• 대한화학회지
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• 제66권1호
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• pp.15-30
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• 2022

본 연구는 과학 실천 수업을 위한 교사학습공동체 중학교 과학교사들의 PCK 요소 간 상호작용 탐색을 목적으로 한다. 이를 위해 교사학습공동체에 참여하는 5명의 교사를 대상으로 사전·사후 설문과 면담, 교사학습공동체 논의 녹음, 수업계획안, 수업 영상, 수업 일기 등의 자료를 수집하여 질적 분석을 하였다. 교사학습공동체 교사들의 과학 실천 수업 PCK 요소 간 상호작용은 일방적으로 영향을 미치는 단방향 상호작용과 서로 영향을 주기도 하고 받기도 하는 양방향 상호작용의 두 가지 유형으로 나타났다. 상호작용이 일회성으로 그치거나 연쇄적으로 일어나기도 했으며, 양방향 상호작용의 경우에는 교사학습공동체 한 모임에서 동시적으로 상호작용이 이루어지거나, 교사학습공동체 여러 모임을 거쳐 연속적으로 양방향 상호작용이 이루어지기도 했다. 본 연구는 교사학습공동체의 협력적 학습 맥락이 다양한 PCK 요소 및 하위요소 간 여러 가지 상호작용을 복합적으로 촉진하는 환경을 조성할 수 있다는 시사점을 제공한다.

• 대한전자공학회논문지
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• 제15권3호
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• pp.24-29
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• 1978

사이크로트론파와 전자속파의 결합에 의한 신형모드의 동작이 관찰되었다. 전파형성 과정을 분석하는 데 전자동력학과 결합모드에 의한 방법이 적용되었으며 유도된 이론적 이득식에서 신형초고주파 증폭기가 설계 제작 되었으며 실험결과잡음이 없이 고전력을 얻을 수 있는 증폭기임이 보여진다.

• 전기학회논문지
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• 제59권11호
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• pp.1929-1935
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• 2010

This paper describes the operation effect of FACTS devices in the Korean power system. At the year of 2010, three FACTS devices is under commercial operation in the Seoul area. Among them, 345kV ${\pm}100MVA$ STATCOM at Mi-Geum substation and 345kV ${\pm}200MVA$ SVC at Dong-Seoul substation are very close at their electrical and geographical distance. Therefore, the additional analysis including interaction and mutual transient is necessary. Therefore, a detailed EMTDC/PSCAD simulation model was developed and steady-state/transient analysis was implemented.

• Journal of Photoscience
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• 제12권1호
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• pp.11-15
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• 2005

The mechanism of interaction of two drugs viz., amoxicillin and cloxacillin with bovine serum albumin has been investigated using fluorescence absorption and circular dichroism spectroscopy. The quenching mechanism of fluorescence of bovine serum albumin by amoxicillin and cloxacillin was discussed. The binding sites number n and apparent binding constant Kwere measured by fluorescence quenching method. The thermodynamic parameters obtained from data at different temperatures were calculated. The distance r between donor (bovine serum albumin) and acceptor (amoxicillin and cloxacillin) was obtained according to Forster theory of non-radiative energy transfer. The effect of common ions on binding constant was also investigated. The results of synchronous fluorescence spectra, UV-vis absorption spectra and circular dichroism of BSA in presence of amoxicillin and cloxacillin show that the conformation of bovine serum albumin changed

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 춘계 학술발표회논문집
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• pp.182-189
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• 2003

Member actions of long-span suspension bridge due to multiple-support motion are generally larger than those for synchronous support motion frequently employed in aseismic design of a conventional structure. In this study, all the sources of the asynchronous support motion are considered including the loss of coherence and the soil-structure interaction as well as the time delay due to wave propagation of seismic waves. The substructure technique analyzing total soil-foundation-structure system as a superposition of two sub-structures including soil-foundation system and structure itself is employed for the seismic response analysis of the suspension bridge. Finally, an application example is presented to demonstrate applicability of the proposed methodology.

• 복식문화연구
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• 제30권5호
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• pp.717-731
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• 2022

The purpose of this study is to suggest effective online pedagogical strategies for a fashion design CAD course to enhance student learning and satisfaction. The study investigated student experience of online learning and compared online learning with a face-to-face learning experience. Student concentration, participation, perceptions of effectiveness of teaching, utilization of learning materials, and satisfaction were analyzed using a 5-point Likert scale. Advantages and disadvantages of online learning as well as advantages of face-to-face learning were also analyzed both quantitatively and qualitatively. Student concentration, participation, and perception of effectiveness of teaching were greater for face-to-face learning with significantly higher concentration on individual practice. Students utilized video recording of synchronous online lectures more actively than PDF lecture notes. The advantages of face-to-face learning were plentiful communication and feedback and easy questioning process as well as high levels of understanding and concentration. Meanwhile, major disadvantages of online learning were the speed of the lecture, lower levels of understanding and concentration, limited peer interaction, and technical problems. Major advantages of online learning were flexibility and convenience, repetitive learning through videos, and instant communication and feedback. Students preferred a blended learning approach for the fashion design CAD course. For effective online learning, it is suggested that instructors frequently question and check student practice through screen share in a private online meeting room and engage activities that are demanding of student interaction. The video recording of synchronous online lectures is also suggested as a supplemental learning material for repetitive learning.

• 전기학회논문지
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• 제64권9호
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• pp.1269-1275
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• 2015

Turbine-generator torsional response is caused by interaction between electrical transient air-gap torque and mechanical characteristics of turbine-generator shafts. There are various factors that affects torsional interaction such as fault, circuit breaker switching and generator mal-synchronizing, etc. Fortunately, we can easily simulate above torsional interaction phenomena by using ElectroMagnetic Transient Program (EMTP). However, conventional EMTP shows the incomplete response of super- synchronous torsional mode since it does not consider turbine blade section. Therefore, in this paper, we introduced mechanical-electrical analogy for detailed modeling of turbine-generator shaft system including low pressure turbine blade section. In addition, we derived the natural frequencies of modeled turbine-generator shaft system including turbine blade section and analyzed the characteristics of mechanical torque response at shaft coupling and turbine blade root area according to power system balanced/unbalanced faults.

• 한국HCI학회논문지
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• 제12권3호
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• pp.5-11
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• 2017

한국 전통춤은 인류의 문화적 자산으로 문화적 활용가치를 가지고 있지만 전수희망자의 부족과 대중적인 무관심으로 소멸의 위기에 처해 있다. 네트워크 기술과 영상매체 기술을 활용한 전통춤의 이러닝(E-Learning)은 위에서 제기한 문제점들을 해결하기 위한 방법이 될 수 있다. 이 연구는 전통춤 교육에 활용될 수 있는 이러닝 교육과정 및 실시간 이러닝 교육시스템들을 제안하였다. 시스템들은 일반인을 대상으로 HCI(Human Computer Interaction) 사용자 평가법에 따라 비교평가하고 피드백 및 교육경험 인터뷰를 실시하였다. 본 연구는 전통춤의 실시간 이러닝 교육시스템을 제안함으로써 공간적 제약을 극복하고 새로운 매체 경험을 통해 무형문화재로서 전통춤을 전승, 보급하는데 기여할 수 있다.

• 전력전자학회논문지
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• 제10권6호
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• pp.610-617
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• 2005

가변속 풍력발전 시스템의 시뮬레이션 모델을 PSCAD/EMTDC 기반으로 개발하였다. 개발된 시뮬레이션 모델은 바람 모델, 회전자 다이나믹스, 동기 발전기, 전력 변환기, 변압기, 배전 선로, 무한 모선 등으로 구성되어 있다. 특히 블레이드의 공기역학적 특성과 전력 변환기의 제어 전략도 포함되어 실질적인 풍력발전기의 동작 특성을 시뮬레이션 할 수 있다. 개발된 시뮬레이션 모델을 이용하여 입력 풍속의 변동, 발전기 주변 부하의 변동, 계통측 전원 전압의 불평형 등의 다양한 조건에서 풍력발전기의 과도 상태 거동 특성을 확인하였다. 본 연구 결과는 앞으로 가변속 풍력발전기와 전력계통의 연계 운전시 신뢰성을 높이고 전력 시스템을 보호하기 위한 기초자료로서 활용될 수 있을 것으로 기대된다.

• Journal of Electrical Engineering and Technology
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• 제2권2호
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• pp.208-215
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• 2007

The significant drawback of the permanent magnet linear synchronous motor (PMLSM) is force ripples, which are generated by the distortion of the stator flux linkage distributions, cogging forces caused by the interaction of the permanent magnet and the iron core and the end effects. This will deteriorate the performance of the drive system in high precision applications. The PMLSM and its parasitic effects are analyzed and modeled using the complex state-variable approach. To minimize the force ripple and realize the high precision control, the components of force ripples are extracted first and then compensated by injecting the instantaneous current to counteract the force ripples. And this method of the PMLSM system is realized by the field oriented control method. In order to verify the validity of this proposed method, the system simulations are carried out and the results are analyzed. The effectiveness of the proposed force ripples reduction method can be seen according to the comparison between the compensation and non-compensation cases.