• Journal of Ecology and Environment
• /
• v.33 no.3
• /
• pp.205-216
• /
• 2010

This research identified a disturbance regime caused by wild boar in a mature Quercus mongolica forest and analyzed the impact of this disturbance on the structure and distribution of herbaceous plants in Mt. Jeombong, Korea. We demonstrate that disturbance by wild boar was most frequent from winter to early spring, but also occurred year round. Areas which were frequently disturbed by wild boar included the mountain ridge, the mild slope on the north face, and sites with high concentration of Erythronium japonicum. The disturbance cycle by the wild boar in this region was estimated at approximately 2.8 years. The wild boar's reduced the community's species diversity and herbaceous coverage, and increased its evenness. This disturbance reduced the coverage of spring ephemeral; Veratrum nigrum var. ussuriense, Symplocarpus niponnicus, Anemone koraiensis and Corydalis turtschaninovii were particularly sensitive. In addition, summer green herbaceous plants such as Astilbe chinensis, Ainsliaea acerifolia, Meehania urticifolia, and Pimpinella brachycarpa were sensitive to the wild boar's. It was found that wild boar ate E. japonicum most selectively of all plants in this investigation area. In conclusion, together with micro-topography, wind, formation of gaps of a forest and rearrangement of litter layer, wild boar's disturbance is an important factor influencing the dynamic changes of an herbaceous community in a mature temperate hardwood forest.

• Journal of The Korean Digital Architecture Interior Association
• /
• v.10 no.3
• /
• pp.39-46
• /
• 2010

Recently, in rural areas have been occurred closed school due to reduce children of people who consider educational environment. In July 2009 statistic, Closed school are ut to 3,348; sale process(61%), lease(25%), neglect(14%). Closed school are not only local community education, but also to act as cultural and historical role. First of all, it will be utilized public facilities as well as welfare facilities for local residents. In this study suggests the welfare facility where is remodelled as good case so that it will use as a data when closed school need remodeling. The main contents is as follows; it is set the slope next to the school building, a classroom is remodelled 2 triple rooms which are installed Ondol and a toilet, teacher's room is converted into the canteen, corridors are converted into the kitchen. Having good condition in the area, close school is appropriate to use welfare facility and also effective to convert teacher's space into normal space, canteen, kitchen. Finally, developed 2~5 composition type of elderly facility.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.46 no.2
• /
• pp.107-114
• /
• 2004

NPS pollutant loads from sandy clayey and clayey loam runoff plots were measured. Runoff plots were 2$\times$10 m in size and 8~10% in slope and paddy area was 4,620 $m^2$. Soybean, corn, tobacco and control (natural weed) were cultured. Precipitation during the growing season of June to October, 2002 was 869.5 mm. Runoff and water quality were measured more than 10 times during the measurements depending on the growing stage. Pollutants loads were estimated by using respective concentration and runoff volume. Runoff occurred when daily rainfall exceeded about 30 mm. The largest runoff was observed from the paddy but pollutant loads were larger from upland crops than those from paddy. SS loads from paddy and upland were 1.4 ton/ha/yr and 3.1~4.3 ton/ha/yr, respectively. COD loads 30 kg/ha/yr and 66~90 kg/ha/yr, T-N loads 13 kg/ha/yr and 14~23 kg/ha/yr, T-P loads 1 kg/ha/yr와 4 kg/ha/yr, nitrate nitrogen loads 1 kg/ha/yr and 4~8 kg/ha/yr, and phosphate phosphorus loads 0 kg/ha/yr and 4~6 kg/ha/yr, respectively. It was concluded that NPS pollutant loads from upland crop culture have greater impact on the quality of the receiving water body than those from paddy culture.

• The Journal of Engineering Geology
• /
• v.32 no.4
• /
• pp.571-583
• /
• 2022

On 7 August 2020, a large-scale catastrophic landslide was triggered by extreme rainfall at Osan village, Gokseong County, South Jeolla Province, South Korea. The initiation mechanism of the Gokseong landslide was different from those typical landslides that occurred in South Korea. Despite the relatively low elevation and slope degree, the landslide had a long runout distance of about 640 m over a total vertical distance of 90 m. A detailed field investigation and chemical analysis were conducted to understand the possible mechanisms for the high-speed and long-runout behavior of the landslide. The terrain controlled the motion behavior of the landslide and the seepage was observed at the whole landslide body. The clay-rich soils covered on granite bedrock of the landslide deposition area from the rice paddy field to the landslide crown. The results of this study may provide basic data for further research on the mechanisms for landslide initiation and propagation.

• Nuclear Engineering and Technology
• /
• v.55 no.4
• /
• pp.1571-1584
• /
• 2023

In this study, a numerical analysis was performed as part of an international joint research project to reproduce a real cable tray fire that occurred in the heater bay area of the turbine building of a nuclear power plant. A sensitivity analysis was performed on various input parameters to derive results consistent with the sprinkler activation time obtained from the fire event analysis. For all sensitive parameters, the normalized sprinkler activation time correlated well with the power function of the normalized sprinkler height. A correlation equation was developed to identify the sprinkler activation time at any location when determining the slope or fire growth rate under the conditions assuming a linear or t-squared heat release rate (HRR) time curve. Various cable fire growth assumptions were used to determine which assumption was better to provide the prediction coincident with the information given from the fire event analysis in terms of the sprinkler activation time and total energy generated from cables damaged by fire. In the comprehensive analysis of all the sensitive parameters, the standard deviation of the input parameters increased as the sprinkler height decreased. Within the range of the sensitivity parameter values given in this study, when considering all sprinkler heights, the standard deviation of the cable model change was the largest and that of the overhang position change was the smallest.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.36 no.2
• /
• pp.59-66
• /
• 2018

This study examined the correlation among topography, forest type, soil and geology in Inje area where landslides occurred during heavy rainfall from July 11 to July 18, 2006 to assess the landslide susceptibility. In order to assess the susceptibility of future landslides, landslides occurred in Inje area were classified into slide type and flow type, and slope angle, aspect, curvature, ridge and valley were extracted from the area. The landslide susceptibility was assessed by applying diameter class, age class, density, and forest type to Bayesianbased LR (Logistic Regression) model and WOE (Weight of Evidence) model, and the fitness of modeling was verified by predict rate curve. As the results of susceptibility assessment, using all landslides without no distintion, it was found that 75% of the LR model and 73% of the WOE model were fit in terms of the top 20% of the landslides. According to slide type and flow type in the top 20% of the landslides, it was found that 71% of the LR model and 69% of the WOE model were fit in terms of the slide type. Whereas, it was found that 86% of the LR model and 82% of the WOE model were fit in terms of the flow type. That is, the results of the LR model showed higher fitness than the results of the WOE model, and the fitness of the flow type was higher than that of the slide type. Consequently, it suggests that it is reasonable to assess and verify the landslide susceptibility according to the types of landslides.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.157-157
• /
• 2019

This study derived the Flood-Inducing-Rainfall (FIR) and the Flood-Inducing-Runoff (FIRO) from the radar-gage composite data to be used as the basis of the flood warning initiation for the urban area of Seoul. For this, we derived the rainfall depth-duration relationship for the 261 flood events at 239 watersheds during the years 2010 and 2011 based on the 10-minute 1km-1km radar-gauge composite rainfall field. The relationship was further refined by the discrete ranges of the proportion of the flooded area in the watershed (FP) and the coefficient variation of the rainfall time series (CV). Then, the slope of the straight line that contains all data points in the depth-duration relationship plot was determined as the FIR for the specified range of the FP and the CV. Similar methodology was applied to derive the FIRO, which used the runoff depths that were estimated using the NRCS Curve Number method. We found that FIR and FIRO vary at the range of 37mm/hr-63mm/hr and the range of 10mm/hr-42mm/hr, respectively. The large variability was well explained by the FP and the CV: As the FP increases, FIR and FIRO increased too, suggesting that the greater rainfall causes larger flooded area; as the rainfall CV increases, FIR and FIRO decreased, which suggests that the temporally concentrated rainfall requires less total of rainfall to cause the flood in the area. We verified our result against the 21 flood events that occurred for the period of 2012 through 2015 for the same study area. When the 5 percent of the flooded area was tolerated, the ratio of hit-and-miss of the warning system based on the rainfall was 44.2 percent and 9.5 percent, respectively. The ratio of hit-and-miss of the warning system based on the runoff was 67 percent and 4.7 percent, respectively. Lastly, we showed the importance of considering the radar-gauge composite rainfall data as well as rainfall and runoff temporal variability in flood warning system by comparing our results to the ones based on the gauge-only or radar-only rainfall data and to the one that does not account for the temporal variability.

• The Journal of Engineering Geology
• /
• v.15 no.2 s.42
• /
• pp.133-144
• /
• 2005

Stability investigations were conducted for the heap of coal associated wastes occurred from D mine located in Gang-Won Province from the geotechnical and environmental engineering aspect, and a countermeasure was also examined to increase the stability in this area. Quality of water flowed from the heap of coal associated wastes was identified as Am. Slope stability investigations were conducted with both circular failure analyses using SLOPILE program and planar failure analyses in cases of dry, rainy, and ordinary slopes. The results of circular failure analyses indicated that the factor of safety is 0.78 for rainy case. for planar failure analyses, the factor of safety decreases with increase the depth and reaches below 1 about 4m depth for rainy case. A retaining wall system with backfill using the recycled-concrete aggregates as a practical scheme was suggested to satisfy both demands: reducing Am generation, and enhancing slope stability in the deposits of coal associated wastes.

• Geotechnical Engineering
• /
• v.9 no.4
• /
• pp.103-118
• /
• 1993

This paper presents the results of investigation of the rainstorm induced landslides occurred in the districts of Yongin, Ansung and Osan on July 21st 1991. More than two thousand and sirs hundred landsilides took place during or after a 3-t hours heavy rainfall and about 466 ha mountain slopes were affected by slope failures. The result of study on the effect of-iainfall on landslides shows that landslides began to occur where daily and maximum hourly rainfall exceeded 114mm and 40mm respectively, and all districts (myun) where maximum hourly rainfall exceeded 62mm were affected by landslides. The morphological study on landslides on Talbongsan area reveals that, by Walker's classi fication using D IL(failure depth ratio), 50% of the landslides were classified as flows, 20% of them as translational slides, and 30% were between flow and slide and there were few rotational slides. Over 90% of landslides tookplace at slopes of 20$^{\circ}$-40$^{\circ}$ in slope and 50m or shorter in length And more than 50% of the crown of slides locates at higher than 0.7 times of slope hight. Any differences between the kinds of tree in landslide resisting effects are shown in this case.

• Korean Journal of Ecology and Environment
• /
• v.46 no.1
• /
• pp.94-102
• /
• 2013

This study was carried out to determine the variation of the water level and crosssection area for investigating changes of stream foreland, and to determine the correlation between the average flow velocity and cross-section area so as to understand the hydrological characteristics of the stream. The slope of the cross-sectional area was changed in water levels of 0.6~1.0 m and 1.8~2.0 m. The first change occurred in the low-water level season, and the second change occurred in the high-water level seasons. It is assumed that the changes occurred due to the geological transfigure. The correlation between the cross-sectional area and the average flow velocity was 0.22~0.86 in the exponential equation and 0.20~0.87 in the linear equation. The low water level had a higher correlation than the high water level, and free weirs in the upper stream showed a very low correlation. Therefore, this study provides novel information for the management of water quality in the riverside, using correlation equations of the water level and flow velocity with the cross section area.