• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.968-974
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• 2010

We assessed the feasibility of discrete wavelet transform (DWT) applied for the spectral processing to enhance the estimation performance quality of soil organic matters using visible-near infrared spectra and mapped their distribution via block Kriging model. Continuum-removal and $1^{st}$ derivative transform as well as Haar and Daubechies DWT were used to enhance spectral variation in terms of soil organic matter contents and those spectra were put into the PLSR (Partial Least Squares Regression) model. Estimation results using raw reflectance and transformed spectra showed similar quality with $R^2$ > 0.6 and RPD> 1.5. These values mean the approximation prediction on soil organic matter contents. The poor performance of estimation using DWT spectra might be caused by coarser approximation of DWT which not enough to express spectral variation based on soil organic matter contents. The distribution maps of soil organic matter were drawn via a spatial information model, Kriging. Organic contents of soil samples made Gaussian distribution centered at around 20 g $kg^{-1}$ and the values in the map were distributed with similar patterns. The estimated organic matter contents had similar distribution to the measured values even though some parts of estimated value map showed slightly higher. If the estimation quality is improved more, estimation model and mapping using spectroscopy may be applied in global soil mapping, soil classification, and remote sensing data analysis as a rapid and cost-effective method.

• The Korean Journal of Air & Space Law and Policy
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• v.34 no.1
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• pp.159-201
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• 2019

Along with Annex 14 Volume I establishment in 1951 and the set-up of restriction surface around the runway, aeronautical technique and navigation performance achieved dazzling growth, and the safety and precision of navigation greatly improved. However, restrictions on surrounding obstacles are still valid for safe operation of an aircraft. Standards and criteria for securing safety of aircraft operating around and on airport is stated in Annex 11 Air Traffic Services and Annex 14 Aerodrome etc. In particular, Annex 14 Volume I presents the criteria for limiting obstacles around an airport, such as natural obstacles such as trees, mountains and hills to prevent collisions between aircraft and ground obstacles, and artificial obstacles such as buildings and structures. On the other hand, Annex 14 Volume I, in the application of the obstacles limitation surfaces, apply the exception criteria, as it may not be possible to remove obstacles that violate the criteria if the aeronautical study determines that they do not impair the safety and regularity of aircraft operation. Aeronautical study has been applied and implemented in various countries including United States, Canada and Europe etc. accordingly, Korea established and amended some provisions of the Enforcement rules of the Aviation Act and established the Aeronautical study guidelines to approve exceptions. However, because ICAO does not provide specific guidelines on procedures and methods of Aeronautical study, countries conducting aeronautical study have established and applied their own procedures and methods. Reflecting this realistic situation, at the 12th World Navigation Conference and at the 38th General Assembly, the contracting States demanded a reexamination of the criteria for current obstacle limitation surfaces and methods of aeronautical study, and the ICAO dedicated a team of experts to prepare new standard. This study, in line with the movement of international change in obstacle limitation surface and aeronautical study, aims to compare and analyze current domestic and external standards on obstacle limitation and height limits, while looking at methods, procedure and systems for aeronautical study. In addition, expecting that aeronautical study will be used realistically and universally in assessing the impact of obstacles, we would recommend the institutional improvement of the aeronautical study along with the development of quantitative analysis methods using the navigation data in the current aeronautical study.

• Particle and aerosol research
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• v.15 no.1
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• pp.37-44
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• 2019

It is recommended for the public to stay at home and to close the doors and windows when a high-particulate-matter environment such as a yellow sand event occurs outside. However, there are lack of empirical studies describing how much outdoor PM infiltrates into a closed house and how much indoor PM an inhabitant is exposed to during the period. In this study, the $PM_{10}$ and $PM_{2.5}$ were measured at the kitchen in an apartment house by an optical particle counter for 3 days including a yellow sand event. The outdoor PMs and the outdoor wind speeds were referred from surrounding weather stations. We analyzed the penetration of $PM_{10-2.5}$ and $PM_{2.5}$ at the test house against the outdoor wind speed supposed corresponding to the change of air exchange rate. In addition, the effect of an indoor activity on change in the indoor PM was investigated. In result, the indoor $PM_{10-2.5}$ was very low even a yellow sand event occurred outside; rather, a contribution of indoor activities to increase in $PM_{10-2.5}$ was higher. In contrast, the indoor $PM_{2.5}$ fluctuated following the outdoor $PM_{2.5}$ trend at high wind speeds or remained almost constant at low wind speed.

• The Korean Journal of Nuclear Medicine Technology
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• v.23 no.1
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• pp.64-68
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• 2019

Purpose In the preparation process for N-13 Ammonia injections, there were radioactive medicines adsorbed on filters remarkably. Hereby, we have compared the adsorption rate and quality test on Millex GS filter and Satorious Minisart filter, both representatively hydrophilic sterilizing filters, also evaluated which filter is more accommodative for N-13 Ammonia injection. Materials and Methods The filters used for sterilization of N-13 Ammonia injections were Millex GS filter($0.22{\mu}m$) mand Satorious Minisart filter ($0.2{\mu}m$), which are generally used to strain aqueous solutions. After the N-13 Ammonia passes through each sterilization filter, the adsorption rate of the filter (n=10) is determined by measuring not only the radioactivity through the filter also the amount of radioactivity remaining in it using a Dose Calibrator. The N-13 Ammonia injections after each filter is tested by the quality control test to conform to the Samsung Medical Center standard. Results The ratio of radioactivity passed through Millex GS indicated $29.0{\pm}17.6%$. Satorious Minisart filters output was $80.9{\pm}3.2%$, respectively. Each ratio of radioactivity adsorbed on the sterile filter was $71.0{\pm}17.6%$ for Millex GS and $19.1{\pm}3.2%$ for the Satorious Minisart filters, respectively. Furthermore, on the ratio of filtered radioactivity, Using Satorious Minisart filter showed about 2.8 times higher than using Millex GS filter. The quality testing of N-13 Ammonia injections through each filter met the Samsung Medical Center standard. Conclusion The Millex GS filter is composed of cellulose acetate and cellulose nitrate, whereas the Satorious Minisart filter if composed only of cellulose acetate. Therefore, the presence of cellulose nitrate in the membrane seems to have made differences. Therefore, the use of Satorious Minisart filter in the preparation of N-13 Ammonia injection solution minimized the loss of radioactive medicines due to filter adsorption, thereby improving the synthesis yield.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.4
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• pp.316-328
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• 2021

In this study, the leaf Na content prediction model for spring potato was established using 400-1000 nm hyperspectral sensor to develop the multispectral sensor for the salinity monitoring in reclaimed land. The irrigation conditions were standard, drought, and salinity (2, 4, 8 dS/m), and the irrigation amount was calculated based on the amount of evaporation. The leaves' Na contents were measured 1st and 2nd weeks after starting irrigation in the vegetative, tuber formative, and tuber growing periods, respectively. The reflectance of the leaves was converted from 5 nm to 10 nm, 25 nm, and 50 nm of FWHM (full width at half maximum) based on the 10 nm wavelength intervals. Using the variance importance in projections of partial least square regression(PLSR-VIP), ten band ratios were selected as the variables to predict salinity damage levels with Na content of spring potato leaves. The MLR(Multiple linear regression) models were estimated by removing the band ratios one by one in the order of the lowest weight among the ten band ratios. The performance of models was compared by not only R2, MAPE but also the number of band ratios, optimal FWHM to develop the compact multispectral sensor. It was an advantage to use 25 nm of FWHM to predict the amount of Na in leaves for spring potatoes during the 1st and 2nd weeks vegetative and tuber formative periods and 2 weeks tuber growing periods. The selected bandpass filters were 15 bands and mainly in red and red-edge regions such as 430/440, 490/500, 500/510, 550/560, 570/580, 590/600, 640/650, 650/660, 670/680, 680/690, 690/700, 700/710, 710/720, 720/730, 730/740 nm.

• Journal of Korea Water Resources Association
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• v.54 no.11
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• pp.903-913
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• 2021

In the flood season, the measurement of the river discharge has many restrictions due to reasons such as budget, manpower, safety, convenience in measurement and so on. In particular, when heavy rain events occur due to typhoons, etc., it is difficult to measure the amount of flood due to the above problems. In order to improve this problem, in this study, a method was developed that can measure the river discharge in a flood season simply and safely in a short time with minimal manpower by combining the functions of a drone and a surface velocity doppler radar. To overcome the mechanical limitations of drones caused by weather issues such as wind and rainfall derived from the measurement of the river discharge using the conventional drone, we developed a drone with P56 grade dustproof and waterproof performance, stable flight capability at a wind speed of up to 36 km/h, and a payload weight of up to 10 kg. Further, to eliminate vibration which is the most important constraint factor in the measurement with a surface velocity doppler radar, a damper plate was developed as a device that combines a drone and a surface velocity Doppler radar. The velocity meter DSVM (Dron and Surface Veloctity Meter using doppler radar) that combines the flight equipment with the velocity meter was produced. The error of ±3.5% occurred as a result of measuring the river discharge using DSVM at the point of Geumsan-gun (Hwangpunggyo) located at Bonghwang stream (the first tributary stream of the Geum River). In addition, when calculating the mean velocity from the measured surface velocity, the measurement was performed using ADCP simultaneously to improve accuracy, and the mean velocity conversion factor (0.92) was calculated by comparing the mean velocity. In this study, the discharge measured by combining a drone and a surface velocity meter was compared with the discharge measured using ADCP and floats, so that the application and utility of DSVM was confirmed.

• Korean Journal of Remote Sensing
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• v.38 no.5_1
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• pp.497-510
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• 2022

Agricultural reservoirs are essential structures for water supplies during dry period in the Korean peninsula, where water resources are temporally unequally distributed. For efficient water management, systematic and effective monitoring of medium-small reservoirs is required. Synthetic Aperture Radar (SAR) provides a way for continuous monitoring of those, with its capability of all-weather observation. This study aims to evaluate the applicability of SAR in monitoring medium-small reservoirs using Sentinel-1 (10 m resolution) and Capella X-SAR (1 m resolution), at Chari (CR), Galjeon (GJ), Dwitgol (DG) reservoirs located in Ulsan, Korea. Water detected results applying Z fuzzy function-based threshold (Z-thresh) and Chan-vese (CV), an object detection-based segmentation algorithm, are quantitatively evaluated using UAV-detected water boundary (UWB). Accuracy metrics from Z-thresh were 0.87, 0.89, 0.77 (at CR, GJ, DG, respectively) using Sentinel-1 and 0.78, 0.72, 0.81 using Capella, and improvements were observed when CV was applied (Sentinel-1: 0.94, 0.89, 0.84, Capella: 0.92, 0.89, 0.93). Boundaries of the waterbody detected from Capella agreed relatively well with UWB; however, false- and un-detections occurred from speckle noises, due to its high resolution. When masked with optical sensor-based supplementary images, improvements up to 13% were observed. More effective water resource management is expected to be possible with continuous monitoring of available water quantity, when more accurate and precise SAR-based water detection technique is developed.

• Korean Journal of Remote Sensing
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• v.39 no.2
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• pp.207-221
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• 2023

This study suggests deep neural network models for estimating air temperature with Level 1B (L1B) datasets of GEO-KOMPSAT-2A (GK-2A). The temperature at 1.5 m above the ground impact not only daily life but also weather warnings such as cold and heat waves. There are many studies to assume the air temperature from the land surface temperature (LST) retrieved from satellites because the air temperature has a strong relationship with the LST. However, an algorithm of the LST, Level 2 output of GK-2A, works only clear sky pixels. To overcome the cloud effects, we apply a deep neural network (DNN) model to assume the air temperature with L1B calibrated for radiometric and geometrics from raw satellite data and compare the model with a linear regression model between LST and air temperature. The root mean square errors (RMSE) of the air temperature for model outputs are used to evaluate the model. The number of 95 in-situ air temperature data was 2,496,634 and the ratio of datasets paired with LST and L1B show 42.1% and 98.4%. The training years are 2020 and 2021 and 2022 is used to validate. The DNN model is designed with an input layer taking 16 channels and four hidden fully connected layers to assume an air temperature. As a result of the model using 16 bands of L1B, the DNN with RMSE 2.22℃ showed great performance than the baseline model with RMSE 3.55℃ on clear sky conditions and the total RMSE including overcast samples was 3.33℃. It is suggested that the DNN is able to overcome cloud effects. However, it showed different characteristics in seasonal and hourly analysis and needed to append solar information as inputs to make a general DNN model because the summer and winter seasons showed a low coefficient of determinations with high standard deviations.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.293-300
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• 2012

This study was to investigate the unsuitable rate of the storage facilities, the changes in corrosion process over time after installation according to the status, the time to install the facilities, years elapsed after facilities installation, inspection of methods and motivation, and so on, based on the results of the inspection at the petroleum storage facilities conducted by domestic soil-relate specialized agency to derive optimal management plans which meet the status of soil contamination facilities. The results showed that the facilities more than 5 years after the initial leak test at the time of the installation need to be inspected periodically by considering costs of leak test and remediation of polluted soil. The inspection period can be decided by cost and leak test methods showing discrepancies for the results obtained from individual test whether it was direct or indirect. To compensate these matters, we suggested that the direct inspection method on regular schedule is recommended. On the other hand, the inspection can be voluntarily completed to ease burden of the results by inspection or equivalent level to this inspection method. Also, it may need improved construction supervision and performance test system to minimize the occurrence of the nature defects in installing the facilities as well as the upgrade program for the facilities during intervals of inspection period.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.5
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• pp.263-270
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• 2006

Purpose: Several radioisotope-labeled thymidine derivatives such as $[^{11}C]$thymidine was developed to demonstrate cell proliferation in tumor. But it is difficult to track metabolism with $[^{11}C]$thymidine due to rapid in vivo degradation and its short physical half-life. 3'-$[^{18}F]$fluoro-3'-deoxythymidine ($[^{18}F]$FLT) was reported to have the longer half life of fluorine-18 and the lack of metabolic degradation in vivo. Here, we described the synthesis of the 3'-$[^{18}F]$fluoro-3'-deoxythymidine ($[^{18}F]$FLT) and compared with $([^{18}F]FET)\;and\;([^{18}F]FDG)$ in cultured 9L cell and obtained the biodistribution and PET image in 9L tumor hearing rats. Material and Methods: For the synthesis of $[^{18}F]$FLT, 3-N-tert-butoxycarbonyl-(5'-O-(4,4'-dimet hoxytriphenylmethyl)-2'-deoxy-3'-O-(4-nitrobenzenesulfonyl)-${\beta}$-D-threopentofuranosyl)thymine was used as a FLT precursor, on which the tert-butyloxycarbonyl group was introduced to protect N3-position and nitrobenzenesulfonyl group. Radiolabeling of nosyl substitued precursor with $^{18}F$ was performed in acetonitrile at $120^{\circ}C$ and deproteced with 0.5 N HCI. The cell uptake was measured in cultured 9L glioma cell. The biodistribution was evaluated in 9L tumor bearing rats after intravenous injection at 10 min, 30 min, 60 min and 120 min and obtained PET image 60 minutes after injection. Results: The radiochemical yield was about 20-30% and radiochemical purity was more than 95% after HPLC purification. Cellular uptake of $[^{18}F]$FLT was increased as time elapsed. At 120 min post-injection, the ratios of tumor/blood, tumor/muscle and tumor/brain were $1.61{\pm}0.34,\;1.70{\pm}0.30\;and\;9.33{\pm}2.22$, respectively. The 9L tumor was well visualized at 60 min post injection in PET image. Conclusion: The uptake of $[^{18}F]$FLT in tumor was higher than in normal brain and PET image of $[^{18}F]$FLT was acceptable. These results suggest the possibility of $[^{18}F]$FLT at an imaging agent for brain tumor.