• The Journal of the Korea Contents Association
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• v.21 no.4
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• pp.14-25
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• 2021

The purpose of this study is to explore what are the interactive factors of synchronous online education in university and identify the level of interaction. This study used mixed research method. As a result of the interaction level, it was recognized that face-to-face education could be more interactive than synchronous online education. Synchronous online education could have better interactive between instructor and learner, and among learners than asynchronous online education. Factors which influencing the interaction were as follows: small group activities and scaffolding, diversification of communication channels and integration of learner's question in learning content. Detrimental elements were distance felt between instructor and learners, low intimacy among learners, content-focused lecture, restrictions on non-verbal communication, unstable systems and misusing microphones. The necessary factors to promote interaction are planning interactive class activities, etc. Based on the results, it was to suggest what kinds of efforts are needed to make interaction more effective in terms of teaching and learning method & activity, tool & system, and environment.

• Phonetics and Speech Sciences
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• v.7 no.1
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• pp.97-105
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• 2015

This research mainly focuses on intonational characteristics of synchronous English speech. Intonation contours were extracted from 1,848 utterances produced in two different speaking modes (solo vs. synchronous) by 28 (12 women and 16 men) native speakers of English. Synchronous speech is found to be slower than solo speech. Women are found to speak slower than men. The effect size of speech rate caused by different speaking modes is greater than gender differences. However, there is no interaction between the two factors (speaking modes vs. gender differences) in terms of speech rate. Analysis of pitch point features has it that synchronous speech has smaller Pt (pitch point movement time), Pr (pitch point pitch range), Ps (pitch point slope) and Pd (pitch point distance) than solo speech. There is no interaction between the two factors (speaking modes vs. gender differences) in terms of pitch point features. Analysis of sentence level features reveals that synchronous speech has smaller Sr (sentence level pitch range), Ss (sentence slope), MaxNr (normalized maximum pitch) and MinNr (normalized minimum pitch) but greater Min (minimum pitch) and Sd (sentence duration) than solo speech. It is also shown that the higher the Mid (median pitch), the MaxNr and the MinNr in solo speaking mode, the more they are reduced in synchronous speaking mode. Max, Min and Mid show greater speaker discriminability than other features.

• Journal of Digital Convergence
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• v.19 no.5
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• pp.57-67
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• 2021

This study explores what factors influence college students' synchronous online learning satisfaction and what advantages and disadvantages exist when it comes to taking synchronous online learning courses. In-depth interview results suggest that advantages of synchronous online learning are convenience (no need for travel, no limitation for study place), saving money, and no worry for contracting Corona 19. However, disadvantages of synchronous online learning are instability of online learning system, lack of interaction between learners and educators, difficulty of instant communication, low education quality, and unfairness of exams. This study found that college students taking synchronous online course think that synchronous online learning is more appropriate for theory-based course than practice-based courses in that theory-based courses are lecture-oriented while practice-based courses require interactivity between learners and educators. This study provides educators a baseline understanding on how college students think over synchronous online learning and how to enhance students' satisfaction with synchronous online learning.

• International Journal of Fluid Machinery and Systems
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• v.10 no.2
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• pp.164-175
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• 2017

Francis turbines are often operated over a wide load range due to high flexibility in electricity demand and penetration of other renewable energies. This has raised significant concerns about the existing designing criteria. Hydraulic turbines are not designed to withstand large dynamic pressure loadings on the stationary and rotating parts during such conditions. Previous investigations on transient operating conditions of turbine were mainly focused on the pressure fluctuations due to the rotor-stator interaction. This study characterizes the synchronous and asynchronous pressure and velocity fluctuations due to rotor-stator interaction and rotating vortex rope during load variation, i.e. best efficiency point to part load and vice versa. The measurements were performed on the Francis-99 test case. The repeatability of the measurements was estimated by providing similar movement to guide vanes twenty times for both load rejection and load acceptance operations. Synchronized two dimensional particle image velocimetry and pressure measurements were performed to investigate the dominant frequencies of fluctuations, vortex rope formation, and modes (rotating and plunging) of the rotating vortex rope. The time of appearance and disappearance of rotating and plunging modes of vortex rope was investigated simultaneously in the pressure and velocity data. The asynchronous mode was observed to dominate over the synchronous mode in both velocity and pressure measurements.

• English Language & Literature Teaching
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• v.7 no.2
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• pp.77-102
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• 2002

Factors affecting foreign language learning task are diverse in nature due to the different social and cultural backgrounds so that learners have to somehow use strategies and expressions to adjust diverse factors to their learning environments. The main purpose of this paper is to show how important NNS vs. NNs interaction through CCDL can be in their enhancement of English proficiency by giving examples from their chatting conversation(written conversation) data collected for over two semesters. Chatting as a means of synchronous communication interaction between students from two different cultural backgrounds can act as a predictor of foreign language achievement. Chatting and Telemeet activities have their own advantages in enhancing communicative competence when learning English. By engaging in these synchronous communication activities learners of English from different cultural backgrounds can acquire unique strategies and expressions from which they learn from each other. In short, this study advocates the importance of strategies and patterns foreign language learners can acquire from interaction among culturally different peer groups.

• Journal of Power Electronics
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• v.7 no.3
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• pp.233-237
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• 2007

This paper deals with the new HVDC interaction which was observed in the Jeju-Haenam HVDC system. The interaction is not from a system malfunction or controller loop problem but from the change of AC network scheme and the network operating condition. We have found that the interaction is caused by the voltage oscillation between synchronous compensator and HVDC shunt reactor. We analyzed the cause of the interaction and suggested a solution.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.1
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• pp.209-219
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• 2011

Most of the computer-based distance learning systems are asynchronous ones that allow students to download from the server the lecture previously given by a lecturer. While these asynchronous systems has the advantage that enable students to view the lecture with no time restriction, the study may not be effective due to the lack of support for real-time interaction between students and lecturers. Based on the student-lecturer-collaboration session model, this paper presents a collaboration session-centric synchronous distance learning system that supports real-time interaction between students and teachers, awareness information during lecture, and feedback from students. Basic feature of the proposed system include audio and video conferencing, text-based chat, and shared slide with annotation support.

• Journal of The Korean Association of Information Education
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• v.16 no.1
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• pp.107-121
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• 2012

The purpose of this study is to develop online synchronous discussion tool based on De Bono's six thinking hats and to investigate availability and improvements of the tool. Analysis of previous studies about synchronous online discussion and six thinking hats and development of design strategies from 3C model, communication, coordination, cooperation, were done. Six thinking hats online synchronous discussion tool was developed and applied four times for 5 weeks in the 'fundamentals of computer science' course of college students majored in computer science. Qualitative data from open-ended survey and reflection paper of students, and field note of participant researchers were analyzed. As a result, six thinking hats online synchronous discussion tool facilitated student's interaction and communication in the aspect of communication, coordination, and cooperation of 3C model. However, some improvements are needed to overcome the limits of text-based online communication and to use six thinking hats online synchronous discussion tool as a tool to promote structured interaction and communication.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.3
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• pp.138-144
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• 2000

The detent force caused by the interaction of magnets with the teeth of a armature core deteriorates the driving performance of a permanent magnet linear synchronous motor. In this paper, we analyze the fields and forces of a linear synchronous motor with segmented or skewed magnet arrangement according to lateral overhang length of permanent magnets. For the analysis, the 3-dimensional equivalent magnetic circuit network method is used. The detent force and the static thrust are analyzed according to the segmented or skewed angle and the overhang length of permanent magnets, and the optimal angles that the detent force is minimized are found out in each case. The analysis results are compared with the experimental ones and shown a reasonable agreement.

• The Journal of Korean Association of Computer Education
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• v.14 no.3
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• pp.63-72
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• 2011

Satisfactory e-learning experience of working part-time adult students is a truly dynamic and multidimensional process that reflects learning needs and abilities. Special attention is given to understanding the role of student-to-faculty interaction, student-to-student interaction, e-learning content and course structure, flow, periodic off-line class meetings and synchronous Q&A sessions. Survey questions were developed and distributed to adult graduate students. Some of them were asked to complete the questions with the most interesting subjects or classes in their mind, and others with the most difficult subjects in their mind. The structural model for each group was tested. The values of path coefficients corresponding to the group with the difficult subjects turn out to be higher for the following paths; a) interaction among professors and students and satisfaction, b) contents quality and flow, c) Q&A and interaction among professors and students, d) Q&A and interaction among students. For the other paths such as interaction among students and satisfaction, contents structure and flow, the coefficient values corresponding to the group with the interesting subjects are higher. Some implications for e-learning design were provided as well.