• Journal of the Society of Naval Architects of Korea
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• v.33 no.1
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• pp.124-134
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• 1996

In this paper the pressures and flowrate distributions in the loading/unloading piping system of LNG carrier have been investigated in the case of unsteady flow state as well as steady one. Under emergency situation the main cargo pumps are forced to fail, and the ESD(Emergency Shut Down) valves and Stop valves are closed within set-time. The surge pressures according to the variations of valve closing time have been computed to recognize the surge phenomenon due to sudden decrease of flowrate. By means of these analysis results, the most important factors on the in-pipe surge phenomenon of cargo loading/unloading piping system of LNG Carrier are the type of ESD and Stop valves, valve closing time, and the pipe arrangements.

• New & Renewable Energy
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• v.20 no.2
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• pp.17-25
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• 2024

In this study, the effect of the time step specified in a computational fluid dynamics (CFD) simulation on load response is analyzed and the drag coefficients of the floating body of floating offshore wind turbines (FOWTs) are estimated. By evaluating the error in the FOWT load response and the change in the drag-coefficient values based on the density of the time intervals, this study aims to establish a time-interval setting that minimizes the time and cost of CFD simulations for selecting drag-coefficient values. Practical CFD utilization strategies necessary for the calibration of medium-to high-fidelity analysis tools are presented. Based on a comparative analysis of CFD simulations conducted at various time intervals, the results confirmed that under a certain time interval that sufficiently considers various factors, the accuracy of the FOWT response with respect to density shows minimal differences, thereby providing an efficient utilization method for CFD simulations in FOWT design and analysis.

• Journal of the Korean Society for information Management
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• v.33 no.1
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• pp.247-268
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• 2016

Although it has been a long subject of study why researchers prefer some cited documents to others, the existing relative researches have had a variety of perspectives on the nature and complexity of the citation behavior and not provided a complete answer to this question. In particular, Korea researchers mainly used statistical analysis of bibliographic information, which has limitations in revealing dynamic and complex cognitive aspects of the citation process. In this study, I investigate the citer perception of citing motives and bibliographic factors through survey and compared the responses according to the researchers' characteristics. After extracting the 22 motivations and 21 factors through the literature analysis and configuring a 5-point Likert scale questions, I conducted a survey in the wat of an e-mail attachment. From the SPSS 22.0, the frequency analysis, t-test, and one-way ANOVA were performed on the 354 valid samples. As a result, it is found that supporting is considered the most important citing motive and social connection, self-citation have little influence. In the case of bibliographic factors, the journal's reputation was recognized the most influential factor and the number of pages and authors was the least. Significant differences in fields of study and research careers were showed in some parts. These results can substantiate earlier studies, determine whether the factors assumed influential in selecting references were intended, and suggest the search point to the specialty library or academic database.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.43-51
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• 2004

As the slenderness ratio of a high-rise building increases, the lateral load resisting system for the building is more often determined by serviceability design criteria. In serviceability design, the maximum drift and the level of vibration are controlled not to exceed the design criteria. Even though many drift method have been developed in various forms, no practical design method for wind induced vibration has been developed so far. Structural engineers rely upon heuristic or experience in designing wind induced vibration. Development of practical design method for wind induced vibration is required. Generally, wind induced acceleration responses are depending on several variables such as the weight density of a building, damping ratio, the natural period, and etc.. All parameters except the natural period or frequency are usually out of reach for structural engineers, then the wind acceleration response may be proportioned to the natural period. Therefore, in this paper, a wind induced vibration design method based on frequency control technique for high-rise is proposed. The method is applied to vibration design of a 25-story office building for performance evaluation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.156-159
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• 2002

This paper presents an experimental study of the surge response characteristics for the primary winding of a pole transformer and ultimately aims at devising countermeasures against the surge in operating transformer. After applying the impulse voltage to the primary of the 30 kVA pole transformer with single bushing, the voltage waveforms were measured at each tap lead and compared with one another. As a result, the voltage peak of the surge propagating in the primary was decreased in magnitude at a constant rate and somewhat delayed compared to the peak of the applied surge as the tap leads were getting closer to the grounding terminal. The voltage measured at the secondary was not delayed in time, different from that at the primary, and it was about 1/6 according to the turn ratio.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.222-225
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• 1999

This paper presents the surges response of the grounding systems using frequency domain electromagnetic field analysis software package. The frequency and time domain performance of a building grounding systems subjected to a lighting strike is described and discussed. The computed scalar potentials is presented graphically as a function of spatial coordinates. A double exponential lighting surge current is injected at one corner or the building grounding systems. Time-variant response of rod, mesh and kit grounding systems under impulse currents have been obtained. This paper deals with the results of studies on the time variation of ground resistance in three grounding systems.

• 프린팅코리아
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• v.11 no.1
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• pp.112-115
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• 2012

국립중앙도서관(관장 우진영)은 최근 국립중앙도서관 국제회의장에서 대한출판문화협회와 공동으로 '도서관과 출판계의 상호발전과 협력'을 주제로 세미나를 개최했다. 김기태 교수(세명대학교)사회로 진행된 이번 세미나는 표정훈 출판평론가의 '최근 우리 출판계 동향과 전망' 발표를 시작으로 곽철완 교수의 '납본제도 현황과 발전', 최성구 출판유통진흥원 기획팀장의 '국제표준도서번호(SBN)제도운영 활성화: 전자출판물, 정부간행물 ISBN 부여 중심으로', 오혜영 국가서지정보센터추진단 사무관의 '출판시도서목록(CIP)제도운영 현황과 신청안내'에 대한 주제발표와 참석자들의 질의 응답 순으로 진행됐다. 본지는 표정훈 출판평론가가 발표한 '최근 우리 출판계 동향과 전망' 발표를 요약 정리한다.

• 프린팅코리아
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• v.10 no.12
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• pp.100-103
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• 2011

국립중앙도서관(관장 우진영)은 최근 국립중앙도서관 국제회의장에서 대한출판문화협회와 공동으로 '도서관과 출판계의 상호발전과 협력'을 주제로 세미나를 개최했다. 김기태 교수(세명대학교) 사회로 진행된 이번 세미나는 표정훈 출판평론가의 '최근 우리 출판계 동향과 전망' 발표를 시작으로 곽철완 교수의 '납본제도 현황과 발전', 최성구 출판유통진흥원 기획팀장의 '국제표준도서번호(ISBN)제도 운영 활성화: 전자출판물, 정부간행물 ISBN 부여 중심으로', 오혜영 국가서지정보센터추진단 사무관의 '출판시도서목록(CIP)제도 운영 현황과 신청안내'에 대한 주제발표와 참석자들의 질의 응답 순으로 진행됐다. 본지는 표정훈 출판평론가가 발표한 '최근 우리 출판계 동향과 전망' 발표를 요약 정리한다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.331-336
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• 2003

본 논문은 마이크로프로세서 및 전력용반도체인 사이리스터로 제어되는L-C 고조파 필터에 관한 것이다. 개발된 고조파 필터는 3상 220[V]이며 25[㎸A]5고조파 제거용이다. 또한 고조파 필터는 콘덴서에 의해 역률을 개선하는 역할을 한다. 고조파 전류 발생시 3사이클 이내에 고조파 필터가 동작하며, 제로 크로싱 제어로 개폐시 과도서지가 발생하지 않는다. 전류변동에 따른 응답속도가 빨라 부수적으로 전압변동에 의한 플리커 현상을 해소시키는 역할도 한다. 개발된 제품에 대하여 안전성능 및 일반성능 실험결과 만족할 만한 결과를 얻었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.593-596
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• 2014

다수의 개발자들이 참여하는 프로젝트에서 개발자들의 필요에 의해 동일한 기능의 유사한 코드가 생성된다. 이것은 시스템 전체적으로 중복 코드가 생성되어 시스템 성능에 영향을 준다. 또한 개발자의 능력에 따라 화면의 응답속도 및 데이터베이스 처리 속도에 차이가 나게 되어 결국 시스템에 악영향을 끼치게 된다. 이러한 문제는 개발자들의 의사소통을 위한 표준 개발 도구를 활용함으로써 해결 가능하다. DBC Editor 는 이클립스 플러그인 기반으로 기동되어 OS 에 영향을 받지 않고 기능별로 독립적인 플러그인을 구성하여 확장 가능하다. 또한 쿼리만을 관리하므로 시스템이 유연해지며 개발자들은 표준화 된 코드개발이 가능하여 개발 생산성을 향상시킬 수 있다.