• Title/Summary/Keyword: 근적상

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Development of a Method for Tracking Sandbar Formation by Weir-Gate Opening Using Multispectral Satellite Imagery in the Geumgang River, South Korea (금강에서 다분광 위성영상을 이용한 보 운영에 따른 모래톱 형성 추적 방법의 개발)

  • Cheolho Lee;Kang-Hyun Cho
    • Ecology and Resilient Infrastructure
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    • v.10 no.4
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    • pp.135-142
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    • 2023
  • A various technology of remote sensing and image analysis are applied to study landscape changes and their influencing factors in stream corridors. We developed a method to detect landscape changes over time by calculating the optical index using multispectral images taken from satellites at various time points, calculating the threshold to delineate the boundaries of water bodies, and creating binarized maps into land and water areas. This method was applied to the upstream reach of the weirs in the Geumgang River to track changes in the sandbar formed by the opening of the weir gate. First, we collected multispectral images with a resolution of 10 m × 10 m taken from the Sentinel-2 satellite at various times before and after the opening of the dam in the Geumgang River. The normalized difference water index (NDWI) was calculated using the green light and near-infrared bands from the collected images. The Otsu's threshold of NDWI calculated to delineate the boundary of the water body ranged from -0.0573 to 0.1367. The boundary of the water area determined by remote sensing matched the boundary in the actual image. A map binarized into water and land areas was created using NDWI and the Otsu's threshold. According to these results of the developed method, it was estimated that a total of 379.7 ha of new sandbar was formed by opening the three weir floodgates from 2017 to 2021 in the longitudinal range from Baekje Weir to Daecheong Dam on the Geumgang River. The landscape detection method developed in this study is evaluated as a useful method that can obtain objective results with few resources over a wide spatial and temporal range.

Unveiling the Potential: Exploring NIRv Peak as an Accurate Estimator of Crop Yield at the County Level (군·시도 수준에서의 작물 수확량 추정: 옥수수와 콩에 대한 근적외선 반사율 지수(NIRv) 최댓값의 잠재력 해석)

  • Daewon Kim;Ryoungseob Kwon
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.25 no.3
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    • pp.182-196
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    • 2023
  • Accurate and timely estimation of crop yields is crucial for various purposes, including global food security planning and agricultural policy development. Remote sensing techniques, particularly using vegetation indices (VIs), have show n promise in monitoring and predicting crop conditions. However, traditional VIs such as the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) have limitations in capturing rapid changes in vegetation photosynthesis and may not accurately represent crop productivity. An alternative vegetation index, the near-infrared reflectance of vegetation (NIRv), has been proposed as a better predictor of crop yield due to its strong correlation with gross primary productivity (GPP) and its ability to untangle confounding effects in canopies. In this study, we investigated the potential of NIRv in estimating crop yield, specifically for corn and soybean crops in major crop-producing regions in 14 states of the United States. Our results demonstrated a significant correlation between the peak value of NIRv and crop yield/area for both corn and soybean. The correlation w as slightly stronger for soybean than for corn. Moreover, most of the target states exhibited a notable relationship between NIRv peak and yield, with consistent slopes across different states. Furthermore, we observed a distinct pattern in the yearly data, where most values were closely clustered together. However, the year 2012 stood out as an outlier in several states, suggesting unique crop conditions during that period. Based on the established relationships between NIRv peak and yield, we predicted crop yield data for 2022 and evaluated the accuracy of the predictions using the Root Mean Square Percentage Error (RMSPE). Our findings indicate the potential of NIRv peak in estimating crop yield at the county level, with varying accuracy across different counties.

Fabrication of LiDAR-detectable Plate-type Black Materials and Application in Hydrophilic Paints (라이다 센서에 인지되는 판상형 검은색 소재의 제조 및 친수성 도료로의 응용)

  • Jiwon Kim;Minki Sa;Chan-Gyo Kim;Ha-Yeong Kim;Yeon-Ryong Chu;Suk Jekal;Chang-Min Yoon
    • Journal of Adhesion and Interface
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    • v.24 no.3
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    • pp.95-99
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    • 2023
  • In this study, LiDAR-detectable black materials are synthesized by coating and reduction of titanium dioxide onto plate-type natural mica, which evaluated practical LiDAR verification. In detail, black TiO2@Mica materials are fabricated by utilizing a sol-gel reaction to coat titanium dioxide onto natural mica, followed by reduction using sodium tetrahydridoborate. Subsequently, Black TiO2@Mica materials are dispersed in hydrophilic transparent varnish and sprayed onto the glass substrate to assess applicability as paints. As a result, Black TiO2@Mica-based paints exhibit true blackness (L*=12.1) and a higher NIR reflectance (30.2 R%). In addition, it was confirmed that as-synthesized Black TiO2@Mica materials are successfully recognized by a LiDAR sensor. This phenomenon is attributed to Fresnel's reflection law, in which light reflection occurs at the interface between natural mica and titanium dioxide with different refractive indices. In this regard, the findings of the study are expected to contribute to the potential utilization of LiDAR-detectable materials in various fields such as autonomous vehicles, robotics, and drones.

Synthesis of LiDAR-Detective Black Material via Recycling of Silicon Sludge Generated from Semiconductor Manufacturing Process and Its LiDAR Application (반도체 제조공정에서 발생하는 실리콘 슬러지를 재활용한 라이다 인지형 검은색 소재의 제조 및 응용)

  • Minki Sa;Jiwon Kim;Shin Hyuk Kim;Chang-Min Yoon
    • Journal of the Korea Organic Resources Recycling Association
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    • v.32 no.1
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    • pp.39-47
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    • 2024
  • In this study, LiDAR-detective black material is synthesized by recycling silicon sludge (SS) that is generated from semiconductor manufacturing process, and its recognition is confirmed using two types of LiDAR sensors (MEMS and Rotating LiDAR). In detail, metal impurities on the surface of SS is removed, followed by coating of titanium dioxide (TiO2) and subsequent chemical reduction to obtain SS-derived black TiO2 (SS/bTiO2) material. As-prepared SS/bTiO2 is mixed with transparent paint to prepare hydrophilic black paints and applied to a glass substrate using a spray gun. SS/bTiO2-based paint shows similar blackness (L*=15.7) compared to commercial carbon black-based paint, and remarkable NIR reflectance (26.5R%, 905nm). Furthermore, MEMS and Rotating LiDAR have successfully detected the SS/bTiO2-based paint. This is attributed to the occurrence of high reflection of light at the interface between the black TiO2 and the silicon sludge according to the Fresnel's reflection principle. Hence, the new application field to effectively recycle silicon sludge generated in the semiconductor manufacturing process has been presented.

A Comparative Study on Synthesis and Characteristics of LiDAR-detectable Black Hollow-Structured Materials Using Various Reduction Methods (다양한 환원법을 활용한 라이다 인지형 검은색 중공구조 물질의 제조 및 특성 비교 연구)

  • Dahee Kang;Minki Sa;Jiwon Kim;Suk Jekal;Jisu Lim;Gyu-Sik Park;Yoonho Ra;Shin Hyuk Kim
    • Journal of Adhesion and Interface
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    • v.25 no.2
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    • pp.56-62
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    • 2024
  • In this study, LiDAR-detectable black hollow-structured materials are synthesized using different reducing agents to evaluate their applicability to LiDAR sensor. Initially, white SiO2/TiO2 core/shell (WST) materials are fabricated via a sol-gel method, followed by a reduction using ascorbic acid (AA) and sodium borohydride (SB). After the reduction, subsequent etching of the SiO2 core leads to the formation of two different black hollow-structured materials (AA-BHT and SB-BHT). The lightness (L*) and near-infrared (NIR) reflectance (R%) of AA-BHT are measured as ca. 19.1 and 34.5 R%, and SB-BHT shows values of ca. 11.5 and 31.8 R%, respectively. While AA-BHT exhibits higher NIR reflectance compared to SB-BHT, it displays slightly lower blackness. Compared with core/shell structured materials, improved NIR reflectance of both AA-BHT and SB-BHT is attributed to the morphology of hollow- structured materials, which increase light reflection at the interface between air and black TiO2 according to the Fresnel's reflection principle. Consequently, both AA-BHT and SB-BHT are effectively detected by the commercially available LiDAR sensors, validating their suitability as black materials for autonomous vehicle and environment.

Properties of Temperature Reduction of Cooling Asphalt Pavements Using High-Reflectivity Paints (고반사 도료를 사용한 차열성 아스팔트 도로포장의 온도저감특성)

  • Hong, Chang Woo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.1
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    • pp.317-327
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    • 2013
  • Air pollution and artificial heat of urban areas have caused the urban heat island in which asphalt pavements absorb solar heat during the daytime and release the heat at night. Hence, in order to improve the environment of urban areas, it is necessary to examine cooling pavements that can reduce heat on road pavements in urban areas. The application of temperature insulation paints on road pavements require to reduce black brightness for visibility, to increase the reflection rate of infrared light and minimize the reflection rate of visible light. In the study, one part of Acrylic-emulsion was used as a main binder, and the changes in black brightness and the changes of addition ratio (0%, 15%, 30%) of hollow ceramics, as well as kinds of paints (carbon black pigment, mixed mineral pigment) were selected as the main experimental factors. The performance of temperature reduction of cooling pavements was analyzed through the reflection rate of spectrum, the reflection rate of solar heat, and the lamp test. Abrasion resistance, UV accelerated weather resistance, and sliding resistance were tested in real situations. In addition, the performance of heat reduction of testing pavements covered with high-reflection paints was analyzed by using an infrared camera. As the test results, when using mixed mineral paints and hollow ceramic of 30%, the reflection rate of spectrum was 43% in the area of near-infrared ray and 17% in the area of visible light at black brightness of $L^*$=42.89 and the reflection rate of solar heat was 27.5%. Total color difference was ${\Delta}E$=0.27 in the test of UV Accelerated Weather Resistance, indicating almost no changes in color. BPN was more than 53 when scattering #2 and #4 silica sand of more than $0.12kg/m^2$. In Taber's abrasion resistance test, abrasion loss was up to 86.4mg at 500 rotations. The performance of heat reduction was evaluated using an infrared camera at the test section applying high-reflection paints to asphalt pavements, in which the results showed that the temperature was reduced by $12.7^{\circ}C$ on CI-30-40 cooling pavements ($L^*$=38.76) and by $14.2^{\circ}C$ on CI-30-60 cooling pavements ($L^*$=57.12).

Heat Shield Property of Nanostructural-regulated Fe2O3/TiO2 Composites Filled with Polyacrylate Paint (나노구조 변화에 의한 Fe2O3/TiO2 복합재료를 충전한 Poly Acrylate 도료의 열차단 특성)

  • Kim, Dae Won;Ma, Young Kil;Kim, Jong Seok
    • Applied Chemistry for Engineering
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    • v.31 no.1
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    • pp.43-48
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    • 2020
  • Fe2O3 nanoparticles with the mixed structure of cubic and nanorod were synthesized by precipitation, hydrothermal, sol-gel method, etching process and heat treatment. Fe2O3/TiO2 core-shell (CS) of type Fe2O3@TiO2 composite was fabricated on a 20 nm nanolayer of TiO2 coated on the surface of Fe2O3 nanoparticles. Fe2O3/TiO2 yolk-shell (YS) composite was prepared by chemical etching and heat treatment of Fe2O3/TiO2 CS nanoparticles. Physical properties of Fe2O3, Fe2O3@TiO2 CS and Fe2O3@TiO2 YS nanoparticles were characterized by FE-SEM, HR-TEM and X-ray diffraction. The solar reflectance, commission internationale de l'Elcairage (CIE) color coordinate and heat shield temperatures of Fe2O3, CS and YS type Fe2O3@TiO2 pigments filled with poly acrylate (PA) paints were investigated by UV-Vis-NIR spectrometer and homemade heat shield temperature measuring device. The Fe2O3@TiO2 YS red pigment filled PA composite exhibited excellent near infrared light reflecting performance and also reduced the heat shield temperature of 13 ℃ than that of Fe2O3 filled counterparts.

Statistical Treatment on Amylose and Protein Contents in Rice Variety Germplasm Based on the Data Obtained from Analysis of Near-Infrared Reflectance Spectroscopy (NIRS) (NIRS 분석 Data에 의한 국내외 육성품종 벼 유전자원의 아밀로스 및 단백질 성분에 대한 통계분석)

  • Oh, Sejong;Chae, Byungsoo;Lee, Myung Chul;Choi, Yu Mi;Lee, Sukyeung;Ko, Ho Cheol;Rauf, Muhammad;Hyun, Do Yoon
    • Korean Journal of Plant Resources
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    • v.31 no.5
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    • pp.498-514
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    • 2018
  • A statistical analysis for 3651 genetic resources collected from China (1,542), Japan (1,409), Korea (413), and India (287) was conducted using normal distribution, variability index value (VIV), analysis of variation (ANOVA) and Ducan's multiple range test (DMRT) based on a data obtained from NIRS analysis. In normal distribution, the average protein content was 8.0%, whereas waxy type amylose and common rice amylose were found to be 8.7% and 22.7%, respectively. The protein contents ranged from 5.4 to 10.6% at the level of 95%. The waxy amylose and common rice amylose ranged from 5.9 to 11.5%, and from 16.9 to 28.5% at 95% confidence level, respectively. The VIV was 0.59 for protein, 0.64 for low amylose, and 0.81 for high amylose contents. The average amylose contents were 18.85% in Japanese, 19.99% in Korean, 20.27% in Chinese, and 25.46% in Indian resources, while the average protein contents were found to be 7.23% in Korean, 7.73% in Japanese, 8.01% in Chinese, and 8.17% in Indian resources. The ANOVA of amylose and protein content showed significant differences at the level of 0.01. The F-test for amylose content was 158.34, and for protein content 53.95 compared to critical value 3.78. The DMRT of amylose and protein content showed significant difference (p<0.01) between resources of different countries. Japanese resources had the lowest level of amylose contents, whereas, the lowest level of protein content was found in Korean resources compared to other origins. Indian resources showed the highest level of amylose and protein contents. It is recommended these results should be helpful to future breeding experiments.

Evaluation of Feed Values for Imported Hay Using Near Infrared Reflectance Spectroscopy (근적외선분광법을 이용한 수입 건초의 사료가치 평가)

  • Park, Hyung Soo;Kim, Ji Hye;Choi, Ki Choon;Oh, Mirae;Lee, Ki-Won;Lee, Bae Hun
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.39 no.4
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    • pp.258-263
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    • 2019
  • Near infrared reflectance spectroscopy (NIRS) has become increasingly used as a rapid and accurate method of evaluating some chemical compositions in forages. The objective of this study was to evaluate the potential of NIRS, applied to imported forage, to estimate the moisture and chemical parameters for imported hays. A population of 392 imported hay representing a wide range in chemical parameters was used in this study. Samples of forage were scanned at 1 nm intervals over the wavelength range 680-2500nm and the optical data was recorded as log 1/Reflectance(log 1/R), which scanned in intact fresh condition. The spectral data were regressed against a range of chemical parameters using partial least squares(PLS) multivariate analysis in conjunction with spectral math treatments to reduced the effect of extraneous noise. The optimum calibrations were selected based on the highest coefficients of determination in cross validation(R2) and the lowest standard error of cross-validation(SECV). The results of this study showed that NIRS predicted the chemical parameters with very high degree of accuracy. The R2 and SECV for imported hay calibration were 0.92(SECV 0.61%) for moisture, 0.98(SECV 0.65%) for acid detergent fiber, 0.97(SECV 0.40%) for neutral detergent fiber, 0.99(SECV 0.06%) for crude protein and 0.97(SECV 3.04%) for relative feed value on a dry matter(%), respectively. Results of this experiment showed the possibility of NIRS method to predict the moisture and chemical composition of imported hay in Korea for routine analysis method to evaluate the feed value.

Supplemental Lighting by HPS and PLS Lamps Affects Growth and Yield of Cucumber during Low Radiation Period (약광기 HPS와 PLS lamp를 이용한 오이의 보광재배효과)

  • Kwon, Joon-Kook;Yu, In-Ho;Park, Kyoung-Sub;Lee, Jae-Han;Kim, Jin-Hyun;Lee, Jung-Sup;Lee, Dong-Soo
    • Journal of Bio-Environment Control
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    • v.27 no.4
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    • pp.400-406
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    • 2018
  • In this experiment the effect of supplemental lighting on the growth and yield of cucumber (Cucumis sativus L. 'Fresh') plants during low radiation period of winter season were investigated in glasshouses using common high-pressure sodium (HPS) lamps and newly developed plasma lighting system (PLS) lamps. Plants grown without supplemental lighting were considered as a control. Supplemental lighting was provided from November 20th, 2015 to March 15th, 2016 to ensure 14-hour photoperiod (natural+supplemental light), also lamps were operated automatically when the outside sun radiation levels were less than $100W{\cdot}m^{-2}$. Spectral analysis showed that HPS lamp had a discrete spectrum, lacked of the radiation in the 400-550 nm wave band (blue-green light), but had a high output in the orange-red region (550-650 nm). A higher red light output resulted in an increased red to far-red (R/FR) ratio in HPS lamp. PLS had a continuous spectrum and had a peak radiation in green region (490-550 nm). HPS has 12.6% lower output in photosynthetically active radiation (PAR) but 12.6% higher output in near infra-red (NIR) spectral regions compared to PLS. Both HPS and PLS lamps emitted very low levels of ultra-violet radiation (300-400 nm). Supplemental lighting both from HPS and PLS lamps increased plant height, leaf number, internode number and dry weight of cucumber plants compared to control. Photosynthetic activity of cucumber plants grown under two supplemental lighting systems was comparable. Number of fruits per cucumber plant (fruit weight per plant) in control, PLS, and HPS plots were 21.2 (2.9 kg), 38.7 (5.5 kg), and 40.4 (5.6 kg), respectively, thereby increasing yield by 1.8-1.9 times in comparison with control. An analysis of the economic feasibility of supplemental lighting in cucumber cultivation showed that considering lamp installation and electricity costs the income from supplemental lighting increased by 37% and 62% for PLS and HPS lamps, respectively.