• Journal of the Korean Society of Safety
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• v.31 no.3
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• pp.22-27
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• 2016

The use of electromagnetic wave has been interested in various energy industry because it enhances a flame stability and provides higher safety environments. However it might increase the pollutant emissions such as NOx and soot, and have harmful influence on human and environments. Therefore, it is very important to understand interaction mechanism between flame and electromagnetic wave from environmental point of view. In this study, an experiment was performed with jet diffusion flames induced by electromagnetic wave. Microwave was used as representative electromagnetic wave and a flickering flame was introduced to simulate the more similar combustion condition to industry. The results show that the induced microwave enhances the flame stability and blowout limit. The unstable lifted flickering flames under low fuel/oxidizer velocity is changed to stable attached flames or lift-off flames when microwave applied to the flames, which results from the abundance of radical pool. However, NOx emission was increased monotonically with increasing the microwave power as microwave power increased up to 1.0 kW. The effects might be attributed to the heating of combustion field and thermal NOx mechanism will be prevailed. Soot particle was examined at the post flame region by TEM grid. The morphology of soot particle sampled in the microwave induced flames was similar to the incipient soot that is not agglomerated and contain a lots of liquid phase hydrocarbon such as PAH, which soot particle formed near reaction zone is oxidized on the extended yellow flame region and hence only unburned young particles are emitted on the post flame region.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.154-154
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• 2018

To interpret the climate projections for the future as well as present, recognition of the consequences of the climate internal variability and quantification its uncertainty play a vital role. The Korean Peninsula belongs to the Far East Asian Monsoon region and its rainfall characteristics are very complex from time and space perspective. Its internal variability is expected to be large, but this variability has not been completely investigated to date especially using models of high temporal resolutions. Due to coarse spatial and temporal resolutions of General Circulation Models (GCM) projections, several studies adopted dynamic and statistical downscaling approaches to infer meterological forcing from climate change projections at local spatial scales and fine temporal resolutions. In this study, stochastic downscaling methodology was adopted to downscale daily GCM resolutions to hourly time scale using an hourly weather generator, the Advanced WEather GENerator (AWE-GEN). After extracting factors of change from the GCM realizations, these were applied to the climatic statistics inferred from historical observations to re-evaluate parameters of the weather generator. The re-parameterized generator yields hourly time series which can be considered to be representative of future climate conditions. Further, 30 ensemble members of hourly precipitation were generated for each selected station to quantify uncertainty. Spatial map was generated to visualize as separated zones formed through K-means cluster algorithm which region is more inconsistent as compared to the climatological norm or in which region the probability of occurrence of the extremes event is high. The results showed that the stations located near the coastal regions are more uncertain as compared to inland regions. Such information will be ultimately helpful for planning future adaptation and mitigation measures against extreme events.

• Journal of Soil and Groundwater Environment
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• v.25 no.4
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• pp.14-27
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• 2020

The drought has occurred from the past, and has caused a lot of damage. It is important to analyze the past droughts and predict them in the future. In this study, the temperature and precipitation of the past and the future from climate change RCP 4.5 and 8.5 scenarios were analyzed for Seosan and Boryeong in the western region of Chungnam Province, which is considered as a drought-prone area on the Korean Peninsula. Comparing Standardized Precipitation Index (SPI) and Effective Drought Index (EDI) based on the past droughts, EDI was verified to be more suitable for the drought assessment. According to RCP 4.5, the frequency and intensity of droughts in the early future (2021~2060) were expected to increase and to be stronger. Particularly, severe droughts were predicted for a long time from 2022 to 2026, and from 2032 to 2039. Droughts were expected to decrease in the late future (2061~2100). From RCP 8.5, drought occurrences were predicted to increase, but the intensity of the droughts were expected to decrease in the future. As a result of evaluation of the frequencies of droughts by seasons, the region would be most affected by fall drought in the early future and by spring drought in the late future according to RCP 4.5. In the case of RCP 8.5, the seasonal effects were not clearly distinguished. These results suggest that droughts in the future do not have any tendency, but continue to occurr as in the past. Therefore, the measures and efforts to secure water resources and reinforcement of water supply facilities should be prepared to cope with droughts.

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.4
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• pp.215-222
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• 2017

The potential change of the cultivation area of main citrus cultivars, satsuma mandarin (Citrus unshiu Marc.) and 'Shiranuhi' mandarin hybrid [(Citrus unshiu ${\times}$ C. sinensis) ${\times}$ C. reticulata] were determined with base year (1981 to 2010) to 2090. The meteorological data provided by the Korea Meteorological Administration (KMA), and the digital agricultural climate map of 30m-solution based on the Representative Concentration Pathways (RCP) 8.5 was used for projection of potential cultivation area. As a result, the potential suitable region of satsuma mandarin included almost Jeju region during base year. At the 2030s, the potential suitable region of satsuma mandarin increased and the cultivable region also increased focused on the coast region of Jeonnam province. From the 2060s, the suitable area spread out to mountain area of Jeju, Jeonnam, Gyeongnam, and the coast region of Kangwon, and the cultivable region expanded to the area of Gyeongbuk, Chungnam, and Jeonbuk. In the case of 'Shiranuhi' mandarin hybrid, the suitable region included only the partial coast area of Jeju, and cultivable area covered Jeju region and the partial southern coast of Jeonnam during the standard period. At the 2030s, the suitable region of 'Shiranuhi' included the current cultivation area of satsuma mandarin, and the cultivable region moved to northward by the partial southern coast region. At the 2090s, the slightly increased suitable region covered all Jeju regions, Jeonnam, Gyeongnam, and the coast area of Kangwon, and the cultivable region proceeded northward focusing on the coastline. In conclusion, the prediction of the potential land for citrus cultivation based on the RCP 8.5 showed that the suitable region of satsuma mandarin decreased, whereas that of cultivation of 'Shiranuhi' increased. Moreover, it was forecasted that citrus cultivation area would extend to Kangwon region at the end of the $21^{st}$ century.

• Korean Journal of Environment and Ecology
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• v.10 no.2
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• pp.171-183
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• 1997

Diversity, abundance, species distributions and distributions of two strategists (specialist and geceralist) of butterflies were investigated monthly from June 1996 to Oct. 1996 by line transect method in the Chunbul-dong valley from park gate to Yangpok Sanjang. The butterfly faunas of the eight regions in Kwangwon province, Gyunggi proavince and Pusan were also studied by the same method to assess diversity and abundance of butterfly community in the study region. The 18 butterfly species in 7 families were found in this study and the 48 butterfly species in 7 families were distributed in the study area from thes study and the other researches. The 30 butterfly species reported in the other studies were not found in this study and Kaniska canace L. of them would be to decrease in density. In the study area, the common species were Artogeia melete M., Neptis sappho P. and Libythea celtis F.. The representative Korean common butterflies such as Artogeia rapae L., Colias erate E. and Papillio xuthus L. were rare. The PCA(Principal Component Analysis) ordinations indicate that habitat disturbance by human would be major factor for butterfly community and species distribution. Difference was not found in diversity according to habitat disturbance. Abundance, however, was higher in the disturbed region than the undisturbed region. Compared with the other regions, abundance was greatly lower and diversity was slightly lower than that of the other regions. Two strategists exhibited different distribution patterns. Generalists were found more commonly in the disturbed region and widely distributed in both of the disturbed region and the undisturbed region than specialists.

• Ocean and Polar Research
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• v.38 no.2
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• pp.89-102
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• 2016

In this study, we evaluated the model performance with respect to Sea Surface Temperature (SST) and Net Heat Flux (NHF) by considering the characteristics of seasonal temperature variation and contributing factors and by analyzing heat budget terms in the Northwestern Pacific and East Asian Marginal Seas ($110^{\circ}E-160^{\circ}E$, $15^{\circ}N-60^{\circ}N$) using the HadGEM2-AO historical run. Annual mean SST of the HadGEM2-AO is about $0.065^{\circ}C$ higher than observations (EN3_v2a) from 1950 to 2000. Since 1960, the model has simulated well the long-term variation of SST and the increasing rate of SST in the model ($0.014^{\circ}C/year$) is comparable with observations ($0.013^{\circ}C/year$). Heat loss from the ocean to the atmosphere was simulated slightly higher in the HadGEM2-AO than that in the reanalysis data on the East Asian Marginal Seas and the Kuroshio region. We investigated the causes of temperature variation by calculating the heat budget equation in the two representative regions. In the central part of the Kuroshio axis ($125^{\circ}E-130^{\circ}E$, $25^{\circ}N-30^{\circ}N$: Region A), both heat loss in the upper mixed layer by surface heat flux and vertical heat advection mainly cause the decrease of heat storage in autumn and winter. Release of latent heat flux through the heat convergence brought about by the Kuroshio contributes to the large surface net heat flux. Positive heat storage rate is mainly determined by horizontal heat advection from March to April and surface net heat flux from May to July. In the central part of the subtropical gyre ($155^{\circ}E-160^{\circ}E$, $22^{\circ}N-27^{\circ}N$: Region B), unlike Region A, vertical heat advection predominantly causes the decrease of heat storage in autumn and winter. In spring and summer, surface heat flux contributes to the increase of heat storage in Region B and the period is two times longer than the period for Region A. In this season, shoaling of the mixed layer depth plays an important role in the increase of SST.

• Journal of the Korean earth science society
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• v.40 no.1
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• pp.56-67
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• 2019

In this study, we analyzed the intensity attenuation for M 6.0, 6.5, and 7.0 earthquakes using the broadband strong ground motion simulation platform based on the physical seismic modeling developed by the US Southern California Earthquake Center (SCEC). The location of the earthquake was assumed to be near the epicenter of the 2016 M 5.8 Gyeongju earthquake, but two of the representative US regional models provided by the SCEC strong ground motion simulation platform were used for the propagation model. One is the Central and Eastern United States (CEUS) model representing the intraplate region, and the other is the LA Basin model representing the interplate region. Five modeling methodologies are presented in the version 16.5 of the simulation platform, and Song and Exsim models were used in this study. In the analysis, we found that different intensity attenuation patterns can be observed with the same magnitude of earthquakes, especially depending on the region (CEUS vs LA Basin). Given the same magnitude and distance, the instrumental intensity in the CEUS region (intraplate) could be larger by a unit of 2 than that in the LA Basin region (interplate). Given the difference of intensity attenuation patterns observed in the study, it is important to know the regional intensity attenuation characteristics to understand the accurate level of seismic hazard imposed in the Korean Peninsula. This study also shows the level of the uncertainty of intensity attenuation if region specific attenuation characteristics are not considered.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.402-412
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• 2023

To cope with climate change, we compared the quality of naked oats (Avena sativa L.) cultivated in different regions. Naked oats were collected from domestic farms in different cultivation regions grouped as G1 and G2 for 3 years (2020-2022). The appearance, quality, and nutritional and functional compounds in the samples were assessed. In terms of appearance quality, the brightness and yellowness of the samples from the G1 region were significantly lower than those of the samples from the G2 region in 2020; however, no differences were observed between cultivation regions in the other 2 years. The results of testing the vitality of naked oats seeds showed that the electrical conductivity value was significantly lower in the samples from the G1 region than in those from the G2 region only in 2022. Among the nutritional components, moisture content was higher in the G2 region than in the G1 region over all 3 years, and the crude protein content was significantly higher in the G2 region than in the G1 region over all years. Carbohydrate content was significantly higher in the G1 region than in the G2 region in all 3 years and was inversely proportional to the crude protein content. The crude fat content tended to be significantly higher in the G1 region than in the G2 region, except in 2022. The levels of beta-glucan, a functional compound rich in naked oats, ranged between 3.4% and 4.2%, and except in 2020, there was no significant difference between cultivation regions. In addition, the content of avenanthramides, representative functional compounds that exist only in oats, was assessed. Over 2 years, in 2021 and 2022, the avenanthramide content was in the range of 2.4-20.7 ㎍/g and tended to be significantly higher in the G2 region than in the G1 region in both years. According to a survey of the average and minimum temperatures during the growing season of naked oats from 2020 to 2022, the average and minimum temperatures in January in the G2 region, which is the cultivation-limit area, were similar to those in Haenam in the G1 region. In conclusion, differences in nutritional and functional compounds were observed in naked oats grown in different cultivation areas. Therefore, considering the cultivation area of naked oats is expanding because of climate change, changes in the compounds that affect quality should be investigated.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.2
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• pp.147-155
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• 2002

In this paper, the regular rotational gaits of the quadruped crawling robot are studied. It is assumed that the proposed regular rotational gaits starts from one of six support patterns in a translational gaits and end up with one of six support patterns in a translational gaits. Noting that six support patterns in a regular translational gait belong to two different groups with respect to regular rotational gait, the static stability margin and the maximum rotational displacement during one rotational stride period for the two representative support patterns are investigated. It is expected that the proposed regular rotational gaits will enhance the omni-directional characteristics of the quadruped crawling robot.

• The Korean Journal of Nuclear Medicine
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• v.7 no.2
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• pp.37-41
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• 1973

Bone scanning was attempted in the five representative cases in various diseases such as primary bone tumor, inflammatory or traumatic changes, secondary metastatic bone tumor and changes in the hematopoietic system with Sr-85 which is available at this time. Each findings were correlated to the X-ray findings. Scan findings were more appreciable than the X-ray findings in elucidation of extent of bone pathology in cases of primary bone tumor and fracture cases. Especially, increased radioactivity was noted on the clinically suspected region which were not demonstrated on the plain X-rays.