• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.167-168
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• 2005

The operational characteristics of the integrated three-phase flux-lock type superconducting fault current limiter (SFCL) were analyzed. The suggested three-phase SFCL consisted of a three-phase flux-lock reactor and three high-Tc superconducting (HTSC) elements. The former has three windings wound on an iron core, each of which has the same turn's ratio between coil 1 and coil 2. The latter are connected in series with coil 2 of each phase. The integrated three-phase flux-lock type SFCL showed the operational characteristics that the fault phase could affect the sound phase, which resulted in quenching the HTSC element in the sound phase. Through the computer simulation applying numerical analysis for its three-phase equivalent circuit, the fault current limiting characteristics of the integrated three-phase flux-lock type SFCL according to the ground fault types were compared.

• 디지털산업정보학회논문지
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• 제8권4호
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• pp.193-203
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• 2012

This study analyzed regular transportation costs between port warehouses and processing plants and between processing plants and central distribution centers and further transportation costs relations according to empty transfer rates in each circulation by examining the distribution routes of imported grain including wheat, barley, corn, and soybean, namely port warehouses, processing plants, and central distribution centers. Based on the results, the study compared and reviewed the logistics transportation costs. The analysis results of the alternative model show that logistics operational costs could be considerably cut down by introducing a flexible vehicle transportation operational method, which is to change the vehicle loading parts for proper substitute transportation after unloading and transport them to other locations such as central distribution centers instead of returning empty, as an alternative to high operational costs deriving from empty vehicle operation in each circulation after unloading items in case of transportation of imported grain and processed items. The results allow for a more realistic approach to general problems with large-scale distribution network operation and provide a theoretical foundation to serve as a guide to establish policies for corporate operation of imported grain logistics systems.

• 한국항공우주학회지
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• 제31권10호
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• pp.40-50
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• 2003

저고도, 태양동기궤도인 아리랑 1호의 최초 임무운영 목표였던 3년 동안 관측된 궤도 변화를 분석하였다. 초기운영기간 동안 최적화된 궤도를 획득하기 위해 총 4회의 궤도조정이 있었으며, 총 8회의 안전모드가 발생하였다. 예상치 않은 안전모드 발생과 임무기간 동안 최고조에 달했던 태양활동이 궤도변화에 미치는 영향을 분석하였고, 초기 궤도조정 완료 직후 임무운영 기간에 대해 예측되었던 장기 궤도예측 결과와 궤도결정을 통해 실측된 궤도와의 차이를 분석하였다. 최적화된 궤도에서부터 운영된 3년의 임무기간 동안 고도를 제외한 나머지 궤도요소들은 설계된 임무궤도 범위 내에서 변화하였고, 태양동기궤도 특성을 유지하였음을 확인하였다.

• Wind and Structures
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• 제20권5호
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• pp.609-622
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• 2015

This study presents a dynamic response analysis of operational and parked wind turbines in order to gain better understanding of the roles of wind loads on turbine blades and tower in the generation of turbine response. The results show that the wind load on the tower has a negligible effect on the blade responses of both operational and parked turbines. Its effect on the tower response is also negligible for operational turbine, but is significant for parked turbine. The tower extreme responses due to the wind loads on blades and tower of parked turbine can be estimated separately and then combined for the estimation of total tower extreme response. In current wind turbine design practice, the tower extreme response due to the wind loads on blades is often represented as a static response under an equivalent static load in terms of a concentrated force and a moment at the tower top. This study presents an improved equivalent static load model with additional distributed inertial force on tower, and introduces the square-root-of-sum-square combination rule, which is shown to provide a better prediction of tower extreme response.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.289-289
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• 2008

We investigated the operational characteristics of the separated three-phase flux-lock type superconducting fault current limiter (SFCL). The single-phase lock type SFCL consist of two coils, which are wound in parallel through an iron core. The high-$T_c$ superconducting(HSTC) thin film connected in series with secondary coil. The separated three-phase flux-lock type SFCL consist of three single-phase flux-lock type SFCL. In a normal condition, the SFCL is not operate. When a fault occurs, the current of a HSTC thin film exceeds its critical current by fault current, the resistance of the HSTC thin film generated. Therefore fault current was limited by SFCL. The separated three-phase flux-lock type SFCL are operated in fault condition such as the the single line-to-ground fault, the double line-to-ground fault and the triple line-to-ground fault. The experimental results, the SFCL operational characteristics was dependent on fault condition.

• 대한산업공학회지
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• 제28권3호
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• pp.302-318
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• 2002

As facing the challenges from many competitors, the Office of Korea Postal Service has issued the fundamental plan of business renovation which includes the master plan of the information systems. In this paper we discuss the design of a to-be information system for postal service, which will be provided for the completion of the master plan. After briefly discussing the issues on developing information system and the current situation, we provide the design concept and the framework of the to-be system based on the bench marking and gap analysis with advanced systems. The to-be system consists of eight subsystems which can be grouped into three categories; intelligent systems, operational systems, and platforms. We develop detailed specification of each subsystem and provide an operational scenario. We also explain how the to-be system compatibly fits into an integrated information system, which will include the postal, banking, and management functions, to perform its ultimate role for the efficient postal service.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 광주전남지부
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• pp.112-113
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• 2006

The operational characteristics of the integrated three-phase flux-lock type superconducting fault current limiter (SFCL) were analyzed. The suggested three-phase SFCL consisted of a three-phase flux-lock reactor and three high-$T_c$ superconducting (HTSC) elements. The former has three windings wound on an iron core, each of which has the same turn's ratio between coil 1 and coil 2. The latter are connected in series with coil 2 of each phase. The integrated three-phase flux-lock type SFCL showed the operational characteristics that the fault phase could affect the sound phase, which resulted in quenching the HTSC element in the sound phase. Through the computer simulation applying numerical analysis for its three-phase equivalent circuit, the fault current limiting characteristics of the integrated three-phase flux-lock type SFCL according to the ground fault types were compared.

• 한국학교보건학회지
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• 제30권3호
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• pp.306-316
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• 2017

Purpose: The purpose of this study was to investigate the operational status and operational problems of health promoting model schools, particularly of the large-sized elementary schools in urban areas. Methods: The study analyzed the data of 14 large-sized elementary schools in urban areas selected from 85 health promoting model schools, an initiative led by the Ministry of Education from 2012 to 2014. Results: The study examined the operation process of health promoting schools in five stages; system development, needs survey & current status survey, school health policy development, program development & execution, and evaluation. In addition, the study discovered three key factors in operating health promoting schools and examined the status of each factor; connection with the curriculum, connection with the community, and consensus among members. Four problems were identified as operational problems: lack of research on faculty health issues, school physical environment and community resources, inadequate presentation of performance indicators, no close coordination in core task development and lack of linkage with the curriculum. Conclusion: It turned out the concept of health promoting school suggested by WHO was relatively faithfully realized in this study. Compared to small-sized elementary schools in rural areas, health promoting schools in this study showed better aspects overall. The connection with the community was good, but the connection with the curriculum was poor.

• 국제지역연구
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• 제22권1호
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• pp.61-78
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• 2018

해외직접투자에서 자회사 운영방식은 크게 수평적 자회사와 수직적 자회사로 구분할 수 있다. 이와 같은 자회사의 운영방식은 진출국의 제도에 따라 차이를 보인다. 본 연구는 제도이론관점에서 국내 전기전자 및 자동차산업의 해외직접투자 기업을 대상으로 진출국 공식적, 비공식적 제도가 해외 자회사 운영 방식선택에 미치는 영향을 실증 분석하였다. 실증분석결과, 진출국 정치적 위험정도가 낮을수록, 문화적 차이가 클수록 수직적 자회사를 선택하는 것으로 나타났다. 반면에 진출국 부패지수가 낮을수록, 경제자유도가 높을수록 수평적 자회사를 선택하는 것으로 나타났다.

• 한국환경과학회지
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• 제27권11호
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• pp.1073-1081
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• 2018

In this study, an operational data set was analysed by establishing a path model to figure out the actual cause-effect relationship of a wastewater treatment plant (WWTP); in particular, for the effluent concentrations of T-N and T-P. To develop the path models, data sets of operational records including effluent concentrations and operational factors were obtained from a field scale WWTP of $680,000m^3$ of treatment capacity. The models showed that the relationship networks with the correlation coefficients between variables for objective expressions indicated the strength of each relationship. The suggested path models were verified according to whether the analyzation results matched known theories well, but sophisticated minute theoric relationships could not be cropped out distinctly. This indicates that only a few paths with strong theoric casual relationships were represented as measured data due to the high non-linearity of the mechanism of the removal process in a biological wastewater treatment.