• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.4
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• pp.368-375
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• 2023

In this study, we examined the error characteristic and bias correction method for one-month temperature forecast data produced through joint development between the Rural Development Administration and the H ong Kong University of Science and Technology. For this purpose, hindcast data from 2013 to 2021, weather observation data, and various environmental information were collected and error characteristics under various environmental conditions were analyzed. In the case of maximum and minimum temperatures, the higher the elevation and latitude, the larger the forecast error. On average, the RMSE of the forecast data corrected by the linear regression model and the XGBoost decreased by 0.203, 0.438 (maximum temperature) and 0.069, 0.390 (minimum temperature), respectively, compared to the uncorrected forecast data. Overall, XGBoost showed better error improvement than the linear regression model. Through this study, it was found that errors in prediction data are affected by topographical conditions, and that machine learning methods such as XGBoost can effectively improve errors by considering various environmental factors.

• Land and Housing Review
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• v.2 no.3
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• pp.269-276
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• 2011

Recently, the chance of dew condensation in apartment buildings is increasing because of several reasons. For example, ventilation rate has been decreased because of high-insulations and airtightness for saving energy. Besides, the humidity has been made by drying washes, cooking and bathing inside of apartment buildings. However, there is lack of resonable design criteria for preventing condensation in real life and real surroundings. Therefore, this study is aimed at making a resonable design criteria of preventing condensation by measuring the indoor temperature and humidity in real life. In addition to this, it is aimed at making a resonable outdoor condition and classifying regions by using weather data. The following are the results. The interior criterion for condensation was set up $25^{\circ}C$ and a relative humidity of 55%. The outdoor criterion for condensation was set up $20^{\circ}C$, $-15^{\circ}C$, and $10^{\circ}C$ respectively for the hard frost, middle, and southern areas.

• Journal of Korea Water Resources Association
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• v.39 no.4 s.165
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• pp.363-372
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• 2006

Many methods have been used to estimate evapotranspiration. However, there is little information about the evapotranspiration from river basins with complicated topographies and variable land use. Remote sensing technique is a probable means to estimate distribution of the evapotranspiration in connection with regional characteristics of vegetation and landuse. The evapotranspiration not only depends on meteorological circumstances but also on the condition of the vegetation. The latter effect can be expressed in terms of NDVI(Normalized Difference Vegetation Index) obtained by NOAA/AVHRR datasets. In this paper, a simple method to estimate evapotranspiration of the Keum river basin is proposed based on NDVI and temperature data.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.2
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• pp.105-113
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• 2001

This study was conducted to reveal the effects of local climatic conditions on the vegetative growth in a mature stand of Korean white pine based on climatic estimates. For this, the annual increments of stand variables such as DBH, height, basal area and volume were measured and estimated for seven years from 1974 to 1980. The local climatic conditions in the study site were also estimated by both a topoclimatological method and a spatial statistical technique. The local climatic conditions were then correlated with and regressed on the growth factors to reveal the relationships between the climatic estimates and the growth. It is found that relatively high temperatures had positive effects on the diameter growth. The yearly diameter growth increased when each of mean, maximum, and minimum temperature during the growing season was high. Height growth showed positively significant correlation with three climatic variables. The most important variable influencing height growth was the average of maximum temperature for 10 months from January to October. It means that the higher the average of maximum temperature for 10 months from January to October is, the more height growth of Korean white pine increases. Other climatic variables related to height growth were average of minimum temperature for 3 months in the early growing season and mean relative humidity for the growing season. Six climatic variables related to temperature had effects on basal area increment and all of them were positively correlated with basal area increment. Especially, temperatures from January to March were important factors affecting the basal area increment. In volume increment, high correlation was also recognized with most of temperature variables. This tendency was the same as the results in diameter and hight increments. This means that the volume growth increases when temperatures during the growing season are relatively high.

• Journal of Bio-Environment Control
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• v.6 no.1
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• pp.34-42
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• 1997

Effects of DIF on stem elongation in plug seedlings of mini tomato ‘Mini Carol’ and on the growth and flowering after transplanting were investigated. Stem elongation of seedlings was mainly influenced by day temperature rather than night temperature. When the effect of ＋DIF was compared to that of -DIF under the same average daily temperature(ADT), day temperature had greater impact on internode elongation than night temperature. On the other hand, leaf unfolding rate increased and compactness decreased as ADT in creased. Differences in internode length affected by DIF during seedlings stage DIF progressively diminished during growth period after transplanting. Node position at which first flower was initiated was lowered as ADT decreased. It was concluded that DIF treatment was an applicable tool for control of stem elongation, particularly to reduce stem length without a noticeably adverse effect on the growth and development of plant after transplanting.

• Journal of the Korean Geographical Society
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• v.36 no.3
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• pp.247-257
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• 2001

The relationships between the distribution of 132 species, 61 genera evergreen broad-leaved trees and shrubs(EBTS) and climatic factors have discussed. The distributional patterns of EBTS were categorized into seven groups on the basis of the number of distributing sites, distributional attitudes and latitudes. Out of seven group. the cold-tolerant EBTS were common at groups I and II, along tilth Empetrum nigrum var. japonicum. Diapensia lapponics subsp. obovata of group III. However, the warmth-tolerant EBTS were rich at groups III. IV V, and VI The lower distributional limits of cold-tolerant EBTS in the groups I and UU decreased as one moves toward south. The upper distributional limit of warmth-tolerant EBTS in the groups III, IV and V decreased with increasing latitude. However. no clear distributional tendency is noticed in the groups VI and VII. The range of warmth-tolerant EBTS appear to show close relationship with the January mean temperature -4 $\^{C}$ and January mean minimum temperature -9$\^{C}$ than others. On the other hand, that of the cold-tolerant EBTS seem to respond well to the August mean temperature 19$\^{C}$ and August mean maximum temperature 26$\^{C}$ than others.

• Journal of Bio-Environment Control
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• v.22 no.1
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• pp.13-18
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• 2013

This study was conducted to examine the effect of temperature and relative humidity (RH) that might affect the pollen germination rate and pollen tube length in oriental melon. The experiment was performed using three cultivars namely 'Mallijangseong', 'Ohbokggul', and 'Joeundae' wherein environmental conditions were controlled by three different temperatures $15^{\circ}C$, $25^{\circ}C$, and $35^{\circ}C$ and also three RH levels 30%, 60%, and 90%. Based on the results in terms of temperature, true to all cultivars, plants exposed to $25^{\circ}C$ had the highest pollen germination rate while plants exposed to $15^{\circ}C$ had the lowest. Among the three cultivars, 'Mallijangseong' had the highest in terms of pollen germination rate, followed by 'Ohbokggul', and lastly was 'Joeundae' that showed the lowest germination rate. In the case of pollen tube length, pollen exposed under $35^{\circ}C$ showed the longest tube length, followed by pollen under $25^{\circ}C$, and pollen under $15^{\circ}C$ remarkably had the shortest tube length. Across the three cultivars 'Ohbokggul' had the longest pollen tube length. In the case of RH, pollen germination response among three cultivars depends on the humidity conditions but based on the results, there was no significant differences although high germination rate was observed in highest humidity condition. Between each cultivar, 'Ohbokggul' had the lowest pollen germination rate compared with 'Mallijangseong' and 'Joeundae' after exposure to different RH conditions wherein pollen germination showed significant differences among treatments. The pollen collected under 60% RH had the longest pollen tube length, followed by 30%, and the shortest was under 90% RH. In general, 'Ohbokggul' had the longest pollen tube length while 'Joeundae' had the shortest among the three cultivars.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.3
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• pp.189-197
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• 2022

This study investigated the antioxidant and yield properties of eight adzuki bean (Vigna angularis L.) cultivars grown under different mean temperatures and sunshine hours in 2020 and 2021. Compared to 2021, which had a normal mean temperature, 2020 showed a lower mean temperature during the pod-extension and grain-filling periods. In addition, due to frequent rainfall during the vegetative period in 2020, there were fewer hours of sunshine in 2020 than in 2021. The adzuki bean yield was approximately 13% lower in 2020 than in 2021 due to the decreased number of pods per plant and 100-seeds weight. 'Hongda' and 'Hongjin' cultivars showed more stable yields than the 'Arari' variety, which is the most commonly cultivated variety in Korea. Moreover, the 'Hongda' and 'Hongjin' cultivars had higher yields than the 'Arari' variety in both years. Compared to 2021, in 2020, when the weather conditions were unfavorable, both antioxidant levels and activity were higher. 'Hongda' had higher antioxidant levels and activity than the other cultivars over the 2 years. These results suggest that the antioxidant levels and activity were good in 2020, with an approximately 13% decrease in yield compared to 2021, which was a normal year with respect to mean temperature and sunshine hours.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.3
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• pp.182-191
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• 2020

A field test and a phytotron study were performed over two years to examine whether rice varieties originated from higher altitude areas have lower optimum grain filling temperatures for yield improvement than the varieties from South Korea. Three varieties originated from North Korea and three varieties from northern China were compared to the same number of varieties from South Korea. In a field study, the optimum grain filling temperatures over 40 days after heading were 22.6 - 23.0℃, 21.5 - 22.3℃, and 21.5 - 23.6℃ for the varieties from North Korea, northern China, and South Korea, respectively, resulting in no significant difference among varietal groups. Meanwhile, the heading dates of the early maturing varieties from North Korea and China were 7 - 12 days earlier than that of the early maturing Odae variety from South Korea during the first transplant of 2017. The phytotron study, in which different temperature regimes were imposed from flowering/fertilization to harvest with constant daily mean temperatures, revealed that milled rice weight did not decrease under low temperatures, even at 16℃, compared to that at 22℃. At the fourth transplant in the field study, mean temperature lower than 10℃ appeared before rice grains were fully developed, resulting in yield reductions. It was concluded that rice varieties adaptable to high-altitude areas do not have lower optimum grain filling temperatures but, instead, possess shorter growth durations. It was further suggested that the optimum grain filling temperature of rice observed under natural conditions could be attributed to the lowering temperature at the late filling stage under temperate climatic conditions.

• Journal of the Korean Wood Science and Technology
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• v.38 no.4
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• pp.349-358
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• 2010

This study was carried out to investigate the optimum condition for sap exudation of Acer mono Max. tree in a site of Mt. Jiri, Hamyang-gun, Korea. Amount of sap exudation, air temperature, relative air humidity, tree diameter at breast height (DBH) and sugar content in sap were monitored during the early springtime, and correlation analysis of several factors was carried out to explain tree-to-tree and date-to-date variations in sap exudation. The correlation, linearlyassociated between DBH and sap amount, was strengthened as daily amount of sap increased, but there was no significant tree-to-tree variation in time and period for sap exudation. When amount of sap exudation was above 10 liter/day, the mean air-temperature was averaged at $1.2{\pm}1.6^{\circ}C$, the minimum at $-4.3{\pm}1.5^{\circ}C$ and the maximum at $11.8{\pm}1.9^{\circ}C$. The maximum air temperature and mean air temperature were significant (p < 0.05) factors for amount of sap in correlation analysis to explain date-to-date variation in sap exudation. Sucrose content in sap was in the range of 1.5 and 1.7% during exudation days, but sharply reduced to 0.6% level at the end of exudation period.