• Journal of Forest and Environmental Science
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• v.30 no.1
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• pp.113-119
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• 2014

To examine the soil reinforcement by the shrub with shallow root systems for slope stability, we developed insitu apparatus for direct shear test and conducted the insitu field tests for Lespedeza cyrtobotrya, a representative revegetation species for artificial hillslopes. The insitu field tests were conducted for two different soil conditions (the rooted soils and non-rooted soils) and we then compared the experimental values with those calculated from the Wu model. The results showed that the soil reinforcement derived from the insitu field tests ranged from 0.01525 to 0.1438 $kgf/cm^2$ while the one calculated from the Wu model ranged from 0.1952 to 0.2696 $kgf/cm^2$. Our finding suggests more field tests are needed to collect the related parameters in the model application thereby predicting the reliable soil reinforcement by the shrub root systems.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.3
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• pp.31-38
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• 2010

Various fundamental and practical theories and technologies are needed for the development of Best Management Practices (BMPs) to manage the problems. The objectives of this paper was to investigate the effect of fertilizer and Non-point suource (NPS) pollution discharges from the field. The effect of fertilizer application was measured with respect to 10 % and 20 % slopes, respectively, using artificial rainfall simulator. The effect of fertilizer application on runoff was not significant because the effect of slope and rainfall intensity were overwhelmed. Runoff from 20 % plots was 21 % larger than that from 10 % plots. While groundwater discharge from 10 % plots was about 70 % larger than that from 20 % plots. It was concluded that runoff and groundwater discharge were largely affected by slope. T-N concentration in groundwater was much higher than that in runoff for both 10 % and 20 % plots. While T-P concentration in groundwater was lower than that in runoff. It explained that T-N moved well through soil pores without adsorption and other chemical reactions but T-P was well adsorbed on the surface of soil particles.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.1
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• pp.1-10
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• 2017

This study has purpose on deducting problems of evacuation plan for vulnerable populations in disaster and suggesting improvement plan through analysis of disaster weakness in domestic rural region aiming at vulnerable populations in disaster like old people containing most of domestic rural population, sometimes being in blind spot of safety when landslide or disaster occur. As a result, we could know that rural regions have high proportion of vulnerable populations in disaster like old people, also being so weak to landslide and slope collapse. So we suggested development of manual describing prevention of disaster and evacuation for vulnerable populations in disaster like old people and disaster evacuation organization for house and minimizing solution for damage of human life through improvement of steep slope evaluation criteria.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.1 no.1
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• pp.54-62
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• 1998

This study measured the shearing resistance of the roots of the Sasamorpha purpurascens, Miscanthus sinensis, Lespedeza cyrtobotrya by the tensile strength gained through their individual tensile test for the Root Reinforcement Model. The results to have measured this stress by experiment are as follows. 1) The mean root diameter of the Lespedeza cyrtobotrya used for this experiment was 2.19mm and the mean tensile stress was calculated as $929.489kgf/cm^2$. As for the Sasamorpha purpurascens, its mean root diameter was 1.727mm, and the mean tensile stress was $292.069kgf/cm^2$. And as for the Miscanthus sinensis, its mean root diameter was 0.814mm, and the mean tensile stress was $696.947kgf/cm^2$. And so, it was grasped that Lespedeza cyrtobotrya was highest in tensile stress. 2) ${\Delta}Cr(kg/cm^2)$ of the shearing resistance calculated by estimating the areal ratio of roots at $10^{-3}$ is $1.069kg/cm^2$ in Lespedeza cyrtobotrya, $0.336kg/cm^2$ in Sasamorpha purpurascens, and $0.801kg/cm^2$ in Miscanthus sinensis. That is, Lespedeza cyrtobotrya has the highest shearing resistance. However, since a precise analysis of the controlled factors of the slope analyses are demanded for more accurate dynamic analyses, the future demands a study on this.

• Korean Journal of Environment and Ecology
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• v.25 no.1
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• pp.31-36
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• 2011

To provide the basic information about slope stability analysis, tensile force and strength of tree roots like Pinus koraiensis, Larix leptolepis, Pinus densiflora, Quercus mongolica, and Alnus japonica were measured and analyzed. As a result, tensile force increases in forms of involution of root diameter. The mean tensile strength of roots like P. koraiensis, L. leptolepis, P. densiflora, A. japonica and Q. mongolica were calculated as $165.38kgf/cm^2$, $172.78kgf/cm^2$, $176.25kgf/cm^2$, $214.29kgf/cm^2$ and $224.19kgf/cm^2$ respectively. It was shown that tensile strength decreasing tendency as root diameter increases. Also, recalculated soil shear strength by tensile strength of the roots like P. koraiensis, L. leptolepis, P. densiflora, A. japonica and Q. mongolica were $0.099kgf/cm^2$, $0.104kgf/cm^2$, $0.106kgf/cm^2$, $0.129kgf/cm^2$ and $0.135kgf/cm^2$ respectively.

• The Journal of Engineering Geology
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• v.18 no.1
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• pp.37-44
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• 2008

KICT has been carrying out inventory research on the cut slopes of national roads. Inventory research results are basic data to cut slope management system. Inventory data are classified by general status, cut slope characteristics and inspector opinion. Inventory data are utilized to figure out dangerous slopes and decide survey ranking of detailed safety diagnostication. This paper drew the distribution area of dangerous cut slopes using inventory data in Chungcheongdo, and verified efficiency on distribution area of dangerous cut slopes by comparing occurrence frequency of real collapsed cut slopes.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.15 no.1
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• pp.1-7
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• 1997

In the digital mapping for data base contruction, the positional information is used as an important tool in LIS/GIS(Land Information System/Geographic Information System) that is used for a facility management, urban/cadastral management as well as in spatial analysis. In this paper, for an error analysis of X, Y coordinates data on digital map, test area was classified by topography, density, and slope. The coordinates on topographic map were assumed as true values and they were compared with the coordinates on digital map. A result of the numerical test show that a vector data of line type had more gross error than vector data of polygon type. And, SME(stanadrd mean error) of urban or intermountain area had small values compared to that of suburban area in topography analysis. The SME of dense and middle zone had small values compared to that of loose zone in density analysis. In another slope analysis. the SME of steep of gentle slope had small values compared to that of flatland.

• Journal of the Korea Safety Management & Science
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• v.8 no.5
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• pp.193-209
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• 2006

Multiple regression is used to examine the relationship between a set of two or more independent variables and one dependent variable. It provides the information necessary to make predictions of the dependent variables based on several independent variables. To do so, the multiple regression equation is extended to: y=$a+{\beta}_1x_1+{\beta}_2x_2+{\ldots}+{\beta}_kx_k$ y=attractiveness a=the value of the intercept ${\beta}_1$=the slope(weighting) of the first variable ${\beta}_1$= the slope(weighting) of the second variable ${\beta}_k$=the slope of the $\kappa$th variable The resulting regression equation of this research is y=$a+{\beta}_1site's\;system+{\beta}_2customer\;satisfaction+{\beta}_3products+{\beta}_4delivery$ y=3.233+0.374(site's system)+0.268(customer satisfaction)+0.17(products)+0.077(delivery)

• Journal of the Korean Geosynthetics Society
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• v.22 no.1
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• pp.67-74
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• 2023

In order to monitor the stability of slopes, research on data-based slope failure prediction and early warning is increasing. However, most papers overlook the quality of data. Poor data quality can cause problems such as false alarms. Therefore, this paper proposes a two-step hybrid approach consisting of rules and machine learning models for quality control of data collected from slopes. The rule-based has the advantage of high accuracy and intuitive interpretation, and the machine learning model has the advantage of being able to derive patterns that cannot be explicitly expressed. The hybrid approach was able to take both of these advantages. Through a case study, the performance of using the two methods alone and the case of using the hybrid approach was compared, and the hybrid method was judged to have high performance. Therefore, it is judged that using a hybrid method is more appropriate than using the two methods alone for data quality control.

• Journal of Ecology and Environment
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• v.43 no.2
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• pp.161-182
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• 2019

Quantifying the amount of carbon pools in forest ecosystems enables to understand about various carbon pools in the forest ecosystem. Therefore, this study was conducted in the Chilimo dry afromontane forest to estimate the amount of carbon stored. The natural forest was stratified into three forest patches based on species composition, diversity, and structure. A total of 50 permanent sample plots of 20 m × 20 m (400 ㎡ ) each were established, laid out on transects of altitudinal gradients with a distance of 100 m between plots. The plots were measured twice in 2012 and 2017. Tree, deadwood, mineral soil, forest floor, and stump data were collected in the main plots, while shrubs, saplings, herbaceous plants, and seedling data were sampled inside subplots. Soil organic carbon (SOC %) was analyzed following Walkely, while Black's procedure and bulk density were estimated following the procedure of Blake (Methods of soil analysis, 1965). Aboveground biomass was calculated using the equation of Chave et al. (Glob Chang Biol_20:3177-3190, 2014). Data analysis was made using RStudio software. To analyze equality of means, we used ANOVA for multiple comparisons among elevation classes at α = 0.05. The aboveground carbon of the natural forest ranged from 148.30 ± 115.02 for high altitude to 100.14 ± 39.93 for middle altitude, was highest at 151.35 ± 108.98 t C ha^-1 for gentle slope, and was lowest at 88.01 ± 49.72 t C ha^-1 for middle slope. The mean stump carbon density 2.33 ± 1.64 t C ha^-1 was the highest for the middle slope, and 1.68 ± 1.21 t C ha^-1 was the lowest for the steep slope range. The highest 1.44 ± 2.21 t C ha^-1 deadwood carbon density was found under the middle slope range, and the lowest 0.21 ± 0.20 t C ha^-1 was found under the lowest slope range. The SOCD up to 1 m depth was highest at 295.96 ± 80.45 t C ha^-1 under the middle altitudinal gradient; however, it was lowest at 206.40 ± 65.59 t C ha^-1 under the lower altitudinal gradient. The mean ecosystem carbon stock density of the sampled plots in natural forests ranged from 221.89 to 819.44 t C ha^-1. There was a temporal variation in carbon pools along environmental and social factors. The highest carbon pool was contributed by SOC. We recommend forest carbon-related awareness creation for local people, and promotion of the local knowledge can be regarded as a possible option for sustainable forest management.