• Proceedings of the Korea Contents Association Conference
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• 2005.05a
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• pp.315-319
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• 2005

In this paper, we present a Petri Net (PN) model for reliability analysis of fault-tolerant database system models that consists of components one shared memory, bus, processors and database (disk). Each component can be failed and repaired individually. The system is operational as long as database and one of component is operational. We develop Stochastic Reward Net (SRN) Model for reliability analysis of database system. SRN is potential to define various reward functions. and can be easily used to obtain performance measures. The modeling techniques using variable cardinality, enabling function, timed transition priority in SRN are shown.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5512-5517
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• 2012

In this paper we suggest multimedia synchronization model that is based on the Petri-net and services desirable quality of service requirement. Proposed model applies variable buffer which can be allowed, and then it presents high quality of service and real time characteristics. This paper decreases the data loss resulted from variation of delay time and from loss time of media-data by means of applying delay jitter in order to deal with synchronization interval adjustment. Plus, the mechanism adaptively manages the waiting time of smoothing buffer, which leads to minimize the gap from the variation of delay time. The proposed paper is suitable to the system which requires the guarantee of high quality of service and mechanism improves quality of services such as decrease of loss rate, increase of playout rate.

• Water for future
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• v.28 no.6
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• pp.203-215
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• 1995

Operation models for storm water pumps in detention pond were developed in order to reduce the damage by inundation in urbanized area. The return periods (10, 20, 30 years) of rainfall were selected to estimate inflow discharge to detention ponds. Inflow hydrographs of detention ponds were derived by using the SWMM, and Petri net diagrams were selected to analyze the pump actions. Safety and efficiency of pumps and detention ponds were estimated by penalty index. In order to verify the models, the models were applied to three selected detention ponds in Seoul area. In numerical experimental results, the developed model 3 is more effective in inland flooding prevention than the existing one, and may be used to design and evaluate detention ponds with real time data of rainfall.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.4
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• pp.467-471
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• 2010

Weblog is one of the most spread web services. The content of the weblog includes daily events and emotions. If we collect personal information using mobile devices and create a weblog, user can create their own weblog easily. Some researchers already developed systems that created weblog in mobile environment. In this paper, user's activity is inferred from personal information in mobile device. The inferred activities and story generation engine are used to generate text for creating a weblog. Finally, the text, photographs and user's movement in Google Map are integrated into a weblog.

• The Journal of Society for e-Business Studies
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• v.14 no.1
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• pp.35-56
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• 2009

Many process modeling techniques, such as Petri-net, UML Activity Diagram, and EPC, are used to design process models. In this paper, we analyze ubiquitous process design based on workflow patterns. In particular, we focus on process design using active rules that have the form of Event-Condition-Action, and deal with the WS-ECA language, which was devised for ubiquitous web services coordination. We first check whether workflow patterns can be designed with ECA rules, and we then provide WS-ECA representations for ECA rules of the patterns. The contribution of this paper is that ECA rule-based process models were presented based on workflow patterns and they can be a guideline for ubiquitous process modeling.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.4
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• pp.487-492
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• 2004

This paper deals with modeling method and application of Fuzzy Discrete Event System(FDES). FDES have characteristics which Crisp Discrete Event System(CDES) can't deals with and is constituted with the events that is determined by vague and uncertain judgement like biomedical or traffic control. In general, the modeling method of CDES has been studied many times, but that of FDES hasn't been nearly studied by qualitative character and scarcity of applicated system. This paper models traffic system with FDES's character in FTTPN and designs a traffic signal controller.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.11
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• pp.2609-2614
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• 2013

Adoption of RFID has become widespread including logistics, drug supply-chain, and healthcare. To adopt RFID, we need to evaluate performance and feasibility of RFID S/W such as EPC Information Service (EPCIS), which demands a variety of test datasets of RFID business events. This paper proposes a novel method for creating RFID business events dataset by means of the simulation of RFID infrastructure. Proposed model provides a flexible representation capability since this is based on well-known petri-net. In addition, it can also be useful when determining adoption of RFID as it supports simulation of RFID environment.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.314-314
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• 1996

We investigate the scheduling problem for periodic job shops with blocking. We develop Petri net models for periodic job shops with finite buffers. A buffer control method would allow the jobs to enter the input buffer of the next machine in the order for which they are completed. We discuss difficulties in using such a random order buffer control method and random access buffers. We thus propose an alternative buffer control policy that restricts the jobs to enter the input buffer of the next machine in a predetermined order. The buffer control method simplifies job flows and control systems. Further, it requires only a cost-effective simple sequential buffer. We show that the periodic scheduling model with finite buffers using the buffer control policy can be transformed into an equivalent periodic scheduling model with no buffer, which is modeled as a timed marked graph. We characterize the structural properties for deadlock detection. Finally, we develop a mixed integer programming model for the no buffer problem that finds a deadlock-free optimal sequence that minimizes the cycle time.

• Journal of The Korean Association of Information Education
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• v.7 no.3
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• pp.309-317
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• 2003

Web-Based Education System changed from one side transmission of information to bi-directional information exchange with user. Accordingly, It had been implemented on 3-tier models with each function separation using database and server side language such as CGI (Common Gateway Interface). But, The CBSD(Component Based Software Development) techniques receives many interests recently, and efforts to apply this are appearing. Thus, In this research implemented component base question solving system. For this, I used EJB(Enterprise Java Beans) that is web server component model, and used Petri-Net for typical specification about message flow between components.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.3
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• pp.626-634
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• 2012

It is required that system can seamlessly identify and manage change history and comprehensive assessment of several types of data as well as individual information of feeding and water environment for scientific and systematic management of fish farming environment and fish farmer. In this study, we implemented the system which can present and simulate current status of water quality and feeding based on th historical data of them, and check changes of state step by step using visual C++. In addition, we proposed the entropy model which can be comprehensive analysis about water quality and feed status information based on knowledge of fisheries. It can be the foundation to create high-level environment model reflecting the more diverse fisheries knowledge such as disease.