• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.1
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• pp.173-185
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• 2015

This study aims to investigate the characteristics and types of car accidents and establish a prediction model by analyzing 456 car accidents having occurred in the 11 tunnels in Busan, through statistical analysis techniques. The results of this study can be summarized as below. As a result of analyzing the characteristics of car accidents, it was found that 64.9% of all the car accidents took place in the tunnels between 08:00 and 18:00, which was higher than 45.8 to 46.1% of the car accidents in common roads. As a result of analyzing the types of car accidents, the car-to-car accident type was the majority, and the sole-car accident type in the tunnels was relatively high, compared to that in common roads. Besides, people at the age between 21 and 40 were most involved in car accidents, and in the vehicle type of the first party to car accidents, trucks showed a high proportion, and in the cloud cover, rainy days or cloudy days showed a high proportion unlike clear days. As a result of analyzing the principal components of car accident influence factors, it was found that the first principal components were road, tunnel structure and traffic flow-related factors, the second principal components lighting facility and road structure-related factors, the third principal factors stand-by and lighting facility-related factors, the fourth principal components human and time series-related factors, the fifth principal components human-related factors, the sixth principal components vehicle and traffic flow-related factors, and the seventh principal components meteorological factors. As a result of classifying car accident spots, there were 5 optimized groups classified, and as a result of analyzing each group based on Quantification Theory Type I, it was found that the first group showed low explanation power for the prediction model, while the fourth group showed a middle explanation power and the second, third and fifth groups showed high explanation power for the prediction model. Out of all the items(principal components) over 0.2(a weak correlation) in the partial correlation coefficient absolute value of the prediction model, this study analyzed variables including road environment variables. As a result, main examination items were summarized as proper traffic flow processing, cross-section composition(the width of a road), tunnel structure(the length of a tunnel), the lineal of a road, ventilation facilities and lighting facilities.

• Journal of Korean Society of Forest Science
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• v.64 no.1
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• pp.33-41
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• 1984

This study was conducted to examine the physiology of pine mushroom mycelia cultured with various media for artificial culture of pine mushroom. The results obtained were as follows: 1) Among the various media, the medium composed of honey, boiled pine mushroom and soil extract fluid, fibrous root extract fluid, dry yeast, $KH_2PO_4$ inositol, folic acid, and biotin was the best for the growth of pine mushroom mycelium. 2) The optimum temperature for germinating pine mushroom spore and for culturing pine mushroom mycelium, was $24^{\circ}C$ and the optimum pH was 4.5. 3) There was no significant difference in growth between the mycelium separated from the tissue of pine mushroom sporophore and that separated from the spore. 4) No noticeable effect was found on the growth if such salts as $ZnSO_4$, $MnSO_4$, $MgSO_4$, $CaCl_2$ and ferric citrate were added to the Hamada's medium. 5) The addition of fibrous root extract promoted the growth of pine mushroom mycelium. 6) As a carbon source of artificial media, honey was more effective than glucose. 7) The culture infiltration of Mortierlla growing often in Fairy Ring was good for the growth of mycelium compared with the control. 8) The addition of fibrous root extract, inositol, biotin, and folic acid to artificial culture media was greatly effective in growth. When the temperature was lowered $19^{\circ}C$ after mycelium has appeared, the formation of primordium was observed.

• Journal of agricultural medicine and community health
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• v.43 no.1
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• pp.9-17
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• 2018

Objectives: This study was to assess the status and awareness of excessive heat exposure among agricultural workers. Methods: We selected a total of 90 farmers from a villages of Gyeongju-si, during August, 2015. We carried out the temperature measurement for nine times and derived Health Index (HI) and Wet Bulb Globe Temperature (WBGT) index. We compared the HI, WBGT and excessive heat warnings. Status of high temperature exposure, lifestyle, medical history, and awareness about excessive health related exposure illness assessed using survey questionnaires. Results: The matching rates between the WBGT and the HI during excessive heat warning were high, but when it was a non-excessive heat warning, there were days of excessive HI or WBGT. Out of 90 farmers surveyed, 78 cases (86.7%) were in their 60s and older age group. Slightly more than two third (71.1%) farmers were farming in the dawn-morning (71.1%), and the daily working hours were less than 4 hours (54.4 %), but only 23.3% among farmers took regular breaks. Of total, 14.4% farmers experienced excessive heat exposure related illness in order of tiredness, lethargy, dizziness, headaches, and sweating. Overall, the awareness of the danger for excessive heat and the heat wave warnings were high at 70.0% and 74.4%, respectively. Conclusions: Politically, the excessive heat warnings should not be taken into account the simple temperature measurement but, have to consider WBGT and HI standards at the same time. Farmers need to be promoted and educated to prevent the excessive heat related illness by periodically increasing their rest time during farming.

• The Korean Journal of Ecology
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• v.24 no.5
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• pp.281-288
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• 2001

The relationships between the growths of Abies koreana W. and climatic factors were analyzed by the use of tree-ring analysis at the subalpine belt of Mt. Halla National Park. The four cores were extracted from each 21 trees at north-facing slope (1,900m a.s.1.). The site chronology was established on the periods from 1912 to 1999. The growth of A. koreana was very poor, in particular in the years of 1982, 1988 and 1996. Simple correlation was employed to analyze the relationship between the growth of A. koreana and climatic factors. The result of simple correlation indicates that the growth of A. koreana represent positive correlations both with the mean temperatures of April and previous November, and the precipitation of previous December and January. The presence of large number of frost-damaged scars in the individual trees of A. koreana implies that local freezing temperature conditions at Mt. Halla have occurred in 1964, 1965 and 1966. The correlations between the fir chronology SOI(Southern Oscillation Index) of previous January, February and November were significantly positive. The growth ratio of A. koreana demonstrates that this species is sensitive to seasonal variations. As the winter temperature rises, the growth ratio of A. koreana decreases, on the other hand, the increase of autumn temperature accelerates the growth ratio of A. koreana. The growth decline of A. koreana was observed from 51 cores out of the 54 cores, and the overall growth declines have initiated at 1978, 1982 and 1988. Distinct growth decline of A. koreana in the range of 70% is noticed at 34 cores out of the 51 cores. The decline of, A. koreana growth appears to be related to the winter temperature which has increased since mid-1970s.

• Journal of Korean Society of Forest Science
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• v.105 no.4
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• pp.401-413
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• 2016

Forest resources utilization and variable disturbance history have been affected the rarity and conservation value of forest relict trees, which served as habitat for forest biodiversity, important carbon stock and cultural role include human and natural history in South Korea. This study was conducted to establish the baseline data for forest resources conservation by clarifying species diversity, spatial distribution and ecological characteristics (individual and habitat) of forest relict trees (DBH > 300 cm) based on the data getting from mountain trail, high resolution aerial photos and field professionals and field survey. As results, 54 taxa (18 family 32 genus 48 species 1 subspecies 3 variety and 2 form) as about 22% of tree species in Korea was identified in the field. 837 individuals of forest relict trees were observed and the majority of the trees was in Pinaceae, deciduous Fagaceae and Rosaceae, which families are abundant in population diversity. High elevation area was important to relict trees as mean altitudinal distribution was 1,200 m a.s.l as likely affected by human activity gradients and mid-steep slope and North aspect was important environment for the trees remain. Many individuals exhibited 'damage larger branch' (55.6%) and consequent relatively lower mean canopy coverages (below 80%). Synthetically, present diversity and abundance of relict forest trees in South Korea were the result of complex process among climate variation, local weather and biological factors and the trees of big and old were estimated to important forest biodiversity elements. In the future, clarifying the role and function of relict trees in forest ecosystem, in- and ex- situ programmes for important trees and habitat, and activities for building the background of conservation policy such as "Guideline for identifying and measurement of forest relict trees".

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.3
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• pp.157-163
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• 2005

The increasing of greenhouse gases may change agricultural environment. The agronomic productivity will depend upon change of temperature, precipitation, solar radiation and fertilization. Particularly, nitrogen fertilization considerably influences rice productivity and agricultural environments. This experiment was conducted to study transformation of nitrogen and to determine the primary yield components responsible for yield differences in paddy soil. $NH_4-N$ concentration of NPK plot in surface water of paddy soil was $2.07mg\;L^{-1}$ at 5 days after transplanting, and then was decreased sharply due to rice absorption and loss to environment. $NO_3-N$ concentration of NPK plot in surface water was $3.97mg\;L^{-1}$ at 10 days after transplanting. $NO_3-N$ concentration range of CRF plot in surface water was $3-5mg\;L^{-1}$ at 30th after transplanting. The accumulation of $NH_3$ volatilization in NPK plot was $22.39kg\;ha^{-1}$, which accounted for 20% of N fertilizer applied but using of CRF fertilizer can reduce $NH_3$ volatilization by 67% in paddy soil. Use efficiency of N fertilizer was not different between CRF70% and CRF100% plot. Rate of N use efficiency were 27.4%, 51.2%, 49.0% in paddy field NPK, CRF70% and CRF100% plots respectively. The yield of CRF70% showed the best effect with 9.3% increase production ratio, compare with NPK plot.

• Journal of Sericultural and Entomological Science
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• v.32 no.2
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• pp.113-117
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• 1990

The recovery of mulberry from a late frost (April 24 to 27) was investigated for four varieties : Kaeryangppong, Cheongilppong, and Jamsang 21 in Cheongju area, Chungbuk Province. 1. Unfavourable meteorlogical conditions for recovery of mulberry followed the early late frost : lower than normal temperatures in mid-April, less sunshine in early and mid-Jay, lower temperatures and early and less precipitation in late-May, and less precipitation than normal in early June. 2. Jamsang 21 grew to the 2-3 leaf stage first, at which time Kaeryangppong and Jamsang 22 were at the 1-2 leaf stage, and Cheongilppong was at the swallow-bill shape-1 leaf stage. 3. The first leaf stage occurred on May 12, 15 days after the frost and, 19 days later in an average year. The difference lasted until the harvesting season, the 6 leaf stage. 4. Young shoot length was 50-58% of that in 1989. Kaeryangppong was the shortest at 50% and the Jamsang 21 highest at 58% of 1989 values. 5. Leaf number was 52-67% that in 1989. Kaeryangppong was the lowest at 52% and the Jamsang 21 highest at 67% of 1989 values. 6. Young shoot and leaf weight was 44-63%, and leaf weight 39-61%, compared to 1989. Kaeryangppong and Cheongilppong were the lowest, Jamsang 21 and Jamsang 22 were the highest, compared to 1989 data. 7. Young shoot length was 50-58% compared with 1989. Kaeryangppong was the lowest as 50%, the highest Jamsang 21 as 58%. 8. Number of leaf was 52-67% compared with 1989. Kearyangppong was the lowest as 52%, the highest Jamsang 21 as 67%. 9. Young shoot and leaf wight was 44-63%, and leaf weight was 39-61% compared with 1989. Kaeryangppong was the lowest, lowest, Jamsang 21 was the highest, Cheongilppong was similar with Kaeryangppong and Jamsang 22 was similar with Jamsang 21. 10. Rate of young shoot and leaf weight to total weight decreased from 75% in 1989 to 55-61% in 1990. Rate of laef weight to young shoot decreased from 72-82% to 67-71%, showed 5-10% decrease. 11. Leaf yield decreased highly in Jamsang 22 as 57% compared with 1989. Kearyangppong 61%, Jamsang 21 64%, Cheonglppong 72%. Leaf yield was 827kg/10g in Kaeryangppong, 1, 000-1, 050kg/10a in the other varieties.

• Journal of the Korean earth science society
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• v.21 no.5
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• pp.623-634
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• 2000

This study was conducted to analyze the patterns associated with the short-term variability of CO$_2$ concentrations over 24-h scale within and across the Korean Peninsula. In the course of our study, we compared the data sets obtained from Moo-Ahn (MAN) station located in the far western coastal area of Korea with those determined from major background observatory stations around the world from the periods of Aug. 1995 to Dec. 1997. The mean CO$_2$ concentration of the MAN area for the whole study periods, when computed using the daily mean values, was found out to be 374.5${\pm}$6.6 ppm (N=884); seasonal mean values were found out to be 378${\pm}$5.2 (spring: N=181), 372${\pm}$10.2 (summer: N =210), 372${\pm}$7.2 (fall: N=243), and 376${\pm}$5.4 ppm (winter: N=206). When the data from MAN was compared with those of major background stations, the effects of both daily and seasonal components appear to vary distinctively across different stations. Those effects are expected to reflect the mixed effects of various factors which include: seasonal pollution patterns, weather conditions, vegetation, and so forth. Based upon this comparative analysis, we suspect that the MAN area is under the strong influence of anthropogenic source processes relative to all the other stations under consideration. If that is not the case, the existence of enhanced CO$_2$ level may be rather ubiquitous phenomena in Korea. More detailed inspection of CO$_2$ behavior from various respects is strongly desired in the future.

• Journal of the Korean earth science society
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• v.33 no.7
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• pp.569-582
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• 2012

The heavy rainfalls caused large property damages and human casualties. For example, Changma caused 0.25 billion dollars in damages and 57 deaths and 112 missing by accompanying the torrentially convective heavy rainfall in Seoul, 2011. In addition, TY15 (Bolaven) caused a small damage by bringing a relatively small amount of rainfall and strong wind in Gwanju, 2012. The investigation and analyses of these mesoscale processes of rainfall events for different physical properties using KLAPS for weather environments of the above cases were performed. These typical and ideal meoscale systems by better and more favorable cloud systems were chosen to retrieve rain intensity from Radar and Chullian data. The quantitative rain intensities of Radar and Chullian differ greatly from the ground-based gauge values with underestimating over 50 mm/hr at the peak time of hourly maximum rain intensity about over than 85 mm/hr. However, the Radar rain intensity demonstrated approximately lower than 35 mm/hr, and the Chullian rain intensity less than 60 mm/hr for Changma in Seoul, 2011. For typhoon (TY15, Bolaven) in Gwangju, similarly, the quantitative rain intensities of Radar and Chullian differ from the ground-based gauge values. At the peak time, the hourly maximum rain intensity of ground-based gauge was more than 15 mm/hr. However, the Radar rain intensity showed lower than 5 mm/hr, and the Chullian rain intensity lower than 10 mm/hr. Regarding the above two cases of typhoon and Changma, even though Radar and Chullian rain intensities have been underestimated when compared to the ground-based rain intensity, the distributions of time scale features of both Radar and Chullian rain intensities still delineated a similar tendency of rain intensity distribution of the ground-based gauge data.

• Journal of the Korean earth science society
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• v.34 no.3
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• pp.224-234
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• 2013

This study examined a strong positive correlation between the North Atlantic Oscillation (NAO) index during June and the total tropical cyclone (TC) genesis frequency in the western North Pacific during July and August. To investigate a possible cause for this relationship, the mean difference between the highest positive NAO years and the lowest negative NAO years was analyzed by dividing into when the El Ni$\tilde{n}$o and La Ni$\tilde{n}$a years were included and when the El Ni$\tilde{n}$o and La Ni$\tilde{n}$a years were not included. When the El Ni$\tilde{n}$o and La Ni$\tilde{n}$a years were included, for the positive NAO years, the TCs mostly occurred in the northwestern region of tropical and subtropical western Pacific, and showed a pattern that migrate from the sea northeast of the Philippines, pass the East China Sea, and move toward the mid-latitudes of East Asia. In contrast, for the negative NAO years, the TCs mostly occurred in the southeastern region of tropical and subtropical western Pacific, and showed a pattern that migrate westward from the sea southeast of the Philippines, pass the South China Sea, and move toward the southern coast of China and Indochinese peninsula. These two different TC migration patterns affect the recurving location of TC, and for the positive NAO years, the recurving of TC was averagely found to take place in the further northeast. In addition, the migration patterns also affect the TC intensity, and the TCs of positive NAO years had stronger intensity than the TCs of negative NAO years as sufficient energy can be absorbed from the ocean while moving north in the mid-latitudes of East Asia. The TCs of negative NAO years showed weak intensity as they get weaken or disappear shortly while landing on the southern coast of China and the Indochinese peninsula. On the other hand, the above result of analysis is also similarly observed when the El Ni$\tilde{n}$o and La Ni$\tilde{n}$a years were not included.