• Title/Summary/Keyword: 초분

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Comparative analysis of water surface spectral characteristics based on hyperspectral images for chlorophyll-a estimation in Namyang estuarine reservoir and Baekje weir (남양호와 백제보의 Chlorophyll-a 산정을 위한 초분광 영상기반 수체분광특성 비교 분석)

  • Jang, Wonjin;Kim, Jinuk;Kim, Jinhwi;Nam, Guisook;Kang, Euetae;Park, Yongeun;Kim, Seongjoon
    • Journal of Korea Water Resources Association
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    • v.56 no.2
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    • pp.91-101
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    • 2023

  • In this study, we estimated the concentration of chlorophyll-a (Chl-a) using hyperspectral water surface reflectance in an inland weir (Baekjae weir) and estuarine reservoir (Namyang Reservoir) for monitoring the occurrence of algae in freshwater in South Korea. The hyperspectral reflectance was measured by aircraft in Baekjae Weir (BJW) from 2016 to 2017, and a drone in Namyang Reservoir (NYR) from 2020 to 2021. The 30 reflectance bands (BJW: 400-530, 620-680, 710-730, 760-790 nm, NYR: 400-430, 655-680, 740-800 nm) that were highly related to Chl-a concentration were selected using permutation importance. Artificial neural network based Chl-a estimation model was developed using the selected reflectance in both water bodies. And the performance of the model was evaluated with the coefficient of determination (R2), the root mean square error (RMSE), and the mean absolute error (MAE). The performance evaluation results of the Chl-a estimation model for each watershed was R2: 0.63, 0.82, RMSE: 9.67, 6.99, and MAE: 11.25, 8.48, respectively. The developed Chl-a model of this study may be used as foundation tool for the optimal management of freshwater algal blooms in the future.

  • https://doi.org/10.3741/JKWRA.2023.56.2.91 인용 PDF

Discussion on Detection of Sediment Moisture Content at Different Altitudes Employing UAV Hyperspectral Images (무인항공 초분광 영상을 기반으로 한 고도에 따른 퇴적물 함수율 탐지 고찰)

  • Kyoungeun Lee;Jaehyung Yu;Chanhyeok Park;Trung Hieu Pham
    • Economic and Environmental Geology
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    • v.57 no.4
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    • pp.353-362
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    • 2024

  • This study examined the spectral characteristics of sediments according to moisture content using an unmanned aerial vehicle (UAV)-based hyperspectral sensor and evaluated the efficiency of moisture content detection at different flight altitudes. For this purpose, hyperspectral images in the 400-1000nm wavelength range were acquired and analyzed at altitudes of 40m and 80m for sediment samples with various moisture contents. The reflectance of the sediments generally showed a decreasing trend as the moisture content increased. Correlation analysis between moisture content and reflectance showed a strong negative correlation (r < -0.8) across the entire 400-900nm range. The moisture content detection model constructed using the Random Forest technique showed detection accuracies of RMSE 2.6%, R2 0.92 at 40m altitude and RMSE 2.2%, R2 0.95 at 80m altitude, confirming that the difference in accuracy between altitudes was minimal. Variable importance analysis revealed that the 600-700nm band played a crucial role in moisture content detection. This study is expected to be utilized in efficient sediment moisture management and natural disaster prediction in the field of environmental monitoring in the future.

  • https://doi.org/10.9719/EEG.2024.57.4.353 인용 PDF

부부과학자-서정헌 ㆍ백명현박사부부

  • Korean Federation of Science and Technology Societies
    • The Science & Technology
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    • v.31 no.6 s.349
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    • pp.82-83
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    • 1998

  • 서울대 화학과 서정헌 교수와 화학교육과 백명현 교수부부는 서울대 화학과 동기생이자 실험실 짝으로 인연을 맺었다. 서교수는 요즈음 인공효소와 바닷물에서 우라늄을 추출해 내는 연구에 빠져 있으며 백교수는 무기재료에 이용될 수 있는 기능성 초분자 및 거대고리분자의 설계, 합성연구로 학문적 성과를 인정받고 있다.

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