• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.487-488
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• 2015

New inverter motor drive systems consume 30%~50% less energy compared to existing motor drive systems. For inverter motor drive systems, the development of a 1200V high side driver is critical. This paper presents an advanced 1200V high side driver with low power consumption and high ruggedness. This solution implements a high voltage level shifter which consumes low power by adding a clamped VGS LDMOS driver to the conventional short pulse generator. Moreover, this paper proposes a highly rugged 1200V LDMOS which improves SOA by limiting the hole current. This paper could be applied to smart power modules used for HVAC (heating, ventilation, and airconditioning) and industrial inverters. Consequently, this paper will provide design engineers with an understanding of how they can make a significant contribution to worldwide energy savings.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.9
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• pp.721-736
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• 2019

In this paper, the behavior of the fire smoke due to the operation of the ventilation systems when the fire occurred in the underground station (6 basement floors) and the tunnel at the great depth was measured. Fire smoke was generated by using a smoke generator which realized heat buoyancy effect by using hot air blower. The two locations of the fire were selected on the platform and on the platform of the tunnel located outside the screen door. A ventilation mode is generally used in which smoke is exhausted through a vent hole provided in a platform when a platform fire occurs. The tests were performed by operating the exhaust through the ventilation holes of the tunnel part located at both ends of the platform. The smoke density and the wind speed/velocity were measured at various positions, and the videos were taken to analyze the movement and smoke of the smoke. In both cases for fire inside the platform and in the railway tunnel, due to the ventilation mode operation of the fan for the platform and the exhaust of the fans in the tunnel smoke were well exhausted and the smoke propagation to the area near the smoke zone was suppressed. The smoke-control mode, which is applied to both fans for the platform and fans for in the tunnel at both ends of the platform, can provide a safer evacuation environment to the passengers from the fire smoke when the platform fire or fire train stops.

• Fashion & Textile Research Journal
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• v.22 no.3
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• pp.271-286
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• 2020

This study evaluated designs via the consumers' function and design preferences survey for using product design images, virtual avatar wearing images and product explanations that identified consumers' function and design preferences for knee protection pads as well as to develop movement assistive knee pad designs. We developed Design A for men and Design B for women. For Design A, the front of the knee supports muscles and alleviates pain with a hole. Mesh material with good ventilation was applied to enhance wearing comfort. The color was achromatic for a modern style, and the hook fastener and loops enabled easy wear and removal of the pad while controlling size and pressure strength. For Design B, taping details seamlessly support muscles in the knee area with fabrics less than 0.1 cm thick and with long sleeves in the diverse sizes. The design's satisfaction assessment showed that potential consumers were satisfied with Design A and Design B for overall design and functional features. Over 77% wanted to use/wear and purchase designs; in addition, over 78% expected it would help with walking and relieve knee pain. The results can be helpful for designers when deciding designs for manufacturing and commercializing kneepad products.

• Journal of the Korean Institute of Gas
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• v.20 no.3
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• pp.59-65
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• 2016

It is imperative to use suitable explosion proof equipments to prevent explosion in different gas facilities. There is no technical standard for the classification of hazardous areas though standard of explosion proof is regulated. In this study, we have adopted Industrial Standard KS to develop the methodology for the prediction of the explosion risk in the natural gas facility with low pressure using the important factors including hole size, hypothetical volume, validation of ventilation effectiveness. The applicability of the developed methodology was evaluated by the comparison with the data obtained from experiments of natural gas explosion.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1326-1330
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• 2008

The failure mode of steel road wheels in a vehicle is cracks from ventilation hole through to contact plane on steel wheel's disc plate. But a number of cracks of Cornering Fatigue Limit Test is on contact plane near to wheel nut mounting area, even though it's satisfied with specified cycles. So this paper searches out causes to improve durability and reliability of C.F.T by uni-axial bending moment test. The verified cause is a "fretting" on contact area of steel wheel. In result, this paper suggests a solution to prevent a fretting by inserting a damping shim, 0.7mm between steel wheel contact areas. Therefore this paper makes it possible to move crack position of C.F.T in steel wheel from contact plane to vehicle's failure mode.

• Fire Science and Engineering
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• v.29 no.6
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• pp.119-128
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• 2015

A fire broke out in a working wood-burning stove and destroyed an idyllic house about two years after it was built. This study analyzed data provided through the court by the fire station, police station, fire insurance investigation agency, house construction company, and wood-burning stove maker Based on the fire pattern of low-temperature long-term ignition that remained in the studs, the fire was found to be caused by the conduction of heat in the fire box to the studs of the wall next to the wood-burning stove. A fire simulation showed that the low-temperature long-term ignition of the studs next to the wood-burning stove occurred because a hole was not made for ventilation in the chimney.

• Journal of the Korean Society of Safety
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• v.33 no.3
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• pp.39-45
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• 2018

The occupational safety and health act defines how to evaluate the explosion hazardous areas according to KS (Korean Industrial Standards). Current KS have to follow IEC (International Electrotechnical Commission) 60079-10-1 1st edition and there has been no change since 2008. And its 2nd edition has been revised in 2015. In this study, IEC 1st Ed. (IEC 60079-10-1 1st edition) is compared with IEC 2nd edition. Total 112 case studies including four materials (methane, propane, benzene, methanol) are selected to test and explosion hazardous ranges evaluated by IEC 1st and 2nd Ed. are analyzed according to various leakage pressures and hole sizes. In order to verify the results calculated by them, PHAST, which is one of the most representative consequence analysis programs, is employed. As a result, it can be concluded that there are many differences between IEC 1st and 2nd Ed. due to the discharge and the ventilation parameters. As comparing with PHAST, it is confirmed that IEC 1st provides more conservative values than PHAST. Even if IEC 2nd Ed. provides more conservative for gases, this fails to provide more conservative values for liquids. Therefore, it is worth to note that a large value between the explosion hazardous ranges value calculated by the IEC 1st Ed. and 2nd Ed. should be selected until further investigation and analysis is made. Morevover, the full consideration for IEC 2nd Ed. have to be needed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.3 s.94
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• pp.311-318
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• 2005

Periodically perforated slot structure in the upper wall of the parallel plate waveguide is analyzed with main interest focusing on the diffraction Properties. The Periodic slot array is of infinite extent in one direction and of finite extent in the other direction. Various numerical results for reflection from the slotted section and transmission beyond the slotted section, and the radiation through the slotted section into the upper half space are presented with the height of feeding parallel plate waveguide, single slot size, and the periodicity between slots as parameters. This study is thought to be helpful to the design of the ventilation hole in the TFT-LCD and PDP.

• Journal of the Korean Society of Safety
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• v.29 no.2
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• pp.24-30
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• 2014

There have been controversies over whether explosion hazardous area(EHA) should be classified for facilities which use lighter-than-air gases such as city gas, hydrogen and ammonia. Two view points are confronting each other: an economic piont of view that these gases are lighter than air and disperse rapidly, hence do not form EHA upon release into the atmosphere, and a safety point of view that they are also inflammable gases, hence can form EHA although the extent is limited compared to heavy gases. But various standards such as KS, IEC, API, NFPA do not exclude light gases when classifying EHA and present examples of EHA for light gas facilities. This study calculates EHA using the hypothetical volume in the IEC code where the hole sizes required for the calculation were selected according to various nominal pipe sizes in such a way to conform to the EHA data in the API code and HSL. Then, 25 leakage scenarios were suggested for 5 different pipe sizes and 5 operating pressures that cover typical operating conditions of light gas facilities. The EHA for the minimum leakage scenario(25 mm pipe, 0.01MPa pressure) was found to correspond to a hypothetical volume larger than 0.1 $m^3$(medium-level ventilation). This confirms the validity of classifying EHA for facilities using lighter-than-air gases. Finally, a computer program called HACPL was developed for easy use by light gas facilities that classifies EHA according to operating pressures and pipe sizes.

• The Research Journal of the Costume Culture
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• v.8 no.1
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• pp.65-76
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• 2000

The purposes of this study were to claassify of clothing-wearing motives, to analyze tendency of fashion in campus, and to propose fashion merchandising plans and marketing strategies of companies for female college students. Research had been done during 1 week each on April and October in 1998 and 1999. Sixty-two students in spring semester and 54 student in fall semester were surveyed and analyzed. Their grades and majors were not considered in this study. Fashion Diary had been written by students and then their statements were analyzed by the means of the qualitative data analysis. Following conclusions were obtained from this study. 1. Clothing-wearing motives were classified with 'group depending on daily work', 'group depending on image', 'group depending on body supplement', 'group depending on weather', 'group of fashion following', 'group depending on courtesy', 'group depending on mood', and 'group of unconcerning'. 2. The fashion tendency of the students were layered look and they preferred casual styles, such as round t-shirts, jean pants, and cardigans. The color of white, black, and gray were prevalent for top wear, and the color of blue, black, beige for bottom wear in both seasons. For shoes, color of black, brown, white were popular. For bags, black, blue, and khaki color were prevailed. 3. The proposals obtained from this study are as follows : 1) Production of clothing enforced functional and practical base is wanted for 'group depending on daily work'. 2) Designs considering body parts such as hip, arm hole, shoulder, and thigh are needed. 3) Utilization of new materials such as waterproof with ventilation, opaque (means 'not see-through'), antipollution finishing process are required. 4) Simple designs of clothing which could be performed by herself with various accessories. Thermochromic materials are wanted for 'group of fashion following'. 5) Diversity of semi-suit is required for 'group depending on courtesy'.