• Journal of Radiation Protection and Research
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• v.36 no.4
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• pp.200-208
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• 2011

The neutron fluence measurement and evaluation technology is very important for material irradiation test. The most essential technology in this study is the neutron irradiation evaluation method using a fluence monitor. The fluence monitors were fabricated with metal wires of the purity ${\geq}$ 99.9%, whose dimensions were 0.1mm diameter, about 3 mm length, and around 150-200 ${\mu}g$ mass range. Three wire samples (Fe, Ni, Ti) were prepared for one irradiation aluminum capsule. Five capsules were irradiated in the OR5 hole of the HANARO reactor at 30 MW power for about 25 days. After irradiation tests, radiation activities were measured with the high purity germanium (HPGe) detector. The reaction rates were calculated by using the measured radiation activity data, and then neutron fluence were obtained from the reaction rates and the weighted neutron cross section with calculated neutron spectrum at the fluence monitor position.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.5
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• pp.553-568
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• 2018

Chromophoric Dissolved Organic Matter (CDOM) plays a dominant role in absorbing UV-VIS light and is also important in the biogeochemical carbon cycle due to the production of carbon dioxide from photo-oxidation at the sea surface in marine environments. Since absorption by CDOM was recently found to be responsible for increasing the energy absorbed in the mixed layer by 40 % over pure seawater, the importance of CDOM absorption in seawater for increasing sea surface temperature has come to be well recognized. We measured aCDOM and the absorption characteristics of CDOM during spring 2012 and 2014 in the southwestern East Sea. Distribution of CDOM in spring 2012 and 2014 was compared and S value was used to find the source of CDOM in the study area. As a result, the average $a_{CDOM}$ was $0.237m^{-1}$ ($0.009{\sim}0.988m^{-1}$) and the average S value was $16{\mu}m^{-1}$,which shows coastal properties. Also a positive correlation between Chl a and CDOM was observed ($r^2=0.34$), with an especially strong correlation near coastal stations. aCDOM in 2014 was about 40 % higher than aCDOM in 2012 during spring in the study area. This difference in aCDOM concentration resulted not only from annual variation but also from stratification and photobleaching in late spring 2012. This observation implies the possibility of flux of carbon dioxide into the atmosphere as a result of photo-oxidation in the East Sea.

• Journal of the Korean Dietetic Association
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• v.23 no.1
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• pp.78-93
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• 2017

The purposes of this study were to assess energy expenditure of eight walking activities in normal weight and overweight or obese high school students and to evaluate the accuracy of two accelerometers worn on the ankle and waist. Thirty-five (male 17, female 18) healthy high school students participated in this study. They were classified into normal weight (n=21) and overweight or obese (n=14) groups. The subjects completed five treadmill walking activities (TW2.4, TW3.2, TW4.0, TW4.8, TW5.6), followed by three self-selected hallway walking activities (walk as if walking and talking with a friend: HWL, walk as if hurrying across the street at a cross-walk: HWB, walk as fast as you can but do not run: HWF). Energy expenditure and metabolic equivalents (METs) were measured using a portable indirect calorimeter, and predicted energy expenditures and METs were derived from two accelerometers placed on the ankle and waist. Measured energy expenditures per body weight (kg) of eight walking activities were significantly higher in the normal weight group than in the obese group and significantly higher in female than male. The ankle accelerometer overestimated energy expenditures and METs (bias 49.4~105.5%), whereas the waist accelerometer underestimated energy expenditures and METs (bias -30.3~-85.8). Except for HWF (fast) activity, METs of seven activities were moderate intensity based on Compendium METs intensity categories. HWF (fast) activity was vigorous intensity. METs from the ankle accelerometer were vigorous intensity except TW2.4 activity (moderate intensity). METs from the waist accelerometer were low intensity (TW2.4, TW3.2, TW4.0, TW4.8, HWL) and moderate intensity (TW5.6, HWB, HWF). Physical activity guidelines were developed based on measured physical activity level of high school students. Further studies should investigate the effects of body composition in larger subjects.

• Journal of the Speleological Society of Korea
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• v.45 no.46
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• pp.69-79
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• 1996

동굴은 미지의 세계이고, 암흑의 신비로운 지하세계이기 때문에 우리 인간에게는 매우 흥미로운 공간이라고 할 수 있다. 그러므로 이러한 공간을 관광자원으로 활용하여 지역주민이 소득을 올리고, 청소년에게 탐험의 세계, 모험의 세계는 물론 자연학습의 현장으로 활용할 수 있게 하는 바람직한 경우도 있다. 그러나 이러한 경우 동굴이 개발되면 전자와 같은 긍정적인 면이 있는 반면에 동굴의 파괴, 오손 및 오염과 같은 악영향을 가져오게 되므로 동굴을 개발할 당시부터 악영향을 최소하기 위해서는 환경보전과 환경보호에 커다란 관심을 가져야 한다. 따라서 본 연구에서는 이제 동굴 개장이 2개월밖에 되지 않은 천곡동굴이 관광지로 개방됨으로써 나타나게 될 환경변화를 미리 살펴보고 그에 대한 대책을 마련하려고 하였다. 그 결과는 다음과 같다. 첫째, 천곡동굴의 경우 동굴 공간이 넓고 관광통로가 왕복통로로 되어 있어 체동인구가 2배가 되므로 많은 관광객의 출입시 동굴 내부의 기온이 상승하기 때문에 동시에 관람할 수 있는 적정 관람객 수를 조절해야 한다. 둘째, 천곡동굴은 개장 시일이 오래 경과하지 않았기 때문에 퇴적물의 파손이 전무하다고 할 수 있다. 따라서 이 상태를 계속 유지하기 위해서 동굴 내부에 관리인을 상주시킨다거나, 입동객의 소지품을 보관할 수 있는 장소를 마련하여 동굴퇴적물을 훼손할 수 있는 물건의 반입을 애초에 방지하는 방안도 필요하다고 본다. 마지막으로, 동굴 개발 당시 조명을 너무 가깝게 설치한 때문에 개방 후 얼마 되지 않았음에도 불구하고 몇 군데에서 녹색균류가 관측되고 있으므로 조명시설의 원거리 조정이나 간접조명 대책을 강구해야 한다.만 아니라 오류의 크기도 확률적으로 변하는 상황을 모형에 반영하여 보다 현실성있게 모형화하였다.균 6.5점(2-9점)으로 대체로 높게 나타났는데 이는 대중매체와 신문, 잡지류를 통한 지식의 정보가 많기 때문으로 생각된다 비만 정도에 따라서는 유의적인 차이를 보이지 않았다. 5. 비만 정도와 상호간의 관계를 보면 BMI 수치가 높을수록 비만인 형제수가 많았으며, 자신의 비만 자각도도 높았다. 편식율은 비만 정도가 낮을수록 높았으며, 식품섭취 빈도 점수는 비만군에서 높았으나, 저녁식사 후 간식섭취는 BMI가 높은 군에서 하지 않는 비율이 더 높았는데 이것은 감수성이 예민한 여학생들이 자신의 외모에 대한 의식적인 노력으로 보인다. 이상과 같은 결과를 종합해 볼 때 중학교 여학생들은 학교수업을 중심으로 비교적 규칙적인 생활을 하고 따로 운동을 할 시간이 많지 않은 것으로 나타났다. 비만과 관련하여서는 유전적인 요인도 중요하지만 식습관 개선과 식품이 적절한 선택 등을 강조하여 연령과 생활환경에 맞는 영양교육이 필요하다고 본다.알 수 있으며, 현미 30% 첨가한 B2가 그 다음 순위로 선호되어, 백설기 제조에서 율무와 현미의 첨가량은 10%가 권장된다.농촌 지역 여고생보다 많이 섭취하였고, 탄수화물은 농촌지역 여고생이 대도시 지역 여고생에 비하여 유의적으로 많이 섭취하였다. 지역별 여고생의 에너지섭취 비율은 탄수화물 : 단백질 : 지방의 섭취 비율이 대도시 60.75% : 16.4% 22.9%이며, 중소도시가 62.7% : 15.7% : 21.5%,농촌이66.8% : 14. l% : 19.1%이었다. 영양지식의 정확도나 인지도는 영양소 섭취와 유의적인

• Journal of the Korean GEO-environmental Society
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• v.11 no.12
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• pp.47-56
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• 2010

The construction of new roads and the consistent extension of already-existing roads or the line-shape revision of those roads are increased with the governmental investment to SOC facilities currently. Accordingly, the road cut slopes are in the trend of rapidly increasing. As the road slope has increased, a lot of human and property damages has entailed consequently and in the local case, numerous studies have carried out aiming at minimizing this damages caused by the rockfall and landslide. In general, standard falling rock prevention facility has employed for most of the local road slope based on "Guide for Installation and Management of Road Safety Facilities" published by MLTM(the Ministry of Land, Transport, and Maritime Affairs) but profound doubt has raised as to whether this rockfall prevention facility would function properly enough to prevent rockfall efficiently without any damages in case of actual occurrence of rockfall. In addition, it is a reality that in most cases, such work is relied on overseas technology as a whole as the local technical level is low and in case of rockfall prevention net, it is judged that a study on rockfall prevention net that is able to endure more powerful rockfall energy is required as the problem including net bursting is taken place as a result of enough bearing force being failed to be demonstrated due to its partial weak point(not uniformly made). Under this background, in this study, three kinds of model depending on mesh size of expanded metal that is considered to have an adoptability as rockfall prevention net, as target are selected and characteristics depending on mesh size of expanded metal is intended to be researched through a pull-out test performance by using pull-out test equipment rockfall prevention net.

• Journal of Climate Change Research
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• v.4 no.4
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• pp.371-384
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• 2013

The appearance of abnormal weather caused by climate change have both direct and indirect impact on the society. Especially, agriculture is brought up as a socially important interest having direct impact of climate change in growth and harvest of crops. This study aims to perform vulnerability assessment for the South Korea's two main imported grains, maize and wheat. The production vulnerability assessment of maize and wheat in USA and China to temperature variability, which has a great impact in production, is performed. First, grain cultivation period which affects productivity of main grain production country was selected based on the main cultivation period from several references and previous studies. Then, Intergovernmental Panel on Climate Change AR5 greenhouse gas scenario RCP(representative concentration pathways)8.5 scenarios was used to select the future climate that correspond to the cultivation period of maize and wheat for each producing country. According to the result of production vulnerability analysis using adaptation (temperature changing trend) and sensitivity(temperature variability), the productivity of wheat was higher in USA, while productivity of maize was higher in China. In the future, the result showed that productivity of all two grains will be favorable in USA. The result of production vulnerability assessment through this study can later be used as a preparation data for the coming fluctuation in grain price due to climate change.

• Korean Journal of Remote Sensing
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• v.34 no.6_1
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• pp.1025-1032
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• 2018

Snow Cover is a form of precipitation that is defined by snow on the surface and is the single largest component of the cryosphere that plays an important role in maintaining the energy balance between the earth's surface and the atmosphere. It affects the regulation of the Earth's surface temperature. However, since snow cover is mainly distributed in area where human access is difficult, snow cover detection using satellites is actively performed, and snow cover detection in forest area is an important process as well as distinguishing between cloud and snow. In this study, we applied the Normalized Difference Snow Index (NDSI) and the Normalized Difference Vegetation Index (NDVI) to the geostationary satellites for the snow detection of forest area in existing polar orbit satellites. On the rest of the forest area, the snow cover detection using $R_{1.61{\mu}m}$ anomaly technique and NDSI was performed. As a result of the indirect validation using the snow cover data and the Visible Infrared Imaging Radiometer (VIIRS) snow cover data, the probability of detection (POD) was 99.95 % and the False Alarm Ratio (FAR) was 16.63 %. We also performed qualitative validation using the Himawari-8 Advanced Himawari Imager (AHI) RGB image. The result showed that the areas detected by the VIIRS Snow Cover miss pixel are mixed with the area detected by the research false pixel.

• Journal of Wetlands Research
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• v.23 no.3
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• pp.260-276
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• 2021

Wetlands are constantly affected by internal and external environments that make up the wetlands, and these effects make wetlands change. East Asia countries where about 15% of Ramsar's registered wetlands are located, is valuable conservation area due to various wetland types and biodiversity. However, due to climate change and other factors, the total area of wetlands has been reduced and biodiversity have been damaged. To mitigate these problems and to manage wetlands efficiently, it is important to identify the factors that change wetlands and to identify how each factor affects them. In this study, we conducted a wetland-related literature analysis in East Asia to derive factors that affect the changes in wetlands, and analyzed the relationships among the factors. Finally we presented research directions considering wetland change factors. In most of the East Asia countries, it was found that there is deficiency in research studies about extraction in direct factors and water-energy infrastructure, tourism & recreation in indirect factors. Also, we presented the necessity for future research using the result between connectivity & relationship analysis and indirect drivers of change and their influence on direct drivers of change. The results of this study could contribute to the establishment of an R&D cooperation system in East Asia region and strengthen wetland management.

• Journal of Internet Computing and Services
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• v.23 no.6
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• pp.79-86
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• 2022

This study aims to analyze the research trends on the civic participation in a smart city and to present implications to policy makers, industry professionals and researchers. As rapid urbanization is defining development trend of modern city, urban problems such as transportation, environment, and energy are spreading and intensifying around the city. Countries around the world are introducing smart cities to solve these urban problems and to achieve sustainable development. Recently, many countries are modifying urban planning from top-down to down-up by actively engaging citizens to participate in the urban construction process directly and indirectly. Although the construction of smart cities is being promoted in Korea to solve urban problems, awareness of smart cities and civic participation are low. In order to overcome this situation, discussions on ideas and methods that can increase civic participation in smart cities are continuously being conducted. Therefore, in this study, by collecting publication containing both 'Smart Cities' and 'Participation (Engagement)' in Scopus DB, the topics of related studies were categorized and research trends were analyzed using topic modeling. Through this study, it is expected that it can be used as evidence to understand the direction of civic participation research in smart cities and to present the direction of related research in the future.

• Tunnel and Underground Space
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• v.33 no.1
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• pp.29-41
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• 2023

The brittleness of rocks plays an important role in determining the fragmentation and failure behavior of rock. However, there is still no standard method to evaluate the brittleness of rock, and previous studies have suggested the several definitions for estimation of brittleness of rock. Even in the process of mechanical rock excavation and drilling, the brittleness of rock is considered as an important property for evaluating the excavation efficiency of mechanical excavators or boreability of rock. The previous studies have been carried out to investigate the correlation between different brittleness of rock and cutting efficiency and boreability of rock. This study introduced a method for calculating the brittleness of rock from punch penetration test, and analyzed the correlation between the brittleness of rock calculated by the uniaxial compressive and Brazilian tensile strengths and that from punch penetration test. From the results of correlation analysis, the relationship between various brittleness was confirmed, and it was found that PSI and BI₃ showed a good correlation with the strength-based brittleness index. In addition, the results indicated that B₃ and B₄ are suitable to represent the brittleness of rock in the field of mechanical rock excavation.