• Proceedings of the KIEE Conference
• /
• 2003.07a
• /
• pp.452-454
• /
• 2003

$SF_6$ gas has been increasingly used as the insulating and arc-suppressing medium in switchgears which are used as the protection devices of power system. Nowadays, most of power companies adopted the $SF_6$ gas-type load break switch for increasing the reliability of distribution network by its superior durability against external environmental condition, in substitution for air-type and oil-type switches. But, it is important to establish the general estimation process for the testing and estimation for long-term reliability. Accordingly, this paper presents the reliability testing method for $SF_6$ gas load break switch which is based on the analysis of the failure mode and the statistics.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.8
• /
• pp.3992-3998
• /
• 2013

This paper is related to the method of adding a emotional speech corpus to a high-quality large corpus based speech synthesizer, and generating various synthesized speech. We made the emotional speech corpus as a form which can be used in waveform concatenated speech synthesizer, and have implemented the speech synthesizer that can be generated various synthesized speech through the same synthetic unit selection process of normal speech synthesizer. We used a markup language for emotional input text. Emotional speech is generated when the input text is matched as much as the length of intonation phrase in emotional speech corpus, but in the other case normal speech is generated. The BIs(Break Index) of emotional speech is more irregular than normal speech. Therefore, it becomes difficult to use the BIs generated in a synthesizer as it is. In order to solve this problem we applied the Variable Break[3] modeling. We used the Japanese speech synthesizer for experiment. As a result we obtained the natural emotional synthesized speech using the break prediction module for normal speech synthesize.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.20 no.10
• /
• pp.839-845
• /
• 2007

In this paper, a polishing pad has been analyzed in detail, to understand surface phenomena of polishing process. The polishing pad plays a key role in polishing process and is one of the important layer in polishing process, because it is a reaction layer of polishing[1]. Pad surface physical property is also ruled by pad profile. The profile and roughness of pad is controlled by different types of conditioning tool. Conditioning tool add mechanical force to pad, and make some roughness and profile. Formed pad surface will affect on polishing performance such as RR (Removal Rate) and uniformity in CMP Pad surface condition is changed by conditioning tool and dummy run and is stable at final. And this research, we want to reduce break-in and dummy polishing process by analysis of pad surface and artificial machining to make stable pad surface. The surface treatment or machining enables to control the surface of polishing pad. Therefore, this research intends to verify the effect of the buffing process on pad surface through analysis of the removal rate, friction force and temperature. In this research, urethane polishing pad which is named IC pad(Nitta-Haas Inc.) and has micro pore structure, is studied because, this type of pad is most conventional type.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2002.05a
• /
• pp.76-84
• /
• 2002

Fracture toughness was considered as one of the good estimates of the paper break tendency of paper web in the press room. Paper break on the paper machine is caused by many factors such as paper machine irregular vibrations, impurities in the fiber furnish, shives, and so on. On the paper machine, the solid content of paper web is changing very rapidly from less than 1% to over 95%. We tried to measure the fracture toughness of paper web at different solid contents for providing the fundamental knowledge of paper break. Stretches of wet web were also measured and compared to the fracture toughness changes. Four different fiber furnishes (SwBKP, HwBKP, ONP, and OCC) were refined to different degrees, and at different solid contents (40%, 60%, 80%, and 95%), their fracture toughnesses were measured. Two fracture toughness measurement methods (essential work of fracture and Tryding's load-widening method) were used, and we found they gave identical results. The stretch curves of the wet webs against the axis of solid contents were very similar to the fracture toughness curves of those.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.19 no.12
• /
• pp.1252-1259
• /
• 2009

Due to the international competition and global pressure, the roll speed is increased. However, higher speeds increase the power density in the process as well as the plant's potential to react with vibrations. Under certain operating conditions, vibrations may occur, which again cause chattermarks, strip rupture or coil break fault. The appropriate condition monitoring is needed to improve product quality and availability. The aim of condition monitoring is to reduce maintenance costs, increase productivity and improve product quality. This paper proposes a condition monitoring tool designed for the classification of coil break fault. This method is used to cold rolling mill for faults monitoring based on vibration and motor current signals. The results show that the performance of classification has high accuracy based on experimental work.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.33 no.5
• /
• pp.37-44
• /
• 2001

Fracture toughness was considered as one of the good estimates of the paper break tendency of paper web in the press room. Paper break on the paper machine is caused by many factors such as paper machine irregular vibrations, impurities in the fiber furnish, shives, and so on. On the paper machine, the solid content of paper web is changing very rapidly from less than 1% to over 95%. We tried to measure the fracture toughness of paper web at different solid contents for providing the fundamental knowledge of paper break. Stretches of wet web were also measured and compared to the fracture toughness changes. Four different fiber furnishes (SwBKP, HwBKP, ONP, and OCC) were refined to different degrees, and at different solid contents (40%, 60%, 80% and 95%), their fracture toughnesses were measured. Two fracture toughness measurement methods (essential work of fracture and Tryding's load-widening method) were used, and we found they gave identical results. The stretch curves of the wet webs against the axis of solid contents were very similar to the fracture toughness curves of those.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.41 no.3
• /
• pp.219-227
• /
• 2021

Numerical simulation with Hwang's scheme, which can analyze shallow-water flow over discontinuous topography, was compared with a laboratory experiment of flooding on a perpendicular floodplain with dam-break flows. The simulation results were in good agreement with the results measured in an experimental flume with a reservoir, channel, and floodplain. The wetting and drying process on a perpendicular floodplain with a dam-break flow was particularly well simulated. The difference in simulation results according to the type of flow resistance was insignificant. The results of this study are expected to improve the accuracy of predicting inundation in urban rivers.

• Korean Journal of Childcare and Education
• /
• v.17 no.4
• /
• pp.49-71
• /
• 2021

Objective: This study aims to explore the experiences of women who take a career break while working in daycare center as a teacher assistant. Methods: Seven assistant teachers and two child care teachers who took more than two years of career break were selected and given in-depth interviews over 17 weeks from August to December in 2020. Results: The results of this study are as follows. First, the women experienced the need for a career transition as an assistant teacher because it was time to for a change. Second, while working as a teacher assistant, they had various experiences and meanings in the process of career transition while playing the role as a teacher in daycare centers. Third, they also had some difficulties in conflict and some needs to build their professional expertise as a teacher. Conclusion/Implications: The study is expected to give insights to understand the difficulties of teachers who had experienced the need for a career transition as teacher assistant and to provide important data to develop teacher professional development.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.6 no.4
• /
• pp.15-21
• /
• 2007

The effect of manufacturing parameters on friction characteristics of motorcycle break system was studied using a disk-on-pad type friction tester. Such parameters conditions have an effect on the frictional factor such as number of ventilated disk hole, applied load, sliding speed, and sliding distance. However, it is difficult to know the mutual relation of these factors. In this study, the friction characteristics using design of experiment containing 4 elements were investigated for an optimal condition for the best motorcycle break system employing regression analysis method. From this study, the result was shown that the applied load in frictional factors was the most important, next to sliding speed, number of ventilated disk hole.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.6 no.4
• /
• pp.86-91
• /
• 2007

The heat generated by the brake system of vehicles results in reduction of friction force on the brake surface and vibration when breaking. These problems play essential part in break's performance. To solve these problems, extensive research has been conducted such as drilling cooling holes on the brake pud, accommodating ventilated holes and etc. In this study, we suggest the compression of brake in circumferential direction in order to improve its cooling performance. And we analyzed comparing temperature distribution which is generated accomplishing heat analysis at each disc.