• Title/Summary/Keyword: 페트리네트

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Availability Analysis of 2N Redundancy System Using Stochastic Models (안정적인 서비스를 위한 2N 이중화 모델의 가용도 분석)

  • Kim, Dong Hyun;Lee, Yutae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.11
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    • pp.2634-2639
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    • 2014
  • The idea of redundancy is used in order to improve the availability of networks and systems and there are various methods for implementing redundancy. To perform the availability analysis various stochastic models have been used. In this paper, 2N redundancy with one active service unit and one standby service unit is considered. To evaluate the expected availability, we model 2N redundancy using Stochastic Reward Nets. This model can be solved using the SPNP package.

Verification of NNI Interworking Protocol of B-ISDN and Internet (B-ISDN과 Internet연등 프로토콜 설계 및 검증)

  • 박석천;김동영;양용석;정영호;이봉영
    • Proceedings of the Korean Information Science Society Conference
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    • 1998.10a
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    • pp.597-599
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    • 1998
  • 기존의 공중전기통신망들이 B-ISDN으로 통합, 발전되어 가는 과정에서 경제성 및 효율성 등의 이유로 인해 필연적으로 기존망과 새로 구현하는 망 사이의 연동과정이 필요하게 되며 가능한 기존망의 기능을 수용하면서 구현될 수 있는 방안이 마련되어야한다. 본 논문에서는 B-ISDN과 Internet의 망간 프로토콜인 B-ISUP와 TCP/IP의 연동 프로토콜을 설계하고 연동 프로토콜을 검증하기 위해 페트리네트(petrinet)의 확장인 프레디키디(predicate)/액션(action) 네트를 이용하여 모델링하였다. 또한 동작성 확인을 위해 도달트리(reachability tree)를 이용하여 설계한 프로토콜이 교착상태(deadlock)없이 정상적으로 수행됨을 보였다.

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종합병원 외래약국을 위한 자동 물류 취급 시스템의 설계 및 실시간 운용

  • 김종원;우중원
    • ICROS
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    • v.3 no.1
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    • pp.75-82
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    • 1997
  • 본 글에서는 자동물류취급시스템을 설치하여 극단적인 다품종소량생산시스템을 모델링하고 분석하여 설계변수들을 결정하는 틀을 설명하였으며, 이에 의해 설치되어진 자동물류취급시스템의 실례를 들어서 자동물류취급시스템이 납기단축과 간접공수절감에 얼마나 효율적인가를 보였다. 본 연구에서 얻어진 결론을 요약하면 다음과 같다. 1) 다양한 정보처리와 실시간 이산현상시스템의 해석 및 검증을 위하여 Colored and Stochastic 페트리네트를 정의하고 이를 이용하여 자동물류취급시스템이 설치되어진 생산시스템에 대한 모델링을 수행하였다. 2) Colored and Stochastic페트리네트 모델에 대한 시뮬레이션을 수행하는 소프트웨어를 개발하여 주어진 모델의 성능평가를 수행하였다. 3) 자동물류취급시스템의 설계변수를 결정하는 알고리즘을 제시하였으며 이에 의거한 시뮬레이션을 통하여 적절한 설계변수를 결정하였다. 4) 자동물류취급시스템이 설치되어진 생산시스템을 대상으로 모델과 설계변수의 타당성을 검증하였다.

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Compositional Analysis of Petri Net Models using Petri net Slices (페트리네트 Slice를 이용한 페트리네트 모델의 합성적 분석)

  • Lee, Woo-Jin;Cha, Sung-Deok;Kwon, Yong-Rae;Kim, Heung-Nam
    • 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.

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An Extended I-O Modeling Methodology based on FSM (유한상태기계에 기반한 확장된 I-O 모델링 방법론)

  • Oh, Soo-Yeon;Wang, Gi-Nam;Kim, Ki-Hyung;Kim, Kangseok
    • Journal of the Korea Society for Simulation
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    • v.25 no.4
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    • pp.21-30
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    • 2016
  • Recently manufacturing companies have used PLC control programs popularly for their automated production systems. Since the life cycle of production process is not so long, the change of the production lines occur frequently. Most of changes happen with modification of the position information and control process of the equipment. PLC control program is also modified based on the fundamental process. Therefore, to verify new PLC program by configuring virtual space according to real environment is needed. In this paper we show a logical modeling method, based on Timed-FSA useful for sequence control and dead-lock prevention. There is a problem wasting user's labor and time when defining a variety of states in a device. To overcome this problem, we propose an extended I-O model based on existing methods by adding a token concept of Petri Nets. Also we will show the usability of the extended I-O modeling through user study.

Availability Analysis of Redundancy Models for Network System with Non-Stop Forwarding (논스톱 포워딩 기능을 지원하는 네트워크 시스템에 대한 다중화 모형의 가용도 분석)

  • Shim, Jaechan;Ryu, Hongrim;Ryu, Hoyong;Park, Jaehyung;Lee, Yutae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.12
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    • pp.2828-2835
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    • 2015
  • In this paper, we analyse the effect of redundancy types and non-stop forwarding scheme on network service availability. We use stochastic reward net models as enabling modeling approach for the analytical evaluation. We first design stochastic reward nets for redundancy models with or without non-stop forwarding and then evaluate their availability using Stochastic Petri Net Package.

Modeling of Virtual Switch in Cloud System (클라우드 시스템의 가상 스위치 모델링)

  • Ro, Cheul-Woo
    • Journal of Digital Convergence
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    • v.11 no.12
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    • pp.479-485
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    • 2013
  • Virtualization is a promising approach to consolidating multiple online services onto a smaller number of computing resources. A virtualized server environment allows computing resources to be shared among multiple performance isolated platforms called virtual machines. Through server virtualization software, applications servers are encapsulated into VMs, and deployed with APIs on top generalized pools of CPU and memory resources. Networking and security have been moved to a software abstraction layer that transformed computing, network virtualization. And it paves the way for enterprise to rapidly deploy networking and security for any application by creating the virtual network. Stochastic reward net (SRN) is an extension of stochastic Petri nets which provides compact modeling facilities for system analysis. In this paper, we develop SRN model of network virtualization based on virtual switch. Measures of interest such as switching delay and throughput are considered. These measures are expressed in terms of the expected values of reward rate functions for SRNs. Numerical results are obtained according to the virtual switch capacity and number of active VMs.

Error Handling SPN Modeling (에러처리 SPN 모델링)

  • Ro, Cheul Woo
    • Proceedings of the Korea Contents Association Conference
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    • 2011.05a
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    • pp.569-570
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    • 2011
  • fault와 에러를 구분하여 정의한 후, 에러처리를 위한 시스템 상태를 fault, 에러, 회복, benign, mon1, mon2의 상세 상태로 분류하고, 이들 상태를 묘사해 줄 수 있는 추계적 페트리 네트를 이용하여 시스템 에러 처리를 모델링 한다. 시스템이 수십년이 지나면 궁극적으로 다운되는 비신뢰도를 모델로 부터 구할 수 있음을 보여준다.

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SRN Hierarchical Modeling for Packet Retransmission and Channel Allocation in Wireless Networks (무선망에서 패킷 재전송과 채널할당 성능분석을 위한 SRN 계층 모델링)

  • 노철우
    • The KIPS Transactions:PartC
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    • v.8C no.1
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    • pp.97-104
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    • 2001
  • In this paper, we present a new hierarchical model for performance analysis of channel allocation and packet service protocol in wireless n network. The proposed hierarchical model consists of two parts : upper and lower layer models. The upper layer model is the structure state model representing the state of the channel allocation and call service. The lower layer model, which captures the performance of the system within a given structure state, is the wireless packet retransmission protocol model. These models are developed using SRN which is an modeling tool. SRN, an extension of stochastic Petri net, provides compact modeling facilities for system analysis. To get the performance index, appropriate reward rates are assigned to its SRN. Fixed point iteration is used to determine the model parameters that are not available directly as input. That is, the call service time of the upper model can be obtained by packet delay in the lower model, and the packet generation rates of the lower model come from call generation rates of the upper model.

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