• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.41 no.1
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• pp.20-29
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• 2012

• Journal of Bio-Environment Control
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• v.5 no.2
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• pp.111-119
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• 1996

The purpose of this study is to construct the main system of simulator for the environment control of agricultural production facilities. The model describing the system was based on the energy and mass balance in an unsteady - state situation. The model consist of the three major parts : the main model, the light model, and the environmental control model, and each part was separated to be developed individually. The main model which is the core of this system includes the thermal model, the soil model, the ventilation model, the cultivation model, and the carbon dioxide model. And also the environmental control model includes the thermal curtain model, the heater/cooler model and the underground heat exchanger model. The equations used in this model were written in analog programming methods using PCSMP The simulator was evaluated through comparison between simulated and measured temperatures controlled during daytime and night. The results showed good agreements between the predicted and measured temperatures.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2001.11a
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• pp.59-62
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• 2001

여름철 온실내 고온 문제를 해결하기 위해 이용되는 자연환기형 포그냉방은 환기가 충분치 못할 경우 온실 내부의 습도가 증가하여 증발 효율이 떨어지는 문제가 발생한다. 제습장치를 이용하여 온실 내부의 상대습도를 낮추면 증발 냉각 효율을 높일 수 있을 것으로 생각된다. 본 연구에서는 제습장치를 이용한 포그냉방 온실에 대한 CFD 모델을 개발하여 온실의 열환경 및 수분 환경을 분석하고자 한다. (중략)

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.310-314
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• 2001

측정의 소급성과 신뢰성을 확보한다는 전제하에 오차의 개념을 버리고 측정시의 측정불확도를 분석하는 것이 측정과학에 있어서 세계적인 추세이다. 본 논문에서는 전달표준인 열전압변환기를 사용하여 고주파전압계의 정밀 교정에서 불확도를 산출하기 위하여 수학적 모델을 설정하고 측정에 관계되는 모든 불확도 요인을 분석하였다. 케이블의 영향과 열전대감지기와 직류전압계의 상관관계, 직류소스, RF소스, 감쇠기, 반사계수와 DUT 등 측정에 있어서 관계되는 모든 불확도요인을 분석하여 확장불확도를 산출하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2195-2201
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• 2009

This paper considers the influence of suction-line heat exchangers on the efficiency of a refrigeration cycle using hydrocarbon refrigerants such as R290, R600a and R1270. These suction-line heat exchangers can, in some cases, yield improved system performance while in other cases they degrade system performance. A steady state mathematical model is used to analyze the performance characteristics of refrigeration cycle with suction-line heat exchanger. The influence of operating conditions, such as the mass flowrate of hydrocarbon refrigerants, inner diameter tube and length of suction-line heat exchanger, to the performance of the cycle is also analyzed in the paper. Results showed that the mass flowrate of hydrocarbon refrigerants, inner diameter tube and length of suction-line heat exchanger, and effectiveness have an effect on the cooling capacity, compressor work and RCI(Relative Capacity Index) of this system. With a thorough grasp of these effect, it is necessary to design the compression refrigeration cycle of hydrocarbon refrigerants using suction-line heat exchanger.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.625-632
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• 2018

This study was done to reduce total energy demand based on resource shortage problems and to provide improvement points for more efficient adjustment of the high insulation standards for saving energy in Korea. The demand sensitivity was fully considered by varying the slope of each building. The energy performance of the building was maximized by the introduction of outdoor air at night. A final low-energy building model was developed with the two measures combined, and the short-term operation of the night-fuzzy ventilation system was simulated. The result showed a reduction of about 6 to 7 percent compared to the base model. The results could have many implications in terms of the need to conduct demand sensitivity analyses in architectural design.

• Tunnel and Underground Space
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• v.27 no.3
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• pp.132-145
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• 2017

Shock loss was not applied for the tunnel ventilation of road tunnel in the past. However, pressure losses due to the shock loss can be significant in network double-deck road tunnel in which combining and separating road structures exist. For the optimum ventilation design of network double-deck road tunnel, this study conducted 3D CFD numerical analysis for the shock loss at the combining and separating flows. The CFD model was made with the real-scale model that was the standard section of double-deck road tunnel. The shock loss coefficient of various combining and separating angles and road width was obtained and compared to the existing design values. As a result of the comparison, the shock loss coefficient of the $30^{\circ}$ separating flow model was higher and that of the two-lane combining flow model was lower. Since the combining and separating angles and road width can be important for the design of shock loss estimation, it is considered that this study can provide the accurate design factors for the calculation of ventilation system capacity. In addition, this study conducted 3D CFD analysis in order to calculate the shock loss coefficient of both combining and separating flows at flared intersection, and the result was compared with the design values of ASHRAE. The model that was not widened at the intersection showed three times higher at the most, and the other model that was widened at the intersection resulted two times higher shock loss coefficients.

• 한국전산유체공학회:학술대회논문집
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• 2007.10a
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• pp.32-38
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• 2007

The increasing demand on the comfortable working conditions in automotive part plant pushes the company to improve working environment of workers. we analyzed thermal flow of an automotive part factory by using CFX code. Internal working environment has been analyzed with/without ventilation system.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.45-50
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• 2005

The supply outdoor airflow rates are calculated and analyzed using a multizone network model in a high-rise residential apartment. The system parameters include parameters related to weather conditions, building conditions, operation conditions, and facility conditions. Simulations are conducted according to the method of design of experiments and analysis of variance is conducted to investigate the effects of parameters on ventilation rate. A correlation equation is derived to predict ventilation rates of the building depending on the various parameters.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04c
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• pp.154-156
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• 2003

모바일 기술의 발달로 인해 모바일 장치를 위한 다양한 지원 모델과 응용 프로그램들이 개발되고 있다. GIS분야에서도 모바일 기술이 접목되어 모바일GIS가 등장하게 되었으며, 모바일GIS를 이용한 다양한 응용 프로그램들이 서비스되고 있다. 기존의 모바일GIS는 국립지리원에서 제공하는 DXF형식의 국가기본수치지도를 원시 데이터로 사용하였으나, 최근에는 모바일GIS에 XML(extensible Markup Language)을 적응하려는 움직임을 보이고 있다. 이를 위해서는 DXF형식의 GIS데이터를 OGC(Open Gis Consortium)에서 제안한 GML(Geography Markup Language)로 변환하기 위한 변환기를 필요로 한다. 본 논문에서는 DXF를 GML로 변환하기 위한 DXF2GML변환기의 효율적인 번역을 위해, DXF와 GML의 의미적 차이를 해결하고 효율적인 변환과정을 구현하기 위한 DXF2GML변환기의 중간코드를 제안하고자 한다. 또한 제안된 중간코드를 적용하여 DXF2GML변환기의 Front-End인 중간코드 생성기와 Back-End인 GML문서 생성기를 구현하고자 한다.