine groups, may produce machine parts in different physical dimensions and lot size. The approach involves the SE&TPN modeling by Petri-nets. The proposed algorithm can handle determining of firing count vector by incidence matrix and adjustment of conflict using the marking of SE&TPN. The SE&TPN is defined as nets that can have at most one token in one place and can have elements such as permissive arcs and inhibitor arcs in addition to elements. The SE&TPN with permissive arcs and inhibitor arcs are intuitively direct approach to increase the modeling power of the SE&TPN. Finally, this paper is to develop a modulation to optimize the system problems of FMS using SE&TPN which describes exactly features of Petri Nets.

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