• Journal of Environmental Health Sciences
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• v.36 no.5
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• pp.411-417
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• 2010

The Seoul metropolitan government has installed soundproofing walls in road tunnels to improve the tunnel environment for pedestrians. To evaluate the efficiency of these soundproofing walls, we measured noise levels and concentrations of $PM_{2.5}$ and ultrafine particles (UFP) in tunnels with or without these walls. Although noise and UFP levels were significantly lower in the tunnels with soundproofing walls, $PM_{2.5}$ levels were significantly higher: but were significantly lowered by use of a ventilation system. When $PM_{2.5}$ and noise levels were simultaneously measured in a tunnel with soundproofing wall, noise level was significantly reduced but $PM_{2.5}$ level was significantly higher. It is concluded that the soundproofing wall can protect pedestrians from noise, but not PM. Installation of a ventilation system is recommended for protection of pedestrians in tunnels with soundproofing walls.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.8
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• pp.907-914
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• 2014

A heuristic search algorithm is proposed to plan a collision free path for robots in an indoor environment. The proposed algorithm is to find a collision free path in the gridded configuration space by proposed heuristic graph search algorithm. The proposed algorithm largely consists of two parts : tunnel searching and path searching in the tunnel. The tunnel searching algorithm finds a thicker path from start grid to goal grid in grid configuration space. The tunnel is constructed with large grid defined as a connected several minimum size grids in grid-based configuration space. The path searching algorithm then searches a path in the tunnel with minimum grids. The computational time of the proposed algorithm is less than the other graph search algorithm and we analysis the time complexity. To show the validity of the proposed algorithm, some numerical examples are illustrated for robot.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.3
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• pp.163-170
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• 2013

The correlation and interaction mechanisms between marine debris and the vegetation zone were studied on the Jinu-do natural beach of the Nakdong river estuary. Laboratory wind tunnel experiments were carried out under the wind-field and bottom-sand conditions using wind tunnel test equipment to investigate the sedimentation characteristics of wind-drift sand deposition around marine debris and the vegetation zone. The major environmental factors/loads considered in this study were the motion of sand by wind on the beach, deposition of marine debris, and change in the vegetation zone/line. When the marine debris was installed in the wind tunnel, deposition at the front of the structure appeared first by wind action, and then deposition developed from behind at 70% of the front ground level. In contrast, in the case of vegetation, the deposition phenomenon appeared first from behind the vegetation zone/line, and was 60% higher than the front. When the height of the debris and vegetation was the same, the required experimental time to bury the vegetation completely was about twice that of the marine debris.

• Journal of Korea Multimedia Society
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• v.16 no.10
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• pp.1196-1203
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• 2013

In general, the cost of transceiver for wireless network configuration is more expensive than that for wired network. However, in case of environmental management system in a tunnel, the cost can be minimized by adopting low rate tranceiver because the amount of the exchanged data for tunnel monitoring is very small. When the obtained data from sensor node is sent directly to the corresponding command node, there is no need to consider routing problem of the data transfer. However in this case, sensor nodes are required to be implemented with high power transmitter and experience high energy consumption. To tackle this problem, relay nodes can be used to transfer the data of tunnel monitoring, and suitable routing protocols for selecting optimum path are needed. Therefore, in this paper, we propose a routing algorithm and a self-configuration protocol for environment management system in tunnel.

• Journal of Bio-Environment Control
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• v.7 no.4
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• pp.311-323
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• 1998

This study was conducted to analyze the temperature characteristics under tunnel type greenhouse to cultivate watermelon in Sungju region. Air temperature of tunnel type greenhouse was descending rapidly after sunset, and the time required the air temperature inside greenhouse nearly reached the outside air temperature was about 2.5 hours. The maximum air temperature in tunnel type greenhouse, in case of high air temperature day, was exceeding 4$0^{\circ}C$ during day time. Air temperature inside greenhouse during night time could sustain about 2~3$^{\circ}C$ higher than the outside air temperature. But it was necessary to supply supplemental heat when the air temperature was below optimum growth temperature. Soil temperature in the depth of 20cm under soil surface could maintain higher than 2$0^{\circ}C$ and the variation range in a day was 3~5$^{\circ}C$, and the soil temperature descending due to irrigation was about 5~6$^{\circ}C$.

• Asian Journal of Atmospheric Environment
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• v.7 no.1
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• pp.38-47
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• 2013

$PM_{10}$ concentrations were measured at four monitoring sites at the Daechaung station of the Seoul subway. The four locations included two tunnels, a platform, and a waiting room. The outside site of the subway was also monitored for comparison purposes. In addition, the effect of the platform screen doors (PSDs) recently installed to isolate the $PM_{10}$ in a platform from a tunnel were evaluated, and a comparison between $PM_{10}$ levels during rush and non-rush hours was performed. It was observed that $PM_{10}$ levels in the tunnels were generally higher than those in the other locations. This might be associated with the generation of $PM_{10}$ within the tunnel due to the train braking and wear of the subway lines with the motion of the trains, which promotes the mixing and suspension of particulate matter. During this tunnel study, it was observed that the particle size of $PM_{10}$ ranged from 1.8 to 5.6 ${\mu}m$. It was revealed that the $PM_{10}$ levels in the tunnels were significantly increased by the PSDs, while those in the platform and waiting room decreased. As a result, in order to estimate the effect of ventilation system on $PM_{10}$ levels in the tunnels, fans with inverters were operated. It was found that the concentration of $PM_{10}$ was below 150 ${\mu}g/m^3$ when the air flow rate into a tunnel was approximately 210,000-216,000 CMH.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.5
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• pp.558-568
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• 2011

Hazardous volatile organic compounds (HVOCs) have been increasingly getting concern in urban air chemistry due to photochemical smog as well as its toxicity or potential hazards. In this study, we investigated their concentrations and the properties in tunnel, urban roadside and residential area. As a result, among 36HVOCs measured in this study, BTEX (benzene, toluene, ethylbenzene, xylene) and dichlorodifluoromethane, 1,2,4-trimethylbenzene, trichlorofluoromethane were detected above the concentration of $1{\mu}g/m^3$ in every sampling site and the most abundant compound was toluene. The other compounds were detected at trace level or below the detection limit. In addition, we found that three CFCs (chlorofluorocarbons), such as CFC-12, CFC-11, CFC-113, were persistently detected because of the emission in the past. Toluene to benzene ratio (T/B) at tunnel and roadside were calculated to be 4.3~5.3 and at residential area 15.4, suggesting that the residential area had several emission sources other than car exhaust. The ratio of X/E (m,p-xylene to ethylbenzene) ratio was calculated to be 1.8~2.1 at tunnel, 1.7 at roadside and 1.2 at residential area, which means this ratio reflected well the relative photochemical reactivity between these compounds. Good correlation between m,p-xylene and ethylbenzene ($r^2$ > 0.85) were shown in every study sites. This indicated that correlation between $C_2$-alkylbenzenes were not severely affected by 3-way catalytic converter. In this study, it was demonstrated that the concentration of benzene was very low, compared with national air quality standard (annual average of $5{\mu}g/m^3$). Its concentration were $2.52{\mu}g/m^3$ in roadside and $1.34{\mu}g/m^3$ in residential area. We thought this was the result of persistent policy implementation including the reduction of benzene content in gasoline enforced on January 1, 2009.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2004.11a
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• pp.363-364
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• 2004

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.04a
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• pp.189-190
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• 1999

• International Journal of Highway Engineering
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• v.12 no.1
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• pp.9-20
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• 2010

This study was intended to identify, among various characteristics of tunnel, the relationship between the design factors comprising the driver's psychological stability, easiness and the sensitivity and then to suggest the mechanism for evaluating the tunnel view, and to that end, the study attempted to evaluate the relations between the physical elements comprising the tunnel shape and the variation of driver's emotional recognition, thereby proposing the measures to create the scenic environment. As a result of LISREL modeling to identify the characteristics of emotional recognition to tunnel view, the elements affecting tunnel view appeared to be emotional image created by the combination of elements comprising the tunnel view. Such emotional image can be explained by design elements and individual characteristics, and the effect of design element appeared to be greater than individual characteristics. The relations between individual characteristics and design element appeared to be positive (+) and the relations between the "safety" and "variability" was significant. And the "safety" have had greater effect on view recognition than "variability", indicating that the drivers tend to give more importance to "safety", but also require the "variability"on the other hand.