• Korean Journal of Environmental Agriculture
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• v.17 no.1
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• pp.59-64
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• 1998

The environmental problem of the rural area has been accelerated in soil as well as water. Soil contamination is usually caused by improper operation of landfills, abandoned mine fields, accidental spills, and illegal dumpings. Once soil contamination is initiated, pollutants migrate and may cause groundwater contamination which takes much effort for remediation. Early detection, therefore, is important to prevent further contamination. Electrical resistivity method was used to detect soil contamination, but it was not effective to the heterogeneous condition. Static cone penetrometer test (CPT) has been used widely to investigate geotechnical properties of the underground. In this study, electrical resistivity method and CPT are combined to improve the applicability of it. The pilot test was performed to examine the variation of electrical resistivity with different soil minerals and pore fluid characteristics. Soil samples used were poorly graded sand, silty sandy soil, and weathered granite soil. For all the cases, electrical resistivity decreased with increasing of moisture content. Soil mineral also affected the electrical resistivity significantly. Above all, leachate addition in the pore fluid was very sensitive and caused decreasing of electrical resistivity markedly. It implies that electrical resistivity method can be applied to investigate pollutant plume effectively. This is specially sure when the sensors contact the contaminated soils directly. The CPT method involves cone penetration to the ground, therefore, underground contamination around the cone could be investigated effectively even for heterogeneous condition as it penetrates if electrical resistivity sensors are attached on the cone.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.6
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• pp.73-82
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• 2005

This study was performed to evaluate the need for heating wastewater to enhance treatment efficiency of organic matter (BOD, SS) during cold winter in newly developed Absorbent Biofilter System (ABS) which was established in the Suwon Campus of the Seoul National University. Treatments consisted of non-heating (2000 year) and heating(2001, 2002 year), and sampled data were analyzed during cold winter period as well as post winter period to investigate the influence of heating after winter season. Even the average air temperature showed only $0.4^{\circ}C$ difference between two experimental years, the difference in the average effluent temperature during cold winter period between heating and non-heating experiment was approximately $11^{\circ}C$. The average effluent concentration of organic matter in non-heating treatment exceeded the Korean standards for water quality of discharged effluent in riparian area (BOD and SS 10 mg/L); however, the standards were met in case of heating treatment during both winter and post winter period. Therefore, the need fur heating wastewater during cold winter season in ABS was justified. On the other hand, there was no improvement of treatment efficiency in T-N and T-p, but we observed the more activated nitrification as increasing the wastewater temperature. Because the average underground temperature was $5^{\circ}C$ higher than the average air temperature during cold winter period, we recommend that the ABS can be established in the underground rather than on-ground for saving the heating cost.

• Journal of Fashion Business
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• v.5 no.2
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• pp.87-104
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• 2001

The purpose of this study is to understand the distributions of fashion market and it's characteristics by investigating the attributes and changes of three representative fashion markets i. e. Chungjang Street Market, Underground Shopping arcades, Department Stores in Kwangju Metropolitan city. This study might contribute to the construction of more attractive fashion markets and also to consumer convenience by providing information about fashion. The method of investigation is by direct market visiting and interview from 2000. 7. 11 until 7. 30. The result is as follows; 1. Chungjang Street: This is the most famous and fashionable area, situated mainly on Chungjang street and Hwangkum-dong. The various kind of designer's boutiques, national brands, wedding shops, multi-shops etc. take place. Teenagers and people in their early twenties are the main customers. This point should be born in mind in a strategy of marketing. 2. Underground Shopping arcades: This market is open to customers of all ages and to the passengers crossing the streets and the purposeful visitors, even in rainy or snow days. However it is hard for novices to find it. 3. Department Stores: There are three department stores which are very competitive with each other by granting not only spacious and comfortable shopping areas but also places for children and cultural activities. The strategy of exhibiting unique items unparalleled in it's quality, might be needed with providing a comfortable parking lot, high quality commodes, appropriate sales program and more effective sales managements.

• Geomechanics and Engineering
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• v.9 no.1
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• pp.57-81
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• 2015

Water inrush and mud outburst always restricts the tunnel constructions in mountain area, which becomes a major geological barrier against the development of underground engineering. In view of the complex disaster-causing mechanism and difficult quantitative predictions of water inrush and mud outburst, several theoretical methods are adopted to realize dynamic assessment of water inrush in the progressive process of tunnel construction. Concerning both the geological condition and construction situation, eleven risk factors are quantitatively described and an assessment system is developed to evaluate the water inrush risk. In the static assessment, the weights of eight risk factors about the geological condition are determined using Analytic Hierarchy Process (AHP). Each factor is scored by experts and the synthesis scores are weighted. The risk level is ultimately determined based on the scoring outcome which is derived from the sum of products of weights and comprehensive scores. In the secondary assessment, the eight risk factors in static assessment and three factors about construction situation are quantitatively analyzed using fuzzy evaluation method. Subordinate levels and weight of factors are prepared and then used to calculate the comprehensive subordinate degree and risk level. In the dynamic assessment, the classical field of the eleven risk factors is normalized by using the extension evaluation method. From the input of the matter-element, weights of risk factors are determined and correlation analysis is carried out to determine the risk level. This system has been applied to the dynamic assessment of water inrush during construction of the Yuanliangshan tunnel of Yuhuai Railway. The assessment results are consistent with the actual excavation, which verifies the rationality and feasibility of the software. The developed system is believed capable to be back-up and applied for risk assessment of water inrush in the underground engineering construction.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.2
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• pp.161-173
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• 2013

When the ground is excavated near the pre-existing structures due to the region restricted condition such as urban area, the ground will be released by the excavation and the temporary wall will be deformed depending on the earth pressure. In this case, issues can be created in terms of stability of pre-existing structures. Firstly, the laboratory model tests were carried out to investigate the ground surface settlement due to the ground excavation according to the excavation methods in this study. Using the ground surface settlement results from model tests, numerical analyses were carried out to study the structure deformation due to the ground excavation according to the excavation methods. Finally, using the structure deformation results from numerical analysis, the damage assessment of structures was carried out by using the strain damage estimation criterion.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1523-1528
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• 2008

In this study, the ventilation system of connection passage and elevator hall of underground parking lot in apartment houses is investigated to extract the data for the installation and the application by the experimentation. In case of the elevator hall, actual air exchange rate is predicted fivefold higher than air exchange rate by infiltration and exfiltration. Ventilation system is installed good by supply air and return air. As the next best thing, it is installed by supply air because of IAQ control. The temperature of connection passage and elevator hall uniformly with $7{\sim}8^{\circ}C$, is maintained even if the operating condition of ventilation system is different. Therefore, the installation of the preheater, which is installed at the inlet of ventilation system for the cold draft in winter, is not essential in southern area of Korea.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.10
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• pp.773-778
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• 2012

A road energy harvester was designed and fabricated to convert mechanical energy from the vehicle load to electrical energy. The road energy harvester is composed of 16 piezoelectric cantilevers. We fabricated prototypes using a vehicle load transfer mechanism. Applying a vehicle load transfer mechanism rather than directly installing energy harvesters under roads decreases the area of road construction and allows more energy harvesters to be installed on the side of the road. The power generation amount with respect to the vehicular velocity change was assessed by installing the vehicle load transfer mechanism form and underground form. The energy harvester installed in the underground form generated power of 4.52 mJ at the vehicular velocity of 50 km/h. Also, power generation of the energy harvester installed in the vehicle load transfer mechanism form was 48.65 mJ at the vehicular velocity of 50 km/h.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.1192-1200
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• 2007

A general rainfall outflow in urban drainage has early time of concentration because urban drainage areas are most paved area. In general, rainfall outflow is flowed in drainage pump station and is discharged to rivers in urban areas. However it is excluded through drainage pumps about a heavy rainfall which exceed the design rainfall and the rainfall outflows increase the urban inundation risk. A current pump operation is control according to water level of collecting well or reservoir in drain pump station. But recently, the localized downpours are happened frequently in urban drainage and the current pump stations are frequently incapable of the heavy rainfall outflows. In this study, a real urban inundation was simulated and the drain capacity of drain pump station was evaluated by analysis about flood-factor in urban underground passage. Then the analysis about the inundation was done by the simulation about the real rainfall which cause the inundation. Also, in the simulation the inundation risk and the evaluation of flood-factor were analyzed according to change of the pump operation rule.

• Tunnel and Underground Space
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• v.20 no.6
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• pp.446-454
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• 2010

CAES-G/T (Compressed Air Energy Storage - Gas Turbine) power generation is a likely option for the buffer facility stabilizing the fluctuation of the renewable powers, such as wind and solar powers. Considering the geological conditions, the underground CAES facility is most probable if the CAES-G/T generation is planed in Korea. In this kind of facility, a concrete plug is installed to seal the compressed air in the container, so that the selection of the shape and dimension of concrete plug could be a critical design factor. The stability evaluation of two types of plug was carried out by investigating the distribution of the factor of safety in the plugs and the distribution of contact pressure over the contact surface. The analysis result shows that the taper-shaped plug is more structurally stable than the wedge-shaped plug for the given geological condition. Possible separation of the rock-concrete interface around the spring line of the wedge-shaped plug is anticipated, which means the possible leakage of compressed air through the side wall and also means the poor mobilization of frictional resistance on that area.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.1
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• pp.11-23
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• 2015

In this study, the new segment assembling method using cable tensible force was developed to improve the problem of bolt assembling method of shield tunnel. In the field test construction, cable assembling method reduced the assembling time of segment in comparison with bolt assembling method because of guide role of segment shear-key. In the result of measuring the necessary time for segment assembling process, it took 420sec to assemble one segment in bolt method and 400sec to assemble one segment in cable method, but in case of using the cable automatic feeder, it could reduce the necessary time as 60sec in comparison with bolt assembling method. The cable automatic system modeling using BIM, that connected shield TBM also will be utilized in the area of design TBM, excavation plan, method process understanding, construction management and so on.