• Korean Journal of Agricultural Science
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• v.43 no.2
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• pp.258-274
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• 2016

Recently, as fluctuations in annual precipitations continue to grow, the frequency of floods and droughts is rapidly increasing. Especially, since many reservoirs are reported as having less capacity and aging faster than large dams, the damages due to floods and droughts are estimated to become more severe. With this background for the present study, field investigation of reservoirs in Chungnam, Chungbuk, and Chonbuk regions was carried out for disaster prevention and the safety management of agricultural reservoirs. Furthermore, embankment transformations were compared and analyzed after the raising of embankments. Based on design methods for remodeling agricultural reservoirs and the results of embankment raising and the problems which occurred on crest, supplementation to the upstream and downstream slopes, control sector, and spillway should be implemented in the existing reservoir. In regard to this, the condition assessment score of compound member of reservoirs was performed, the Chungnam region score was in the 3.11-4.73 range. In addition, reservoirs in Chungbuk scored in the 4.00-4.49 range, and reservoirs in Chonbuk scored in the 3.90-4.60 range. Applying current precision safety inspection practices to small reservoirs requires economic expenses and time, for which assessment items are too varied and complex. Therefore, subdivided condition assessment items and criteria should be improved and streamlined by deleting, reducing, combining, and selecting only the riskiest factors. In the future, reservoirs should be periodically monitored and systemically managed and rational plans for maintenance and repairs should be used as reinforcement methods.

• Journal of the Korean Geotechnical Society
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• v.32 no.6
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• pp.5-16
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• 2016

In the geosynthetics-reinforced piled embankment the effects of soft soil stiffness, friction angle of the fill material, tensile stiffness of geosynthetics, and height of the embankment on the load transfer soil arch measured by the critical height were numerically investigated. Results from parametric studies show that the magnitude of the soft soil stiffness is the most influencing factor on the critical height. The contour charts of the critical height with respect to the combination of the soft soil stiffness and other parameters were presented. The charts show that the critical height sensitively varies with the combination of the soft soil stiffness and the height of embankment. Under the sufficiently low stiffness of soft soil, the critical height sensitively varies with the friction angle of the fill material. Once the geosynthetic layer is placed, however, the magnitude of the tensile stiffness of the geosynthetic layer hardly influences the critical height of the soil arch.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.520-525
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• 2001

It's strongly recommended to check upon the slope stability of soil nearby railroad, since the freezing-thawing repeat in long term may cause decrease of slope stability. The study is, therefore, focused on the strength characteristic transformation of soil, measuring it experimentally, throughout physical and mechanical tests operated by the freezing-thawing repeat tests. The sampling of weathered soil used for the embankment materials along the domestic railway lines are classified by parent-rock, and then collected after it in the first hand. It tells that Uniaxial strength and axial strain were decreased simultaneously as the frequency of freezing-thawing repeat increased and its range was reduced into 25～85 percentage off comparing to uniaxial strength of unfreezing-soils when about 100 times of freezing-thawing repeats occurred. Following the result of direct shear tests, the cohesion of freezing-soil with freezing-thawing repeats shows 11∼60 percentage less than that of unfreezing-soil but the change of internal friction angle of the soil is extremely slight, enough to ignore. As a result. it could be found that strength characteristic transformation has highly correlated with freezing-thawing repeat.

• Korean Journal of Heritage: History & Science
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• v.50 no.4
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• pp.104-121
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• 2017

The present study attempted to produce the floor plan of the surroundings near Geumcheongyo Bridge in Changdeokgung Palace of the Late Joseon Period through the use of rubber sheeting transformation based on the drawing principles of "Donggwoldo(東闕圖)". First, the study compared the actual sizes of the major buildings that have existed since the production of "Donggwoldo(東闕圖)" with the sizes depicted in the picture to reveal that the front elevation of the buildings was produced by reducing it by approximately 1/200. However, the study could not confirm the same production proportions for the side elevation. Only the lengths of the side elevation were depicted at around half of the actual proportions, and as the diagonal line angles were found to be at an average of $39^{\circ}$, the study confirmed they were drawn in a manner similar to cabinet projection. Second, the study created an obliquely projected floor plan by inversely shadowing the drawing principles of "Donggwoldo(東闕圖)" and produced a floor plan of the surroundings near Geumcheongyo Bridge in Changdeokgung Palace through the use of rubber sheeting transformation. Projective transformation was confirmed as most suitable during the transformation, and with standard error of 2.1208m, the relatively high accuracy of the transformation shows that the production of a floor plan for "Donggwoldo(東闕圖)" is significant. Furthermore, it implies the possibility of producing floor plans for various documentary paintings produced using the paralleled oblique drawing method in addition to "Donggwoldo(東闕圖)". Third, the study evaluated the accuracy of the spatial information provided by the produced floor plan by comparing the three items of Geumcheongyo Bridge location, Geumcheongyo Bridge and Jinseonmun Gate arrangement, and Geumcheon stone embankment location. The results confirmed the possibility of utilizing the floor plan as a useful tool which helps understand the appearance of the surroundings at the time of "Donggwoldo(東闕圖)" production because it is parallel to the excavation results of the Geumcheongyo Bridge and its context. Therefore, the present study is significant in that it seeks the possibility of producing spatial information recorded in "Donggwoldo(東闕圖)" by applying rubber sheeting transformation and consequently in that it presents a new methodology for understanding the appearance of the East Palace of the Late Joseon Period.

• Journal of the Korean GEO-environmental Society
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• v.12 no.10
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• pp.39-49
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• 2011

Recently PBD method, one of acceleration of consolidation methods is used in the soft ground to shorten consolidation time for fast settlement during construction. It is economical and easy to work. Discharge capacity of PBD is sensitive in proportion to thickness of soft ground layer, and drainage of PBD declines due to disturbance effect in surrounding ground by mandrel used for vertical drainage setting and setting machines and type. Also, deviation of discharge capacity is large according to ground condition, construction condition and soil properties. In addition, when embankment loading is not conducted instantly after PBD setting due to rain or lack of embankment material supply, it causes leaving period problems. But cause and analysis of those problems for discharge capacity is lack. So, in this test, ground improvement and discharge capacity is investigated by implementing composite discharge capacity test for analysis of an effect factor of PBD discharge capacity with leaving period. After fixing the vertical drain on a cylindrical cylinder, put churned sample into the cylinder. Then leave 0day, 30day, 60day and 90day. And then, load following the loading step of 30, 70 and 120kPa using a pressure device. As a result, the longer leaving period, discharge capacity is reduced. It is caused by a decrease of discharge area caused by creep transformation moisture absorption of PBD filter after long leaving period.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.6
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• pp.1063-1076
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• 2017

To improve the productivity of the earthwork, a fleet management system for construction equipment was suggested in previous studies. But there were some gaps between theory and practice. To overcome this problem, some opinions are gathered form experts and field engineers and four improvements have been proposed and reflected in the system. First, the previous system consists of one hardware module, so it is hard to install it at a control office and construction equipment at the same time. The server module for the office and the mobile module for construction equipment are separately developed. Second, the transportation algorithm that is used in the previous system can generate shortest paths for the earthwork distribution, but embankment areas are not gathered. This situation leads to a decrease in compaction productivity. A modified algorithm for earthwork distribution is suggested. Third, the automated coordinate transformation is performed to show the position of construction equipment on the 3D terrain in real-time. Fourth, construction equipment groups should be formed in the initial stage of earthwork and the number of equipment of each groups should be changed by operation status and site environment. But this functions did not work properly in the previous system. This problem is corrected in the proposed system. The improvements can make the proposed system much more realistic one and can leads to an increase in the productivity of earthwork operations.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.35 no.3
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• pp.13-21
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• 2017

The Cho-yeon Pavilion located in the Wangdae village in Samcheong-ri, Songgwang-myeon, Suncheon-si, was transformed into a place of refuge, a shrine, a vacation home, a lecture hall for kings. Based on the change, the current study has explored the periodic changing placeness and the transformation of cultural landscape and has figured out the meaning. The result of this study is as follows. First, "Cho-yeon", named by Yeonjae Song, Byeong-Seon, originated from Tao Te Ching of Lao Tzu. The concept is found not only in the Cho-yeon Pavilion in Suncheon but also in various places, such as, the Cho-yeon-dae in Pocheon, of the Cho-yeon-dae in Gapyeong, of the Cho-yeon-dae of the embankment behind the Gioheon of Changdeok-gung Garden, Cho-Yeon-Mul-Oe old buildings, including Jung(亭), Dae(臺), Gak(閣), of Ockriukag in Yuseong, etc. This shows that taoistic Poongrhu was naturally grafted onto confucian places, which is one of the examples of the fusion of Confucianism, Buddhism, and Taoism. Second, the placeness of the Cho-yeon Pavilion area is related to a legend that King Gong-min sought refuge here at the end of the Koryo Dynasty. The legend is based on the Wangdae village(king's region), Yu-Gyeong(留京)(the place where kings stayed), rock inscription of Wang-Dae-Sa-Jeok, Oh-Jang-Dae (the place where admiral flags were planted), and the Mohusan Mountain. Third, the Cho-yeon Pavilion not only has a base(the vacation home) that reflects confucian values from the rock inscription(趙鎭忠別業, 趙秉翼, 宋秉璿) of the beautiful rock walls and torrents but also has territoriality as taoistic Abode of the Immortals (there are places where people believe taoist hermits with miraculous powers live within 1km of the pavillion: Wol-Cheong(月靑), Pung-Cheong(風靑), Su-Cheong(水靑), Dong-Cheon(洞天). The Cho-yeon Pavilion also reflects the heaven of Neo-Confucianism for, pursuing study, and improving aesthetic sense by expanding its outer area and establishing the nine Gok: Se-Rok-Gyo(洗鹿橋)., Bong-Il-Dae(捧日臺), Ja-Mi-Gu(紫薇鳩), Un-Mae-Dae(雲梅臺), Wa-Ryong-Chong(臥龍叢), Gwang-Seok-Dae(廣石臺), Eun-Seon-Gul(隱仙窟), Byeok-Ok-Dam(碧玉潭), and Wa-Seok-Po(臥石布). In sum, the Cho-yeon Pavilion is a complex cultural landscape. Fourth, the usage of the Cho-yeon Pavilion was expanded and transformed: (1)Buddhist monastery${\rightarrow}$(2)Confucian vacation home${\rightarrow}$(3)Vacation home+Taoistic Poongrhu Place${\rightarrow}$(4)Vacation Home+Taoistic Poongrhu Place+Lecture Hall(the heaven of Neo-Confucianism). To illustrate, in 7978, the place served as Buddist Monk Kwang-Sa's monastery; in 1863, Cho, Jin-Choong established a vacation home by building a shrine in front of the tomb of his ancestor; in 1864, Cho, Jae-Ho expanded its usage to a vacation home to serve ancestors as a taoistic place by repairing the pavilion with roof tiles; and after 1890, Cho, Jun-Sup received the name of the pavilion, Cho-yeon, from his teacher Song, Byeong-Seon, and used the Pavilion for a lecture hall.