• Journal of the Korean Chemical Society
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• v.66 no.1
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• pp.15-30
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• 2022

The purpose of this study was to examine interactions among components of pedagogical content knowledge of middle school science teachers in a teacher learning community targeting science practice-based instruction. Data collection consisted of pre and post questionnaire and interview with each of five science teachers, audio-recording of teacher discussion in a teacher learning community, lesson plans, teacher written reflection, and video-recording of teaching practice. Qualitative data analysis revealed that there were two types of interactions, i.e., one-way interaction and two-ways interaction among components of pedagogical content knowledge of science teachers in a teacher learning community. There were also consecutive interactions as well as one-shot interaction. For two-ways interaction there were synchronous two-ways interaction in a teacher learning community meeting as well as consecutive two-ways interaction along with several meetings. This study provides implications that collaborative learning context in a teacher learning community should stimulate various types interactions among components of pedagogical content knowledge.

• Journal of the Korean Institute of Telematics and Electronics
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• v.15 no.3
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• pp.24-29
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• 1978

A new mode of operation is observed in this paper which involves the tractive wave interaction between a cyclotron ways and a synchronous electron beam. The wave interaction is analysed by using both electron dynamics and coupled-mode methods. The gain expression derived from the analysis prognoses a new type of improved uhf amplifier with low noise and high power. Based on the theoretical analysis, experimental tubes have been designed, constructed arid exporimented. As a result, a low noise amplifier is anticipated well into millimeter lave region.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.11
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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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• v.12 no.1
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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

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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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.

• The Research Journal of the Costume Culture
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• v.30 no.5
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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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.9
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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.

• Journal of the HCI Society of Korea
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• v.12 no.3
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• pp.5-11
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• 2017

Korean traditional dance has cultural value and is human's cultural heritage. But they are in danger which is caused by lack of bearers and public interest. E-Learning of traditional dance using network technology and digital media can be a solution to extinction problem. The aim of this study is to propose the E-Learning courses and systems for learning traditional dance. E-Learning systems were evaluated in accordance with the HCI (Human Computer Interaction) user evaluation. This study contribute to overcoming distance constraints by offering synchronous E-Learning education system of traditional dance as intangible cultural heritage through new media experience.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.6
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• pp.610-617
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• 2005

A variable speed wind turbine simulation model for grid connection is developed based on PSCAD/EMTDC. The model consists of wind model, rotor dynamics, synchronous generator, power converter, transformer, distribution line and infinite bus. Implementation of blade characteristics and power converter control strategies are included. Several transient case studies are performed including wind speed change, local load change and grid-side voltage unbalance using developed simulation model. The results of this work can be utilized for study of actual interaction between wind turbine and grid for reliable operation and protection of power system.

• Journal of Electrical Engineering and Technology
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• v.2 no.2
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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.