• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.6 s.249
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• pp.587-593
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• 2006

A ventilated disc brake having semi-cylindrical grooves has been proposed to improve the thermal judder by way of heat transfer enhancement. The local heat transfer coefficients were measured in the flow passage of disc brake. These measured local heat transfer data were utilized to do the finite element numerical analysis which predicts the maximum temperatures on the disc brake. The results show that the maximum temperatures on the disc surface with semi-cylindrical grooves are approximately 35.2% lower than those without them.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.249-252
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• 2002

최근 수년동안 의료 X-선 장비의 고전압 발생용 전원장치는 고주파 인버터 형태로의 개발이 가속화되어 단시간 촬영의 고성능화와 장치의 소형화 그리고 고전압 리플의 저감에 따른 피폭량 감소가 실현되고 있다. 본 논문은 이에 따른 의료 진단용 X-선 발생 시스템에서 40kW(125kV, 800mA)급 고주파 전원 발생장치 개발에 관한 것으로 고주파 고전압 인버터, 고주파 고전압 변압기를 포함한 고전압 발생 회로, X-선 관전압, 관전류 제어부, 시스템 구동부의 설계 개발에 대하여 기술하였고, 전체 구성된 시스템의 실험 파형에 따른 동작 특성을 제시하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.694-696
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• 2002

Growth behaviors of carbon nanotubes (CNTs) are studied in terms of catalyst by using scanning electron microscopy and transmission electron microscope (TEM). Catalyst films deposited on various substrates are agglomerated into nano-islands during the heat-up to the growth temperature. In particular, we focus on the direct investigation of the microstructures of the CNTs and the interface of CNTs-catalyst-substrate using cross-sectional TEM. We investigate relationship to the subsequent CNTs growth on each nucleation site. The growth of CNTs depends on the catalyst itself but not the silicide formation between the catalyst and the substrate.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.203-207
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• 2002

In order to evaluate the aging of mineral oil immersed distribution transformers, it gathered some insulation oil in over loaded and long time(exceed their service life, 13yrs.) aged transformers in the field, we measured moisture content, acid number, dielectric strength of the oil as defined in KS C 2101 standard. And also, it had been measured dielectric constant, specific resistant, $tan{\delta}$ on aged transformer oil at from $10^{\circ}C$ to $130^{\circ}C$. These results are compared with a new mineral oil. From this study, it can be considered that the analysis of mineral oil may be suitable for evaluation of life expectancy in distribution transformers

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.254-257
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• 2010

최근 모바일 컴퓨팅 기술이 급격이 발전하면서, 이동 애드-혹 네트워크(Mobile Ad-Hoc Network, MANET)에 대한 연구가 활발히 진행되고 있다. 그러나 대다수의 MANET에 관한 연구는 하나의 MANET 내에서 이루어지는 라우팅 방법이나 에너지 관리에 대한 것으로 MANET 내에서 검색에 실패 했을 경우에 대한 해결 방법은 없는 상태이다. 본 논문에서는 하나의 MANET에서 검색에 실패한 경우에 기반망인 무선 AP를 이용하여 또 다른 MANET으로 연결하고 정보를 검색 할 수 있도록 탐색범위 확장을 위한 방법을 제안한다. 본 논문에서 제안한 방법은 보다 넓은 범위에서 필요로 하는 정보를 가진 단말을 탐색할 수 있게 함으로써 MANET에서의 검색 성공률을 높일 수 있다.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.77-80
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• 2007

In this paper, the method which can protect the situation of possible data corruption when collision has happened during I/O data exchange between device and tasks is presented. Also, an example diagram of mechanism according to this introduced method is shown and the effect and merits and demerits of the method is evaluated.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.12
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• pp.1183-1189
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• 2010

Shock-resistance test for a real equipment for a normal vessel is one of the difficult problem in many cases because of terrible cost and weight. An analysis technique to evaluate the shock resistance in a design stage is necessary, instead In this paper, the process to evaluate the shock resistance of a propulsion motor for naval vessels was presented based on German navy's BV043 regulation. The shock signal to impose the equipment under the test was first evaluated, and was then applied to the structural FE model of the equipment. From the transient FEA, the time history of von-Mises stress was obtained by the mode superposition method. The shock resistance was evaluated using the peak value of the von-Mises stress.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.10a
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• pp.270-272
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• 2002

Competitive species have the same spatial distribution (habitat) and foraging behavior (niche), while non-competitive species have either different feeding behavior or spatial distribution. Therefore, ecological segregation among species of fish results rfom differences in foraging behavior and spatial distribution (Allen, 1984; Zhang 1988). To explore these ecological strategies among major small fish pelagics in Korean waters, distribution of CPUE in the Korean large purse seine fishery were examined. (omitted)

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2012.04a
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• pp.121-124
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• 2012

오늘날 급속한 산업사회 및 환경변화로 인하여 불특정 다수인들이 생활하는 공간들이 고층화 및 대형화가 가속되면서 여러 가지 문제점들이 나타나고 있으며, 그중 특히 소방안전에 있어서 현실을 만족하지 못하는 부분이 적지 않다. 이러한 문제점들을 보완하기 위하여 소방장비에 적용되어지는 소방펌프의 문제점들을 보완하고 이를 적극 활용하여 새로운 소화체계의 개선과 장비 운영의 효율화를 기하고자 하며, 앞서 연구 개발된 회전용적형 펌프에 기동성과 다양성을 접목하여 기존의 소방시스템에 적극 활용하고자 한다. 그간 법적인 문제로 인하여 원심펌프 이외의 펌프를 소방장비에 적용하기에는 현실적으로 적지 않은 어려움이 있었다. 전술한 문제점을 보완하여 기동성과 접근성을 도출하여 초기화재에 보다 효과적으로 대응하는 소방장비의 접목 가능성을 제시하고자 한다.

• Journal of the Korea Safety Management & Science
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• v.15 no.2
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• pp.205-215
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• 2013

As far as recent investment in railway, disused railway yards is increased in each line and region. As a result, the interest of the related local government and agencies has increased on utilizing disused railway yards. In this study, we investigated the status of the disused railway yards and conducted legal review on the use of disused railway yards. In addition, we analyzed the disused railway yards use practices through case analysis and also suggested plans to diversify the ways of their usage.