• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2010년도 학술발표회
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• pp.1596-1599
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• 2010

Group method of data handling neural networks model (GMDH-NNM) is used to estimate daily pan evaporation (PE) using limited climatic variables such as max temperature ($T_{max}$), min temperature ($T_{min}$), mean wind speed ($W_{mean}$), mean relative humidity ($RH_{mean}$) and sunshine duration (SD). And, for the performances of GMDH-NNM, it is composed of training and test performances, respectively. The training and test performances are carried out using daily time series data, respectively. From this research, we evaluate the impact of GMDH-NNM for the modeling of the nonlinear time series data. We should, thus, construct the credible data of the daily PE data using GMDH-NNM, and can suggest the methodology for the irrigation and drainage networks system. Furthermore, this research represents that the strong nonlinear relationship such as pan evaporation modeling can be generalized using GMDH-NNM.

• 한국작물학회지
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• 제48권5호
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• pp.397-401
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• 2003

This experiment was conducted to know the characteristics of kernel growth as affected by various temperature regimes during grain filling using the varieties Hwaseongbyeo, Ilpumbyeo and Chucheongbyeo. The rice plants tested were grown in the natural condition at 1/5000a Wagner pots until flowering. After flowering, the rice plants were moved to controlled temperature conditions in a phytotron. The minimum/maximum daily temperature in the phytotron was controlled by 12/18, 15/21, 18/24, 21/27, and 24/$30^{\circ}C$, respectively. The grain weights were measured every three days after treatment. The mean daily kernel growth rate during active grain filling period showed different responses among varieties under various temperature regimes. The kernel growth rate of Chucheongbyeo was seriously reduced as temperature regimes were decreased. However, that of Ilpumbyeo was not influenced so critically. Ilpumbyeo showed some advantages in grain filling under low temperature regimes compared to Chucheongbyeo. The lag phase in grain filling of Chucheongbyeo was the longest among tested varieties, followed by Hwaseongbyeo under daily mean temperature regime of $15^{\circ}C$. Kernel weight of Ilpumbyeo increased fast in early grain filling phase under low temperature. This characteristic may be favorable for grain filling in temperate zone where the daily mean temperature is drastically dropped during grain filling period. Regression analysis with kernel growth rate and temperature showed the estimated critical low temperature for grain filling among varieties were $9^{\circ}C$, $12^{\circ}C$, $13^{\circ}C$ in Ilpumbyeo, Hwaseongbyeo and Chucheongbyeo, respectively. Under moderate temperature the duration of grain filling of Ilpumbyeo was longer than that of Chucheongbyeo. However, Under low temperature that of Ilpumbyeo was more favorable than Chucheongbyeo.

• Journal of Ecology and Environment
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• 제33권1호
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• pp.37-45
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• 2010

I conducted extensive analyses of daily weather data of precipitation and temperature monitored from the Surface Synoptic Meteorological Station in Seoul from 1 October 1907 to 31 December 2009 to understand how the climate is changing and the ecological implications for Seoul, Korea. Statistical analyses of the data, including the lengths of seasons and growing degree-days (GDD), showed a clear warming trend in the Seoul area over the study period. The mean daily temperature in Seoul increased by $2.40^{\circ}C$ over the period of one hundred years, which was about three times faster than the global trend and it was striking to notice that mean daily temperature in Seoul in recent 30 years was increasing with the rate of $5.50^{\circ}C$ per hundred years, which is an extremely fast rate of increase in temperature. In the last 100 years, an increase in the number of summer days was apparent, coupled with a reduction in the average number of winter days for about 27 to 28 days based on the analysis of mean daily temperature. Although the lengths of spring and autumn have not changed significantly over the century, early initiations of spring and late onsets of autumn were quite apparent. Total annual precipitation significantly increased at the rate of 2.67 mm/year over the last 100 years, a trend not apparent if the analysis is confined to periods of 30 to 40 years. The information has the potential to be used not only for better understanding of ecological processes and hydrology in the area, but also for the sustainable management of ecosystems and environment in the region.

• 한국환경보건학회지
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• 제38권3호
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• pp.184-194
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• 2012

Objectives: We investigated the effects of air pollution on allergic diseases (allergic rhinitis, asthma, atopic dermatitis) in metropolitan cities in Korea, adjusting for meteorological factors. Methods: Data on daily hospital visits and hospital admissions for 2003-2010 was obtained from the National Health Insurance Cooperation. Meteorological data was obtained from the Korea Meteorological Administration. We then calculated daily mean temperature, daily mean humidity, daily mean air pressure at sea level, and diurnal temperature range. We used data on air pollution provided by the National Institute of Environmental Research. Maximum daily eight-hour average ozone concentrations and the daily mean $PM_{10}$ were used. We estimated excess risk and 95% confidence interval for the increasing interquatile range (IQR) of each air pollutant using Generalized Additive Models (GAM) that appropriate for time series analysis. Results: In this study, we observed an association between ozone and hospital visits for allergic rhinitis, asthma, and atopic dermatitis in all metropolitan cities, adjusting for temperature, humidity, air pressure at sea level, diurnal temperature range, and day of the week. Ozone was associated with hospital visits for allergic rhinitis, asthma, and atopic dermatitis across all metropolitan cities. However $PM_{10}$ was associated with allergic-related diseases in only select cities. Also, ozone and $PM_{10}$ were associated with hospital admission for asthma in all cities except Gwangju. Hospitalization for the other diseases failed to show consistent association with air pollutants. Conclusion: In the findings of this study, there was a significant association between air pollutants and allergic-related diseases. More detailed research subdivided age group or conducting meta-analyses combining data of all cities is required.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2006년도 학술발표회 논문집
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• pp.1497-1500
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• 2006

The cooling effect of paddy fields was compared with those of other land-use areas (upland, urban park, and urban residential area) during midsummer. The temperature were monitored using data logger at one hour intervals in study sites. Diurnal temperature range of study areas in clear days was larger than in cloudy days. Also, diurnal temperature ranges in paddy field, upland, and park areas were larger than those in the urban residential area during clear days. The paddy field or upland area has shown more remarkable cooling effect compared to urban residential areas: Mean duration of temperature below $25^{\circ}C$ in the paddy field area is longer(7 to 8 hours) than in the residential area; The time to fall to below $25^{\circ}C$ in the paddy field area is sooner than in the residential area; Mean daily minimum temperature in the paddy field area is much lower than in the residential area.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2010년도 학술발표회
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• pp.1439-1442
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• 2010

Time-lag recurrent neural networks model (Time-Lag RNNM) is used to estimate daily pan evaporation (PE) using limited climatic variables such as max temperature ($T_{max}$), min temperature ($T_{min}$), mean wind speed ($W_{mean}$) and mean relative humidity ($RH_{mean}$). And, for the performances of Time-Lag RNNM, it is composed of training and test performances, respectively. The training and test performances are carried out using daily time series data, respectively. From this research, we evaluate the impact of Time-Lag RNNM for the modeling of the nonlinear time series data. We should, thus, construct the credible data of the daily PE using Time-Lag RNNM, and can suggest the methodology for the irrigation and drainage networks system. Furthermore, this research represents that the strong nonlinear relationship such as pan evaporation modeling can be generalized using Time-Lag RNNM.

• 한국작물학회지
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• 제52권1호
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• pp.112-121
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• 2007

Grain filling is a crucial factor that determines grain yield in crops since it is the final process directly associated with crops' yield performance. Grain filling process can be characterized by the interaction of rate and duration of grain filling. This study was conducted, using 16 temperate japonica rice genotypes, with aims to (1) seek variations in grain filling duration and rate on area basis, (2) compare the contribution of grain filling duration and rate to grain yield, and (3) examine the influence of temperature and solar radiation for effective grain filling on grain yield in relation to grain filling duration and rate. Grain filling rate and duration exhibited highly significant variations in the ranges of $20.7{\sim}46.3\;g\;m^{-2}d^{-1}\;and\;11.2{\sim}35.5$ days, respectively, depending on rice genotypes. Grain yield on unit area basis was associated positively with grain filling duration but negatively with grain filling rate. Grain filling rate and duration were negatively correlated with each other. Final grain weight increased linearly with the rise in both cumulative mean temperature and cumulative solar radiation for effective grain filling. Higher cumulative mean temperature and cumulative solar radiation for effective grain filling were the results of longer grain filling duration, but not necessarily higher daily mean temperature and daily solar radiation for effective grain filling. Grain filling rate demonstrated an increasing tendency with the rise in daily mean temperature for effective grain filling but their relationship was not obviously clear. It was concluded that grain filling duration, which influenced cumulative mean temperature and cumulative solar radiation for effective grain filling, was the main factor that determined grain yield on unit area basis in temperate Japonica rice.

• 한국토양비료학회지
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• 제26권4호
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• pp.289-293
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• 1993

수학적(數學的) 방법(方法)을 이용하여 일평균토심(日平均土深)10cm온도(溫度) 추정(推定)을 검토(檢討)하기 위하여 수원기상태(水原氣象台)에서 조사(調査)된 토양온도(土壤溫度)(1982~1988) 자료를 이용하여 다음과 같은 결과(結果)를 얻었다. 1. 월평균토심(月平均土深)10cm온도(溫度)는 1월에 최저온도(最低溫度) 8월에 최고온도(最高溫度)를 나타내었으며, 1500GMT에서 가장 큰 폭(幅)을 지닌 년변이(年變異)를 보였으며 그리고 0900GMT에서 저온(低溫) 1500GMT에서 고온(高溫)을 나타내었음. 2. 토심(土深)10cm온도(溫度)의 하강(下降) 및 상승(上昇)은 연변이(年變異)를 나타내었으며, 토심(土深)10cm온도(溫度)는 큰 변이성(變異性)을 나타내었음. 3. 수원지방(水原地方)의 순평균토심(旬平均土深)10cm온도(溫度)에 대한 날짜수(數)(D)의 회귀식(回歸式)은 다음과 같다. ($r=0.997^{**}$) Y= 13.05-6.58sin($2{\pi}D$.365) -12.45cos($2{\pi}D$/365) 4. 수원지방(水原地方)의 순평균토심(旬平均土深)10cm온도(溫度)의 실측치(實測値)에 대한 추정식(推定植)의 회귀식(回歸式)은 다음과 같다($r=0.994^{**}$, 표준오차(標準誤差)=$0.75^{\circ}C$) Y=-0.188+0.984X 5. 일평균토심(日平均土深)10cm온도(溫度) 추정치(推定値)의 75%는 실측치(實測値)와 ${\pm}20^{\circ}C$ 오차(誤差)가 있었음 6. 1~5월 까지의 추정치(推定値)는 실측치(實測値)보다 높았으며, 6~12월 까지의 추정치(推定値)는 실측치(實測値)보다 낮았음.

• 한국농공학회논문집
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• 제49권1호
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• pp.79-88
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• 2007

We investigated the characteristics of temperature variations under different land covers (paddy field, upland, urban park, and urban residential area) during hot summer (July 15 to August 19, 2005). The temperatures were monitored using data loggers at one hour intervals in study sites. The mean temperature generally increased with the distance from edge of paddy fields, being $1.5^{\circ}C$ higher at a site 170-m far from paddy fields than at a paddy field area at 22 h. The mean daily temperatures in the study period followed the ordo. of paddy field $(26.6^{\circ}C)$ < upland $(27.0^{\circ}C)$ < park $(27.5^{\circ}C)$ < residential area $(28.0^{\circ}C)$. The paddy field area has shown remarkable cooling effects compared to the residential area: Mean duration of temperature below $25^{\circ}C$ in the paddy field area was longer (8.6 hrs) than in the residential area; The time to fall to below $25^{\circ}C$ in the paddy field area was sooner (22.4 hr) than in the residential area; Mean daily minimum temperature in the paddy field area was much lower $(2.4^{\circ}C)$ than in the residential area. More research is needed to better clarify the mechanism of cooling effect of a paddy field area by investigating heat balance of a paddy field.

• 대기
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• 제33권5호
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• pp.477-492
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• 2023

Based on the new climate normals (1991~2020), annual mean, maximum and minimum temperature is 12.5℃, 18.2℃, and 7.7℃, respectively while annual precipitation is 1,331.7 mm, the annual mean wind speed is 2.0 m s^-1, and the relative humidity is 67.8% in the Republic of Korea. Compared to 1981~2010 normal, annual mean temperature increased by 0.2℃, maximum and minimum temperatures increased by 0.3℃, while the amount of precipitation (0.7%) and relative humidity (1.1%) decreased. There was no distinct change in annual mean wind speed. The spatial range of the annual mean temperature in the new normals is large from 7.1 to 16.9℃. Annual precipitation showed a high regional variability, ranging from 787.3 to 2,030.0 mm. The annual mean relative humidity decreased at most weather stations due to the rise in temperature, and the annual mean wind speed did not show any distinct difference between the new and old normals. With the addition of a warmer decade (2011~2020), temperatures all increased consistently and in particular, the increase in the maximum temperature, which had not significantly changed in previous decades, was evident. The increasing trend of annual and summer precipitation by the 2010s has disappeared in the new normals. Among extreme climate indices, MxT30 (Daily maximum temperature ≥ 33℃ days), MnT25 (Daily minimum temperature ≥ 25℃ days), and PH30 (1 hour maximum precipitation ≥ 30 mm days) increased while MnT-10 (Daily minimum temperature < -10℃ days) and W13.9 (Daily maximum wind speed ≥ 13.9 m/s days) decreased at a statistically significant level. It is thought that a detailed study on the different trends of climate elements and extreme climate indices by region should be conducted in the future.