• Nuclear Engineering and Technology
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• v.41 no.5
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• pp.739-746
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• 2009

This paper introduces facility operation modeling and simulation based primarily on a discrete event system modeling scheme. Many modern industrial facilities are so complex that their operational status cannot be estimated by simple calculations. In general, a facility can consist of many processes and transfers of material between processes that may be modeled as a discrete event system. This paper introduces the current status of studies on operation modeling and simulation for typical nuclear facilities, along with some examples. In addition, this paper provides insights about how a discrete event system can be applied to a model for a nuclear facility. A headend facility is chosen for operation modeling and the simulation, and detailed procedure is thoroughly described from modeling to an analysis of discrete event results. These kinds of modeling and simulation are very important because they can contribute to facility design and operation in terms of prediction of system behavior, quantification of facility capacity, bottleneck identification and efficient operation scheduling.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1428-1432
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• 2007

One of the most important targets of transportation is to transport human and commodities to the destination safely. Railway has low risk, compared with land, ocean and flight route and it assures high security as well as high speed driving, since it runs on regular track. However, train accident may result in tragic accident due to small carelessness, so special event recorder is preferably used in order for clarity of responsibility in case of accident, maintenance of signal device and defect analysis. JRU(Juridical Recorder Unit) for ATC/ATS/ATP can be more advanced event recorder. Event recorder of KTX-I which is running now is installed one by one on each leading car and last car, and operation plan of event recorder in case of single trainset is suggested. But regarding train operation of multi-coupled trainset operation such as KTX-II, more detailed study is required for event recorder revitalization and record data process method. Therefore, this research aims at operation plan used in existing event recorder, and suggests effective operation and management plan of event recorder in multi-coupled trainset such as new High Speed Train.

• Journal of Computational Design and Engineering
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• v.1 no.4
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• pp.233-242
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• 2014

A magnetically levitated vehicle (Maglev) system is under commercialization as a new transportation system in Korea. The Maglev is operated by an unmanned automatic control system. Therefore, the plan of train operation should be carefully established and validated in advance. In general, when making a train operation plan, statistically predicted traffic data is used. However, a traffic wave often occurs in real train service, and demand-driven simulation technology is required to review a train operation plan and service quality considering traffic waves. We propose a method and model to simulate Maglev operation considering continuous demand changes. For this purpose, we employed a discrete event model that is suitable for modeling the behavior of railway passenger transportation. We modeled the system hierarchically using discrete event system specification (DEVS) formalism. In addition, through implementation and an experiment using the DEVSim++ simulation environment, we tested the feasibility of the proposed model. Our experimental results also verified that our demand-driven simulation technology can be used for a priori review of train operation plans and strategies.

• Journal of Sport and Applied Science
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• v.3 no.1
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• pp.1-14
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• 2019

Numerous types of sporting events have been hosted in Korea during the last decades. Sport events produce various types of data, and there is a clear necessity of storing and utilizing this information. From this background, the purpose of this study is to draw complex sports categories from international sport events life cycles in order to categorize standards of knowledges management system. This study utilized qualitative methods: expert groups discussion for overall life cycle steps and in-depth interviews for detail life cycle steps. The results show that there are several life cycle steps: bidding, preparation, operation, evaluation, post management steps. To be more specific, for the bidding step, there are check, plan, implementing detail phase; and the preparation step is based on event preparation Basis Build, event preparation implementation, test and supplementation phases. For the operation step, event operation system switch, event operation during the period, finish operation phases are deducted. Evaluation and post management step do not have detail phases. Efforts to store and utilize knowledge can be one of the starting points to make the operation of sport events efficiently.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.341-347
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• 2009

In high speed railway, event recorder system stores a train speed and the related data for train operation in real time. Using those information, we can analysis the train operation and the reason of train accident. Analysis software gets the stored data from Event Recorder and shows the status of various signals related with train operation. Using it, also we can analysis the train operation before and after the given time. In this paper we propose the analysis software to show and analysis the operation of high speed train. The method of transferring the stored data from Event Recorder into Analysis Software is proposed. We develop the efficient procedure to store the transferred data into analysis system. Also the effective method to show the store data and to analysis them is studied for finding the cause of train accident.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.70-77
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• 2002

Necessity of the tole-operation has been increased in many fields. Since the Internet is inexpensive and available all over the world, it is a strong candidate for the transmission media of the tole-operation. However, the Internet has random time delays that may cause instability in the system especially if the tole -operation is bilateral. In the past few years many attempts have been made to overcome the random time delay, So far, they are still insufficient in terms of performance. The ‘Variable holding time’ is introduced to improve the performance of the ‘Event based tole-operation’ which controls a system with a non-time action reference. By holding each event for proper time, the system can quickly respond and be stabilized. The proper holding time should be selected based on the characteristics of the task that the system performs. The factors that reflect those characteristics are investigated. The fuzzy logic is employed to obtain the proper holding time for each event while the tole-operation system is in operation. The experimental results presented in this paper verify effectiveness of the proposed method.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1962-1967
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• 2008

A event recorder system stores a train speed and the related information for train operation in real time. Using those information, we can analysis the train operation and the reason of train accident. Currently the event recorder only manipulate the data related the train operation mechanically and electrically. In this paper we propose the event recorder to record the voice communication between the manager in the control center and train operator. By recording the voice communication in the high speed train, the correctness of analysis of train accident can be increased. The system architecture of the event recorder with voice recording is studied and interface between other equipment is proposed. And the software architecture of new event recorder is developed. We study the method of converting analog voice signal into digital data and compressing method. Also the architecture of memory to store the compressed voice data and regeneration of original analog voice are studied.

• Journal of Internet Computing and Services
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• v.20 no.6
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• pp.21-28
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• 2019

Process mining is state-of-the-art technology in the workflow field. Recently, process mining becomes more important because of the fact that it shows the status of the actual behavior of the workflow model. However, as the process mining get focused and developed, the material of the process mining - workflow event log - also grows fast. Thus, the process mining algorithms cannot operate with some data because it is too large. To solve this problem, there should be a lightweight process mining algorithm, or the event log must be divided and processed partly. In this paper, we suggest a set of operations that control and edit XES based event logs for process mining. They are designed based on relational algebra, which is used in database management systems. We designed three operations for tailoring XES event logs. Select operation is an operation that gets specific attributes and excludes others. Thus, the output file has the same structure and contents of the original file, but each element has only the attributes user selected. Union operation makes two input XES files into one XES file. Two input files must be from the same process. As a result, the contents of the two files are integrated into one file. The final operation is a slice. It divides anXES file into several files by the number of traces. We will show the design methods and details below.

• Journal of the Korean Dietetic Association
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• v.12 no.3
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• pp.235-242
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• 2006

The purpose of this study of was to provide basic data for preparing event menus to increase customer's satisfaction by investigating university students' participation and preference for the event menus in the foodservice operations. The questionnaires were distributed to 300 customers from August 1 to 31, 2005. 88.0% of the questionnaires were analyzed. Statistical analysis of data was performed using SAS package program(version 8.2) for descriptive analysis and $χ^2$-test, t-test, one-way ANOVA, Duncan multiple range test. The results of this study can be summarized as follows : 50.4% of the students have participated in foodservice operation's event and the average degree of the satisfaction was 2.67 out of 5. The type of the events customers have most frequently participated in were the national holiday·subdivisions of the season event(47.3%), the day event(34.1%), environment event(26.9%) and so on. In large classification, preferred were season event(85.2%), international food event(76.9%), and healthy food event(73.1%) and so on. In small classification, orgarnic food event(53.0%), summer fruits festival(41.3%), midsummer event(36.6%) and christmas event(34.4%) and so on. From now on, the event reflecting customers' expectation and requirement should be planned and implemented.

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2812-2820
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• 2020

House load operation (HLO) occurs when the generator supplies power to the house load without triggering reactor trips during grid disturbances. In Korea, the HLO capability of optimized power reactor 1000 (OPR1000) plants has prevented several reactor trips. Operational experiences demonstrate the difference in the reactor trip incidence due to grid disturbances between OPR1000 plants and Westinghouse plants in Korea, attributable to the availability of the HLO capability. However, probabilistic safety assessments (PSAs) for OPR1000 plants have not considered their specific design features in the initiating event analyses. In an at-power PSA, the HLO capability can affect the initiating event frequencies of general transients (GTRN) and loss of offsite power (LOOP), resulting from transients within the grid system. The initiating event frequencies of GTRN and LOOP for an OPR1000 plant are reduced by 17.7% and 78.7%, respectively, compared to the Korean industry-average initiating event frequencies, and its core damage frequency from internal events is reduced by 15.2%. The explicit consideration of the HLO capability in initiating event analyses makes significant changes in the risk contributions of the initiating events. Consequently, for more realistic at-power PSAs in Korea, we recommend incorporating plant-specific HLO-related design features when estimating initiating event frequencies.