• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권2호
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• pp.69-75
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• 2006

This paper deals with the optimum design solution on reduction of torque ripple for a Synchronous Reluctance Motor with concentrated winding using response surface methodology. The coupled Finite Elements Analysis (FEA) & Preisach model have been used to evaluate the nonlinear solution. Comparisons are given with characteristics of a SynRM according to the stator winding, slot number, open width of slot, slot depth, teeth width variation in concentrated winding SynRM, respectively. This paper presents an optimization procedure using Response Surface Methodology (RSM) to determine design parameters for reducing torque ripple. RSM has been achieved to use the experimental design method in combination with finite Element Method (FEM) and well adapted to make analytical model for a complex problem considering a lot of interaction of design variables. Moreover, Sequential Quadratic Problem (SQP) method is used to solve the resulting of constrained nonlinear optimization problem.

• International Journal of Contents
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• 제9권3호
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• pp.19-28
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• 2013

This paper, based on a qualitative ethnographic study among college of education students, examines the online interactional processes surrounding academic discourse socialization. Data for this paper come from a larger study of an academic classroom community of graduate students and their instructor. In this study, I looked into the ways computer-mediated communication (CMC) contexts factor into graduate students' academic literacy experience in a graduate classroom, therein enculturating them into their new academic community. I focus on cases of nonnative graduate students in a content course in the department of educational psychology at a large southwestern university in the U.S. I explore the agency of the focal participants in terms of the roles they played in the classroom discourse highlighting the dialectical and interactional perspective of academic discourse socialization. This paper focused on the construction of varied participant roles of the focal students. It further examines student reactions and responses to these constructions during synchronous CMC activity.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 추계학술대회 논문집
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• pp.172-174
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• 2008

The detent force of the permanent magnet linear synchronous motor (PMLSM) is caused by the interaction between the permanent magnet and the iron core of the mover without input current. It is a function of the mover position relative to the stator. This paper proposes a control based method to reduce the detent force for the PMLSM. This detent force that can be predicted by finite element method (FEM) is compensated by injecting the instantaneous current using the field oriented control (FOC) method. Both the simulated and experimental results are reported to validate the effectiveness of this proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.19-21
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• 1998

The problem in improving the positioning precision of a Permanent Magnet Linear Synchronous Motor (PMLSM) is the detent force caused by the interaction of the magnets with the teeth of stator. This paper presents 3-Dimensional Equivalent Magnetic Circuit Network Method (3-D EMCN) for the analysis of PMLSM. 3-D EMCN is a numerical analysis method which supplements magnetic equivalent circuit by using numerical technique. We analyzed the fields and forces of PMLSM in case of skewed magnet and axially segmented magnet construction.

• Journal of Power Electronics
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• 제19권2호
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• pp.569-579
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• 2019

A robust controller is designed based on feedback linearization and sliding mode control to damp sub-synchronous control interaction (SSCI) in doubly fed induction generator (DFIG) wind power plants (WPPs) interfaced with the grid. A feedback-linearized sliding mode controller (FLSMC) is developed for the rotor-side converter (RSC) through feedback linearization, design of the sliding mode controller, and parameter tuning with the use of particle swarm optimization. A series-compensated 100-MW DFIG WPP is adopted in simulation to evaluate the effectiveness of the designed FLSMC at different compensation degrees and wind speeds. The performance of the designed controller in damping SSCI is compared with proportional-integral controller and conventional sub-synchronous resonance damping controller. Besides the better damping capability, the proposed FLSMC enhances robustness of the system under parameter variations.

• 디지털융복합연구
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• 제18권12호
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• pp.69-79
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• 2020

본 논문은 대학 교육에 있어서 실시간 온라인 교육의 효과적인 운영을 위한 고려요소를 탐색하는 목적을 지닌다. 대학 교육에서 실시간 온라인 교육이 확대되고 있다. 하지만 성공적인 운영이 이루어지기 위해 고려해야 할 핵심 요소가 무엇인지를 학습자의 경험과 인식을 통해 종합적으로 탐색한 연구는 미흡하다. 그룹면담을 통한 질적 분석과 다차원척도 분석법을 활용하여 학습자의 경험과 인식을 통해 고려요소와 개선방안을 확인하였다. 연구 결과, 효과적인 운영을 위해 상호작용이 중요하게 고려되어야 하며, 학습자 간 라포 형성이 이루어져야 한다. 활동을 촉진하는 다양한 활동 도구가 통합된 시스템 개선과 함께 교수자는 퍼실리테이터 역할을 중점적으로 수행해야 하며 학습자는 몰입이 이루어질 수 있도록 환경을 조성해야 한다. 온라인 교육 유형들에 대해서 학습자들은 활동성과 동일 시간성으로 구분하였다. 향후 실시간 온라인 교육의 특성을 고려한 최적화된 수업 설계전략을 개발할 필요가 있다.

• 대한통합의학회지
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• 제9권2호
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• pp.53-61
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• 2021

Purpose : The purpose of this study is to explore the effectiveness of online blended learning(asynchronous online learning class 1+synchronous online learning class 2) method and discuss the applicability of online blended learning. In this study, we will analyze the differences in class satisfaction and academic achievement between asynchronous online learning and online blended learning classes, and discuss the strengths, weaknesses, and satisfactions of online blended learning. Methods : The subjects of this study were 39 of the occupational therapy students who took the 'child development' course. Asynchronous online learning class was applied for 1-6 weeks and online blended learning was applied for 9~14 weeks. The online blended learning class consisted of 1 hours synchronous online learning and 2 hours asynchronous online learning. For the asynchronous online learning, the screen recording program of OBS Studio was used, and for the synchronous online learning, the Zoom program was used. The results of course evaluation and academic achievement of students according to the type of lecture were compared, and a survey was conducted on the satisfaction of online blended learning. Results : The results of this study are as follows. First, satisfaction(A class: t=-4.19, p=.001, B class: t=-7.94, p=.00) with online blended learning classes was significantly higher than asynchronous online learning. Second, when applying online blended learning class, academic achievement(t=-10.58, p=.00) was significantly higher. Third, the online blended learning class showed the highest satisfaction in improving the interest in the subject, and it was found to be helpful in online class management, professor-student interaction, and class content understanding. Conclusion : We have found that online blended learning can compensate for the shortcomings of online lectures and increase the quality of the lectures and the satisfaction of students. The application of online blended learning should be supplemented according to the characteristics of each class, and I hope that blended online teaching methods can be developed based on new ideas in the future.

• 한국멀티미디어학회논문지
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• 제1권2호
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• pp.215-223
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• 1998

본 논문에서는 월드와이드웹에 기반하면서 사용자간 상호작용을 극대화할 수 있는 통합 가상교육시스템인 WebClass를 설계하고 구현한 방법을 소개한다. 기존 가상교육 시스댐은 사용자간 상호작용 모텔을 제시하지 않고 다양한 상호작용 기능을 포함함으로써 각 기능들이 유연하게 통합되지 못했다 WebClass에서는 다양한 교수 모델을 지원하기 위한 상호작용 모텔을 설정하고 그 모텔에 기반하여 사용자와 가상교육시스템간의 상호작용을 지원하는 사용자 인터페이스를 설계하고 구현하였다. 따라서 단순한 기능위주의 통합이 아닌 사용자간의 상호작용을 기본으로 하여 다양한 상호작용 기능을 갖는 통합 가상교육시스템을 개발하였기 때문에 가상교육이 갖는 상호작용의 부족을 최대한 보완하였다. WebClass에서는 사용자간의 상호작용을 위해 비동기 공유 기능과 동기 공유 기능올 모두 지원한다 이들 공유 기능들은 유기적으로 결합하고 유연한 사용자 인터페이스를 사용하여 서로 통합함으로써 사용자간의 상호작용을 극대화하여 효율적인 가상교육을 지원할 수 있게 하였다.

• Bulletin of the Korean Chemical Society
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• 제32권9호
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• pp.3261-3266
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• 2011

The interaction of bilobalide (BB) and ginkgolides B (GB) with bovine serum albumin (BSA) was investigated by fluorescent technique and UV/vis absorption spectroscopy. The results showed that BB and GB could intensively quench the fluorescence of BSA through a static quenching procedure. The binding constants (Ka) and the average binding distance between the donor (BSA) and the acceptor (ginkgolides) were obtained ($r_{BB}$ = 5.33 nm and $r_{GB}$ = 4.20 nm) by the theory of non-radiation energy transfer, and then the thermodynamic parameters such as ${\Delta}S^0$ (0.17-0.32 kJ/mol), ${\Delta}G^0$ (-20.76 ~ -17.79 kJ/mol) and ${\Delta}H^0$ (32.47-76.52 kJ/mol) could be calculated, respectively. All these results revealed that the interaction of BB and GB with BSA were driven mainly by hydrophobie force. The synchronous fluorescence spectroscopy was applied to examine the effect of two ginkgolides on the configuration of BSA. The configuration alteration of BSA could be induced by the hydrophobicitv environment of tyrosine with the increase of the drug concentration.

• 한국CDE학회논문집
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• 제20권4호
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• pp.337-347
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• 2015

This paper presents a dynamic association and natural interaction method for multi-displays composed of smart devices. Users can intuitively associate relations among smart devices by shake gestures, flexibly modify the layout of the display by tilt gestures, and naturally interact with the multi-display by multi-touch interactions. First of all, users shake their smart devices to create and bind a group for a multi-display with a matrix configuration in an ad-hoc and collaborative situation. After the creation of the group, if needed, their display layout can be flexibly changed by tilt gestures that move the tilted device to the nearest vacant cell in the matrix configuration. During the tilt gestures, the system automatically modifies the relation, view, and configuration of the multi-display. Finally, users can interact with the multi-display through multi-touch interactions just as they interact with a single large display. Furthermore, depending on the context or role, synchronous or asynchronous mode is available to them for providing a split view or another UI. We will show the effectiveness and advantages of the proposed approach by demonstrating implementation results and evaluating the method by the usability study.