• Korean Journal of Remote Sensing
• /
• v.37 no.5_2
• /
• pp.1295-1305
• /
• 2021

Satellite-derived ocean color products are required to effectively monitor clear open ocean and coastal water regions for various research fields. For this purpose, accurate correction of atmospheric effect is essential. Currently, the Geostationary Ocean Color Imager (GOCI)-II ground segment uses the reanalysis of meteorological fields such as European Centre for Medium-Range Weather Forecasts (ECMWF) or National Centers for Environmental Prediction (NCEP) to correct gas absorption by water vapor and ozone. In this process, uncertainties may occur due to the low spatiotemporal resolution of the meteorological data. In this study, we develop water vapor absorption correction model for the GK-2 combined GOCI-II atmospheric correction using Advanced Meteorological Imager (AMI) total precipitable water (TPW) information through radiative transfer model simulations. Also, we investigate the impact of the developed model on GOCI products. Overall, the errors with and without water vapor absorption correction in the top-of-atmosphere (TOA) reflectance at 620 nm and 680 nm are only 1.3% and 0.27%, indicating that there is no significant effect by the water vapor absorption model. However, the GK-2A combined water vapor absorption model has the large impacts at the 709 nm channel, as revealing error of 6 to 15% depending on the solar zenith angle and the TPW. We also found more significant impacts of the GK-2 combined water vapor absorption model on Rayleigh-corrected reflectance at all GOCI-II spectral bands. The errors generated from the TOA reflectance is greatly amplified, showing a large error of 1.46~4.98, 7.53~19.53, 0.25~0.64, 14.74~40.5, 8.2~18.56, 5.7~11.9% for from 620 nm to 865 nm, repectively, depending on the SZA. This study emphasizes the water vapor correction model can affect the accuracy and stability of ocean color products, and implies that the accuracy of GOCI-II ocean color products can be improved through fusion with GK-2A/AMI.

• Journal of Microbiology and Biotechnology
• /
• v.16 no.12
• /
• pp.2000-2003
• /
• 2006

A gene (GenBank AF096282) coding for a $\alpha$-glucosidase (TcaAG, EC 3.2.1.20) from Thermus caldophilus GK24 was expressed in Saccharomyces cerevisiae, a generally recognized as safe (GRAS) host. The thermostable $\alpha$-glucosidase was produced inside of the GRAS host at 0.04 unit/mg-dry cell by the constitutively expressing ADH1 promoter and at 1.2 unit/mg-dry cell by the inductively expressing GALl0 promoter, respectively. No $\alpha$-glucosidase activities were found in the medium when the MF-alpha signal sequence from S. cerevisiae or $\alpha$-amylase signal sequence from Aspergillus oryzae were fused before the $\alpha$-glucosidase gene for the secretion.

• Aerospace Engineering and Technology
• /
• v.12 no.2
• /
• pp.156-162
• /
• 2013

In the communication between satellite and ground station, data rate can be determined from the data volume and required transmission time. Increasing data rate can be limited according to the available bandwidth. For the reason, it has been popularly studying on high spectral-efficient modulation scheme in large volume data application such as digital video broadcasting service. This paper presents the conceptual design of UHRIT broadcasting in GEO-KOMPSAT-2A (GK2A) mission by using DVB-S2 standard. Based on the recently determined data rate, UHRIT bandwidth was calculated at the various modulation schemes and code rates of DVB-S2 standard. Receiving performance of global user station was also evaluated thorough link analysis by considering that user station is located at the edge of beam coverage. Finally, maximum data rate was analyzed in a situation that COMS HRIT bandwidth should be alternatively applied for UHRIT downlink.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.40 no.11
• /
• pp.1537-1543
• /
• 2011

We investigated the anti-diabetic effects of Hemicentrotus pulcherrimus (sea urchin, SU) shells on non-obese type 2 diabetic Goto-Kakizaki (GK) rats. We measured body weight, blood glucose, and plasma insulin levels and conducted an oral glucose tolerance test (OGTT). The SU shells (100 and 200 mg/kg) significantly reduced the blood glucose of GK rats from 203.8${\pm}$29.8 mg/dL to 138.5${\pm}$21.2 mg/dL at after 4 weeks of daily oral administration. However, plasma insulin levels at the same time were not changed by treatment with SU. During the OGTT, the SU-treated GK rats maintained a lower blood glucose level than the control group for 15 to 120 min. Based on these results, SU shells are considered to be effective in improving glucose tolerance. These results suggest that SU shells have unique properties to lower blood glucose, raise insulin sensitivity, and improve insulin resistance in GK rats.

• Journal of Positioning, Navigation, and Timing
• /
• v.13 no.2
• /
• pp.199-206
• /
• 2024

The GEO-KOMPSAT-2A (GK2A) satellite, which was launched in December 2018, carries weather observation payloads and uses the image navigation and registration system to calibrate the observation images. The calibration system requires accurate orbit prediction data and depends on the accuracy of the orbit determination accuracy. In order to find a possible way to improve the current orbit determination accuracy of the GK2A flight dynamic subsystem module, orbit determination software was developed to independently evaluate the orbit determination accuracy. A comprehensive satellite dynamic model is applied for a batch-type least squares filter. When determining the orbit, thrust firing during station-keeping maneuvers and wheel-off loading maneuvers is taken into account. One month of GK2A ranging data were processed to estimate the satellite position on a daily basis. The orbit determination error was evaluated by comparing estimates during overlapping estimation intervals.

• Proceedings of the Korean Environmental Health Society Conference
• /
• 2002.04a
• /
• pp.3-5
• /
• 2002

A measurement of indoor microorganism using Reuter Centrifugal Air Sampler(RCS) was undertaken during October 1991-February 1999 and 6-Stage Cascade Air Sampler was undertaken during May 2001-June 2001 in Seoul. The results were as follows : 1. The average of total microorganism collected on the agar strip GK-A media were, in the order, subway station, hospital, underground shopping center, department store, book store, theater, sports facility, educational institution, office building in sites. 2. The average of staphylcocci collected on the agar strip GK-S media, in the order, were subway station, underground shopping center, hospital and department store, department store, theater, office building, sports facility and educational institution in sites. 3. The average of fungus collected on the agar strip GK-HS media, in the order, were Underground hospital, shopping center, theater, subway station, department store, book store, sports facility, educational institution, and office building in sites

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.11 no.2
• /
• pp.210-213
• /
• 2008

Hyperacute liver failure from mushroom intoxication in children is rare and has a low survival rate. We report a case of hyperacute liver failure from mushroom intoxication in a 29-month-old boy. The patient ingested a mushroom about three days prior to presentation. He was admitted to the hospital with vomiting, abdominal pain, seizures, and hematemesis. During the hospitalization the patient developed hepatic encephalopathy (stage IV-a), and a coagulopathy. He recovered fully with specific medication, Penicillin GK and N-acetylcysteine.

• Korean Journal of Remote Sensing
• /
• v.38 no.5_1
• /
• pp.647-660
• /
• 2022

To prepare an atmospheric correction model suitable for CAS500-4 (Compact Advanced Satellite 500-4), this letter examined an atmospheric correction experiment using Sentinel-2 images having similar spectral characteristics to CAS500-4. Studies to compare the atmospheric correction results depending on different Aerosol Optical Depth (AOD) data are rarely found. We conducted a comparison of Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes (FLAASH), Sen2Cor, and Second Simulation of the Satellite Signal in the Solar Spectrum - Vector (6SV) version 1.1 and 2.1, using Geo-Kompsat 2A (GK2A) Advanced Meteorological Imager (AMI) and Aerosol Robotic Network (AERONET) AOD data. In this experiment, 6SV2.1 seemed more stable than others when considering the correlation matrices and the output images for each band and Normalized Difference Vegetation Index (NDVI).

• Journal of Astronomy and Space Sciences
• /
• v.35 no.3
• /
• pp.175-183
• /
• 2018

Many recent satellites have mission periods longer than 10 years; thus, satellite-based local space weather monitoring is becoming more important than ever. This article describes the instruments and data applications of the Korea Space wEather Monitor (KSEM), which is a space weather payload of the GeoKompsat-2A (GK-2A) geostationary satellite. The KSEM payload consists of energetic particle detectors, magnetometers, and a satellite charging monitor. KSEM will provide accurate measurements of the energetic particle flux and three-axis magnetic field, which are the most essential elements of space weather events, and use sensors and external data such as GOES and DSCOVR to provide five essential space weather products. The longitude of GK-2A is $128.2^{\circ}E$, while those of the GOES satellite series are $75^{\circ}W$ and $135^{\circ}W$. Multi-satellite measurements of a wide distribution of geostationary equatorial orbits by KSEM/GK-2A and other satellites will enable the development, improvement, and verification of new space weather forecasting models. KSEM employs a service-oriented magnetometer designed by ESA to reduce magnetic noise from the satellite in real time with a very short boom (1 m), which demonstrates that a satellite-based magnetometer can be made simpler and more convenient without losing any performance.

• Preventive Nutrition and Food Science
• /
• v.19 no.4
• /
• pp.281-290
• /
• 2014

The aim of the present study was to evaluate the anti-diabetic, anti-inflammatory, antioxidant potential, and total phenolic content (TPC) of green and red kohlrabi cultivars. Anti-diabetic and anti-inflammatory activities were evaluated via protein tyrosine phosphatase (PTP1B) and rat lens aldose reductase inhibitory assays and cell-based lipopolysaccharide (LPS)-induced nitric oxide (NO) inhibitory assays in RAW 264.7 murine macrophages. In addition, scavenging assays using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical, and peroxynitrite ($ONOO^-$) were used to evaluate antioxidant potential and TPC was selected to assess phytochemical characteristics. Between the two kohlrabi cultivars, red kohlrabi (RK) had two times more TPC than green kohlrabi (GK) and showed significant antioxidant effects in DPPH, ABTS, and $ONOO^-$ scavenging assays. Likewise, methanol (MeOH) extracts of RK and GK inhibited LPS-induced NO production in a dose dependent manner that was further clarified by suppression of iNOS and COX-2 protein production. The MeOH extracts of RK and GK exhibited potent inhibitory activities against PTP1B with the corresponding $IC_{50}$ values of $207{\pm}3.48$ and $287{\pm}3.22{\mu}g/mL$, respectively. Interestingly, the RK MeOH extract exhibited significantly stronger anti-inflammatory, anti-diabetic, and antioxidant effects than that of GK MeOH extract. As a result, our study establishes that RK extract with a higher TPC might be useful as a potent anti-diabetic, antioxidant, and anti-inflammatory agent.