• 한국시뮬레이션학회논문지
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• 제11권2호
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• pp.77-88
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• 2002

Petri nets is a widely used formalism for specification and analysis of concurrent systems which is a subclass of discrete event systems. The DEVS (Discrete Event System Specification) formalism provides a general framework for specification of discrete event systems in a hierarchical, modular form. Often, modeling a discrete event system may employ both Petri Nets and DEVS formalism. In such a case low-level operational logics are modeled by Petri Nets and high-level managements by the DEVS formalism. Analysis of the system requires simulation of the overall system. This paper presents an algorithm for transformation of Petri Nets to DEVS formalism. The transformation enables modelers to simulate an overall system, which consists of DEVS models and Petri Nets models, in a unified DEVS simulation environment such as DEVSim++. An example for such transformation will be given.

• 수산해양기술연구
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• 제39권1호
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• pp.50-55
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• 2003

자원관리형 자망$.$통발 어구어법 기술개발을 위한 연구의 일환으로 서해구의 자망$.$통발어업에 대한 현황을 파악하고, 서해구의 대표적인 어종 중의 하나인 민어를 어획대상으로 하는 민어 연안 유자망어업과 피뿔고둥을 주 어획대상으로 하는 기타 통발어업을 연구대상으로 선정하여 현장조사 등을 통하여 조업실태와 대상어종의 체장조성 등을 조사한 결과는 다음과 같다. 1. 서해구의 연안어업 총 허가건수는 12,944건(조업건수 7,558건; 2001년 12월말 현재)이며, 그 중에서 자망어업이 5,154건(조업건수 3,724건)으로 39.8%, 통발어업이 1,025건(조업건수 662건)으로 7.6%를 차지하였으며, 서해구에서의 조업율은 연안 자망어업과 연안 통발어업이 각각 72.3%와 64.6%로서 타 업종에 비해 비교적 높은 편이었다. 2. 민어 유자망어업의 주어기는 7월 중순부터 9월 초순까지이며, 주어장은 서해 남부 연안의 섬주변의 수심 약 15∼50m(주로 30m 이내)이고, 조업은 저질이 펄 또는 사니질인 해역에서 사리때를 전후하여 1일 1∼2회 1주일 정도 창조시 투망하여 1∼2시간 정도 어구가 조류에 표류하도록 한 후 양망하는 것으로 조사되었다. 3. 민어 유자망어업의 현장조사 결과 어획된 139마리의 체장 범위는 43.0∼120cm이고, 모우드(mode)는 85cm였으며, 꽃게$.$병어$.$가오리 등이 소량 혼획되었다. 4. 서해구에서의 피뿔고둥을 주대상으로 하는 기타 통발어업은 꽃게 어기(9월 초순∼10월 중순)를 제외한 시기에 연중 조업하며, 서해 연안의 수심이 10∼20m이고 저질이 사니질인 해역에서 보통 전날 투망하여 다음 날 양망하는 것으로 조사되었다. 5. 기타 통발어업의 현장조사 결과 조사기간 중 어획된 피뿔고둥 5,372마리의 갑장 범위는 4.5∼8.5cm이고, 모우드(mode)는 7.5cm였으며, 피뿔고등 91.7%, 배꼽고등 4.8%, 민꽃게$.$쥐노래미$.$조피볼락 등이 3.5% 정도 혼획되었다.

• 충청수학회지
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• 제23권1호
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• pp.109-117
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• 2010

In this paper, we define the concept of a c-net and study the convergence of c-nets. Also we show that a c-net in a topological space X has a convergent sub-c-net if and only if X is a $Lindel{\ddot{o}}f$ space, if every $G_{\delta}$ set is open in X.

• 한국경영과학회지
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• 제19권3호
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• pp.131-138
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• 1994

Petri Nets are a graphical and mathematical modeling and promising tool for describing and studying that are characterized as being concurrent, asychronous, dynamic, distributed and parrallel. The purpose of this paper is to analyze FMS Throughout-Rate by development of Petri Nets So, it applied to FMS composed of 7 machines and 4 different job types. The result of this paper shows the advantage of using Petri Nets.

• 한국시뮬레이션학회논문지
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• 제11권2호
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• pp.67-75
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• 2002

This paper proposes a parallel simulation algorithm for bounded Petri nets in a single processor, which exploits the SIMD(Single Instruction Multiple Data)-type parallelism. The proposed algorithm is based on a data packing scheme which packs multiple bytes data in a single register, thereby being manipulated simultaneously. The parallelism can reduce simulation time of bounded Petri nets in a single processor environment. The effectiveness of the algorithm is demonstrated by presenting speed-up of simulation time for two bounded Petri nets.

• 산업경영시스템학회지
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• 제28권3호
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• pp.36-41
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• 2005

페트리 네트(Petri Nets)는 이산 사건 시스템을 모델링할 수 있는 그래픽하고, 수학적인 도구이다. 본 연구는 유연제조 시스템을 확률적인 페트리 네트(Stochastic Petri Nets)중의 하나인 임베디드 마코프 체인(Embeded Markov Chain)에 도입하고, 임베디드 마코프 체인의 방법 중에 하나인 일반화된 확률적 페트리 네트(Generalized Stochastic Perti Nets)에 적용시켰다. 그리고 결과치의 정확성을 알아내기 위하여, 페트리 네트 시뮬레이션과 아레나를 사용하여 실행하였다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1993년도 Fifth International Fuzzy Systems Association World Congress 93
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• pp.1338-1341
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• 1993

We present here two Petri nets formalisms that can deal with uncertainty by the use of necessity-valued logic. The first and basic model, called necessity-valued Petri nets (NPN), can at the same time deal with uncertainty on markings are on transitions. The second model, called necessity-valued Petri nets (TNPN), is an extension of both NPN and timed Petri nets.

• 수산해양기술연구
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• 제53권1호
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• pp.1-11
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• 2017

Fishing pots are one of the important fishing gears in our coastal and offshore fisheries. In terms of a sustainable use of marine resources, there are concerns about the ghost fishing by lost pots. It is reported that 10 to 70% of the pots are abandoned or lost annually. This study is to compare the catching efficiency of drum type whelk pots that are made of biodegradable nets to those made of the ordinary nets, in the eastern coast of Korea. Five types of drum pots were used with combination of biodegradable nets and ordinary (PA, PE) nets applied to the main and funnel parts of the pots: pots with biodegradable nets (Bio+Bio); pots with PE net (PE+PE); pots with body and funnel made of biodegradable nets and PE nets respectively (Bio+PE); pots with body and funnel made of PE nets and PA nets respectively (PE+PA); pots with body and funnel made of PE nets and biodegradable net respectively (PE+Bio). Field experiments were conducted from June $18^{th}$, 2015 to August $7^{th}$, 2015 using a commercial fishing vessel in the Uljin waters on the eastern coast of Korea. Two fleets of pots with one hundred in each, 20 pots of each type, were casted for 8 to 15 days to analyze their catching efficiency. The catch of target species, whelks, was 202,563.0 g with catch rate of 38.7% of the total catch, while the bycatch was 320,709.7 g with the rate of 61.3% of the total catch. The catch of whelks was the highest in the Bio+PE pots (46,020.3 g), followed by the Bio+Bio pots (42,027.5 g), the PE+Bio pots (41,849.9 g) and the lowest being PE+PE pots (38,054.2 g). Compared to the conventional pots, the pots with biodegradable nets on the body or entrance part had slightly higher catch rate for both the target species and the bycatch. The PE+PE had the lowest catch rate. There is no significant difference in catch between the pots with biodegradable nets and the ordinary nets for the target species such as Buccinum opisthoplectum, Neptunea eulimata, Buccinum striatissimum. Consequently, using biodegradable nets for the conventional whelk pots can reduce ghost fishing by lost gears while keeping the performance of the pots.

• 한국CDE학회논문집
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• 제22권2호
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• pp.162-171
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• 2017

Unmanned military vehicles (UMVs) are most commonly characterized as dealing with dull, dirty, and dangerous tasks with automation. Although most of the UMVs are designed to a high degree of autonomy, the human operator will still intervene in the robot's operation, and teleoperate them to achieve his or her mission. Thus, operator capacity, together with robot autonomy and user interface, is one of the most important design factors in the research and development of the UMVs. Further, communication may affect the operator task performance. In this paper, we analyze the operator performance and the communication effects on the operator performance by using the extended Petri nets, called OTSim nets. The OTSim nets was designed by the authors, being extended using pure Petri nets.

• 전자공학회논문지A
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• 제31A권10호
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• pp.119-131
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• 1994

In this paper, we first propose a new FPGA routing method in which seversal netw are routed concurrently by applying the readitional maze routing method. We then introduce CMRF (concurrent maze Router for FPGA) which can be used for the routing of FpGAs of symmetrical array type by applying our new routing method. Given a set of nets, the proposed routing method performas the maze propagation and backtracing independently for each net and determines the routing paths concurrently by competition among nets. In CMRF, using this routing method, q nets are selected from the nets to be routed and they are routed concurrently, where q is the user given parameter determined by considering the computing environment. This process is repeated until either all the nets are routed or the remaining unrouted nets fail to their maze propagations. The routing of these nets are completed using the rip-up and rerouting technique. We apply our routing method to ten randomly generated test examples in order to check its routing performance. The results show taht as we increase the value of q, the routing completion rate increases for all the examples. Note that when q=1, our method is similar to the conventinal maze routing method. We also compare CMRF with the CGE method which has been proposed by Brown et.al. For the five benchmark examples, CMRF complete the routing with less wire segments in each connection block than the wire segments needed in the CGE method of 100% routing.