• Progress in Superconductivity and Cryogenics
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• v.18 no.4
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• pp.30-34
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• 2016

In this study, a SFCL-combined DC circuit breaker system was proposed by applying the current-limiting technology for DC circuit breaking. The SFCL-combined circuit breaker system consists of a mechanical DC circuit breaker combined with superconductors. To ensure the reliable structure and operation of the SFCL-combined circuit breaker system, a simulation grid was designed using the EMTDC/PSCAD program, and simulation was conducted. The results showed that the SFCL-combined DC circuit breaker system with superconductors limited the maximum fault current by 37%. In addition, the burden on the DC circuit breaker was decreased by 87%.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.147-154
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• 2001

Dynamic behavior of high speed train is very important because the high speed train should be safe and satisfied with the ride comfort. An eddy current brake system is mounted on trailer bogie and wheelset. The eddy current braking force longitudinally exerts on the articulated trailer bogie and the attraction force vertically exerts on the wheelset. Because a frame of eddy current brake system is flexible, these forces generate the vertical vibration at middle point of the frame. Also, the vibration change the vertical clearance between an electromagnet and top of rail which affect the magnitude of braking and attracting forces. Therefore, the dynamic behavior of the eddy current braking system must be predicted for design the dynamic characteristic of its mounting system when normally operate on rail which have irregularity. Vampire program is used for Prediction of the dynamic behavior of an eddy current braking system.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.2
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• pp.170-175
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• 2008

This paper describes the exact short-circuit current calculation technique for the single-phase transformer which is installed in the three-phase systems and shorted in the secondary side. Not only the results for a short-circuit current calculation in the existing literatures are wrong, but also little literature deals with the short-circuit current for a single-phase transformer. So, this paper presents a theoretical study and calculation method for a single-phase short current. The validity of the presented method is investigated through Simulation using "Power Tools" and "PSim" program.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.9-14
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• 2008

The effects of baffles in PEM fuel cell with parallel flow channel has been simulated by using conmmercial program. The simulation has been conducted through the channel and there are four different heights of baffles, No Baffle($H_b$=0), Partially Blocked Baffle(0.25, 0.5, 0.75), Fully Blocked Baffle(1) conditions. The result shows that current density changes while placing a baffle at the various positions along the channel. Current density with a single baffle is higher than that without baffle and current density using Fully Blocked Baffle(FBB) is much higher than current density using Partially Blocked Baffle(PBB). When the baffle is closer to outlet of the channel, current density increases. It is found that pressure is related to current density. If the pressure is higher, the better performance will be expected.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.5
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• pp.879-884
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• 2009

A Method for detection of saturation of a current transformer(CT) is proposed. The algorithm is initiated when the end point of a saturation period is detected. This detection is achieved by checking the time interval between the adjacent zero-crossing points of the second derivative of the secondary current. Once the end point of the saturation period is detected, the beginning point of the corresponding saturation period is determined by backward examination of the sum of the secondary current from the end point. The performance of the algorithm was evaluated for a-g faults on a 345 kV 100km overhead transmission line. The Electromagnetic Transient Program(EMTP) was used to generate fault current signals for different fault inception angles and different remanent fluxes. The performance evaluation shows that the proposed algorithm successfully detects the saturation period even in the presence of a remanent flux.

• Progress in Superconductivity and Cryogenics
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• v.12 no.3
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• pp.39-43
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• 2010

In Korea, 22.9kV hybrid SFCL (Superconducting Fault Current Limiter) has been developed and carried out long-term field tests in Gochagn power test center of KEPCO through DAPAS program. The SFCL will be installed at a distribution line of Icheon substation in Korea. For the successful application, we have to design the specifications considering real power system operation. This paper proposes a concept of the operating current based rms value for the protection coordination with protective delays and studies a proper range of the current in Korean distribution power system.

• Korean Institute of Interior Design Journal
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• v.19 no.6
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• pp.121-128
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• 2010

Interior design education has been developed rapidly since the discipline established in Korea in 1980s but unfortunately the development was without any progressive transition until 1990's. When Korean Institute of Interior Design/KIID inaugurated in 1992, interior design education and related research activities began to be intensified. Despite its effort, there were still confusion about the discipline as there were many similar discipline tracks (architecture, design, fine art, & home economic, etc.) each having an own definition of interior design and introducing different aspects of educating the subject. Education program for interior design still not sufficiently supporting the needs of today's rapidly changing industry nor to prepare the diverse needs of the client. In order for interior design major to be effective in the future and fulfill the needs of current industry development within our society, re-evaluation of our current interior design educational programs in Korea is important. This study will be the beginning of a research series. As the first part of the research series, this particular study has been focused on reviewing of current status of interior design majors in the nation and its current condition. While making suggestion for the changes in curriculum, the following points will have to be considered as basic principle. First, understanding the duality of technology and design to accommodate the contents of design discipline. Second, understanding the need of practice and theory combined for practical education. And lastly, considering ways to adopt the human experience in order to develop creativity in oneself. The focus of this research is only on the interior design discipline, and research method as the following; first, analyze current status by reviewing admission data for 2010. Second, process a survey regarding the interior design education and practice-related issues in admissions and collect opinions from educators and professional designers in the field. Thirdly, with reference to previous studies, suggestions will be made for the discipline to be effective in the field. As mentioned earlier, this study series will continue and develop to suggest improvement in interior design program as well as to provide curriculums for students get ready for the industry with more up-to-date knowledges and creativities.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.6
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• pp.138-146
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• 2010

DC railway power supply system generally uses the running rails as negative-polarity return conductor for traction load current, and the induced rail potential and stay current cause serious problems to any electrified matter in the underground and also safety problems to human body. This paper presents a new algorithm for the analysis of the rail potential and the stray current in DC railway power system operated under independent/parallel power feeding mode. The effect of load current fluctuation during train operation is also calculated by using TPS(Train Performance Simulation) program to analysis the variation of the railway potential and stray current along railway track. Simulation program is developed based on the proposed algorithm and case studies are provided.

• Ocean and Polar Research
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• v.28 no.2
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• pp.209-214
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• 2006

The East Sea Branch (ESB) of KORDI will be launched in 2008. She will take a role of monitoring the sea surface topography and temperature by satellites, short- and long-term sea levels by tide gauges, coastal currents and open-sea circulation by setting up coastal radars and mooring current-meters and acoustic equipments, as well as monitoring nearshore processes, coastal erosion and water pollution. A basic program of coastal zone management will help ocean-policy makers to set up right decisions based upon scientific background of the regional data in the East Sea. Networking among the neighboring countries around the sea will supply more useful information not only for experts but also for ordinary vacationers or fishermen. In order for this program to be successfully settled down during the next decade, it is necessary for a leader to have the right vision to attract more experts from global brain pools and to manage the ESB as a leading-edge observatory in the world. Details about this leading-edge operational program are introduced in the text.

• International Journal of Contents
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• v.10 no.3
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• pp.55-63
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• 2014

Existing science education that excludes narrative thinking impedes the understanding of the context of workbook content. The object of this research is to develop a storytelling-learning program based on narrative thinking to elevate learners' interest in science and expand their inventive problem-solving abilities. Following an analysis of the current Korean curriculum, eight types of storytelling materials that utilize local content were developed for grades 7-9. The learning program used quest storytelling and was designed such that learning activities such as investigation, discussion, and experimentation were included in the process of solving each quest. Learners experienced an interest in storytelling learning resulting from participation in this storytelling-learning program. Moreover, learners demonstrated inventive problem-solving abilities in the process of completing the stories. During the process of assembling the storytelling materials, the students interacted with enthusiasm and generated ideas. The teachers indicated a positive feedback to the storytelling program as a new attempt to stimulate learners' interests. In the future, with continuous development and application, storytelling-science-learning programs that base science learning on narrative thinking are expected to be successful.