• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.2
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• pp.328-332
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• 2010

The SLF(Short Line Fault) breaking capability test for high voltage class $SF_6$ GCB(Gas Circuit Breaker) was conducted. Simplified LC resonant circuit test facility was used for SLF breaking test. During test, Test current was measured by Rogwski coil and arc voltage was measured by voltage divider. Arc conductance was calculated by using these test results before 200ns at current zero. Critical arc conductance value at rated voltage 145kV class is about 2.3mS regardless of breaking current magnitude and arc conductance value at rated voltage 170kV class is about 2.6mS.

• Journal of Periodontal and Implant Science
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• v.39 no.2
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• pp.111-118
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• 2009

Purpose: The integrity of interproximal hard/soft tissue has been widely accepted as the key determinant for success or degree of root coverage following the connective tissue graft. However, we reason that the gingival biotype of an individual, defined as the distance from the interproximal papilla to gingiva margin, may be the key determinant that influence the extent of root coverage regardless of traditional classification of gingival recession. Hence, the present study was performed with an aim to verify that individual gingival scalloping pattern inherent from biotype influence the level of gingival margin following the connective tissue graft for root coverage. Methods: Test group consisted of 43 single-rooted teeth from 21 patients (5 male and 16 female patients, mean age: 36.6 years) with varying degrees of gingival recession requiring connective tissue graft; 20 teeth of Miller class I and 23 teeth of Miller class III gingival recession, respectively. The control group consisted of contralateral teeth which did not demonstrate apparent gingival recession, and thus not requiring root coverage. For a biotype determination, an imaginary line connecting two adjacent papillae of a test tooth was drawn. The distance from this line to gingival margin at mid-buccal point and this distance (P-M distance) was designated as "gingival biotype" for a given individual. The distance was measured at baseline and 3 to 6 months examinations postoperatively both in test and control groups. The differences in the distance between Miller class I and III were subject to statistical analysis by using Student.s t-test while those between the test and control groups within a given patient were by using paired t-test. Results: The P-M distance at 3 to 6 months postoperatively was not significantly different between Miller class I and Miller class III. It was not significantly different between the test and control group in a given patient, either, both in Miller class I and III. Conclusions: The amount of root coverage following the connective tissue graft was not dependent on Miller's classification, but rather was dependent on P-M distance, strongly implying that the gingival biotype of a given patient may play a critical impact on the level of gingival margin following connective tissue graft.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.8
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• pp.23-32
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• 1993

This paper presents a decomposition method to evaluate the performance measures of the serial production lines with unreliable machines and finite buffers. This method is to decompose the transfer line into a set of two machine lines for analysis. Bases on this approximation method, we consider nonhomogeneous lines. In such lines, the machines may take the different lengths of time performing operations on parts. A new transformation is employed in order to replace the line by a homogeneous line. The approximate transformation enables one to determine parameters of performance such as production rate and average buffer levels, and it also shows better application for a large class of systems.

• Journal of the Korean Institute of Educational Facilities
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• v.9 no.3
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• pp.23-34
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• 2002

This paper is to analyse the major impact of the new era of information technology on the changes being made in physical environment of existing corporate training centers through the case of on- and off-line LG academies. By the analysis, some interesting features are to be found which can be a hint for the future planning and design of corporate training centers. Unlike the expectation in the early stage of changes, the rapid growth of on-line education forms a very strong partnership with the existing in-house training programs at all levels. Understanding of such key issues surrounding the use of facilities is specific to the formation of an effective environment for training programmes. After all aspects of the facility uses-not just the class rooms, but also the residential, dining, recreational, and support areas, as well as on-line type of educational services-are carefully examined, a design guideline is identified as considerations for guestrooms, classrooms, public facilities, the recreational areas, and the audio-visual provisions.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.4
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• pp.26-33
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• 2019

This study is a thermal and flow analysis of Organic Rankine Cycle (ORC) pipe line for 250 kW grade waste gas heat recovery. We attempted to obtain the boundary condition data through the process design of the ORC, which can produce an electric power of 250 kW through the recovery of waste heat. Then, we conducted a simulation by using STAR-CCM+ to verify the model for the pipe line stream of the 250 kW class waste heat recovery system. Based on the results of the thermal and flow analyses of each pipe line applied to the ORC system, we gained the following conclusion. The pressure was relatively increased at the pipe outside the refracted part due to the pipe shape. Moreover, the heat transfer amount of the refrigerant gas line is relatively higher than that of the liquid line.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.41-45
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• 2019

In this paper, we propose the interference cancellation scheme of end-to-end method algorithm for power line communication (PLC) systems in smart grid. The proposed scheme estimates the channel noise information of receiver by applying a deep learning model at the receiver. Then, the estimated channel noise is updated in database. In the modulator, the channel noise which reduces the power line communication performance is effectively removed through interference cancellation technique. As an impulsive noise model, Middleton Class A interference model was employed. The performance is evaluated in terms of bit error rate (BER). From the simulation results, it is confirmed that the proposed scheme has better BER performance compared to the theoretical model based on additive white Gaussian noise. As a result, the proposed interference cancellation with deep learning improves the signal quality of PLC systems by effectively removing the channel noise. The results of the paper can be applied to PLC for smart grid and general communication systems.

• Agricultural and Biosystems Engineering
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• v.4 no.1
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• pp.1-7
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• 2003

Internal defects such as browning of the flesh and blackening and rot of the ovary of pear can be easily developed because of the inadequate environmental conditions during the storage and distribution of fruit. The quality assurance system for the agricultural product is to be settled in Korea. All defected agricultural products should be excluded prior to the distribution to enhance the commercial values. However, early stage on-line defect detection of agricultural product is very difficult and even more difficult in a case of the internal defects. The goal of this research is to develop a system that can detect and classify internal defects of agricultural produce on-line using VIS/NIR transmittance spectroscopy. And Shingo pear, which is one of the famous species of Korean pear, was used for the experiment. Soft independence modeling of class analogy (SIMCA) algorithm was employed to analyze the transmittance spectroscopic data qualitatively. On-line classification system was constructed and classification model was developed and validated. As a result, the correct classification rate (CCR) using the developed classification model was 96.1 ％.

• Journal of information and communication convergence engineering
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• v.9 no.6
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• pp.769-774
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• 2011

IT technology based projects was conducted to implement education on producing creative ideas through on-line education and grasp thinking disposition of students in terms of creativity education efficiency. The differences in idea creation among students according to thinking dispositions were analyzed through qualitative evaluation and quantitative evaluation of project and its result was drawn. The purpose of this study was to help cultivate a man of ability who will make a great contribution to knowledge information society by proposing education model based on new method of teaching and learning.

• Journal of Science Education
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• v.44 no.2
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• pp.240-258
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• 2020

The advances in science technology brought about a new form of learning called flipped-learning: a combination of on-line and off-line learning. A flipped learning is a form of blended learning which has become quite popular, nowadays, in the field of education. Despite the emphasis on the importance of medical humanities in medical education program, there are no effective teaching and learning models to realize the purpose of medical humanities education. This study explores the possibility of flipped-learning to apply medical humanities classes. The class was designed based on the ADDIE model consisting of five stages, analysis - design - development - execution - evaluation. In order to do 'flipped-learning,' the instructor reconstructs the purpose of medical humanities education, instructional purpose and content, and analyzed learner. The contents of the medical humanities class were structured considering the purpose of the introduction to the medical humanities in the medical education program and the competencies that medical personnel should have in the developed health care environment. The instructor produces a video of the lecture and makes it possible to use LMS (Learning Management System) before and after classes, and conducts discussion activities so that learner-learner and learner-teacher interaction could actively occur during the class. The result of applying medical humanities lesson as flipped learning is as follows: First, it can realize the essence of medical humanities education. Second, it contributes to strengthening the competencies of health care provider. Third, flip learning can be used as a new teaching strategy for medical humanities education. The result of this study is expected to suggest new ways of introduction to teaching method in the traditional medical humanities class and contribute to the practice of designing and doing flipped learning of medical humanities class in the future.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.830-837
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• 2010

Since it started the researches on a maglev train on 1960, Germany and Japan arrived to putting to practical use level and accomplished most tests from their test-line. Korea is in progress the preparation for a practical use of low-speed maglev train in 110 [km/h] class and Korea Railroad Research Institute(KRRI) is in progress of a research about core technology of maglev system for high-speed tube train of 700 [km/h] class. In this paper, authors suggest an effective design method of Linear Synchronous Motor(LSM) for high-speed tube train of 700 [km/h] class which has a wound type electro-magnet. Then, authors calculate a variety of properties by changing speed of the LSM model which is designed by a method based on some theoretical equations. Then, authors verify the validity of the method based on some theoretical equations through a verification of property values by Finite Element Method(FEM) analysis method. Finally, in order to design a shape of pole-shoe part of LSM electro-magnet which is hard to design with a basic design method, authors analyze a transition of property values by changing a pole-shoe width and current of the electro-magnet through an analytical method by FEM.