• Proceedings of the KSEEG Conference
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• 2002.04a
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• pp.420-422
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• 2002

• Journal of The Geomorphological Association of Korea
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• v.19 no.3
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• pp.71-82
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• 2012

This research was carried out to estimate annual erosion and retreat rates by using datum-point and to identify the characteristics and causes of seasonal variations of sea-cliff slope in Pado-ri, Taean-gun. In the result, the erosion and retreat rates of sea-cliff were increased from spring to summer. The rates were increased rapidly between August and October, caused by the effects of extreme weather events such as severe rainstorms and typhoons, etc. Since then, the erosion and retreat rates of sea-cliff were decreased gradually, but the rates were increased again in winter due to the storm surge and mechanical weathering resulting from the repeated freezing and thawing actions of bed rocks. The factors that affect erosion and retreat rates of sea-cliff include the number of days with antecedent participation and daily maximum wave height. In particular, it turned out that the erosion is accelerated by strong wave energy during storm surges and typhoons. The annual erosion and retreat rates of study area for the past two years(from May 2010 to May 2012) were approximately 44~60cm/yr in condition of differences in geomorphological and geological characteristics at each point. These erosion and retreat rates were found to be higher than results of previous researches. This is caused by coastal erosion forces strengthened by extreme weather events. The erosion and retreat process of sea-cliff in the study area is composed by denudation of onshore areas in addition to marine erosion(wave energy).

• Journal of Korean Society of Forest Science
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• v.84 no.2
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• pp.239-246
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• 1995

This research aimed at the contribution to obtaining the scientifical data which were required for planning she environmentally sound and sustainable management, particularly in the field of the logging road construction. Main natural environmental variables including natural vegetation, rainfall, soil runoff were measured in the logging road on-sites and analysed. This project was carried out at the (mt.)Paekunsan Research sorest of Seoul National University, located in Gwangyang, Chollanam-do in southern part of Korea, from 1993 to 1994. 1. The explanatory variables for erosion and sedimentation on logging road surface were accumulated rainfall, erosion distance, cross-sectional gradient, and soil hardness. The erosion and sedimentation on logging road was increasing positively in proportion to the accumulated rainfall, soil distance from starting point of the logging road, and cross-sectional gradient. 2. On cut-slope of logging road, cut-slope shape, part of the slope, plant coverage, soil hardness, sand content, accumulated rainfall, clay content, and silt content were effective factors. Cut-slope erosion and sedimentation on logging roam increased as with the lower plant coverage, the lower accumulated rainfall, the high sand content in the soil. 3. On fill-slope of logging road, there were three significant variables such as total rainfall and number of rainfall-storm. Fill-slope erosion and sedimentation had a positive correlation with the amount of rainfall, the number of rainfall, the soil hardness. 4. The total erosion and sedimentation on logging road were $5.04{\times}10^{-2}m^2/m^2$ in logging road construction year, $7.37{\times}10^{-2}m^2/m^2$ in next year. The erosion and sedimentation on logging road surface were 32.7% of total erosion and sedimentation on Logging road in construction year, and 57.1% in next year, respectively. The erosion and sedimentation on cut-slopes were 30.4% on logging road in construction year, fill-slopes of total erosion and sedimentation and 21.0% in next year, respectively. The erosion and sedimentation on fill-slopes were 36.9% on logging road in construction year, 21.9 in next year. To decrease the erosion and sedimentation at the logging road from the beginning stage of construction, the effective revegetation works should be implemented on the cut-slope and fill slopes, and erosion control measures such as optima. road design must be constructed on read surface.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.4
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• pp.43-51
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• 2003

The purpose of this study was evaluate to the stability on cut slope of forest roads by forest environmental factors. The total of 19 environmental factors on cut slope of forest roads were investigated in about 42.74km constructed during 1987 to 1993 in Gyeongnam and Jeonnam province. The evaluation of slope stability in forest roads were conducted by the discriment analysis. The main factors influencing the stability of cut slope were significant in order of coverage, soil hardness, degree of slope, altitude, silt loam, convex(凸) and compound(凹凸). The centroids value of discriminant function in the stability and unstability area estimated to -1.194 and 1.127, respectively. The boundary value between two groups related to slope stability was -0.072. The prediction rate of discriminant function for stability evaluation of was as high as 90.4%.

• Journal of Korean Society of Forest Science
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• v.29 no.1
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• pp.54-101
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• 1976

This study was conducted on the major factors affecting soil erosion and surface run-off. In order to investigate the processes and mechanisms of soil erosion on denuded forest-land in Korea, and to systematize the magnitudes of influences and interactions between individual factors, the five major factors adopted in these experiments are soil textures (coarse sand and clay loam), slope steepness ($10^{\circ}$, $20^{\circ}$, $30^{\circ}$ and $40^{\circ}$), rainfall intensities (50, 75 and 100mm/hr), slope mulching methods (bare, coarse straw-mat mulching, grass mulching and anti-erosion liquid mulching) and vegetation densities (sparse, moderate and dense). The processes and mechanisms of soil erosion, and the effects of mulchings on soil erosion as well as surface run-off rates were studied algebraically with four parts of laboratory experiments under the simulated rainfall and another part of field experiment under the natural rainfall. The results in this study are summarized as follows: 1. Experiment factors and surface run-off rates The surface run-off rates under the natural rainfall were resulted about 24.7~28.7% from the bare slopes, about 14.0~16.4% from the straw-mat mulched slopes, about 7.9~9.1% from the liquid mulched slopes, and about 5.6~7.2% from the grass mulched slopes respectively. The surface run-off rates under the simulated rainfall differed greatly according to the rainfall intensity and the mulching method. 2. Magnitudes of influences and interactions of the individual factor on the surface run-off rates. The experimental analyses on the major factors(soils, slopes, rainfalls, mulchings and vegetations) affecting the rates of surface run-off, show that the mean differences of surface run-off rate are significant at 5% level between the soil texture factors, among the slope steepness factors, among the rainfall intensity factors, among the mulching method factors, and among the vegetation density factors respectively. The interactions among the individual factor have a great influence(significant at 1% level) upon the rate of surface run-off, except for the interactions of the factors between soils and slopes; between slopes and vegetations; among soils, slopes and rainfalls; and among soils, slopes and mulchings respectively. On the bare slopes under the simulated rainfall, the magnitude of influences of three factors(soils, slopes and rainfalls) affecting the rate of surface run-off is in the order of the factor of rainfalls, soils and slopes. The magnitude of influences of three factors (soils, rainfalls and mulchings) affecting the rate of surface run-off, on the mulched slopes under the simulated rainfall is in the order of the factor of mulchings, rainfalls and soils and that of influences of the factor of soils, slopes and mulchings is in the order of the factor of mulchings, soils and slopes. On the vegetation growing slopes under the simulated rainfall, the magnitude of influences of three factors (soils, slopes and vegetations) affecting the rate of surface run-off is in the order of the factor of vegetations, soils and slopes. In the same condition of treatments on the field experiment under the natural rainfall, the order of magnitude of influences affecting the rate of surface run-off is the factor of mulchings, soils and slopes. 3. Experiment factors and soil losses The soil losses of the experiment plots differed according to the factors of soil texture, slope steepness, rainfall intensity and mulching method. The soil losses from the coarse soil were increased about 1.1~1.3 times as compared with that of fine soil under the natural rainfall, while the soil losses from the fine soil were increased about 1.2~1.3 times compared with that of coarse soil under the simulated rainfall. The equation of $E=aS^b$ (a, b are constant) between the slope steepness (log S) and soil losses (log E) under the simulated rainfall were developed. The equation of $E=aI^b$ (a, b are constant) between the rainfall intensity (log I) and soil losses (log E) were developed, and b values have a decreasing tendency according to the increase of the slope steepness and rainfall intensity. The soil losses under the natural rainfall were appeared about 38~41% from the coarse straw-mat mulched slopes, about 20~22% from the liquid mulched slopes, about 14~15% from the grass mulched slopes as compared with that of the bare slopes respectively. The soil loss from the vegetation plots showed about 7.1~16.4 times from the sparse plot, about 10.0~17.9 times from the moderate plot and about 11.1~28.1 times from the dense plot as compared with that of the bare slopes. 4. Magnitudes of influences and interactions of the individual factor on the soil erosion. The experimental analyses on the major factors(soils, slopes, rainfalls, mulchings and vegetations) affecting the soil erosion, show that the mean differences of soil losses are highly significant between the soil texture factors, among the slope steepness factors, among the rainfall intensity factors, among the mulching method factors and among the vegetation density factors respectively. The interactions among the individual factor have mostly great influences upon the soil erosion. The magnitude of influences of three factors (soils, slopes and rainfalls) affecting the soil erosion on the bare slopes under the simulated rainfall is in order of the factor of rainfalls, soils and slopes. On the mulched slopes under the simulated rainfall, the magnitude order of influences of three factors(soils, rainfalls and mulchings) affecting the soil erosion is the factor of mulchings, rainfalls and soils, and the order of influences of factor of soils, slopes and mulchings is the factor of mulchings, soils and slopes. On the vegetation growing slopes under the simulated rainfall, the magnitude of influences of three factors (soils, slopes and vegetations) affecting the soil erosion is in the order of the factor of slopes. vegetations and soils. In the same condition of treatments on the field experiment under the natural rainfall, the order of magnitude of influences of three factors (soils, slopes and mulchings) affecting the soil erosion is the factor of mulchings, of slopes and of soils.

• Journal of Korean Society of Forest Science
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• v.107 no.4
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• pp.385-392
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• 2018

The slope stabilization analysis was performed by conducting survey and selecting the representative section in order to improve slope composition and management technology of masonry embankments in the quarry area, The mean slope of the masonry retain wall (A, B, C, D, E, F) was $38.5^{\circ}$, although the steep slope of the lowest slope (A) as $59^{\circ}$. The horizontal distance of the masonry embankments is 66.2 m and the slope height is 48.3 m. However, the inclination of the masonry embankments is relatively steep and visually unstable. The slope stability analysis for the slope stability analysis was taken into account during the drying and saturation. The slope stability analysis during saturation was performed by modeling the fully saturated slope. The strength constants of the ground were divided into two groups. The safety factor for dry period was 1.850 and the safety factor for rainy season was 1.333. The safety rate of dry period and rainy season was above 1.5 and 1.2. However, the weathered granite on the upper part of the masonry embankments at the time of heavy rainfall is considered to have a high risk of slope erosion and collapse. Therefore, it is considered necessary to take measures for stabilization through appropriate maintenance such as drainage installation.

• Journal of Korean Society of Forest Science
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• v.82 no.4
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• pp.354-365
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• 1993

The purpose of this investigation is to point out the physical fixation and stability of banking slopes of forest roads by invasion of trees. We investigated the situations of sediment discharge and coverage of invaded trees at banking slopes of forest roads. The coverage of invaded trees were calculated from crown injection based on the stable slope and was compared with length of slope, slope gradient, and passage years after construction of forest road. 1. We investigated on the sediment discharge and the invasion of trees at banking slopes, which were actually observed 8 forest roads of Kyonggi-Do and Kangwon-Do. 2. There was no physical stability of the banking slope due to the surface erosion and slope failure, but the tree invasions were active at the stable plots. 3. The length of slope was constructed to 4.0m to 61.0m and recent forest road was mainly constructed to the slopes longer than 30m. There was strong regional effect between the length of slope and the coverage of invaded trees and the above two factors were inversely proportional to each other. 4. There was no significant relationship between the slope gradient and the coverage of invaded trees and the slope constructed within the angle of repose showed the relatively high coverage of invaded trees. 5. There was no significant relationship between the passage years and the coverage of invaded trees in the same investigative region after the construction of forest road. But there was a gradually increasing relationship of tree invasion between above two factors. However, there was some limitation to expect the invasion of the tree species. 6. In the light of the above results, we suggest that the construction of forest road may need foundation work and vegetation work simultaneously for the physical stability to make the environment of tree plantation and that the reasonable increase of construction cost of forest road may be prior to the other factors.

• Journal of Korea Water Resources Association
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• v.51 no.8
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• pp.665-676
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• 2018

Interrill erosion on a hillslope results from the combined action of the detachment of soil particles by raindrop impact and the sediment transport of surface runoff. This study newly defined the rainfall power which detaches soil particles and the sheet-flow power contributed to sediment transport in terms of energy expenditure rate of soil erosion and presented the effective power equation for interrill erosion by rainfall-induced sheet flow. The rainfall and sheet-flow power was evaluated by factors related with rainfall, slope, and runoff and coefficients of the power equation were analyzed based on references. Futhermore it was confirmed that the relative scales between the rainfall power and the sheet-flow power according to rainfall intensity reflect on the hydrological response and physical process of interrill erosion. From application of the field data for surface runoff and soil erosion it was verified that the rainfall and sheet-flow power is an appropriate equation to estimate a interrill erosion.

• Journal of Forest and Environmental Science
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• v.7 no.1
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• pp.35-41
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• 1990

This study was conducted to find out the suitable gradient and length of the slope from the landslide of banking slope and cutting slope caused by rainfall. The survey was carried out on forest road built in 1986. And the period of survey was from June, 1989 to August, 1989 after dividing the forest road into A and B. The survey plots consisted of the 12 banking slopes and 6 cutting slopes. The results obtained from the study were summarized as follows; 1. The rate of landslide appeared 75% in A forest road, 50% in B forest road, and then the average 67% in A and B forest road. But the value of landslide showed considerably low. 2. Because of landslide chiefly occuring on banking slope of $36^{\circ}{\sim}38^{\circ}$ and on cutting slope of $42^{\circ}{\sim}43^{\circ}$, it is suitable to decide the banking slope and cutting slope below each $36^{\circ}$ and $40^{\circ}$. 3. Landslide was the same on banking slopes through the length of slope. The best suitable length of slope is below 4m in cutting slope.

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.157-160
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• 2003

해마다 늘고 있는 토사유출희 인한 피해는 자연재해의 측면에서 매우 중요한 과제로 다루어지고 있으며, 토사유출에 의한 환경피해를 최소화하기 위해 토양유실량의 산정에 많은 연구가 진행되고 있다. 그러나 사면에서의 토양유실량 산정방법 및 산정된 결과에 대한 검증 역시 현실적으로 매우 어렵기 때문에 일반적으로 국내에서는 토양유실량산정을 위해 범용토양유실공식(Universal soil loss equation)을 사용하고 있다. 범용토양유실공식(USEL)은 실험적 근거가 미비한 국내실정에서 일반적으로 활용되고 있기 때문에 공식의 적용에 대한 다양한 실험적 연구가 필요하였다. 따라서 본 연구는 남한강 유역 여주-이포 구간을 대상으로 2002년 6월부터 2002년 10월까지 수행된 자연 상태에서의 토양침식실험과 실험지역의 USLE의 적용을 검토하였다. 토양침식실험을 통하여 산정된 침식율과 범용토양유실공식의 결과를 비교하였으며 USLE의 인자에 따른 토양유실량 산정 결과의 변화를 검토하고자 하였다. 남한강 유역에서의 토양침식 실험결과 자연 상태에서 연간토양유실량은 평균 12.54ton/acre/year이었으며, 최소 0.1ton/acre/year, 최대 34.06ton/acre/year로 나타났다. USLE에 의해 계산된 연간토양유실량은 17.15ton/acre/year로서 실험결과와는 많은 차이가 있었다. 이러한 차이는 토양유실량 산정에 필요한 다양한 조건을 정량화하는 과정에서 발생하는 것으로, USLE식에 활용되는 인자의 적용방법에 따라 커다란 차이를 보였다. 따라서 USLE에 의해 산정된 결과를 사용하기 위해서는 다양한 조건에 대한 검토가 이루어져야하며 USLE 산정에 관한 지속적인 실험적 연구가 이루어져야 하겠다. 증가할 것이다. 또한 부분육을 이용한 완전제품, 적색육제품, 유기농이나 별미식 제품과 같은 형태의 다양한 포장육 제품이 도입 될 것으로 생각되어진다.e in vitro SPF test method will be able to be used as an alternative method for in vivo SPF in case of lotion and cream. replica. A statistically significant improvement of Star Fruit Leaf Extract BG30-treated site was seen in decreased wrinkles. Star Fruit Leaf Extract BG30 results in clinically visible improvement in wrinkling when used topically for 5 weeks. 또한 관계마케팅, CRM 등의 이론적 배경이 되고 있는 신뢰와 결속의 중요성이 재확인하는 결과도 의의라고 할 수 있다. 그리고 신뢰는 양사 간의 상호관계에서 조성될 수 있는 특성을 가진 반면, 결속은 계약관계 초기단계에서 성문화하고 규정화 할 수 있는 변수의 성격이 강하다고 할 수가 있다. 본 연구는 복잡한 기업간 관계를 지나치게 협력적 측면에서만 규명했기 때문에 많은 측면을 간과할 가능성이 있다. 또한 방법론적으로 일방향의 시각만을 고려했고, 횡단적 조사를 통하고 국내의 한 서비스제공업체와 관련이 있는 컨텐츠 공급파트너만의 시각을 검증했기 때문에 해석에서 유의할 필요가 있다. 또한 타당성확보 노력을 기하였지만 측정도구 면에서 엄격한 개발과정을 준수하지는 못했다. 향후에는 모바일 컨텐츠 파트너의 기업의 특성을 조사하여 관계성 변수와의