• Tunnel and Underground Space
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• v.13 no.3
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• pp.235-243
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• 2003

Recent worldwide trends show that tunnel length is getting longer, and the demand for longitudinal ventilation system with jet-fans in highway tunnels has also increased mainly due to the economic reasons. Improvements in vehicle engine subsequently reduced required ventilation rate(Qreq) which is the decisive factor in choosing the optimal ventilation system. Qreq contour map is a graph that defines the relationship among tunnel length, grade and required ventilation rate. It is important to understand the variation of Qreq in order to evaluate the characteristics of ventilation system with jet fans. Therefore this study aims at studying a graphical method for determining the characteristics of jet-fm ventilation system using Qreq contour map. Also, this study focuses on traffic composition on local highways.

• Korean Institute of Interior Design Journal
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• v.18 no.6
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• pp.104-114
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• 2009

The purpose of study was understanding necessity of environment design for underground parking lot in residential design plan and grasping design plans of 'Activity Support' that considerate women, exclude women's unsecured feeling at underground parking lot. The inquiry analyzed 6 design plan in design competition that considerate women according to precede studies, a theory of CPTED, a design guide for wayfinding, and survey. A ramp, circulation, entrance, lighting, ventilation, and space design plan are proceed on this study The result are as below. First, a rectilinear figure ramp suits entrance plan on the circulation, but if it is not possible, cross-using of rectilinear and curvilinear figure ramp plan is desirable. Second, on the circulation plan, vehicles circulation plan and equality parking distribution plan got accomplished generally, and help senses of direction because it is planed network systemize. On a large scale underground parking lot, simplify parking circulation to convenience entrance and exit for weak in sense of direction. Third, the shape and material that‘s environmentally conscious will be in use to the entrance plan. As the first stage to the underground, artwork that women prefer can modulate the rejection of underground space. Forth, natural lighting system and ventilation can make the environment-friendly space, decrease the women’s rejection to the underground, it can also keep a natural watch on the space. Fifth, on the space design plan, it can use bright and comfortable design of wall and ground to decrease the women‘s rejection, also it is useful to the sense of direction. LED indirect lighting plan that 58.7% of women prefers on survey reflects women’s state of desire that bright and atmosphere. In addition, proper use of plans that subsidiary facilities, rest area with Sunken, and nature-friendly material can minimize differences of underground and ground parking lot.

• Journal of computational fluids engineering
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• v.18 no.3
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• pp.72-78
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• 2013

The turbulent flow behavior of air supply and exhaustion in the Shin-gum-ho subway station is analyzed for ordinary and emergency state. The depth of Shin-gum-ho station is 43.6m which consists of the island-type platform(8th floor in underground) and a two-story lobby (first & second floor in underground). An emergency stairway connects between the platform and the lobby. Ventilation operation mode for ordinary state is set up as a combination of air supply and exhaustion in the lobby and platform, while for emergency state it is set up as a full air supply in the lobby and a full exhaustion in the platform. The entire station is covered for simulation. The ventilation diffusers are modeled as 95 square shapes of $0.6m{\times}0.6m$ in the lobby and as 222 square shapes of $0.6m{\times}0.6m$ and 4 rectangular shapes of $1.2m{\times}0.8m$ in the platform. The total of 7.5million grids are generated and whole domain is divided to 22 blocks for MPI efficiency of calculation. Large eddy simulation(LES) is applied to solve the momentum equation and Smagorinsky model($C_s$=0.2) is used as SGS(subgrid scale) model. The time-averaged velocity fields are compared to experimental data and show a good agreement with it.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.2
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• pp.135-148
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• 2005

In the stage of conceptual design for the construction and operation of the geologic repository for radioactive wastes, it is important to consider a repository ventilation system which serves the repository working environment, hygiene & safety of the public at large, and will allow safe maintenance like moisture content elimination in repository for the duration of the repositories life, construction/operation/closure, also allowing safe waste transportation and emplacement. This paper describes the possible ventilation system design criteria and requirements for the prospective Korean radioactive waste repositories with emphasis on the underground rock cavity disposal method in the both cases of low & medium-level and high-level wastes. It was found that the most important concept is separate ventilation systems for the construction (development) and waste emplacement (storage) activities. In addition, ventilation network system modeling, natural ventilation, ventilation monitoring systems & real time ventilation simulation, and fire simulation & emergency system in the repository are briefly discussed.

• Journal of Environmental Health Sciences
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• v.30 no.5 s.81
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• pp.353-357
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• 2004

The purpose of this research is to characterize formaldehyde as trace toxic air pollutant in the underground spaces in Gyungnam province. Air samples of formaldehyde were taken in the three underground spaces for ten months from April 2003 to January 2004. The IAQ(Indoor Air Quality) of underground spaces were controled using central ventilation(supply/exhaust) system. The levels of GM of airborne formaldehyde concentrations in three sampling spaces were well below applicable standards, Korean Ministry of Environment, 0.1 ppm. However, some sample of airborne formaldehyde concentrations in underground spaces 'B' and 'C' were in excess of standard, due to the commercial products in shop, structural material, and the climate having high humidity and temperature. There are statistical differences in levels of formaldehyde by sampling spaces (p=0.086).

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.919-929
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• 2009

2008, Seoulmetro transports an average of 3,952,000 passengers every day with a 0.8% increase of the daily ridership compared to last year.(Korean Economics '09.01.21) Seoul subway systems ridden by a considerable number of Seoul citizens place their top priority on swiftness, safety and clean underground air quality so as to meet the customer satisfaction. One of the most important problems is to eliminate minute dust(PM10) among the pollutants such as the gas attributable to air pollution and floating particulate matter defined by the ordinance of the Ministry of Environment. Seoulmetro install and operate many kinds of air filtration facilities, however we've launched a research on "Standardization Plan on Underground Air Filtration Facility" for the installation and improvement of optimum standardized air filtration system. As a preliminary study, we're going to consider ventilation system and air filter to supply filtered metropolitan outdoor air aimed at ensuring clean underground environment.

• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.208-214
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• 2009

지하 복수층 주차장은 도시의 밀집화 및 자동차의 급격한 증가로 인한 토지부족 및 주차난을 해소할 수 있는 좋은 방법이다. 하지만 인체유해 배출가스의 집중으로 환기의 중요성이 대두되는 추세에도 불구하고 실제로는 시공이 완료 된 후에나 오염도 측정이 가능하다. 이러한 이유로 CFD 시뮬레이션으로 시공이전의 지하 복수층 주차장의 공기오염도를 예측했다. CFD 시뮬레이션은 예산과 시간을 절감한 공기오염도 예측이 가능하다. 실제의 당산근린공원의 지하주차장을 대상으로 오염도를 예측했다. 급기에만 강제유동을 일으키는 2종과 배기에만 강제유동을 일으키는 3종 기계환기법, 그리고 급배기에 강제유동을 일으키는 1종기계환기법을 각각 적용하여 공기오염도를 계산했다. 지하1층과 지하2층의 입구 및 출구유속을 10, 15m/s로 하여 실내평균연령과 실내평균환기효율을 살펴보았다. 계산결과는 급기와 배기에 강제유동을 동시에 일으키는 1종 기계환기법의 값과 비교하였다.

• Smart Structures and Systems
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• v.30 no.5
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• pp.433-446
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• 2022

Despite efforts to reduce unexpected accidents at confined construction sites, choking accidents continue to occur. Because of the poorly ventilated atmosphere, particularly in long, confined underground spaces, workers are subject to dangerous working conditions despite the use of artificial ventilation. Moreover, the traditional monitoring methods of using portable gas detectors place safety inspectors in direct contact with hazardous conditions. In this study, a long-range (LoRa)-based wireless safety monitoring system that features the network organization, fault-tolerant, power management, and a graphical user interface (GUI) was developed for underground construction sites. The LoRa wireless data communication system was adopted to detect hazardous gases and oxygen deficiency within a confined underground space with adjustable communication range and low power consumption. Fault tolerance based on the mapping information of the entire wireless sensor network was particularly implemented to ensure the reliable operation of the monitoring system. Moreover, a sleep mode was implemented for the efficient power management. The GUI was also developed to control the entire safety-monitoring system and to manage the measured data. The developed safety-monitoring system was validated in an indoor testing and at two full-scale water pipeline construction sites.

• Tunnel and Underground Space
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• v.6 no.1
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• pp.64-68
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• 1996

Analyzed in this paper is fluid flow in the region near the exhaust and blower ports of the ventilation ducts inside a vehicle tunnel. Theoretical analysis shows that prediction of the energy loss in this region is important for designing the ventilation system. A finite-difference numerical model for the two-dimensional turbulent flow field was used to obtain the flow solution as well as the energy loss. It was shown that the blower-nozzle angle ($\beta$) had an important role in establishing both the pressure gradient and the energy loss, while the effect of the distance between two ports on them was not so significant.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.177-188
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• 2019

The purpose of the optimization of the installation of supply/exhaust ports for tunnels with transverse ventilation system is to supply fresh air from outside to inside of tunnels uniformly and exhaust pollutant from tunnels properly for creating safe and clean environment for tunnel users. For this purpose, a ventilation port area optimization program was developed to obtain a uniform supply or exhaust air volume inside a great depth double deck tunnel with transverse ventilation system. In order to area optimize the developed port sizing program, the wind velocity was measured in the duct of the currently operated tunnel with semi-transverse ventilation. Also 3D cfd was performed on the same tunnel and cfd results were compared to the measured value. As a result, the error rate between the predicted value from the program and measured value was 6.72%, while the error rate between the predicted value from the program and 3D cfd analysis value was 4.86%. Both of comparison results show less than 10% of error rate. Thus It is expected that supply/exhaust port optimization design of transverse ventilation tunnel can be possible with using this large exhaust port area optimization program.