• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.06a
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• pp.69-73
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• 1998

경기도 퇴촌에 위치한 경희대학교 연습림내의 경사도와 수종을 달리하는 3개의 서로 다른 임반에서 등고선을 따라 지표면의 토층분화를 조사하였고 이에 따른 수분침투특성을 조사하였다. 3개의 임반은 낙엽송, 잣나무 및 굴참나무의 천연활엽수로 구성되었고 이에 구성 수종에 따라 지표면에 퇴적되는 O, A, B층의 깊이를 달리한다. 토층분화 길이는 3개 임반 모두 경사도가 낮은 하부사면에서 양호하게 발달하였으며 경사도가 높은 산사면이나 수간우가 많은 일부 지역에서는 유거수에 의해 유기물이나 표층토가 유실되어 바로 암반층 또는 풍화층이 나타나는 경향을 보이고 있다. 그러나 잣나무 임반의 경우 밀식 수간에 의해 유기물퇴적층과 A층의 발달이 다른 낙엽송이나 굴참나무 임반보다 토층 발달 깊이가 약 2배 이상으로 깊게 발달되었다. 그리고 조사된 임반의 하부사면의 경우 A층의 발달이 약 35cm부터 약 60cm에 이르고 있으나 토성을 구성하는 요소 중 직경 2mm 이상의 자갈에 토양입자들이 전체 토양의 40%정도를 차지하고 있다. 이러한 토층분화 특성을 달리하는 임반에서의 수분 이동특성은 퇴적된 유기물의 두께가 깊으면 깊을수록 수분침투율은 낮아지는 반면 포면 유거수량은 증가하는 경향을 보여주고 있다. 그리고 지표면, 유기물 퇴적층 아래, 지표면으로부터 30cm 아래에 설치된 Lysimeter를 이용하여 조사된 침출수의 분포는 전체를 100으로 환산시 지표면은 약 55%, 유기물퇴적층 아래는 30%, 그라고 30cm의 위치에서는 나머지 15%정도의 침출수가 포집되었다. 따라서 본 실험의 결과를 살펴보았을 때 지표 층에 존재하는 유기물이 전체 수분이동에 영향을 미치는 것으로 조사되었다.양 실험 결과, 서식지에서 조사된 결과인 잎과 줄기에서 Pb$\alpha$ 추정시에는 SeaWiFS 위성과 관련된 global algorithms 중에서 490nm와 555nm의 복합밴드를 포함하는 OC2 알고리즘(ocean color chlorophyll 2 algorithm)을 사용하는 것이 OC2 series 및 OC4 알고리즘보다 좋은 추정 값을 도출할 수 있을 것으로 기대된다.환경에서는 5일에서 7월에 주로 이 충체의 유충이 발육되고 전파되는 것으로 추측되었다.러 가지 방법들을 적극 적용하여 금후 검토해볼 필요가 있을 것이다.잡은 전혀 삭과가 형성되지 않았다. 이 결과는 종간 교잡종을 자방친으로 하고 그 자방친의 화분친을 사용할 때만 교잡이 이루어지고 있음을 나타내고 있다. 따라서 여교잡을 통한 종간잡종 품종육성 활용방안을 금후 적극 확대 검토해야 할 것이다하였다.함을 보이고 있다.X> , ZnCl$_{3}$$^{-}$같은

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.917-926
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• 2021

Lodging rice is one of critical agro-meteorological disasters. In this study, the UAV-based multispectral imageries before and after rice lodging in rice paddy field of Jeollanamdo agricultural research and extension servicesin 2020 was analyzed. The UAV imagery on 14th Aug. includesthe paddy rice without any damage. However, 4th and 19th Sep. showed the area of rice lodging. Multispectral camera of 10 bands from 444 nm to 842 nm was used. At the area of restoration work against lodging rice, the reflectance from 531 nm to 842 nm were decreased in comparison to un-lodging rice. At the area of lodging rice, the reflectance of around 668 nm had small increases. Further, the blue and NIR (Near-Infrared) wavelength had larger. However, according to the types of lodging, the change of reflectance was different. The NDVI (Normalized Difference Vegetation Index) and NDRE (Normalized Difference Red Edge) shows dome sensitivities to lodging rice, but they were different to types of lodging. These results will be useful to make algorithm to detect the area of lodging rice using a UAV.

• Journal of Bio-Environment Control
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• v.31 no.1
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• pp.1-7
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• 2022

Strawberry is a stand-out cultivating fruit in Korea. The optimum production of strawberry is highly dependent on growing environment. Smart farm technology, and automatic monitoring and control system maintain a favorable environment for strawberry growth in greenhouses, as well as play an important role to improve production. Moreover, physiological parameters of strawberry plant and it is surrounding environment may allow to give an idea on production of strawberry. Therefore, this study intends to build a machine learning model to predict strawberry's yield, cultivated in greenhouse. The environmental parameter like as temperature, humidity and CO₂ and physiological parameters such as length of leaves, number of flowers and fruits and chlorophyll content of 'Seolhyang' (widely growing strawberry cultivar in Korea) were collected from three strawberry greenhouses located in Sacheon of Gyeongsangnam-do during the period of 2019-2020. A predictive model, Lasso regression was designed and validated through 5-fold cross-validation. The current study found that performance of the Lasso regression model is good to predict the number of flowers and fruits, when the MAPE value are 0.511 and 0.488, respectively during the model validation. Overall, the present study demonstrates that using AI based regression model may be convenient for farms and agricultural companies to predict yield of crops with fewer input attributes.

• Korean Journal of Remote Sensing
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• v.39 no.6_2
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• pp.1541-1551
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• 2023

Radiometric calibration is a fundamental step in ocean color remote sensing since the step to derive solar radiance spectrum in visible to near-infrared wavelengths from the sensor-observed electromagnetic signals. Generally, satellite sensor suffers from degradation over the mission period, which results in biases/uncertainties in radiometric calibration and the final ocean products such as water-leaving radiance, chlorophyll-a concentration, and colored dissolved organic matter. Therefore, the importance of radiometric calibration for the continuity of ocean color satellites has been emphasized internationally. This study introduces an approach to improve the radiometric calibration algorithm for the visible bands of the Geostationary Ocean Color Imager-II (GOCI-II) satellite with a focus on stability. Solar Diffuser (SD) measurements were employed as an on-orbit radiometric calibration reference, to obtain the continuous monitoring of absolute gain values. Time series analysis of GOCI-II absolute gains revealed seasonal variations depending on the azimuth angle, as well as long-term trends by possible sensor degradation effects. To resolve the complexities in gain variability, an azimuth angle correction model was developed to eliminate seasonal periodicity, and a sensor degradation correction model was applied to estimate nonlinear trends in the absolute gain parameters. The results demonstrate the effects of the azimuth angle correction and sensor degradation correction model on the spectrum of Top of Atmosphere (TOA) radiance, confirming the capability for improving the long-term stability of GOCI-II data.

• Journal of Soil and Groundwater Environment
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• v.6 no.4
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• pp.51-59
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• 2001

Column and box tests were performed to investigate the removal efficiency of NAPL using the surfactant enhanced flushing In heterogeneous medium. Homogeneous Ottawa sand and heterogeneous soil were used to verify the increase of remediation efficiency for the surfactant enhanced flushing in column test. Box tests with two different heterogeneous sub-structure were performed to quantify the capability of the surfactant enhanced flushing as a remediation method to remove NAPL from the heterogeneous medium. Two different grain size sand layers were repeated in the box to simulate the heterogeneous layer formation and the modified fault structure was built to simulate the fault system in the box. O-xylene as a LNAPL and PCE as a DNAPL were used and oleamide as a non-ionic surfactant. The maximum NAPL effluent concentration with 1% oleamide flushing in the homogeneous column test increased about 460 times compared to that with only water flushing and about 250 times increased in the real soil column test. In heterogeneous medium, the maximum effluent concentration increased about 150 times in 1% oleamide flushing and most of NAPL were removed from the box within 8 pore volume flushing, suggesting that the removal efficiency increased very much compared to in only water flushing. Results investigated the capability of the surfactant enhanced remediation method to remove NAPL even in heterogeneous medium.

• Journal of Korea Soil Environment Society
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• v.2 no.2
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• pp.9-24
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• 1997

Surfactant-aided in situ soil flushing has been proposed as an alternative for the expensive and time consuming 'pump and treat' technology in remediation of contaminated soil and groundwater Injected surfactants can effectively solubilize contaminants sorbed to the soil matrix or nonaqueous phase liquids(NAPLs) in residual saturation. The contaminants solubilized in groundwater are recovered and treated further. The theoretical background of the technology and the results of the field operations, mostly in the US. were summarized. In addition, the factors crucial to the successful application of the technology were discussed. Cost analyses and technical limitations in current applications were also discussed. In conclusion, it is likely that in situ surfactant flushing become a viable option for soil remediation in limited cases. Currently, further advances with respect to operation cost and to treatment efficiency are required for more extensive application of the technology. However, the current trends in soil remediation, specially the growing emphasis on risk based corrective action and natural attenuation, will increase the competitiveness of the technology. For example, removal of easily washable contaminants by short term soil flushing followed by long term monitoring and natural attenuation can greatly reduce the operation cost and time.

• Journal of Soil and Groundwater Environment
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• v.7 no.4
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• pp.31-39
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• 2002

Pollutants from industry, mining, agriculture, and other sources have contaminated sediments in many surface water bodies. Sediment contamination poses a severe threat to human health and environment because many toxic contaminants that are barely detectable in the water column can accumulate in sediments at much higher levels. The purpose of this study was to make optimal treatment and disposal plan o( sediment for water quality improvement in small-scale resevoir based on an evaluation of degree of contamination. The degree of contamination were investigated for 23 samples of 9 site at different depth of sediment in small-scale J river. Results for analysis of contaminated sediments were observed that copper concentration of 4 samples were higher than the regulation of hazardous waste (3 mg/L) and that of all samples were exceeded soil pollution warning levels for agricultural areas. Lead and mercury concentration of all samples were detected below both regulations. Necessary of sediment dredge was evaluated for organic matter and nutrient through standard levels of Paldang lake and the lower Han river in Korea and Tokyo bay and Yokohama bay in Japan. The degree of contamination for organic matter and nutrient was not serious. Compared standard levels of Japan, America, and Canada for heavy metal, contaminated sediment was concluded as lowest effect level or limit of tolerance level because standard levels of America and Canada was established worst effect of benthic organisms. The optimal treatment method of sediment contained heavy metal was cement-based solidification/stabilization to prevent heavy metal leaching.