• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.1
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• pp.9-14
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• 2010

This experiment was carried out to know adaptability and forage production and quality of sorghum and sorghum $\times$ sudangrass and sudangrass hybrids at paddy field from 2007 to 2008 at Chungnam province. Among growth characters, 'Sordan 79' hybrid was somewhat strong for waterlogging, and higher sugar content and good at the 2nd regrowth, disease and insect resistance. Fresh yield of 'Sordan 79' hybrid was the highest as 92,492 kg per ha among 10 Sorghum and Sorghum $\times$ Sudangrass hybrids. The dry yield of 'Sordan 79' hybrid was also the highest as 21,090kg per ha. The result of this study showed that 'Sordan79' hybrid had good growth characters and forage productivity and crude protein (CP) and in vitro dry matter digestibility (IVDMD) at paddy field in middle region of South Korea.

• The Journal of the Petrological Society of Korea
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• v.24 no.3
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• pp.181-191
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• 2015

The Bakseok of Geunjeongjeon Hall in Gyeongbokgung Palace is platy floor stone acting as drainage, protected glaring and sliding. The Bakseoks were composed of anisotropic medium-grained biotite granite with a weak myrmekitic texture. Interpretation of transportation process for the Bakseok and original granite provenance trace of and analyze of identity based on ancient writings and detail field survey. As a result, the very similar granite with the Bakseok in lithology, composition mineral, texture and geochemical characteristics was found around Mt. Nakgasan in the Seokmodo Island. There were interpreted stonework process of the Bakseok used exfoliation granite dome with physical weathering properties in Seokmodo Island, to get platy stone economically stonework at the state level as a minimized on burden of supply and men power.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.2
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• pp.57-65
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• 2003

Mapping of salinity distribution in the reclaimed lands was attempted by using the electromagnetic inductance technique. Field study was conducted to monitor ground conductivity with an electromagnetic inductance, EM 38 (Geonics), and electrical conductivity of the saturated extract, ECe of the soils, at the Daeho reclaimed land. EM values of horizontal mode, EMh, and vertical mode, EMv, mode were recorded at the interval of $2m{\times}2m$ from the ground. Soil samples were taken through the profile down to 100cm for calibration. ECe of poor drained area of Daeho, were in the range of $19.50-91.50ds\;m^{-1}$, while ECe of well-drained area ranged from $1.10-34.40ds\;m^{-1}$. Multiple regression equations for the measured EMv, EMh, and ECe were highly significant. The EMh showed higher correlation with ECe than EMv. With the multiple equation, ECgM could be calculated. Correlation between ECe and ECgM was the highest ($r=0.753^{***}$), when EMI readings were taken on the ground. The relationships were highly significant below 30 cm height of measurement, With the EM38 measurement, the salinity distribution was effectively expressed for the experimental filed in Daeho reclaimed land.

• Korean Journal of Environmental Agriculture
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• v.17 no.2
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• pp.132-135
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• 1998

This study was conducted to obtain basic information for soil improvement in flower crop cultivating greenhouse soil through survey on the chemical and physical properties of greenhouse soils. Total of 85 Flowcultivating farms were surveyed and analysis was done on the soil characteristics, amounts of chemical fertilizer and soil amendmentuse. The result are as follows: In soil properties of flower cultivating greenhousees, silt clay loam was 51%and 68% of the surveyed soils had good drainage condition. Ground water table was over 90-120cm which was optimum range for flower cultivation. Flower cultivating farms had problem with accumulation of fertility. Nitrate nitrogen was accumulated in Gypsophila paniculate farms and available phosphorus, and exchangeable postassium were significantly higher in greenhouse soils about 2 times than in open field soil. Application amount of chemical feltilizers in greenhouses were nitrate 211,phosphorus 135, and potassium 132kg/ha, respectively. Amount of organic matter used in greenhouse were high in order of cattle manure> compost> organic fertilizer> poultry manure> swine manure and their application amounts were69, 103, 32, 20, and 43 MT/ha, respectively.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.400-400
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• 2015

기후변화로 인해 예측하기 어려운 강우패턴의 변화와 도시화로 인한 불투수면의 증가로 도심지는 매년 침수위험에 노출되어 있다. 배수시설의 개선은 인구밀도가 높고 유동인구가 많은 도심지에서 이루어지기 쉽지 않은 상황이며, 강우패턴의 변화는 예측과 대처가 어려운 상황이다. 이러한 이유로, 침투증진을 통해 직접유출수를 줄이는 연구 중 LID(Low Impact Development)에 대한 관심이 높아지고 있다. LID기법은 도시화로 증가된 불투수면을 투수면으로 대체하여 저류, 침투, 여과, 증발산을 유도하여 물 순환 회복에 기여할 수 있는 방법으로 옥상녹화, 투수성포장, 침투 트렌치 등의 기술요소가 있다. LID 기술요소에 대해 국외의 경우 설치방안과 평균적인 저감효과를 메뉴얼로 제시하고 있지만, 강우 및 토지의 지역적 편차가 큰 국내에 적용하기에는 어려운 상황이다. 또한, LID 모델링의 경우 유역 내 적용 면적에 따른 유출저감효과를 제시하는 연구결과는 다수 제시되고 있지만, 적용 면적과 지점에 따라 효율성을 제시하는 점에서는 다소 미흡한 상황이다. 따라서 LID 기술요소 별 설계 사례와 GIS를 바탕으로 유역 내 적용 지점과 면적을 산출하고, 적용 지점 및 면적에 따른 저감 효율을 분석하는 것이 필요하다. 본 연구는 SWMM모형을 이용하여 LID 기술요소 중 옥상녹화를 적용하여, 강우 강도와 적용지점 및 면적에 따른 유출저감 효율을 분석하고자 한다. 연구지역은 청계천 유역으로 총 면적의 75% 이상이 주거지, 상업지, 교통시설 등을 포함한 불투수면으로 이루어져있는 도시 지역이다. 강우자료는 10년, 30년, 80년 빈도 확률강우량을 적용하였으며, 옥상녹화를 적용하기 위한 지점과 면적은 GIS를 기반으로 산정하였다.

• Journal of the Korean Geosynthetics Society
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• v.23 no.1
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• pp.17-25
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• 2024

The Voids in the Mineral Aggregate (VMA) within asphalt mixtures play a crucial role in defining the mixture's structural integrity, durability, and resistance to environmental factors. Accurate prediction and optimization of VMA are essential for enhancing the performance and longevity of asphalt pavements, particularly in varying climatic and environmental conditions. This study introduces a novel machine learning framework leveraging ensemble machine learning model for predicting VMA in asphalt mixtures. By analyzing a comprehensive set of variables, including aggregate size distribution, binder content, and compaction levels, our framework offers a more precise prediction of VMA than traditional single-model approaches. The use of advanced machine learning techniques not only surpasses the accuracy of conventional empirical methods but also significantly reduces the reliance on extensive laboratory testing. Our findings highlight the effectiveness of a data-driven approach in the field of asphalt mixture design, showcasing a path toward more efficient and sustainable pavement engineering practices. This research contributes to the advancement of predictive modeling in construction materials, offering valuable insights for the design and optimization of asphalt mixtures with optimal void characteristics.

• Journal of Korea Water Resources Association
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• v.53 no.8
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• pp.583-595
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• 2020

In this study, using the RCP scenario for Hyoja Drainage subbasin of Cheonggyecheon, we analyzed the change with the Historical and Future rainfall calculated from five GCMs models. As a result of analyzing the average rainfall by each GCMs model, the future rainfall increased by 35.30 to 208.65 mm from the historical rainfall. Future rainfall increased 1.73~16.84% than historical rainfall. In addition, the applicability of LID element technologies such as porous pavement, infiltration trench and green roof was analyzed using the SWMM model. And the applied weight and runoff for each LID element technology are analyzed. As a result of the analysis, although there was a difference for each GCMs model, the runoff increased by 2.58 to 28.78%. However, when single porous pavement and Infiltration trench were applied, Future rainfall decreased by 3.48% and 2.74%, 8.04% and 7.16% in INM-CM4 and MRI-CGCM3 models, respectively. Also, when the two types of LID element technologies were combined, the rainfall decreased by 2.74% and 2.89%, 7.16% and 7.31%, respectively. This is less than or similar to the historical rainfall runoff. As a result of applying the LID elemental technology, it was found that applying a green roof area of about 1/3 of the urban area is the most effective to secure the lag time of runoff. Moreover, when applying the LID method to the old downtown area, it is desirable to consider the priority order in the order of economic cost, maintenance, and cityscape.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4832-4836
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• 2012

In general, there are needed lots of time and experiments for determination of optimum asphalt content and mix design. The experimental results are highly depended on the skill of testers. Bailey suggested the proper aggregate gradation of hot mix asphalt are a function of special size and passing percent of the specified aggregate to reduce the test errors. In this paper, the asphalt mix designs of 19mm dense graded mix and PA-20mm for FHWA were carried out, using Bailey's method. The use of Bailey method can cut down the testing times to get the proper aggregate gradation for asphalt mix design. In case of 19mm dense graded asphalt mixture, the measured values of CA, $FA_c$, $FA_f$ are 0.724, 0.440, and 0.455, which are within the suggested values by Bailey. Also, in case of PA-20 graded asphalt mixture, the measured values of CA, $FA_c$, $FA_f$ are 0.646, 0.476, and 0.450, respectively.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.344-344
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• 2022

최근 기후변화에 따른 집중호우, 태풍의 규모 및 빈도가 증가하고 있다. 도시지역은 전통적인 배수체계가 한계에 도달함에 따라 기후변화에 대한 취약성이 다른 지역에 비하여 더욱 크게 나타나 기후변화에 효과적으로 적응하기 위한 방안으로 도심녹지, 빗물정원, 투수포장 등 그린인프라 확충의 중요성이 부각되고 있다. 본 연구에서는 도시하천 유역 내 그린인프라 확충에 따른 강우유출특성의 변화를 살펴보고자 하였다. 그린인프라의 확충은 불투수층을 투수층으로 변화시켜 물순환 건전화에 기여한다. 본 연구에서는 부산의 대표적인 도시하천 유역인 온천천유역을 대상으로 강우유출모형인 HSPF를 적용하여 유역 내 투수층 증가에 따른 유출특성의 변화를 살펴보았다. 온천천 유역을 세 개의 소유역(온천천 상류, 세병교, 온천천 하류)으로 구분하고 현재 상황(불투수면적비 각각 90.98, 92.96, 94.25%)에서 불투수면적을 10%씩 감소시켜가며 유역 내 지표유출량, 침투량의 변화를 살펴보았으며, 온천천 유량(갈수량, 저수량, 평수량, 풍수량, 홍수량)의 변화를 분석하였다. 분석 결과 유역 내 불투수면적 감소에 따라 강수의 침투가 증가하고 이에 따른 지표유출이 감소함을 확인할 수 있었다. 유역 내 불투수층이 감소함에 따라 지표유출량은 최대 32%까지 감소하고 침투량은 최대 71%까지 증가하는 것으로 나타났다. 또한 온천천의 갈수량, 저수량, 평수량, 풍수량은 증가하는 반면, 홍수 시의 유량을 의미하는 홍수량은 최대 15% 이상 감소하는 것을 알 수 있었다. 이는 유역 내 불투수층의 감소를 통해 평상시에는 추가적인 하천유량 확보가 가능하며, 홍수 시에는 반대로 홍수량을 저감시킴으로써 이에 따른 피해를 줄일 수 있음을 의미한다. 본 연구를 통해 그린인프라가 하천유량 확보 및 홍수량 저감을 통해 유역의 물순환 건전화에 긍정적인 영향을 미치는 것을 알 수 있었다. 따라서 효과적인 기후변화 적응을 위해 도시하천 유역의 그린인프라 확충을 위한 노력을 기울일 필요가 있다.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.3
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• pp.215-222
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• 1999

Platycodon root contains abundant pharmaceutical substances and is widely used as a food and a medicinal herb. This study was conducted to determine the cultural environment and soil morphological characteristics of platycodon. Sampling sites were Keochang 4, Kimhae 7, Haman 6, Chinju 6 and Koseong 3 fields in Kyongnam province and Hongcheong 6 fields in Kangwon province. The average continious cropping year was highest Chinju 8.0-years old, whereas lowest Hongcheon 2.3-years old. The average cropping area and compost application were highest Hongcheon 1.3ha and $108Mg\;ha^{-1}$ respectively than other areas. The slope was in order to Koseong steep slope with 35%. Koechang 28%, Flaman 16%, Chinju 11.7%, Kimhae 11% and Hongcheon 7.5%. The drainage classes was well drained in Koechang. Kimhae, Chinju and Koseong, while it s poorly drained in Hongcheon and Haman. Distribution of topography was highest rolling 37.9% and drainage classes was highest well drained 48.3%. The root disease incidence rate was in the order of Haman 56.8%, Hongcheon 52.5%, Kimhae 36.7%, Koechang 35.3%, Chinju 32.3% and Koseong 30.0%. The yield at the Chinju $36.17Mg\;ha^{-1}$ was higher than that of Koseong $25.00Mg\;ha^{-1}$, Kimhae $13.57Mg\;ha^{-1}$, Koechang $11.75Mg\;ha^{-1}$, Haman $9.50Mg\;ha^{-1}$ and Hongcheon $5.24Mg\;ha^{-1}$. The average temperature was correlated with the disease incidence rate by $Y=3.07X^2-87.16X+649.26(R^2=0.947^{**})$ and yield by $Y=-478.68X^2+13403X-90836(R^2=0.763^*)$. The root disease incidence rate was correlated with drainage classes Y=19.1X-5.26($R^2=0.592{***}$), topography Y=9.68X+10.77($R^2=0.205^{**}$) and slope Y=0.85X+-27.88 ($R^2=0.143^*$). The yield was correlated with drainage classes Y=-10X+42($R^2=0.348^{**}$), topography Y=-5.34X+34.5 ($R^2=0.134^*$) and slope Y=-0.68X+25.48($R^2=0.129^*$). The optimum cultivated land of perennial platycodon was average temperature $14^{\circ}C$, direction of southeast, topography of flat or undulating, slope of 0-6%, well drained.