• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.1
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• pp.87-94
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• 2010

This study mainly focused on the subsurface settlement due to shallow and deep tunneling in sandy ground. In order to figure out theoretical deformation patterns in association with the ground loss during the progress of tunneling, laboratory model tests using aluminum rods and finite element analyses using the CRISP program were carried out. As a result of comparison between the model test and the finite element analysis, the similar deformation patterns were found. In addition, it was identified that the most K values obtained from both the FEA and the model tests were distributed between Dyer et al. (1996) and Moh et al. (1996) of the field observation data. Based on the model test data, the linear equation of K for the sandy soil could be obtained.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.319-322
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• 1998

A 20 GHz 2-stage MMIC (Monolithic Microwave Integrated Circuits) LNA(Low Noise Amplifiers) has been designed. The pHEMT with gate length of 1.15 um has been used to provide ultra low noise and high gain amplification. Series and Shunt feedback circuits were interted to ensured high stability over frequency range of DC to 60 GHz. The size of designed MMIC LNA is 2285um x 2000um(4.57mm2). The simulated noise figure of MMIC LNA is less than 1.7 dB over frequency range of 20 GHz to 21 GHz.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.2
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• pp.141-148
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• 2015

This paper presents a sun-synchronous orbit design which effectuvely includes the requirements derived from spacecraft to ground station contact and spacecraft to target image accessibility. For this purpose, operation parameters of multiple spacecraft are defined as Contact Overlap, Contact Overlap Gap, Access Overlap, Access Overlap Gap. These parameters are used to form a Figure of Merit that reflects the operational requirements. The Figure of Merit is optimized to increase the efficiency of operating multiple spacecraft in constellation and is used to determine the operational orbit of each spacecraft that constitutes the constellation.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.409-416
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• 2000

This research aims at evaluating the seismic performance of the existing R/C bridge piers which were nonseismically or seismically designed in accordance with the provision of Korea Highway Design Specification. Further experimental investigations have been doing to figure out the retrofitting effects of nonseismic R/C bridge piers confined with glass fiber at the plastic hinge zone. Pseudo-dynamic tests have been carried out on nine scaled R/C column specimens to investigate their hysteretic behavior under earthquake loading, Test parameters are axial load input ground motion confinement steel ration glass fiber and etc,

• Journal of the Korean Geotechnical Society
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• v.30 no.3
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• pp.5-16
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• 2014

Soil-nailing has two main resistance factors: skin friction between ground and grouting; and tension load of reinforced material. These two factors will affect the load-displacement curve when performing soil-nailing pullout tests. The purpose of this paper is to figure out the shear behavior between ground and soil-nailing focusing on the net load-displacement behavior during soil-nailing pullout tests. Firstly, the net load-displacement curve between ground and grouting is estimated theoretically. Then, in-situ pullout load tests are performed on various ground conditions to obtain the load-displacement curve occuring between ground and grouting. Since the measured shear displacement includes elongation of the reinforced material (steel nails), the net load-displacement curve can be obtained by subtracting the elongation magnitude of steels from the measured displacement. It was found that the measured net load-displacement curve matches reasonably well with the theoretically estimated curve.

• Journal of Soil and Groundwater Environment
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• v.6 no.2
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• pp.31-38
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• 2001

An illegal landfill In Korea was evaluated in a view of environmental quality to figure out reusing the area. The sampling spots were selected at a point in the landfill and three points in it's around area(two points in a paddy soils and one in a farm field). The eleven pollutants regulated in the Korean Soil Environmental Preservation Act (KSEPA) were analysed from the soil sample with the method of the KSEPA. As the results of the analysis the level of concentration with most samples indicated the requirement of the KSEPA. The concentration of soil samples met the standard: however, some pollutants in the ground water and leachate showed higher concentration than that of the requirement. Therefore, we must consider the treatments of the pollutants in the ground water and leachate when designing this landfill area for reusing.

• 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 the Korean Institute of Rural Architecture
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• v.24 no.3
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• pp.31-38
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• 2022

The purpose of this study is to rediscover the gestalt psychological value of the Landscaping structure and architectural landscape in the vulnerable village consulted by experts in 2021 year. For this study, nine villages called of Saethul Maul were surveyed, and two of them were analyzed for landscape composing of gestalt psychology. The two villages, Yulwon and Jeonchon, included the case where the landscaping structure of residence was viewed from outside the village and the case from within the village. Psychological distance of the villages is analyzed by D/H ratio for the scenery seen from lanes. There are three expected conclusions. First, in terms of gestalt psychology, the buildings mean a figure, and the rice field in front of the village, the mountains behind the village, and the lanes represent a landscape structure consisting a background(ground). It captures the unique landscape aesthetics of the vulnerable village. Second, the landscape seen in the village shows various differences in horizontal distance and vertical height of the lane, so even if the psychological distance gives a sense of closure, it gives a sense of rhythm and change. However, considering the psychological distance (D/H ratio) when the roads are expanded for the fire car, the village landscape can be re-formed by safety and function. Third, the architectural landscape of Yulwon village is characterized by the harmonious arrangement of traditional houses, Narack-Doiji (rice barn), and wooden building (agricultural barn) in the background of chestnut tree hill behind the village. It is necessary to reduce the use of industrial materials and restore the valuable architectural landscape of the vulnerable village.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.3
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• pp.383-392
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• 2015

In subsea tunnelling, prediction of the fractured zone (or water bearing zone) ahead of tunnel face saturated by seawater with high water pressure has been a key factor for safe construction. This study verified the feasibility of utilizing induced polarization (IP) survey at tunnel face for predicting the ground condition ahead of the subsea tunnel face. A pore model was proposed to compute chargeability in granular material, and the relationship correlating chargeability with the variables affecting the chargeability was derived from the model. Parametric study has been performed on the variables to figure out the most influential factors affecting the chargeability. The results of the parametric study show that the size of narrow pores ($r_1$) and the salinity of pore water are the most influential factors on chargeability. Laboratory tests were conducted on various types of ground condition by changing the salinity of pore water, the thickness of the fracture zone and the existence of gouge (weathered granite) within the joints of the fractured zone to figure out the effect of the ground characteristics on the IP phenomenon. Test results show that the chargeability of the fractured zone saturated by seawater increases if the joints in the fractured zone are filled with gouge since the infilled gouge will decrease the size of narrow pores ($r_1$).

• Journal of the Korean Geotechnical Society
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• v.26 no.6
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• pp.5-19
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• 2010

The purpose of this study is to figure out the effect of pressurized grouting on the pullout resistance and the group effect of the compression ground anchor by performing pilot-scale chamber tests and field tests. The laboratory tests are carried out for 3-types of soils which are abundant in the Korean peninsular. Experimental results showed that the enlargement of anchor diameters estimated from the cavity expansion theory matches reasonable well with that obtained from experiments. Moreover, the required injection time as a function of the coefficient of permeability of each soil type was proposed. A series of in-situ anchor pullout tests were also performed to experimentally figure out the effect of pressurized grouting on the pullout resistance. Experimental results also showed that the effect of the pressurized grouting is more prominent in a softer ground with smaller SPT-N value in all of the following three aspects: increase in anchor diameter; pullout resistance; and surface roughness. The pressurized grouting effect in comparison with gravitational grouting was found to be almost nil if the SPT-N value is more than 50. Based on experimental results, a new equation to estimate the pullout resistance as a function of the SPT-N value was proposed. And based on in-situ group anchor pullout tests results, a new group effect equation was proposed which might be applicable to decomposed residual soils which are abundant in the Korean peninsular.