• Journal of KIISE:Computing Practices and Letters
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• v.15 no.7
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• pp.500-504
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• 2009

A reliability of software is a type of nonfunctional requirement. Traditionally, a validation of the reliability is processed at the integration phase in software development life cycle. However, it increases the cost and the risk for the development. In this paper, we propose reliability analysis method based on mathematical analytic model at the architecture design phase of the development process as follows. First, we propose the software modeling methodology for reliability analysis using Hierarchical combined Queueing Petri Nets(HQPN). Second, we derive the Markov Reward Model from the HQPN based model. We apply our approach to the video conference system to verify the usefulness of our approach. Our approach supports quantitative evaluation of the reliability.

• Journal of Information Technology Application
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• v.2 no.1
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• pp.113-137
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• 2000

Even though there is no doubt that ERP(Enterprise Resource Planing) system is a prevailing solution for integrating corporate information, many companies still hesitate adopting ERP system because of a great deal of cost including maintenance cost. In special, unless consulting knowledge that is infused into process reengineering phase or adequately embedded in customized ERP system is upgraded on time, then we cannot guarantee the optimality of system performance. Hence, this paper aims to construct an ERP system that adapts itself to environmental changes that are issued by database and users. To do so, we adopt intelligent agent technology and Petri net theory. The agents autonomously cooperate each other to investigate databases and to find any exceptional changes and analyze how the changes will affect ERP performance. The dynamics of the agents are represented as Petri nets. The newly proposed ERP system is to make corresponding BPR processes maintain optimality. To show the feasibility of the proposed ERP maintenance system, logistics component is described as an illustrative example.

• Journal of the Korea Society for Simulation
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• v.15 no.1
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• pp.1-10
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• 2006

The Flexible Management System (FMS) consists of parallel and concurrent machines, pieces of equipment, and carrying systems classified as buffers, tools, and routers, respectively. The concurrent flow of multiple productions in a system is competed with one another for resources and this resulting competition can cause a deadlock in FMS. Since a deadlock is a condition in which the excessive demand for the resources being used by others causes activities to stop, it is very important to detect and prevent a deadlock. Herein a new algorithm has been studied in order to detect and prevent deadlocks, after defining a relationship between the general places and resource share places in Petri nets like as DAPN: Deadlock Avoidance Petri Net. For presenting the results, the suggested algorithms were also adapted to the models that demonstrated FMS features.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.14 no.5
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• pp.511-520
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• 1989

Generally, Intelliget link is made of drawing picture that is amalgated in two conception of communication and processing. This is a new system of information transmission having fuction being able to handle een though the former information transmission can not be possible. That Intelligent link is to say that function of each segment by working software can be anailable at general purposed pipeline processing system, general purpose pipeline have a different working time in function of segmant, work asynchronizing pipeline. in the papers, graphic design is easy to understand the sense of sight model by Petri Net that is simple regulation. it can translate into working of asynchronzing pipeline by working of calculator of simulation.

• Journal of the Korea Society for Simulation
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• v.17 no.3
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• pp.75-83
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• 2008

A deadlock is a condition in which the excessive demand for the resources being used by others causes activities to stop and it is one of the important problems in process control system to detect and prevent deadlocks. While the reachability analyze methods or divide subnets for analyzing methods are well used, it requires a lot of times and effects to analyze the detection of the deadlock status. Furthermore, it could not be effective if the model is complex or huge. Therefore, it is necessary to develop a new and more efficient deadlock detection algorithm. In this paper, a deadlock detection conditions after analyzed the Petri Net using the transitive matrix has been proposed to solve these problems. For presenting the results, the suggested deadlock detection algorithm was also adapted to an illustrated FMS (Flexible Manufacturing System) model.

• Journal of the Korea Society of Computer and Information
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• v.14 no.1
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• pp.173-181
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• 2009

This paper proposes an algorithm to transform RDF(Resource Description Framework) models for ontology into CPN(Colored Petri Net) models. The algorithm transforms the semantics of the RDF model into the topology of the CPN by mapping the classes and the properties of the RDF onto the places of the CPN model then reflects the RDF statements on the CPN by representing the relationships between them as token transitions on the CPN. The basic idea of reflecting the RDF statements on the CPN is to generate a token, which is an ordered pair consisting of two tokens (one from the place mapped into the subject and the other one from the place mapped into the object) and transfer it to the place mapped into the predicate. We have actually built CPN models for given RDF models on the CNPTools and inferred and extracted answers to the RDF queries on the CPNTools.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.491-495
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• 2002

In the paper, a Visual factory model for a optical-components manufacturing process is built. The optical-components manufacturing process is composed of 3 operation processes; optical sub assembly process, package assembly process, and fiber assembly process. Each process is managed not a batch mode, which is one of most popular manufacturing styles to produce a great deal of industrial output, but though a modular cell. In the processes, a modular cell has to be processed independently of the other cells. Optimization for the composition of assembly cell in the optical-components system is made by the Visual factory model.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06b
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• pp.189-192
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• 2011

클라우드 컴퓨팅에서 사용되는 웹 서비스들은 BPEL에 의해 여러 서비스들이 새로운 웹 서비스로 조합 되어지며, 서비스가 제대로 동작하는지를 검증하기 위해 Petri nets, Abstract State Machine(ASM), BPECalculus 등의 검증 방법을 사용한다. 이러한 검증 방법은 BPEL을 사용하여 새로 만들어진 웹 서비스들이 안정적으로 동작하는지를 검증하는 것으로, 웹 서비스 설계와 검증이 서로 분리되어 있다. 본 논문에서는 명세, 분석 및 검증의 전 과정에서 프로세스의 포함관계, 상태정보, Interaction, Mobility 등을 그래프로 표현하며, 한 단계의 그래프를 통하여 시스템 전체의 복잡도 및 시스템의 행위를 예측할 수 있는 Onion Visual Language(OVL)을 사용하여 BPEL로 설계 되는 클라우드 웹 서비스들을 OVL로 변환 후 이를 분석 및 검증한다. 추후 OVL은 서로 다른 클라우드 안에서의 웹 서비스 재사용을 위한 동일성 검증을 위한 방법으로 사용될 수 있다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.725-730
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• 1996

In this work, the software behavior under memory faults in operation phase is modeled and simulated using the stochastic activity network, generalized stochastic Petri nets. This networks permit the representation of concurrency, timeliness, fault tolerance, and degradable performance of system and provide a means for determining the stochastic behavior of a complex system. We estimate the reliability of an application software in the digitized system in nuclear power plants and show the sensitivity of the software reliability to the major physical parameters which affect the software failure in normal operation phase. We found that the effects of the hardware faults on the software failure should be considered for predicting the software dependability accurately in operation phase.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.10a
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• pp.161-164
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• 2000

A cyclic shop is a production system that repeatedly produces identical sets of jobs, called minimal part sets, in the same loading and processing sequence. We consider a version of cyclic shop where the operations are processed and unloaded within time limits, so called a time window. We model the shop using an event graph model, a class of Petri nets. To represent the time window constraint, we introduce places with negative time delays. From the shop modeling graph, we develop a linear system model based on the max- plus algebra and characterize the conditions on the existence of a stable schedule.