• Korean Journal of Remote Sensing
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• v.25 no.1
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• pp.45-59
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• 2009

This research presents the effect of Asian dust on the derived sea surface temperature (SST) from measurements of the Advanced Very High Resolution Radiometer (AVHRR) instrument flown onboard NOAA polar orbiting satellites. To analyze the effect, A VHRR infrared brightness temperature (TB) is estimated from simulated radiance calculated from radiative transfer model on various atmospheric conditions. Vertical profiles of temperature, pressure, and humidity from radiosonde observation are used to build up the East Asian atmospheric conditions in spring. Aerosol optical thickness (AOT) and size distribution are derived from skyradiation measurements to be used as inputs to the radiative transfer model. The simulation results show that single channel TB at window region is depressed under the Asian dust condition. The magnitude of depression is about 2K at nadir under moderate aerosol loading, but the magnitude reaches up to 4K at slant path. The dual channel difference (DCD) in spilt window region is also reduced under the Asian dust condition, but the reduction of DCD is much smaller than that shown in single channel TB simulation. Owing to the depression of TB, SST has cold bias. In addition, the effect of AOT on SST is amplified at large satellite zenith angle (SZA), resulting in high variance in derived SSTs. The SST depression due to the presence of Asian dust can be expressed as a linear function of AOT and SZA. On the basis of this relationship, the effect of Asian dust on the SST retrieval from the conventional daytime multi-channel SST algorithm can be derived as a function of AOT and SZA.

• Journal of the Korean earth science society
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• v.27 no.4
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• pp.450-463
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• 2006

Seasonal threshold values for fog detection over the ten airport areas within the Korean Peninsula have been derived from the data of polar-orbit Aqua/Terra MODIS and geostationary GOES-9 during a two years. The values are obtained from reflectance at $0.65{\mu}m\;(R_{0.65})$ and the difference in brightness temperature between $3.7{\mu}m\;and\;11{\mu}m\;(T_{3.7-11})$. In order to examine the discrepancy between the threshold values of two kinds of satellites, the following four parameters have been analyzed under the condition of daytime/nighttime and fog/clear-sky, utilizing their simultaneous observations over the Seoul metropolitan area: brightness temperature at $3.7{\mu}m$, the temperature at $11{\mu}m,\;the\;T_{3.7-11}$ for day and night, and the $R_{0.65}$ for daytime. The parameters show significant correlations (r<0.5) in spatial distribution between the two kinds of satellites. The discrepancy between their infrared thresholds is mainly due to the disagreement in their spatial resolutions and spectral bands, particularly at $3.7{\mu}m$. Fog detection from GOES-9 over the nine airport areas except the Cheongju airport has revealed accuracy of 60% in the daytime and 70% in the nighttime, based on statistical verification. The accuracy decreases in foggy cases with twilight, precipitation, short persistence, or the higher cloud above fog. The sensitivity of radiance and reflectance with wavelength has been analyzed in numerical experiments with respect to various meteorological conditions to investigate optical characteristics of the three channels.

• Food Science and Preservation
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• v.19 no.6
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• pp.818-824
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• 2012

In this study, danmuji samples stored at 5 and $25^{\circ}C$ were examined for three weeks to observe the changes in the color, property of matter, and microorganisms of danmuji, and its sensory properties, during its storage. The difference in the brightness and redness of danmuji and danmuji filtrate as their storage period became longer was not big but was significant, and their yellowness decreased following storage at both 5 and $25^{\circ}C$. The hardness of the danmuji sample stored at $5^{\circ}C$ showed the greatest value at day 7 while that of the danmuji sample stored at $25^{\circ}C$ showed the greatest value at day 14. It was found in the examination of the total cell number of the stored danmuji that the total cell number was $10^5CFU/g$, with almost no change, but in the case of the danmuji filtrate, the cell number increased from the latter part of the storage. The number of yeast fungi increased until storage day 7 for both the danmuji sample stored at $5^{\circ}C$ and that stored at $25^{\circ}C$. The cell number of danmuji did not change since then while the cell number of the danmuji filtrate constantly increased. As for the sensory properties of each stored danmuji, the overall taste preference was highest at storage days 14 and 21 ($5^{\circ}C$), and the overall scent preference was high for the danmuji that had been stored for 7 days ($5^{\circ}C$), but there was no significant difference. The texture and color of and the overall preference for the danmuji stored at $25^{\circ}C$ significantly decreased as the storage period got longer. All in all, the preference for the danmuji stored at $5^{\circ}C$ was higher than that for the danmuji stored at $25^{\circ}C$, although there was no significant difference. Thus, it is thought that $5^{\circ}C$ is more appropriate than $25^{\circ}C$ as the storage temperature of danmuji products.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.4
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• pp.63-68
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• 2010

The Color Management System in recent printers adopts ICC profiles for both monitors and printers. However, the ICC profile doesn't contain the characteristics of reproduced color on each monitor, because the color on each monitor is changed by user adjustment such as color temperature, brightness, and contrast adjustment. It is also depended on the backlight type and lifetime. As a result, unwanted color is reproduced on the printed paper, not like that on the monitor. To overcome the color difference between monitors and printers, it is needed to control the information of ICC profile. That is, first, the ICC profile is generated by the measurement of monitors having user set, then, through the CMS, the color on monitors can be produced on printed paper. However, it is difficult to apply the above system for normal users due to absence of measuring equipment and time consuming process. Therefore, this paper proposes a novel color matching technique based on the estimation of condition for each monitor having user set. The estimation is performed by a simple comparison visual test using a test image on printed paper and monitor. Then, the condition of monitor is applied to the ICC profile. As a result, the new ICC profile contains the color difference between user monitor and printer. The experimental results show the printed images using our proposed method have almost similar color with those on monitors.

• Journal of the Korean earth science society
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• v.37 no.7
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• pp.389-397
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• 2016

In order to investigate the light curve difference in visual and infrared wavelength of ${\delta}$ Scuti variable Bo Lyn, observations were performed using BOAO 1.8m reflecting telescope and an infrared detector, KASINICS, with J, H, and Ks filters. Infrared light curves of total 7 nights were obtained between March and April in 2011, and those were compared to the V-filter light curve to examine the differences in period, time of maximum light, amplitude, and shape. From the periodic analysis of infrared light curve, a single frequency of $f_1=10.712cycle/day$, $P=0.09335{\pm}0.00002days$ was obtained, and there was no difference in the period along different wavelengths. In the infrared light curve, a frequency of $2f_1$ was detected. This frequency well explains the asymmetric shape of light curve, one of the characteristics of high-amplitude ${\delta}$ Scuti variables. We compared the locations of the measured infrared maxima and the predicted maxima of V-filter, finding that the times of maxima were delayed about 0.3 phase at infrared wavelengths. Amplitude ratios were adopted to be ${\Delta}J/{\Delta}V=0.328$, ${\Delta}H/{\Delta}V=0.216$, and ${\Delta}Ks/{\Delta}V=0.211$, with the range of variation being smaller at longer wavelengths. It seems that the differences in the times of maxima and amplitude occurred because the changes in brightness of a pulsating variable star are mainly caused by the change in temperature.

• Journal of Bio-Environment Control
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• v.29 no.2
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• pp.153-160
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• 2020

This study was conducted out to investigate the effect of harvest time of the day, precooling or not, and temperature of precooling and storage on the marketability in strawberries 'Maehyang' for export in May. Strawberry colored with 60±5% of the skin was harvested at 07:00 am or 15:00 pm, respectively. After harvesting, some strawberries were precooled to 0, 2, 4℃ for 3 hours in the cold store, respectively, and the others were kept at room temperature. And then, strawberries were stored at low temperature in the cold store set at 4, 8 or 10℃ storage temperatures. The weight loss rate, firmness, soluble solids content, color, incidence of gray mold of strawberries were measured at two days intervals during storage for 14 days. Both 07:00 am and 15:00 pm harvest, fruits as the storage periods lapses increased weight loss rate compared to the weight at harvest time of the day, and the difference in the weight loss rate of fruits depending on the treatment was greater at 15:00 pm harvest than at 07:00 am. Firmness tended to increase again after 8th day at 07:00 am or 15:00 pm harvest, respectively. In the afternoon harvest, 10℃ storage without precooling showed the lowest fruit firmness on the 2nd day after storage. The soluble solids content at 07:00 am or 15:00 pm harvest tended to be maintained at high value with precooled and stored at low temperature as storage days elapse. The color values were significantly higher at 'L' indicating brightness and lower at 'a', indicating redness at low storage temperature regardless of harvesting time of the day and whether it was precooling or not. The incidence of gray mold was higher at 15:00 pm harvest than at 07:00 am harvest, and it was significantly higher in the treatments stored at 10℃ after precooling similarly. In this study, strawberry 'Maehyang' for export harvested at 07:00 am and stored at 4℃ after precooling at 0℃ maintained the best shelf life, therefore, it is judged that desirable to harvest in the morning with low temperature and to precool and store at low temperature.

• Journal of the Korean earth science society
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• v.37 no.7
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• pp.434-447
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• 2016

This study analyzed mass concentrations of PM10 and PM2.5, as measured at Tae-ahn and Gang-nae, Cheongju in central Korea over the period from 2011 to 2015. Higher mass concentrations of PM10, with the exception of dustfall cases during the period of winter and spring, reflected the influence of a prevailing westerly airflow, while the level of PM10 stayed at a low level in summer, reflecting the influence of North Pacific air mass and frequent rainfall. Accordingly, cases where a daily PM10 average of $81{\mu}gm^{-3}$ or over (exceeding the status of fine dust particles being 'a little bit bad') were often observed during the period of winter and spring, with more cases occurring in parts of Tae-ahn that are located close to the sources of pollutant emission in eastern China. Dustfall usually originated from dust storms made up of particles $2.5{\mu}m$ or over in diameter. However, anthropogenic haze displayed a high composition ratio of particulate less than $2.5{\mu}m$ in diameter. Accordingly, brightness temperature difference (BTD) values from the Communication, Ocean and Meteorological Satellite (COMS) were $-0.5^{\circ}K$ or over in haze with fine particulate. PM10 mass concentrations and NOAA 19 satellite BTD for haze cases were analyzed. Though PM10 mass concentrations were found to be lower than $200{\mu}g\;m^{-3}$, the mass concentration ratio of PM2.5/PM10 was measured as higher than 0.4 and BTD was found to be distributed in the range from -0.3 to $0.5^{\circ}K$. However, the BTD of dustfall cases exceeding $190{\mu}g\;m^{-3}$, were found to be less than 0.4 and BTD was found to be distributed in the range less than $-0.7^{\circ}K$. The result of applying BTD threshold values of the large-scale transport of haze proved to fall into line with the range over which aerosols of MODIS AOD and OMI AI were distributed.

• Journal of the Korean earth science society
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• v.26 no.3
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• pp.283-296
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• 2005

The effect of ozone and surface temperature on the ozone band at $9.7{\mu}m$ has been investigated from radiative transfer theory together with observations in order to derive empirical methods for remotely sensing ground-ozone concentration. Simultaneous observations of satellite (MODIS Aqua; ECT 13:30) and ground-ozone at 79 stations have been used over the Seoul Metropolitan Area (SMA; 125.7-127.2 E, 37.2-37.7 N) during four ozone-warning days in the year 2003. Cloud effect on the band in the methods was filtered out based on synoptic observations. Upwelling radiance values at $9.6{\mu}m$ which have been estimated at the given ozone concentration of 327-391 DU depend on surface temperature (Ts) showing $5.52\~5.78Wm^{-2}sr^{-1}\;at\;Ts = 290 K,\;and\;9.00\~9.57Wm^{-2}sr^{-1}$ Ts = 325K. Thus, the partitioned contributions of ozone and temperature to intensity of ozone absorption band are $0.26Wm^{-1}sr^{-1}/64\;DU\;and\;0.31 Wm^{-2}sr^{-1}/35K$, respectively. Here the intensity which has been used to remotely detect ground-ozone concentration from infrared satellite measurement is defined as the difference in brightness temperature between $11{\mu} m\;and\;9.7{\mu}m (i.e.,\; T_{11-9.7})$. The methods in this study have been applied to estimate ground-ozone from MODIS data in cases that there are significant correlations between the band intensity and ground-ozone. The values of estimated ozone significantly correlate (0.49-0.63) with ground observations at a significance level of $1\%$. For the improved methods, further study may be required to use tropospheric ozone rather than ground-ozone, considering the variation stratospheric ozone.

• Food Science and Preservation
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• v.19 no.4
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• pp.510-518
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• 2012

In this research, to modernize traditional food and to make functional bokryung-byung, bokryung-byungwas made with Poriacocos Wolf powder added. During its storage, its moisture content ranged from 42.89 to 44.85%. The control group had the highes tmoisture content (44.85%), and it was reduced significantly as the Poriacocos Wolf powder in creased. The longer the storage period was, the lower the pH and the higher the acidity was. The total bacterial count increased from 2.70 to 3.00 Log CFU/g right after the manufacture and increased rapidly on the fourth day of the storage with more than 7.00 Log CFU/g. There was no difference between the control group and the bokryung-byung, though. The Hunter's color value after the manufacture, with the increase in the added Poriacocos Wolf powder, showed a significantly reduced brightness, but significantly increased redness and yellowness. Their chromaticity did not change, how ever, during their storageat a temperature of $20^{\circ}C$. The hardness, solidity, gumminess, and cohesiveness of the bokryung-byung increased, unlike in the control group, and its brittleness increased. In terms of the overall preference, the preference for the control group was high, but was higher when 5 % Poria cocos Wolf powder was added during the manufacture of the bokryung-byung. As a result of these correlations, it is believed that elastic and chewy dduks are preferred and bokryung-byungs could be developed as functional dduks.

• Journal of the Korean earth science society
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• v.43 no.2
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• pp.239-252
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• 2022

Quality control methods for the first G-band vapor radiometer (GVR) mounted on a weather aircraft in Korea were developed using the GVR Precipitable Water Vapor (PWV). The aircraft attitude information (degree of pitch and roll) was applied to quality control to select the shortest vertical path of the GVR beam. In addition, quality control was applied to remove a GVR PWV ≥20 mm. It was found that the difference between the warm load average power and sky load average power converged to near 0 when the GVR PWV increased to 20 mm or higher. This could be due to the high brightness temperature of the substratus and mesoclouds, which was confirmed by the Communication, Ocean and Meteorological Satellite (COMS) data (cloud type, cloud top height, and cloud amount), cloud combination probe (CCP), and precipitation imaging probe (PIP). The GVR PWV before and after the application of quality control on a cloudy day was quantitatively compared with that of a local data assimilation and prediction system (LDAPS). The Root Mean Square Difference (RMSD) decreased from 2.9 to 1.8 mm and the RMSD with Korea Local Analysis and Precipitation System (KLAPS) decreased from 5.4 to 4.3 mm, showing improved accuracy. In addition, the quality control effectiveness of GVR PWV suggested in this study was verified through comparison with the COMS PWV by using the GVR PWV applied with quality control and the dropsonde PWV.