• Korean Journal of Remote Sensing
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• v.38 no.2
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• pp.179-188
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• 2022

Global warming causes climate change and increases extreme weather events worldwide, and the occurrence of heatwaves and droughts is also increasing in Korea. For the monitoring of extreme weather, various satellite data such as LST (Land Surface Temperature), TCI (Temperature Condition Index), NDVI (Normalized Difference Vegetation Index), VCI (Vegetation Condition Index), and VHI (Vegetation Health Index) have been used. VHI, the combination of TCI and VCI, represents the vegetation stress affected by meteorological factors like precipitation and temperature and is frequently used to assess droughts under climate change. TCI and VCI require historical reference values for the LST and NDVI for each date and location. So, it is complicated to produce the VHI from the recent satellite GK2A (Geostationary Korea Multi-Purpose Satellite-2A). This study examined the retrieval of VHI using GK2A AMI (Advanced Meteorological Imager) by referencing the historical data from VIIRS (Visible Infrared Imaging Radiometer Suite) NDVI and LST as a proxy data. We found a close relationship between GK2A and VIIRS data needed for the retrieval of VHI. We produced the TCI, VCI, and VHI for GK2A during 2020-2021 at intervals of 8 days and carried out the interpretations of recent extreme weather events in Korea. GK2A VHI could express the changes in vegetation stress in 2020 due to various extreme weather events such as heatwaves (in March and June) and low temperatures (in April and July), and heavy rainfall (in August), while NOAA (National Oceanic and Atmospheric Administration) VHI could not well represent such characteristics. The GK2A VHI presented in this study can be utilized to monitor the vegetation stress due to heatwaves and droughts if the historical reference values of LST and NDVI can be adjusted in a more statistically significant way in the future work.

• Korean Journal of Remote Sensing
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• v.37 no.6_1
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• pp.1767-1772
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• 2021

Global satellite observation surface albedo data over a long period of time are actively used to monitor changes in the global climate and environment, and their utilization and importance are great. Through the generational shift of geostationary satellites COMS (Communication, Ocean and Meteorological Satellite)/MI (Meteorological Imager sensor) and GK-2A (GEO-KOMPSAT-2A)/AMI (Advanced Meteorological Imager sensor), it is possible to continuously secure surface albedo outputs. However, the surface albedo outputs of COMS/MI and GK-2A/AMI differ between outputs due to Differences in retrieval algorithms. Therefore, in order to expand the retrieval period of the surface albedo of COMS/MI and GK-2A/AMI to secure continuous climate change monitoring linkage, the analysis of the two satellite outputs and errors should be preceded. In this study, error characteristics were analyzed by performing comparative analysis with ground observation data AERONET (Aerosol Robotic Network) and other satellite data GLASS (Global Land Surface Satellite) for the overlapping period of COMS/MI and GK-2A/AMI surface albedo data. As a result of error analysis, it was confirmed that the RMSE of COMS/MI was 0.043, higher than the RMSE of GK-2A/AMI, 0.015. In addition, compared to other satellite (GLASS) data, the RMSE of COMS/MI was 0.029, slightly lower than that of GK-2A/AMI 0.038. When understanding these error characteristics and using COMS/MI and GK-2A/AMI's surface albedo data, it will be possible to actively utilize them for long-term climate change monitoring.

• Atmosphere
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• v.26 no.2
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• pp.215-226
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• 2016

Conceptual models to analyze both typhoon and Changma using products extracted by the GEO-KOMPSAT-2A (GK-2A) are suggested in this study. The GK-2A which is scheduled to be launched in 2018 has a high resolution, 16 channels, and 52 products. This means GK-2A is expected to obtain high quality images and products, which can detect severe weather earlier than the Communications, Ocean and Meteorological Satellite (COMS). Since there are not enough conceptual models for typhoon and Changma using satellite images and products, our conceptual model can increase both the applicability of satellite data and the accuracy of analysis. In the conceptual model, typhoons are classified as three types by prevailing factors; 1) heavy-rainfall type, 2) wind type, and 3) complex type. For Changma, two types are divided by the characteristics; band type and heavy-rainfall type. Among the high resolution 52 products, each type of typhoon and Changma are selected. In addition, the numerical products and dynamic factors are considered in order to improve conceptual models.

• Nutrition Research and Practice
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• v.3 no.1
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• pp.23-30
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• 2009

The aim of this study was to examine the hypoglycemic effect of chlorella in 6 week-old type 2 diabetic Goto-Kakizaki (GK, n=30) rats and 6 week-old normal Wistar (n=30) rats. Animals were randomly assigned to 3 groups respectively, and were fed three different experimental diets containing 0%, 3% or 5% (w/w) chlorella for 8 weeks. In diabetic GK rats, the insulinogenic-indices were not significantly different among the groups. The concentrations of fasting plasma glucagon and hepatic triglyceride, and the insulin/glucagon ratios of the GK-3% chlorella and GK-5% chlorella groups were significantly lower than those of the GK-control group. The HOMA-index and the concentrations of fasting blood glucose and plasma insulin of the GK-3% chlorella and GK-5% chlorella groups were slightly lower than those of the GK-control group. In normal Wistar rats, the insulinogenic-indices were not significantly different among the normal groups, but that of the Wistar-5% chlorella group was slightly higher than the other groups. The concentrations of fasting blood glucose and plasma insulin, and the HOMA-index of the Wistar-5% chlorella group were a little higher, and the fasting plasma glucagon concentration and the insulin/glucagon ratio of the Wistar-5% chlorella group were significantly higher than those of the Wistar-control and Wistar-3% chlorella groups. In conclusion, this study shows that the glucose-stimulated insulin secretion was not affected by the intake of chlorella, which could be beneficial, however, in improving insulin sensitivity in type 2 diabetic GK and normal Wistar rats.

• Atmosphere
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• v.24 no.2
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• pp.265-281
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• 2014

Currently, Korea is developing a Cheollian follow-on satellite program, named as Geostationary Korea Multipurpose Satellite 2 (GK-2), which consists of two satellites. One satellite (GK-2A) is dedicated to the meterological mission, while the second one (GK-2B) hosts two main payloads for the ocean and environmental application. As GK-2A is dedicated to the meteorological mission unlike Cheollian, there have been discussions on the possibility of transferring the responsibilities of the GK-2A program to the Korea Meteorological Administration. To help resolve any consumptive disputes or to find an efficient way for the GK-2A program, the events happened after the successful launch of the first meteorological satellite TIROS-1 in the U.S. in April 1960 are investigated. With the successful demonstration of usefulness of TIROS-1 for the meteorological applications, organizations such as the Weather Bureau and the Department of Defense, responsible for the real time application of the TIROS 1 data, strongly requested for an operational meteorological satellite program which resulted in the plan for the National Operational Meteorological Satellite System (NOMSS). The plan was strongly supported by Kennedy Adminstration and was put forwarded for the new program under the responsibility of Weather Bureau to the Congress. However, the responsible Committee on Science and Aeronautics sided with NASA and requested major revision of the responsibility. Due to many unfavorable conditions, Weather Bureau accepted the requests and signed with NASA on the agreement for the operational meteorological satellite. However, with the delay of Nimbus satellite which is planned to be used for the prototype of the operational satellite and changes of the unfavorable situations, the Weather Bureau could draw a second agreement with NASA. The new agreement reflected most propositions requested by the Weather Bureau for the NOMSS plan. Until now the second agreement is regarded as the basic principles for the operational meteorological satellite program in the U.S. This study investigates the backgrounds and processes of the second agreement and its implications for the GK-2 program.

• Applied Biological Chemistry
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• v.38 no.5
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• pp.376-381
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• 1995

Thermus caldophilus GK24 was selected as sources of thermostable alkaline phosphatase from a survey of extreme thermophile. T. caldophilus GK24 was tested for production of alkaline phosphatase by addition of various concentration of sodium glutamate, bactotryptone, glucose and yeast extract to basal salts. Sodium glutamate was found to be effective for the alkaline phosphatase induction. The optimal induction medium for production of alkaline phosphatase involves the addition of 0.3% sodium glutamate, 0.2% bactotryptone and 0.5% glucose to basal salts. The activity of the enzyme in optimal induction medium increased nearly 6-fold/ml than basal medium and 27.5-fold/ml than standard medium. T. caldophilus GK24 alkaline phosphatase was found to be inducible. When starved of inorganic phosphate, T. caldophilus GK24 produces the enzyme alkaline phosphatase. The addition of inorganic phosphate to growth medium had a repressive effect on enzyme synthesis.

• Preventive Nutrition and Food Science
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• v.5 no.4
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• pp.189-193
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• 2000

Preservative and antimutagenic effects of green tea leaves added Chinese cabbage kimchi (GK1, GK2, GK3, and GK4 : 1, 2, 3 and 4 of green tea leaves (GTL) in proportion of 100 of salted Chinese cabbage were added to kimchi) were compared to those of the Chinese cabbage kimchi without GTL (control kimchi, CK). Fermentation period of GKs was further delayed than that of CK. The initial pH and acidity between GKs an CK were similar, but the time reach optimally ripened status of kimchi (pH 4.3) was different. CK took 6 days, while GK1, GK2, GK3 and GK4 took 6, 10, 12 and 14 days at 10℃, respectively. The growth of Leuconostoc sp. and Lactobacilus sp. in GKs delayed comparing to those in FCK. Among GKs, as the added amount of green tea leaves increased, the growth of lactic acid bacteria was retarded. The antimutagenic effects of juices from GKs and CK were studied against aflatoxin B₁(AFB₁) in the Ames test on Salmonella typehimurium TA100 and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in the SOS chromotest using E. coli PQ37. Juices from optimally ripened GKs (pH 4.3) showed 52∼76% inhibition rates against the indirect mutagen, aflatoxin B₁ induced mutagenicity while 49% inhibition rate by CK in the Ames test. Juices from GKs and CK showed 44∼67% and 36% inhibition rate against direct mutagen, MNNG (70 ng/assay) induce mutagenicity in the SOS chromotest. Thus GKs delayed fermentation period of kimchi and exhibited higher antimutagenic activity than CK.

• Tunnel and Underground Space
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• v.19 no.2
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• pp.71-76
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• 2009

The GK immersed tunnel as a part of Busan-Geoje Fixed Link Project, is the first attempt in Korea. In spite of existing of many difficulties in construction like the absent of construction cases in Korea, the connection work under approximately 50 m below sea level and weak ground condition, etc., now eight caissons were installed successfully on the accurate position and we are going to install upto the twelfth caisson in this year. The purpose of this paper is to introduce design and construction conditions of the GK immersed tunnel to advise the tunnel designers who will handle the similar project.

• BMB Reports
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• v.30 no.5
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• pp.356-361
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• 1997

We cloned a cDNA (pPRC-1) which was comprised of 841 nucleotides from the cDNA library of a male ICR mouse submandibular gland ($SMG^+$). The nucleotide sequences of pPRC-1 were identical to those of exons 2 and 3 of the mGK-21 gene, a potentially functional glandular kallikrein identified in a Balb/c mouse, except for one nucleotide residue. Although this substitution changes Ile (ATT) in pPRC-1 to Val (GTT) in mGK-21, this difference has been explained by strain polymorphism. From the amino acid sequences predicted from its cDNA, we speculated that mGK-21 gene products/pGK21 consist of 261 amino acids including the $NH_2$-terminal signal peptide (residues 1~17), the short propeptide (residues 17~24), and the active peptide (residues 25~261). Although we did not demonstrate the enzyme activity of pGK21, it was assumed that pGK 21 was involved in the maturation of certain bioactive polypeptide(s) in mouse SMG for the following reasons : (a) mGK-21 gene was apparently expressed in a male ICR mouse SMG: (b) the proposed active site $His^{65}$, $Asp^{120}$, and $Ser^{213}$ residues were completely conserved in pGK21 just like other glandular kallikreins; (c) the cloned cDNA was translated to a predicted 27 kDa polypeptide chain in vitro: (d) the 27 kDa polypeptide chain produced by CHO cells was produced to a putative active form by trypsin.

• Korean Journal of Poultry Science
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• v.37 no.1
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• pp.23-33
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• 2010

The current study was performed to develop natural bio-active substances as additives for the production of high quality broiler chickens. A total of 120 male 3 day-old broiler chicks were randomly allocated to CON (control), GK2.5 (ginkgo leaf 2.5%), GK5.0 (ginkgo leaf 5.0%), PK2.5 (pumpkin 2.5%) and PK5.0 (pumpkin 5.0%) of five groups in cages (24 birds per group). All birds were fed corresponding diets from 3 to 35 d of age and determined growth performance and biological parameters including blood biochemical profiles, antioxidant status and intestinal microflora. During the entire feeding trial, GK5.0 and PK5.0 groups resulted in a significantly (P<0.05) higher FCR than GK2.5 and PK2.5 groups. Plasma triglyceride significantly (P<0.05) increased in GK5.0 group compared with the other groups, and the level of alanine transaminase (ALT) increased (P<0.05) in GK5.0 and PK5.0 groups compared with that in PK2.5 group. Dietary addition of ginkgo leaf and pumpkin significantly (P<0.05) increased superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the small intestine. Also, the addition of 2.5% ginkgo leaf significantly (P<0.05) increased the activities of SOD, GSH-Px and glutathione-S-transferase (GST) in the liver. Futhermore, muscle GST activity significantly (P<0.05) enhanced by dietary addition of ginko leaf and pumpkin. However, the level of lipid peroxidation (MDA) in the small intestine and muscle turned to be higher (P<0.05) in PK5.0 group. The colony forming units (CFU) of E. coli in intestinal digesta significantly (P<0.05) decreased in both ginko leaf and pumpkin supplemented groups compared with CON group. In conclusion, dietary addition of 2.5% ginko leaf and pumpkin as dietary sources can be applicable for the production of high quality broiler chickens.