• Journal of Korea Water Resources Association
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• v.57 no.6
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• pp.421-435
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• 2024

In April 2023, a wildfire broke out in Gangneung located in the east coast region due to the influence of the Yanggang-local wind. In this study, GIS-based RUSLE(Revised Universal Soil Loss Equation) and SEMMA (Soil Erosion Model for Mountain Areas) were used to evaluate the erosion rate due to vegetation recovery in a small watershed of the Gangneung WUI(Wildland-Urban Interface) fire. The small watershed of WUI fire has a low altitude range of 10-30 m and the average slope of 10.0±7.4° which corresponds to a gentle slope. The soil texture was loamy sand with a high organic content and the deep soil depth. As herbaceous layer regenerated profusely in the gully after the wildfire, the NDVI (Normalized Difference Vegetation Index) reached a maximum of 0.55. Simulation results of erosion rates showed that RUSLE ranged from 0.07-94.9 t/ha/storm and SEMMA ranged from 0.24-83.6 t/ha/storm. RUSLE overestimated the average erosion rate by 1.19-1.48 times compared to SEMMA. The erosion rates were estimated to be high in the middle slope where burned pine trees were widely distributed and the slope was steep and to be relatively low in the hollow below the gully where herbaceous layer recovers rapidly. SEMMA showed a rapid increase in erosion sensitivity under at certain vegetation covers with NDVI below 0.25 (Ic = 0.35) on post-fire hillslopes. Gentle slopes with high organic content and rapid recovery of natural vegetation had relatively low erosion rate compared to steep slopes. As subsequent infrastructure and human damages due to sediment disaster by heavy rain is anticipated in WUI fire areas, the research results may be used as basic data for targeted management and decision making on the implementation of emergency treatment after the wildfire.

• Journal of Wetlands Research
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• v.18 no.1
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• pp.45-57
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• 2016

Levee safety is being evaluated using one of the several failure causes including overtopping, infiltration and erosion or 1D hydraulic analysis considering physical characteristics of levee in practical engineering works. However, mentioned evaluation methods are not able to consider various failure causes of levee at the same time and to get reliable results where requires the accurate topographic information. This study proposed the flood hazard index which is able to consider several hazard factors involving overtopping, infiltration and erosion risk simultaneously. The index was generated from results of 2D hydraulic analysis reflecting accurate topographic information. The study areas are the confluences of the Nakdong River and two streams(Gamcheon and Hoecheon). Levee safety was evaluated using results based on 2D hydraulic analysis considering riverbed changes of before and after dredging work in the study area. This study will contribute to estimate the reliable safety evaluation of levee where may have hazards during extreme flood events.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.12
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• pp.1804-1808
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• 2003

A layer experiment was conducted to determine the effects of supplementary methionine chelates (Cu, Zn and Mn), individual or in combination, on laying performance, eggshell quality, gizzard erosion, and IgG level of serum for 8 weeks. Five hundred 96-wk-old force molted ISA Brown layers were assigned to five dietary treatments. Basal diet was formulated to meet or exceed the nutrients requirements listed in NRC (1994). Five experimental diets were control, Zn-methionine chelate (Zn-Met) supplemented, Cumethionine chelate (Cu-Met) supplemented, Zn-Mn-methionine chelate (Zn-Mn-Met) supplemented and Zn-Mn-Cu-Met supplemented diet. Each treated diet was supplemented with respective mineral(s) at the level of 100 ppm in the form of methionine chelate. Egg production was increased by Cu-Met supplementation but decreased by Zn-Met supplementation. Egg weight was significantly (p<0.05) lower in Cu-Met treatment than those of the control and Zn-Met treatment. Specific gravity of eggs and eggshell strength were highest and soft egg production was lowest in Cu-Met treatment. Gizzard erosion index was significantly increased by supplementation of Cu-Met, Zn-Mn-Met or Zn-Mn-Cu-Met. Zinc content in liver significantly increased by Zn-Met, but not by Zn-Mn-Cu-Met treatment. In conclusion, 100 ppm Cu in Cu-Met chelate improved laying performance and eggshell quality but also increased gizzard erosion index. Supplementation of Zn-Met or its combination with other mineral chelates had no beneficial effects on laying performance and eggshell quality.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.8
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• pp.1174-1178
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• 2006

An experiment was conducted to investigate the effects of dietary supplementation of copper chelates in the form of methionine, chitosan and yeast on the performance of laying hens. Four hundred ISA Brown layers, 84 wks old, were assigned to 4 treatments: control, 100 ppm Cu in methionine chelate (Met-Cu), 100 ppm Cu as chitosan chelate (Chitosan-Cu) and 100 ppm Cu as yeast chelate (Yeast-Cu). Each treatment had five replicates of 20 hens. Hen-day and hen-housed egg production and egg weight were significantly (p<0.05) increased by Met-Cu supplementation. The increase by Chitosan-Cu and Yeast-Cu supplementation was not significant. Contrast of the control vs. Cu chelates showed egg weight was significantly (p<0.05) increased by Cu chelate supplementation. Soft-shell egg production was significantly (p<0.05) reduced by supplementation of Cu chelates. Met-Cu treatment showed the lowest incidence of soft egg production. Gizzard erosion index was increased by Cu chelate supplementation. Crude fat in liver, total cholesterol in yolk and Cu content in liver and yolk were not significantly influenced by Cu chelate supplementation. It was concluded that dietary supplementation of 100 ppm Cu as Met-Cu significantly increased egg production and egg weight. Cu-Met chelate was also effective in reducing soft-shell egg production but increased gizzard erosion index.

• Economic and Environmental Geology
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• v.55 no.5
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• pp.541-550
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• 2022

A pre-existing landform is created by weathering and erosion along the bedrock fault and the weak zone. A neotectonic landform is formed by neotectonic movements such as earthquakes, volcanoes, and Quaternary faults. It is difficult to clearly distinguish the landform in the actual field because the influence of the tectonic activity in the Korean Peninsula is relatively small, and the magnitude of surface processes (e.g., erosion and weathering) is intense. Thus, to better understand the impact of tectonic activity and distinguish between pre-existing landforms and neotectonic landforms, it is necessary to understand the development process of pre-existing landforms depending on the bedrock characteristics. This study used a two-dimensional numerical landscape evolution model (LEM) to study the spatio-temporal development of landscape according to the different erodibility under the same factors of climate and the uplift rate. We used hill-slope indices (i.e., relief, mean elevation, and slope) and channels (i.e., longitudinal profile, normalized channel steepness index, and stream order) to distinguish the difference according to different bedrocks. As a result of the analysis, the terrain with high erosion potential shows low mean elevation, gentle slope, low stream order, and channel steepness index. However, the value of the landscape with low erosion potential differs from that with high erodibility. In addition, a knickpoint came out at the boundary of the bedrock. When researching the actual topography, the location around the border of difference in bedrock has only been considered a pre-existing factor. This study suggested that differences in bedrock and various topographic indices should be comprehensively considered to classify pre-existing and active tectonic topography.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.713-723
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• 2023

Climate change is significantly affecting coastal areas, and its impacts are expected to intensify. Recent studies on climate change adaptation and risk assessment in coastal regions increasingly integrate the concepts of recovery resilience and vulnerability. The aim of this study is to develop a measurement model for coastal hazard recovery resilience in the context of climate change adaptation. Before constructing the measurement model, a comprehensive literature review was conducted on coastal hazard recovery resilience, establishing a conceptual framework that included operational definitions for vulnerability and recovery resilience, along with several feedback mechanisms. The measurement model for coastal hazard recovery resilience comprised four metrics (MRV, LRV, RTSPV, and ND) and a Coastal Resilience Index (CRI). The developed indices were applied to domestic coastal erosion cases, and regional analyses were performed based on the index grades. The results revealed that the four recovery resilience metrics provided insights into the diverse characteristics of coastal erosion recovery resilience at each location. Mapping the composite indices of coastal resilience indicated that the areas along the East Sea exhibited relatively lower coastal erosion recovery resilience than the West and South Sea regions. The developed recovery resilience measurement model can serve as a tool for discussions on post-adaptation strategies and is applicable for determining policy priorities among different vulnerable regional groups.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2001.11a
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• pp.66-68
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• 2001

An experiment was conducted investigate the of supplemental Cu and Zn methionine chelates on the performance, nutrient digestibility, serum IgG level, gizzard erosion, and Cu and Zn contents in the liver and excretion of broiler chickens. One thousand hatched broiler chickens (Ross) of one day old were assigned to 4 treatments:control(T1), 100ppm of copper in the from of Cu-methionine chelate(Cu-Met, T2), 100ppm of zinc in the from of Zn-methionine chelate(Zn-Met, T3) and 100ppm of copper plus 100ppm of zinc in the from of methionine chelate(Cu-Zn-Met, T4). Each treatment had four replications of 50 bird each. Weight gain of chicks fed chelated products were significantly higher than that of chicks fed control(P＜0.05).Combination of Cu and Zn chelates(Cu-Zn-Met) tended to show the best growth rate and feed conversion ratio. Nutrient digestibilities were not affected by dietary treatments. Serum IgG level of chicks fed Cu-Zn-Met was significantly higher than that of chicks fed control(P＜0.05). Gizzard erosion index was not significantly different among treatments. Contents of Cu and Zn in liver were not significantly affected by dietary treatments, whereas excretions of these minerals were significantly affected by dietary treatments.

• Wind and Structures
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• v.29 no.5
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• pp.313-321
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• 2019

The wind blowing at high velocity in an open storage yard leads to wind erosion and loss of material. Fence structures can be constructed around the periphery of the storage yard to reduce the erosion. The fence will cause turbulence and recirculation behind it which can be utilized to reduce the wind erosion and loss of material. A properly designed fence system will produce lesser turbulence and longer shelter effect. This paper aims to show the applicability of Support Vector Machine (SVM) to predict the recirculation length. A SVM model was built, trained and tested using the experimental data gathered from the literature. The newly developed model is compared with numerical turbulence model, in particular, modified $k-{\varepsilon}$ model along with the experimental results. From the results, it was observed that the SVM model has a better capability in predicting the recirculation length. The SVM model was able to predict the recirculation length at a lesser time as compared to modified $k-{\varepsilon}$ model. All the results are analyzed in terms of statistical measures, such as root mean square error, correlation coefficient, and scatter index. These examinations demonstrate that SVM has a strong potential as a feasible tool for predicting recirculation length.

• Journal of Environmental Impact Assessment
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• v.15 no.6
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• pp.357-372
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• 2006

The excessive land activities in farming can cause soil erosion, inundation by a flood, and fallow. So far land evaluation has been analyzed using the land use limitation derived from the excessive land activities. This study was done for evaluating the agricultural fields by using 3 land use limitations, inundation potential, soil erodibility potential, and fallow potential. The study area is Ibang-myeon, Changnyeong-gun, Gyeongnam-province, Korea. A logistic regression model was applied to recognize the inundation potential by a flood in the Nakdong river basin. And potential soil erodibility index (PSEI) was derived from USLE model to analyze the soil erodibility potential. And a probability model from a logistic regression model was applied to detect the fallow potential. Therefore, we found 220.7ha for the 4th grade and 86.1ha for the 5th grade was analyzed as water damage potential. Large area near Nakdong river have problem to grow the rice due to the damage by water inundation. And 213.6ha for the 3rd grade and 103.3ha for 4th grade was detected as a result of the analysis of soil erosion potential. The soil erosion potential was high when within-field integrity of soil was not stable, or the kinetic energy was high or the slope length was long due to a steep slope of a specific land. And 869.1ha for 3rd grade, 174.9ha for 4th grade, and 110.6ha for 5th grade was detected to be distributed having the fallow potential. Especially, a village, having a steep mountain, had 249.5ha for the 3rd grade, which was 28.7% of total area showing the 3rd grade. Finally, Three villages, including An-ri, Geonam-ri, Songgok-ri, showed they had largest area of the suitable land in the study area. These villages had similar topographic condition where they were far from Nakdong river, and they had relatively higher elevation and flat lands.

• Journal of Korea Water Resources Association
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• v.46 no.9
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• pp.885-896
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• 2013

SEMMA (Soil Erosion Model for Mountain Areas) should be revised to apply on mountain watershed of large scale. In this study, the basic structure of original SEMMA and methods to calculate main parameters are reviewed and the revised parameters are presented to expand a range of application. SEMMA-Ic is new model revised by a rate of vegetation cover which is substituted for index of vegetation structure to use specially NDVI for large scale areas. The correlation coefficient and the Nash-Sutcliffe simulation efficiency for the revised model decreased rather than those of original model. However the evaluation of the revised model on watershed showed the approximate simulation with measured sediment yield and the underestimated simulation when sediment yield is large. The additional research for channel erosion is needed so that soil erosion model for hillslopes is used to estimate sediment yield from a watershed.