• Journal of the Korean GEO-environmental Society
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• v.12 no.9
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• pp.13-20
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• 2011

There are many mountains in Korean Peninsula, and those used for the construction of roads and railways sectors are forming slopes. Slope collapse occurs with falling rocks and landslide because of the relaxation of the thawing rocks. The heavy rain in summer can also significantly contribute to the process, and abnormal climate change is much more influential than before. Therefore, rockfall-related accidents in rainy season are easily accessible in media every year. There has been a lot of research on application of strengthening compensation of the sections in order to minimize casualties and property damage. Rockfall Protection Net, however, has not been focused on much in the field yet. This study highlights the need of Rockfall Protection Net, since it can segregate the falling rocks inside the net relatively safely. Although there has been a little doubt about the effectiveness of rockfall protection facilities, it is obvious that relevant studies dealing with the solidity of the net are necessary for the rockfall protection net to be capable of supporting rockfall energies. As a result, Expanded metal strength is much more durable compared to the PVC coating net, and it is regarded as an excellent alternative material for the Rockfall Protection Net. In this study, the applicability of Expanded Metal as the alternative of Rockfall Protection Net is verified experimentally.

• Journal of Korean Society of Rural Planning
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• v.17 no.3
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• pp.67-80
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• 2011

This study was conducted to understand the distribution characteristics of old tree (protected tree) and propose the effective management plan for old tree to make hold a sustained function as natural and cultural resources in rural area. We surveyed 96 old trees at 69 farm villages in Yaesan-gun, South Chungcheong Province. The species of tree was investigated with Zelkova serrata, Ginkgo biloba, Quercus acutissima, Pinus densiflora, Celtis sinensis, and Juniperus cbinensis order. Most of them located at the inside (43.6%) and the entrance (35.1%) of a village, and at mountain slope (31.9%) and alluvial plain (25.3%) in terms of distribution topography. The existing place of pollution source was investigated with 61%, and the pollution sources were blocks, construction materials, cement packings, farm machines and living garbage. The place where the rates of bare ground were more than 50% for the root region of a protection tree was 63%. The tree surgical operation was investigated in 37.5% of protection trees, and 12.5% of protection trees were investigated with a tree surgical operation being immediately. The average score for health condition of old tree at study sites was 18.6 points. A monitoring class was divided by public monitor 59.3%, main monitor 38.5%, and dead tree 2.2% on the basis of that information. Hereafter, we will conduct to promote the management guideline and develope culture contents through additional investigation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6565-6574
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• 2013

Precast concrete blocks are used mainly for score protection, slope protection and riverbed structure protection, etc. Because these concrete blocks are exposed to water or wetting environments, the steel rebar used as reinforcements in concrete blocks can corrode easily. Corrosion of the steel rebar tends to reduce the performance and service life of the concrete blocks. In this study, Glass Fiber Reinforced Polymer(GFRP) rebar, which does not corrode, was applied instead of a steel rebar to prevent performance degradation of the blocks. Recycled concrete aggregate and high early strength cement(HESC) were used in the concrete mix for field applicability. The experiment results showed that the workability and form removal strength of the recycled aggregate concrete using HESC showed comparable results to normal concrete and the compressive strength at 28 days increased by about 18% compared to normal concrete. The load resistance capacity of the recycled aggregate concrete blocks reinforced with a GFRP rebar increased by approximately 10~30% compared to common concrete block.

• Korean Journal of Environmental Agriculture
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• v.24 no.1
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• pp.29-33
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• 2005

To develop proper soil management practices for reducing soil erosion, experiments were carried out by using lysimeters in Pyeongchang highland, Korea. Lysimeters installed at Hoenggye bad 13% slope, 15 m slope length and 3 m width. Lysimeters with 23% slope, 15 m slope length and 3 m width were also installed at Yongsan. Soil textures in Hoenggye and Yongsan lysimeter plots were silty clay loam and sandy loam, respectively. In the lysimeters potato was cultivated, and slant furrow culture and contour culture were applied. Up-down furrow and continuous fallow lysimeter was included in the experiments as a control plot. For the slant furrow and contour culture methods, minimum furrow mulching and gravel barrier were placed at each end of the furrows in the lysimeters from April to October in 2000 and 2001 to prevent soil and nutrient losses. In Heonggye, in two years experiments, average soil loss of 17 Mg/ha was found in the up-down and continuous fallow lysimeter and 2.6 Mg/ha from furrow minimum straw and slant furrow treatment, and 1.8 Mg/ha from slant furrow and gravel bag treatment. In the contour culture, the soil losses were further reduced. In Yongsan, soil loss in the slant furrow culture without any protection treatment was 167 Mg/ha, and the soil loss was reduce to 61 and 86 Mg/ha with minimum straw and gravel bag treatments, respectively. The soil loss could be reduced more than 45% by furrow minimum straw and gravel barrier. The furrow minimum straw or gravel bag barrier successfully reduced soil loss in clay loam soil in Heonggye, but still the treatments were not enough to reduce soil loss in saprolite piled sandy loam soil in Yongsan.

• The Journal of Engineering Geology
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• v.30 no.1
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• pp.71-84
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• 2020

Various geological structures are found on the slope of Bangnim district in Pyeongchang, Gangwon-do, based on the Paleozoic Joseon Supergroup Limestone. The recumbent fold observed on the slope is a very rare geological structure that has not been found in Korea, and has important academic value in exploring the formation process of the Paleozoic geological structures in the Gangwon region. In this study, discussed the geological value of the geological structure observed on the slope of the road, and studied the management method of rockfall problem slopes. The state of development of recumbent folds has conservation value in geological scarcity and specificity. Preservation management measures should be prepared through the protection of slopes and measures to reduce of rockfall risks as geoheritage with an important value in geology science and education. Furthermore, it is expected to be preserved and utilized as a geopark.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.712-721
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• 2017

Recently, the intensity and frequency of floods has increasing worldwide, and flood disasters have become a big problem. Flood disasters, which account for the largest portion of disasters, are floods accompanied by typhoons and localized heavy rainfall. As a result, they cause damage of levee overtopping, in which the water level of a river rises to the levee crown. Therefore, countermeasures are essential and necessary because of the damage to the facility itself as well as to life and other property. The damage magnitude depends on the collapse of the levee. A levee that is difficult to collapse will reduce the discharge inland significantly. Accordingly, the protection of the inland slope, where the collapse of the levee is initiated, is one of the most important countermeasures In this study, revetments with various porosity and forms were suggested and hydraulic experiments were carried out for each type. The hydraulic experiments showed that the stability of a revetment in an inland slope is strongly correlated with the weight per unit area of the revetment. The relationship between the critical velocity, which is the velocity at the moment of leaving the revetment, and the weight per unit area was derived. Through this study, by applying the nature friendly revetment, which has not yet been applied to Korea, it is expected that life and property damage caused by levee overtopping during flooding can be reduced, and a nature friendly river space can be constructed.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.3
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• pp.81-90
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• 2016

It is significant to redevelop the deterioration reservoir through raising for countermeasure to climate change and Earthquake improvement of reservoir. This study aims to investigate the behavior of deterioration reservoir with poor-fabricated core subjected to raising water level and earthquake using numerical analysis. From the analysis results, water level raising and earthquakes induce crack and subsidences at the crown and the front side of deterioration reservoir. For the reinforcement of the deterioration reservoir is required appropriate measures method and raised method suitable, drainage and slope protection method judged to be necessary.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.7
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• pp.668-673
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• 2011

This paper presents design and control of a wheelchair robot for handicapped or elderly persons. Novel multi-functional design concepts are introduced. The first function is to balance the chair always parallel to the flat ground so that the driver feels comfortable when he/she drives on the slope. The second function is to help the driver to stand up by pushing the chair so that the driver can get out from the chair with ease. The third design is to make it foldable for easy carrying for automobiles. The last function is an immediate stop and start protection. Experimental studies are conducted to demonstrate the feasibility and functionality of each mechanical design.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.38-41
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• 2001

This paper presents a digital current differential protection algorithm for a transformer in power system. This algorithm uses an FIR filter to improve the performance of the relay. This paper presents a practical method setting the operating slope of the relay and reduce ct mismatch. A series of EMTP simulation results have shown effectiveness of the algorithm under various type of transformers and conditions.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1284-1292
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• 2015

As visual surveillance systems become more and more common in human lives, approaches based on these systems to solve security problems in practice are boosted, especially in railway applications. In this paper, we first propose a robust snag detection algorithm and then present a railway security system by using a combination of multiple sensors and the vision based snag detection algorithm. The system aims safety at several repeatedly occurred situations including slope protection, inspection of the falling-object from bridges, and the detection of snags and foreign objects on the rail. Experiments demonstrate that the snag detection is relatively robust and the system could guarantee the security of the railway through these real-time protections and detections.