• International Journal of Contents
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• v.7 no.4
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• pp.64-69
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• 2011

Recently, as smart devices are distributed more and more, the need for education of developing contents based on smart media increases. In order to develop contents based on smart media, it is necessary to learn new programming language as well as to understand the structure of platforms as device-manufacturers and communication companies have different platforms. Generally, the problem in education of programming is that it can provide learning to understand the language stage by stage, but it is difficult to suggest a clear result such as completion of learner's project from macroscopic and integrated approach. Especially, there is a difficult of learning several programming languages due to the characteristics of platforms in developing smart contents. Accordingly, in the education of programming for developing smart contents, it is not appropriate to use the traditional teaching method of programming which conducts projects from an integrated point of view after learning the grammatical elements of the language. This paper aims to suggest the top-down teaching method as an effective teaching method for developing contents based on smart media, and to analyze the effect after developing and applying the suggested teaching model.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1724-1726
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• 2001

This paper deals with the characteristics of the potential rises of down-conductor due to lightning surge currents. Direct lightning strikes can cause high impulse currents to the lightning protection system(LPS) of a building. These high impulse currents have the front time as short as 1[${\mu}s$]. In this case, the induced voltages caused in a closed circuit inside the building can be very high and cause damage or submit people to electric hazard. So, the LPS has to be designed to ensure safety condition to person and acceptable levels of induced voltages to the electrical and electronic equipments. The results of the potential rises related to the bonding conditions between the grounding conductor and metal raceway and the type of down-conductors are introduced.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.12
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• pp.996-1003
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• 2002

Heat transfer characteristics were investigated for the falling film flowing down the outside of an electrically heated vertical tube. Water was used for the falling film, and its Reynolds number was varied in the range of 70～500. Because water is heated and evaporated as it flows down, both sensible and latent heat transfer should be considered. The effect of the surrounding air movement was investigated by changing the direction of the air injection; without air injection, parallel-flow, and counter-flow. For all cases, sensible teat transfer rate was almost linearly increased with the increasing film flow rate. It was found that the film heat transfer coefficient was hardly influenced by the parallel air flow. However, the counter-flow of air reduced the heat transfer coefficient, which might be caused by the uneven distribution or flooding of the film. At high heat flux, a sudden change of the film heat transfer coefficient was detected as the film flow rate reached the transition value. It is supposed that this phenomenon was caused by the change in the film flow pattern.

• International journal of advanced smart convergence
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• v.2 no.2
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• pp.19-22
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• 2013

As the demand of the LED for lighting that emits light by p-n junction is increasing, studies on heatproof plate technology is being conducted to minimize the temperature of the LED lighting. As for the temperature of the LED devices, their light emitting efficiency decreases and the maximum lifespan drops down to 1/5. Therefore there are heat dissipation studies going on to minimize the heat. For LED heat dissipation, aluminum heat sink plates are mostly used. For this paper, we designed heat sink that fits residential 20W COB LED Down Light; packaged the heat sink and 20W COB and analyzed and evaluated the thermal properties through a Solidworks flow simulation. We are planning to design the optimal heat sink plate to solve the thermal agglomeration considering TIM(Thermal Interface material).

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.494-497
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• 2006

For commercialization of polymer electrolytemembrane fuel cell (PEMFC), durability of membrane electrode assemblies (MEAs) has to be improved. Especially, long-term stability of MEA is one of the most important issues for frequent shut-down and start-up processes of PEMFC. The degradation of MEA could be attributed to chemical attack of hydrogen peroxide radicals that are formed at high cell voltages without any special treatment to remove residual hydrogen from anode gas channel after shut-down of the fuel cell. In this study, we investigated the long-term stability of MEA under different on/off operation conditions. Residential hydrogen gas was removed from the anode flow channel by purging air or nitrogen. Also, a dummy resistance was applied to the fuel cell to exhaust residential hydrogen at the anode. In these cases, MEA showed much more stable durability. Electrochemical characteristics of the fuel cell were measured byrepeating the on/off cycles with the hydrogen removal processes. Also, degradation of MEA components was examined by SEM, TEM and XRD analyses.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.10
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• pp.916-922
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• 2008

AC PDP with MgO protective layer coated with the optimum evaporation rate of $5{\AA}/s$ can generate more enhanced efficiency through the vacuum in-line sealing process. However, the optimized process conditions still require the optimum driving scheme on the ramp-up and ramp-down slope of the reset waveform for enhancing the efficiency. In this paper, for the in-situ vacuum sealed PDP with the optimum evaporation rate of MgO protective layer, the address delay time was investigated with various slopes of ramp waveform during a reset ramp-up and ramp-down period. In this study, the minimum statistical delay time was obtained at the ramp-up rate of $6.0 V/{\mu}s$ and the ramp-down rate of $0.7 V/{\mu}s$ of the reset waveform.

• Journal of the Korea Fashion and Costume Design Association
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• v.7 no.3
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• pp.145-156
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• 2005

The purpose of this study was to identify the characteristics of export clothing articles in Korea. For the purpose, the proportion and unit price of each export clothing articles were analyzed to each important market. The results of the study were as follows : First, on the proportional aspect, to all world market, SITC 845(Articles of apparel, of textile fabrics, n.e.5.), 842(Women's clothing, of textile font knittedabrics), and 841 (Men's clothing of textile fabrics, not knitted), 844(Women's clothing, of textile, knitted or crocheted) and 846(Clothing accessories, of textile fabrics), 848(Articles of apparel, clothing access., excluding textile), 843(Men's or boy's clothing, of textile, knitted, crocheted.) in order were in large exported, after the mid-1990's. To each important market, the proportion of export clothing articles was varied. Second, on the unit price aspect, to all world market, the unit price of export clothing articles went down slightly. For each item, 844(Women's clothing, of textile, knitted or crocheted) went up a little, 843(Men's or boy's clothing, of textile, knitted, croche.) and 845(Articles of apparel, of textile fabrics, n.e.s.) went down a little, 841(Men's clothing of textile fabrics, not knitted), 842(Women's clothing, of textile fabrics), 846(Clothing accessories, of textile fabrics) and 848(Articles of apparel, clothing access., excluding textile) went down greatly. The unit price to industrialized countries, newly industrializing countries, developing countries in order was high, reflecting the developing stage of each nation's.

• Journal of Korean society of Dental Hygiene
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• v.12 no.4
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• pp.685-693
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• 2012

Objectives : This research was conducted to find the subjective symptoms of musculoskeletal system for main jobs and job posture. Methods : A survey was conducted from September 15, 2011 to October 7, 2011 and 357 dental hygienists were responded. The survey was consisted of the working environment and medical equipments, psycho-social characteristics, health habits and education, job posture, subjective symptoms of musculoskeletal system pain, and so on. Results : In the survey on the frequency of job posture of dental hygienists by jobs, said they cast down or tilt their head by 15 degrees or more or twist or bend their back. The result of the analysis on the subjective symptoms of musculoskeletal system by main job showed that they experienced a pain in neck, shoulder, and back, although the order differed. The order of subjective symptoms of musculoskeletal system for casting down or turning head by 15 degrees or more, twisting or bending back, having shoulders not parallel to the ground, sitting at the end of a chair, and supporting the whole body with one leg or pressing on a pedal for treatment was from the shoulders to the neck to the back. The order of subjective symptoms of musculoskeletal system for having arms too far from the body or hunching for treatment and bending wrists inward or outward for treatment was from the shoulders to the back to the neck. Conclusions : Due to the characteristics of the job which requires one to have a proper view of a patient's oral cavity, most of the postures included casting down of head or bending of back. Therefore a development of new postures is needed to replace the existing job postures which pressure the musculoskeletal system. And shift rotation can be used as a preventive measure.

• Journal of the Korean Society of Clothing and Textiles
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• v.40 no.5
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• pp.801-814
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• 2016

This study uses the "Sejong chronicles" ritual manual to investigate the movements and roles of provincial governors during the enshrinement rituals of the royal portrait, the official uniforms of the provincial governors in their roles, and the characteristics of the official uniforms system for local governors in the early Joseon Dynasty. The results of this study are as follows. Provincial governors who participated in the enshrinement rituals of the royal portrait were governors 'en route' and governors 'in destination'. The movements of the governor 'en route' followed the provincial borders, official residences, and neighboring provincial borders. The movements of the governor 'in destination' followed the provincial borders, the official residence, and jinjeon. The roles of the governors included the welcoming ceremony, the bow-down ceremony, the front guard, and the farewell ceremony. The governors 'en route' wore Jobok in the welcome ceremony, and a Sibok in the bow-down ceremony before the farewell. The governor 'in destination' wore Jobok in the welcome ceremony, and Jobok (or Sibok if Jobok was not available) in the bow-down ceremony before the farewell. The characteristics of the official uniforms system for local governors in the Joseon Dynasty were as follows. First, the governors wore different uniforms depending on the importance of the rituals in the early Joseon Dynasty. Second, the names of official uniforms Sang-bok and Si-bok were used interchangeably in the early Joseon Dynasty. Third, local governors were allowed to wear Sangbok (or Sibok) instead of Jobok.

• Journal of the Korean Society for Heat Treatment
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• v.18 no.6
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• pp.355-361
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• 2005

In this study, the effects of the maximum undeformed chip thickness on grinding characteristics of hardened steel in down-grinding have been investigated. The meaured grinding forces become larger as the workpiece velocity increases. The specific energy, e decreases as the maximum undeformed chip thickness increase. When the maximum undeformed chip thickness is the same, the specific energy, e decreases as the grain size increases.