• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.565-570
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• 2007

The explosionproof apparatus is a devices that is enclosed in a case capable of withstanding an explosion of a specified gas or vapor that may occur within it and of preventing the ignition of a specified gas or vapor surrounding the enclosure by sparks, flashes, or explosion of the gas or vapor within, and that operates at such an external temperature that a surrounding flammable atmosphere will not be ignited thereby This kind of exeplosionfproof devices should be installed suitable for the characteristics of the space or process condition that should be protected to prevent explosion or fire. But, due to the lack of information and techniques on the explosionproof technology, some dangerous area is not properly protected from an explosion or it cost too much to implement the explosionproof devices. In this report, the basic guidelines and several case studies of explosionproof devices installation will be introduced to be of help to field safety engineer.

• Industrial Engineering and Management Systems
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• 제3권2호
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• pp.123-128
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• 2004

A tree structure model has been proposed for representing the unequal-area facility layout. Each facility has a different rectangular shape specified by its area and aspect ratio. In this layout problem, based on the assumption that the shop floor has enough space for laying out the facilities, no constraint is considered for a shop floor. Objectives are minimizing total part movement between facilities and total rectangular layout area where all facilities and dead spaces are enclosed. Using the genetic code corresponding to two kinds of information, facility sequence and branching positions in the tree structure model, a genetic algorithm has been applied for finding non-dominated solutions in the two-objective layout problem. We use three kinds of crossover (PMX, OX, CX) for the former part of the chromosome and one-point crossover for the latter part. Two kinds of layout problems have been tested by the proposed method. The results demonstrate that the presented algorithm is able to find good solutions in enough short time.

• 설비공학논문집
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• 제8권2호
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• pp.230-239
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• 1996

A multi-faceted experimental investigation has been carried out to study the cooling performance for stacked modules in arrays of heat generating rectangular modules deployed along PCB's in the enclosed cabinet. The main parameters which have an important effect on cooling characteristics are flow velocity, channel spacing, installation of fan unit, attachment of heat sink, and acoustic noise. The results of individual effect are very helpful for the electronic packaging designer. In order to improve the cooling performance, it is certain that the enlargement of channel space is obviously effective, while this id disadvantageous in high density electronic packaging. Each of the paameters is quantitatively examined as cooling performance and the correlation of Reynolds number to Nusselt number is compared with previous study.

• 한국주거학회논문집
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• 제15권6호
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• pp.57-65
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• 2004

This paper has attempted to analyze the site planning theories of Raymond Unwin (1863-1940), who is called the father of British town planning. A prominent contribution of his was to establish both the site planning of garden suburb and urban housing style in British type. Here it attempts to analyze how he greatly and firmly established the concept of Housing Group, and how he got this the concept from the life and spatial composition of villages. It could be pointed out that the main factors of the Unwin theory are social mixture, creation of community consciousness and informal landscape design, and that the small enclosed space with plenty of amenity is his main theme. It is pointed out that the Unwin theory is composed of recognizing urban life as totality, and group planning theory, and that he definitely originated a new technique: Housing Group. It is analyzed that the syntactic relations between the group planning theory and housing designs in the English garden suburbs are epitomized in Hampstead Garden Suburb, Middlesex.

• 동굴
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• 제70호
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• pp.63-74
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• 2006

소리의 파동, 특히 밀폐된 동굴 속에서 일어나는 음향파동에 대한 과학적 접근과 함께 첨단과학을 통한 소리의 분석기법을 통하여 소리과학과 동굴 및 그 구조에 따른 음파의 공명(증폭)현상과 인류생활의 소리문화의 상관성을 재조명하였다. 따라서 동굴 속에서 음악을 연주하는 경우 작은 소리라도 매우 웅장한 소리효과를 낼 수 있으며, 고음보다는 저음에서의 울림효과를 크게 가져 올 수 있다. 특히 이러한 파동현상과 음향효과를 통하여 기 발굴된 동굴의 체계적 관리 방안과 미 발굴 지하 동굴의 발굴에도 적용할 수 있을 것으로 기대되며, 동굴의 음향파동현상을 응용한 기술로 지각운동과 변화 및 동굴의 상태 분석과 변화 요인을 관찰하는데 효과적인 역할과 방법을 제공할 수 있을 것으로 기대된다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.444-447
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• 2007

The free flow of fine bubbles generated by electrolysis and smoke flow in a space enclosed by fire were recently found to show the same tendency thus leading to the introduction of a research technique. The research experimentally models smoke diffusion and flow in parallel and slanted tunnels using the fine hydrogen bubbles generated by electrolysis in a water tank. Visualization laser with wavelength of 532nm and output power of 1000mW is used to visualize effectively the cross section of fine hydrogen bubble flows generated in a model tunnel.

• 대한전기학회논문지
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• 제32권9호
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• pp.297-304
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• 1983

본 논문은 전하중첩법과 유한요소법을 결합하여 전계를 계산하는 것을 다루었다. 이 방법은 전하중첩법과 유한요소법의 단점을 보완하고 장점을 살리기 때문에 무한원을 포합한 장, 다매질장, 공간전하장 등의 전계계산을 적용할 수 있다. 이방법에 의해서 축대칭장과 2차원장의 전계계산에 필요한 Computer Program이 개발되었으며 비교적 정확학 계산을 얻었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.688-694
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• 2009

As a drive system for next generation train, we have been making research and development of a direct drive traction motor system without the conventional reduction gear. This traction motor is expected to have many advantages such as low noise, reduced maintenance, and energy saving. Due to the demand for high-output motors in the limited space between the wheels, open-ventilating traction motors with gear box have been widely used for many years. However, a conventional open-ventilating traction motor is necessary periodical disassembly to remove the accumulated dust from open-air ventilation. Reducing this burden, as well as increasing energy efficiency and reducing noise, would benefit the next generation of traction motors. To address these needs, KRRI have been developing a fully enclosed type direct drive motor(DDM) with high-efficiency permanent magnet for the next generation train.

• 설비공학논문집
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• 제9권4호
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• pp.484-496
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• 1997

The fluid flow and heat transfer characteristics of conjugate forced and natural convection in the triple-glazed airflow window, where the outer air passes through a space contrived between the interior and exterior window panes, were studied numerically by a finite volume method for the elliptic form of the Navier-Stokes equations. The investigation focused on the influence of window geometry, ventilastion rate and solar energy on the temperature, velocity distribution and thermal performance of the airflow window. The comparison between the triple-glazed airflow window and the enclosed triple-glazed window was also made to evaluate the effect of buoyancy upon which the thermal performance of the window depended.

• 대한기계학회논문집A
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• 제28권2호
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• pp.118-124
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• 2004

The objective of the paper is to demonstrate the noise reduction characteristics of an air-gap resonator, which is composed of an air gap and a partition sheet. By means of installing the air-gap resonator in an enclosed cavity, acoustic resonance can be effectively suppressed using a small space. In particular, it is revealed from a simple, one-dimensional model that the air-gap resonator serves as the Helmholtz resonator that generally absorbs acoustic resonance energy at its resonance frequency. As a result, the air-8ap resonator also has a resonance frequency, which can be predicted with a simple frequency equation derived in the paper. Finally, verification experiments show that the air-gap resonator can be effectively designed by predicting a reasonable gap thickness using the simple frequency-equation.