• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.1
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• pp.19-27
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• 2012

The open-top chamber (OTC) system is designed for long term studies on the climate change impact on the major tree species and their community in Korea. In Korea Forest Research Institute (KFRI), the modified OTC system has been operating since September 2009. The OTC facility consists of six decagon chambers (10 meters in diameter by 7 meters high) with controlled gas concentration. In each chamber, a series of vertical vent pipes are installed to disperse carbon dioxide or normal air into the center of the chamber. The OTC is equipped with remote controlled computer system in order to maintain a stable and elevated concentration of carbon dioxide in the chamber throughout the experimental period. The experiment consisted of 4 treatments: two elevated $CO_2$ levels ($1.4{\times}$ and $1.8{\times}$ ambient $CO_2$) and two controls (inside and outdoors of the OTC). Average operational rate was the lowest (94.2%) in June 2010 but increased to 98% in July 2010 and was 100% during January to December 2011. In 2010~2011, $CO_2$ concentrations inside the OTCs reached the target programmed values, and have been maintained stable in 2011. In 2011, $CO_2$ concentrations of 106%, 100% and 94% of target values has been recorded in control OTC, $1.4{\times}$ $CO_2$-enriched OTC and $1.8{\times}$ $CO_2$-enriched OTC, respectively. With all OTC chambers, the difference between outside and inside temperatures was the highest ($1.2{\sim}2.0^{\circ}C$) at 10 am to 2 pm. Temperature difference between six OTC chambers was not detected. The relative humidity inside and outside the chambers was the same, with minor variations (0~1%). The system required the highest amount of $CO_2$ for operation in June, and consumed 11.33 and 17.04 ton in June 2010 and 2011, respectively.

• Korean Journal of Remote Sensing
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• v.38 no.6_2
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• pp.1691-1707
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• 2022

Cheonji Lake, the caldera of Baekdu Mountain, located on the border of the Korean Peninsula and China, alternates between melting and freezing seasonally. There is a magma chamber beneath Cheonji, and variations in the magma chamber cause volcanic antecedents such as changes in the temperature and water pressure of hot spring water. Consequently, there is an abnormal region in Cheonji where ice melts quicker than in other areas, freezes late even during the freezing period, and has a high-temperature water surface. The abnormal area is a discharge region for hot spring water, and its ice gradient may be used to monitor volcanic activity. However, due to geographical, political and spatial issues, periodic observation of abnormal regions of Cheonji is limited. In this study, the degree of ice change in the optimal region was quantified using a Landsat -5/-7/-8 optical satellite image and a Modified U-Net regression model. From January 22, 1985 to December 8, 2020, the Visible and Near Infrared (VNIR) band of 83 Landsat images including anomalous regions was utilized. Using the relative spectral reflectance of water and ice in the VNIR band, unique data were generated for quantitative ice variability monitoring. To preserve as much information as possible from the visible and near-infrared bands, ice gradient was noticed by applying it to U-Net with two encoders, achieving good prediction accuracy with a Root Mean Square Error (RMSE) of 140 and a correlation value of 0.9968. Since the ice change value can be seen with high precision from Landsat images using Modified U-Net in the future may be utilized as one of the methods to monitor Baekdu Mountain's volcanic activity, and a more specific volcano monitoring system can be built.

• Pediatric Infection and Vaccine
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• v.9 no.1
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• pp.79-84
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• 2002

Purpose : About 41% of obtained group A streptococci in the 1998 was reported as erythromycin-resistant streptococci in Seoul, Korea. The most common T serotype was T12, followed by T4 and T28. We'd like to monitor the serological changes and antibiotic sensitivity test of Streptococcus pyogenes obtained from the patients with pharyngotonsillitis and invasive diseases from 1999 through 2001. Also, it could be proposed to choose the proper antibiotic selection in the area where the rate of erythromycin-resistant streptococci is high. Methods : From Jan. 1999 to Oct. 2001, 208 isolates of group A streptococci were collected from inpatients and outpatients with pharyngotonsillitis, scarlet fever, and invasive infections in Seoul and Southern part of peninsula. All isolates were serotyped by T-agglutination, minimum inhibitory concentrations(MICs) which were determined by agar dilution methods, according to the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS). Results : The most common T serotype was T12(29.8%), followed by T1(23.1%), T4 (14.9%). T1 was prominent serotype compared with previous year. T serotyping, among 25 isolates obtained from the patients with scarlet fever in Southern part of peninsula mostly, was T12, T1, and T4 in order of frequency. All the isolates tested were susceptible to penicillin, cefprozil, vancomycin, ceftriaxone, and chloramphenicol. However, 23 isolates(14.2%) was resistant to erythromycin and 18 isolates(11.1%) was resistant to clarithromycin. Serotype T12 was found to be the most resistant serotype to erythromycin and/or clarithromycin. Conclusion : High rate of erythromycin-resistant streptococci which surveyed in 1998 were reduced to 14.2% in this study. We should have to further evaluate the reason of decreased resistant strains and consider the resistant strains of streptococci in choosing the antibiotics. There was no serological characteristics according to the types of disease entities. Between the serologic distributions in Seoul and the Southern part of peninsula area are same, we could presume that the serological typing of strains obtained over the country may be not different.

• Journal of the Korean Association of Geographic Information Studies
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• v.24 no.4
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• pp.41-54
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• 2021

It is very essential to estimate the water body area using remote exploration for water resource management, analysis and prediction of water disaster damage. Hydrophysical detection using satellites has been mainly performed on large satellites equipped with optical and SAR sensors. However, due to the long repeat cycle, there is a limitation that timely utilization is impossible in the event of a disaster/disaster. With the recent active development of Micro satellites, it has served as an opportunity to overcome the limitations of time resolution centered on existing large satellites. The Micro satellites currently in active operation are ICEYE in Finland and Capella satellites in the United States, and are operated in the form of clusters for earth observation purposes. Due to clustering operation, it has a short revisit cycle and high resolution and has the advantage of being able to observe regardless of weather or day and night with the SAR sensor mounted. In this study, the operation status and characteristics of micro satellites were described, and the water area estimation technology optimized for micro SAR satellite images was applied to the Daecheong Dam basin on the Korean Peninsula. In addition, accuracy verification was performed based on the reference value of the water generated from the optical satellite Sentinel-2 satellite as a reference. In the case of the Capella satellite, the smallest difference in area was shown, and it was confirmed that all three images showed high correlation. Through the results of this study, it was confirmed that despite the low NESZ of Micro satellites, it is possible to estimate the water area, and it is believed that the limitations of water resource/water disaster monitoring using existing large SAR satellites can be overcome.