• Journal of The Korean Association of Information Education
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• v.13 no.1
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• pp.41-49
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• 2009

It's going to be ubiquitous environment which is able to use web pages independent of time and a place by recent development of mobile techniques. On this, we improved the leveled reading supporting system according to U-learning environment and make student to read on both Off-line and On-line through connecting to E-book service. So we developed the reading supporting system which can improve the interests in reading and reading skill and proved the effects. U-learning based leveled reading education support system could be helped develop the reading ability by raising the interest in the activities reading and after reading.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.726-732
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• 2014

A current flowing through a distribution conductor produces induced voltage, which is harmful to a telecommunication line. Previous research on induced voltage has been focused on single-circuit lines in the distribution system. However, the double-circuit lines, referred to as parallel distribution lines, are widely used in distribution systems because they have significant economic and environmental advantages over single-circuit lines. Therefore, a study on the induced voltage in double-circuit lines is needed. This paper presents a method of calculating the induced voltage in a parallel distribution system using four-terminal parameters and vector analysis. The calculation method is verified by the Electromagnetic Transient Program (EMTP) simulation.

• Communications of Mathematical Education
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• v.23 no.2
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• pp.313-325
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• 2009

The purpose of this paper is to design a cyber mathematics mentoring system which is helpful for interactive mathematics mentoring among mentors and learners. We review theories about various technological tools that are related to students' interest, participation and motivation in the course of on-line and off-line activities, and we also research the effectiveness of such tools. Also we consider educational implications of the cyber mathematics mentoring system for pre-service teachers, in-service teachers, learners and mentors.

• Journal of Engineering Education Research
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• v.24 no.1
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• pp.34-45
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• 2021

This research is a case study about "Critical Thinking and Debate Education" class which was done for freshmen at the engineering college of "S" Women's University. Real time remote classes through LMS and ZOOM were the most effective tools under on-line circumstances, considering the fact that video lectures only cannot cultivate students' capabilities of critical thinking and communication. Throughout the analysis on students' self-reflection journals and lecture evaluations, this paper examined considerable future points and the pros and cons of "Critical Thinking and Debate Education" under online presentation and discussion situation. As research outputs, students told they could feel less nervousness and anxiety when they exercise and have a presentation because they could choose familiar space for them. In addition, students also told that they feel comfortable about both self-feedback and peer evaluation, repeatedly seeing the recorded video clip. However, on the contrary, sometimes students felt uncomfortable due to unstable internet connection through the online classes, and they also were regretful about the missing chances of interaction between a teacher and students and of intimate exchanges among students. They also told they had felt a kind of limit of enhancing their presentation skills just in front of the monitor. Considering these outcomes, this research paper points out that online education needs to be proceeded by strengthening multi layered feedback to students with the build-up of a non-face-to-face stable educational infrastructure, application of online instructional strategy, and utilization of YouTube platform and video contents. Through this research paper, I hope the new system of encompassing on/off line "Critical Thinking and Debate Education" and effective teaching and learning method can be developed soon by strengthening the strength of online education.

• Management & Information Systems Review
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• v.14
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• pp.79-99
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• 2004

Cyber education system service is in the field of software service which is highlighted after the latter half of 1990'. But the progress of this service is impeded by the lack of back office which contributes to the evaluation of learning achievement and the management of learning progress. This article points out the problem of current back office which is the most important in the cyber education system, and focuses on the new intelligent learning achievement evaluation module. First, we define the cause and effect between the learning stages using by fuzzy implication which is the important part of fuzzy theory. Next, we suggest the model which generates the results of the learning achievement evaluation. This model, suggested by this article, may contribute to the development of the cyber education system by improving the current on-line education service.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.4
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• pp.36-41
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• 2014

Most faults that occur on transmission lines are caused by extreme weather with lightning storms in the distance. These are not only prolongs the time of removing and recovering, but also increases economical damages. If faults can be precisely located, maintenance crews can reach them quickly, and remove the faults in time. So, the precise locating of the faulted point on a transmission line is very important to improve the system reliability, and decreases economic damages as an inherent consequence of long term outages. Also, fault location methods are becoming of much importance for utilities and research. In this paper, two single-terminal impedance-based fault location techniques will be investigated to show the reliability and evaluated the performance of reactance and Takagi method by using MATHCAD program simulations.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1456-1458
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• 1999

As the system reliability of power supply is highly increased, we need distribution maintenance techniques without any power interruption. To meet such an increasing demand, a groat deal of hot line work on the high voltage overhead distribution lines has been carried out. In this regard, Hot line work techniques has being applied widely. However, hot line work techniques can not cover all kinds of work without interruption. To cope with those problems, the temporary power supply work technique such as bypass cable truck technique, temporary switch technique and mobile transformer technique was developed and applied. This paper presents the most optimal method according to distribution work contents through the comparison and analysis the characteristis and problems of the existing various work techniques. Also this paper suggested the countermeasers of the prsent problems.

• Journal of The Korean Association of Information Education
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• v.23 no.1
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• pp.29-38
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• 2019

The purpose of this study was threefold: to design and develop a smart teaching and learning system based on flipped learning for elementary subject matter education; to apply the system to the elementary classroom; and to examine the effects of the system on students' achievement and satisfaction levels. The system was composed of a video part, a date part, and a learning line part. Presentations, preinstructional videos, and spreadsheets were created for the flipped classroom. The results of the analyses indicated that the teaching and learning system positively influenced students' achievement and satisfaction levels. The study concluded with the implications of the study and suggestions for the future study.

• Journal of Korea Multimedia Society
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• v.9 no.5
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• pp.658-670
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• 2006

As the educational media tends to be more digitalized and individualized, the learning paradigm is dramatically changing into e-learning. Existing on-line courseware gives a learner more chances to learn when they are home with their own PCs. However, it is of little use when they are away from their digital media. Also, it is very labor-intensive to convert the original off-line contents to on-line contents. This paper proposes education mobile contents(EMC) that can supply the learners with dynamic interactions using various multimedia information by recognizing real images of off-line contents using mobile devices. Content-based image retrieval based on object shapes is used to recognize the real image, and shapes are represented by differential chain code with estimated new starting points to obtain rotation-invariant representation, which is fitted to computational resources of mobile devices with low resolution camera. Moreover we use a dynamic time warping method to recognize the object shape, which compensates scale variations of an object. The EMC can provide learners with quick and accurate on-line contents on off-line ones using mobile devices without limitations of space.

• Structural Engineering and Mechanics
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• v.78 no.1
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• pp.87-102
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• 2021

Long span cross-rope suspension structure is an innovative structural system evolved from typical Cross-Rope Suspension (CRS) guyed tower, a type of supporting system with short span suspension cable supporting overhead power transmission lines. In mountainous areas, the span length of suspension cable was designed to be extended to hundreds or over one thousand meters, which is applicable for crossing deep valleys. Vortex Induced Vibration (VIV) of overhead power transmission lines was considered to be one of the major factors of its fatigue and service life. In this paper, VIV and its controlling by Stockbridge damper for long span CRS was discussed. Firstly, energy balance method and finite element method for assessing VIV of CRS were presented. An approach of establishing FE model of long span CRS structure with dampers was introduced. The effect of Stockbridge damper for overall vibration of CRS was compared in both theoretical and numerical approaches. Results indicated that vibration characteristics of conductor in long span CRS compared with traditional tower-line system. Secondly, analysis on long span CRS including Stockbridge damper showed additional dampers installed were essential for controlling maximum dynamic bending stresses of conductors at both ends. Moreover, factors, including configuration and mass of Stockbridge damper, span length of suspension cable and conductor and number of spans of conductor, were assessed for further discussion on VIV controlling of long span CRS.