• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.3
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• pp.200-207
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• 2003

'||'||'||'&'||'||'||'quot;Overheating index'||'||'||'&'||'||'||'quot;, the normalized difference in incident solar energy between a target surface and a level surface, is helpful in estimating the spatial variation in daily maximum temperature at the landscape scale. It can be computed as the ratio of the 4-hour cumulative solar irradiance surplus or deficit from that over a level surface to the maximum possible deviation (15 MJ $m^{-2}$ ) during the midafternoon. Ecosystem models may, for simplicity, use an empirical proxy (exposure index) variable combining slope and aspect in place of the overheating index to account for the variation of midafternoon solar irradiance. A comparative study with real-world landscape data was carried out to evaluate the performance of exposure index in replacing the overheating index. Overheating indices for summer solstice, fall equinox and winter solstice were calculated at 573,650 grid cells constituting the land surface of Donggye-Myun, Sunchang County in Korea, based on a 10-m DEM. Exposure index was also calculated for the same area and fitted for the variation of overheating index to derive a 2$^{nd}$ -order linear regression equation. The coefficient of determination ($R^2$) was 0.50 on summer solstice, 0.56 on fall equinox, and 0.44 on winter solstice, respectively. These are much lower than the theoretically calculated $R^2$ values ranging from 0.7 in summer to 0.9 in autumn. According to our study, exposure index failed to accurately predict the cumulative solar irradiance over a complex terrain, hindering its application to daily maximum temperature estimation. We suggest direct calculation of the overheating index in preference to using the exposure index.

• Korean Journal of Remote Sensing
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• v.34 no.3
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• pp.481-494
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• 2018

The accurate radiative transfer model simulation is essential for an accurate ozone profile retrieval using optimal estimation from backscattered ultraviolet (BUV) measurement. The input parameters of the radiative transfer model are the main factors that determine the model accuracy. In particular, meteorological parameters such as temperature and surface pressure have a direct effect on simulating radiation spectrum as a component for calculating ozone absorption cross section and Rayleigh scattering. Hence, a sensitivity of UV ozone profile retrievals to these parameters has been investigated using radiative transfer model. The surface pressure shows an average error within 100 hPa in the daily / monthly climatological data based on the numerical weather prediction model, and the calculated ozone retrieval error is less than 0.2 DU for each layer. On the other hand, the temperature shows an error of 1-7K depending on the observation station and altitude for the same daily / monthly climatological data, and the calculated ozone retrieval error is about 4 DU for each layer. These results can help to understand the obtained vertical ozone information from satellite. In addition, they are expected to be used effectively in selecting the meteorological input data and establishing the system design direction in the process of applying the algorithm to satellite operation.

• Journal of Bio-Environment Control
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• v.22 no.3
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• pp.270-278
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• 2013

The objective of the present study is to provide data needed to decide covering method to be able to increase the thermal insulation and light transmittance efficiency of commercial greenhouse. The thermal insulation effect, PPF transmittance and quantity of condensation water were estimated in experimental tomato greenhouses covered with three types of coverings of single layer, air inflated and conventional double layers covering. The overall heat flow of air inflated double layers greenhouse was similar to that of conventional double layers greenhouse, but the temperature between covering material and thermal screen in air inflated double layers greenhouse was lower than that in conventional double layers greenhouse at the same outside temperature condition due to air leakage through the gap of roof vent. The overall heat transfer coefficients acquired by experiment that was performed in single layer and conventional double layers greenhouses were close to those obtained from model experiment. Even though the PPF transmittance of air inflated double layers greenhouse was lower than that of single layer greenhouse, which was greater than that of conventional double layers greenhouse. The quantity of condensation water on covering surface of single layer greenhouse was greater than that of air inflated double layers greenhouse due to lower covering surface temperature.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.3
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• pp.209-215
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• 2007

To improve the accuracy of frost warning system for pear orchard in a complex terrain in Naju area, the daily minimum temperature forecasted by Korea Meteorological Administration (KMA) was interpolated using a regional climate model based on topoclimatic estimation and optimum scale interpolation from 2004 to 2005. Based on the validation experiments done for three pear orchards in the spring of 2004, the results showed a good agreement between the observed and predicted values, resulting in improved predictability compared to the forecast from Korea Meteorological Administration. The differences between the observed and the predicted temperatures were $-2.1{\sim}2.7^{\circ}C$ (on average $-0.4^{\circ}C$) in the valley, $-1.6{\sim}2.7^{\circ}C$ (on average $-0.4^{\circ}C$) in the riverside and $-1.1{\sim}3.5^{\circ}C$ (on average $0.6^{\circ}C$) in the hills. Notably, the errors have been reduced significantly for the valley and riverside areas that are more affected by the cold air drainage and more susceptible to frost damage than hills.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.1
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• pp.15-25
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• 2020

Biogas production potential was experimentally estimated for mono- and co-digestion of cow manure and waste grass. The two organic wastes were mixed at five different ratios (100:0, 75:25, 50:50, 25:75, 0:100) on the volatile solids basis, and were assessed using biochemical methane potential (BMP) test. Thee reaction temperatures, 25℃, 30℃ and 35℃, were applied as well, resulting in 15 different combinations for the test. The results showed that both higher temperature and waste grass mixing ratio resulted in higher methane yield and maximum methane production rate. Based on the experimental results, a theoretical farm- or community-scale (240 or 2400 ㎥) anaerobic digester was designed to evaluate the energy balance associated with mono- and co-digestion of the wastes at different temperatures. Although the energy production increased as the temperature and the waste grass mixing ratio increased, the net energy gain, energy production subtracted by energy consumption for heating and maintenance, was estimated to be the highest at 30℃, followed by at 35℃ and 25℃. Therefore, it is advised that both the experimental methane production and the detailed design parameters must be considered for the optimization of the net energy gain from these wastes.

• Journal of the Korea Concrete Institute
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• v.18 no.6 s.96
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• pp.759-767
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• 2006

This paper presents a method to estimate the setting time of concrete using super retarding agent(SRA) and fly ash(FA) under various curing temperature conditions by applying maturity based on equivalent age. To estimate setting time, the equivalent age using apparent activation energy($E_a$) was applied. Increasing SRA content and decreasing curing temperature leads to retard initial and final set markedly. $E_a$ at the initial set and final set obtained by Arrhenius function showed differences in response to mixture type. It is estimated to be from $24{\sim}35KJ/mol$ in all mixtures, which is smaller than that of conventional mixture ranging from $30{\sim}50KJ/mol$. Based on the application of $E_a$ to Freisleben-Hansen and Pederson's equivalent age function, equivalent age is nearly constant, regardless of curing temperature and SRA contents. This implies that the concept of maturity is applicable in estimating the setting time of concrete containing SRA. A high correlation between estimated setting time and measured setting time is observed. Multi-regression model to determine appropriate dosage of SRA reflecting FA contents and equivalent age was provided. Thus, the setting time estimation method studied herein can be applicable to the concrete containing SRA and FA in construction fields.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.6
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• pp.71-77
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• 2014

In this paper, we investigated the effects of high-energy electron beam irradiation (HEEBI) on the optical transmittance of InGaZnO (IGZO) films grown on transparent Corning glass substrates, with a radio frequency magnetron sputtering technique. The IGZO thin films deposited at low temperature were treated with HEEBI in air at room temperature (RT) with an electron beam energy of 0.8 MeV and doses of $1{\times}10^{14}-1{\times}10^{16}electrons/cm^2$. The optical transmittance of the IGZO films was measured using an ultraviolet visible near-infrared spectrophotometer (UVVIS). The detailed estimation process for separating the transmittance of HEEBI-treated IGZO films from the total transmittance of IGZO films on transparent substrates treated with HEEBI is given in this paper. Based on the experimental results, we concluded that HEEBI with an appropriate dose of $10^{14}electrons/cm^2$ causes a maximum increase in the transparency of IGZO thin films. We also concluded that HEEBI treatment with an appropriate dose shifted the optical band gap ($E_g$) toward the lower energy region from 3.38 to 3.31 eV. This $E_g$ shift suggested that HEEBI in air at RT with an appropriate dose acts like a thermal annealing treatment in vacuum at high temperature.

• Korean Journal of Environmental Biology
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• v.28 no.1
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• pp.30-39
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• 2010

We researched community structure, species composition, and habitat environment of Dendropanax morbifera populations distributed in Goheung, Haenam, Wando (I.), and Bogildo (I.) at south coast of the Korean Peninsula. Our research was also estimated possible area for growth of Dendropanax morbifera by analyzing meteorological factors of the habitat thereof. Dendropanax morbifera community divided into Castanopsis cuspidata var. sieboldii group and Carpinus laxiflora group by difference of species composition. Broad-leaved evergreens showed high dominance value in view of rNCD in Dendropanax morbifera community as follows: Camellia japonica (100.0), Quercus acuta (88.6), Castanopsis cuspidata var. sieboldii (55.8), Dendropanax morbifera Lev. (41.4), Trachelospermum asiaticum var. intermedium (23.8), Eurya japonica (19.9) and Ligustrum japonicum (11.5). In the population distribution, 94.2% of Carpinus laxiflora group consisted of sapling and small size class that are less than 5 cm in DBH while 54.2% of Castanopsis cuspidata var. sieboldii group did. The soil environment of habitat showed low soil acidity, good organic matter and water content, and good drainage. The distribution area of Dendropanax morifera habitat had $13^{\circ}C$ or more in annual mean temperature, $7.4^{\circ}C$ or more in daily minimum temperature, $100^{\circ}C$ month or more in warmth index, and approximately 1,344 mm in mean annual precipitation. Dendropanax morifera habitat corresponded to evergreen broad-leaved forest zone located in islands and coast in the southwest region of the Korean Peninsula. The northern limit line of Dendropanax morifera community was determined as Gunsan-Jeongeup-Gwangju-Jinju-Pohang-Youngdeok line based on $13^{\circ}C$ in annual mean temperature that was confirmed in natural habitat of Dendropanax morifera community.

• Magazine of the Korean Society of Agricultural Engineers
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• v.22 no.3
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• pp.37-45
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• 1980

This study was carried out to investigate the consumptive use of water for red peppers and soy beans. The correlation between the soil moisture contents and the selected meteorological factors during the growing season was analyzed. Characteristics of the drought at Jinju, Yeosu, Gwangju, and Mokpo area were figured out in view of frequency analysis. The results obtained from this study could be used as a reasonable criteria for the estimation of the duty of water in the design of upland irrigation systems. Obtained results are summarized as follows: 1. Red peppers were grown at the three levels of soil moisture contents; 75 percent, 50 percent, and 25 percent, respectively. The red pepper grown at the 75 percent of soil moisture content showed the highest yield. The total evapotranspiration during the growing season from red peppers was 471. lmm, which was 86.6mm less than the pan evaporation. 2. The soy bean grown at 75 percent soil moisture content showed the highest yield, although there was no signicant difference in yields among treatments. The total evapotranspiration during the growing season from the soy bean was 342.8 mm, which was 119.2mm less than the pan evaporation. 3. Coefficients of consumptive use(k) and meteorological data are shown on Table-9. 4. The significant correlations between the evapotranspiration and the humidity and daily temperature range were observed. Results are shown on Table-11.. Evaporanspiration can be easily estimated from the humidity and daily temperature range by using the equation...... (1) Ept=4.808-0.041H+0.207T.......(1) where, Ept; evapotranspiration(mm/day) H ; humidity(%) T ; daily temperature range ($^{\circ}C$) 5. The variations of soil moisture content during the growing season at the soil depth of 5cm, 15cm, and 45cm are shown on Fig. 4~9. The results of the correlation analysis between the evapotranspiration from the crops and the soil moisture content are shown on Table-12. The evapotranspiration can be estimated from soil moisture content at the different depth of the soil by using the equation....... (2). Ept = 3.433 - 0. 364M1 +0. 359M$_2$- 0. 055M$_3$....... (2) where, Ept; evapotranspiration (mm/day) M1 soil moisture meter reading at 5cm depth M$_2$; " 15cm " M$_2$; " 40cm " 6. The estimated probab]e successive dry days in selected areas are shown on Table 13. Gumbel-Chow method was used to calculate the probable successive dry days. Further investigation are required to obtain the more detailed and reliable results.

• Journal of Korea Water Resources Association
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• v.33 no.4
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• pp.471-482
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• 2000

Surface energy balance components were evaluated by Landsat TM data and GIS with meteorological data. Calibration and validation for the applicability of this methodology were made through the estimating of the large-scale evapotranspiration (ET). In addition, sensitivity and error analysis was conducted to see the effects of the surface energy balance components on ET and the accuracy of each components. Bochong-chon located on the upper part of Guem River basin was selected as the case study area. Spatial distribution map of ET were produced for five dates: Jan. 1, Apr. 3, May. 10, and Nov. 27, 1995. The study results showed tat ET was greatly varied with the aspect and theland use type on the surface. In the case of having northeast and southeast in the aspect, ET was linearly increased depending on growing net radiation. While surface temperature has a high value, NDVI(Normalized Difference Vegetation Index) has a low value in the vegetated area. Therefore, ground heat flux was increased but ET was relatively decreased. The results of sensitivity and error analysis showed that net radiation is most sensitive and effective, ranging from 12.5% to 23.6% of sensitivity. Furthermore, the surface temperature, air temperature, and wind speed have the significant effects on ET estimation using remotely sensed data.