• Proceedings of the Korean Geotechical Society Conference
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• 2010.09c
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• pp.66-71
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• 2010

This paper studies the effect of saturation of backfill on the seismic stability of reinforced soil walls (RSWs) using centrifuge shaking table tests. For comparison, degradation of static stability and seismic stability of a RSW under unsaturated condition was also investigated. Test results showed that the RSW under saturated condition had enough static stability. However, seismic stability of saturated RSW significantly decreased as compared with that under unsaturated condition. The saturated model RSW did not collapse, though it showed large deformation. It maintained sufficient stability after shakings although a clear slip surface appeared in the backfill. Finally, it is discussed how to evaluate residual stability of RSWs damaged by earthquakes with test results and the simple evaluation method proposed by authors.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.747-749
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• 2003

For forest fire monitoring in relatively cool area like Siberia, design of Decision Support System (DSS) is proposed. The DSS is consisted of three different algorithms to detect potential fires from NOAA AVHRR image. The algorithm developed by CCRS (Canada Center for Remote Sensing) uses fixed thresholds for multi-channel information like one by ESA (European Space Agency). The algorithm of IGBP (International Geosphere Biosphere Program) involves contextual information in deriving fire pixels. CCRS and IGBP algorithms are rather liberal compared to more conservative ESA algorithm. Fire pixel information from the three algorithms is presented to the user. The user considers all these information in making decision about the location fire takes place.

• International journal of advanced smart convergence
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• v.8 no.1
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• pp.147-152
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• 2019

This study aims to explore the understanding of and the interest in realistic digital contents and examine their effectiveness, by implementing and applying VR around the science subject in middle schools. It organized each group of two for cooperative activities, in order to implement VR for 52 middle school students located at Y-county, who understood study contents and agreed to participate in the study. Then, it implemented and applied realistic digital contents regarding a change in the science geosphere and many kinds of forces, by extracting and designing them. As they implemented and applied VR around contents interest in science subject. VR assisted lessons made statistically significant differences in understanding and effectiveness of realistic digital contents. It will provide basic data used to cultivate future talents who can prepare for a change in the educational paradigms along with the fourth industrial revolution and adapt to the future knowledge-based society.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.44-44
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• 2023

지표면 위 에너지 수지, 즉 순 복사에너지가 어떤 비율로 지열, 현열, 잠열로 분할되는지를 이해하는 것은 매우 중요한 문제이지만, 에너지 분할과 주변 환경 변수 사이의 인과관계를 역학적으로 설명하는 것은 난제로 남아있다. 이 연구에서는 지표면 에너지 분할에서 어떠한 조건에서라도 보편적으로 발견되는 특성을 찾아서 다양한 식생 조건에서 관측된 복사에너지 및 열 플럭스 관측소의 자료를 토대로 각 에너지 항의 시간 변동성을 분석했다. 시계열 분석을 위해 공분산 기법을 통해 관측한 현열 및 잠열 자료를 제공하는 Fluxnet 자료를 사용했으며, International Geosphere-Biosphere Programme (IGBP) 구분법에 따라 낙엽수림, 상록수림, 농지 및 사바나에 위치한 관측소의 자료를 비교 분석했다. 모든 관측소에서 에너지 수지에서 현열과 잠열의 합이 전체 순 복사에너지에서 차지하는 비중은 시간에 따라 큰 변화를 보이지 않는다는 특성을 발견했다. 하지만, 현열 또는 잠열이 차지하는 비중은 큰 계절성을 보여주고 있었다. 이를 종합하면 현열과 잠열이 상호보완적으로 발생한다는 것을 의미한다. 한편 시간에 따른 두 열 플럭스의 움직임은 해당 관측소 근처에서 서식하는 식생 특성과 깊게 관련됐음을 확인했다.

• Journal of Gifted/Talented Education
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• v.24 no.2
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• pp.271-288
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• 2014

This study aimed to investigate the perception of earth system thinking of science gifted students in future problem solving (FPS) in relation to climate changes. In order to this study, the research problem associated with climate changes was developed through a literature review. The thirty seven science gifted students participated in lessons. The ideas in problem solving process of science gifted students were analyzed using the semantic network analysis method. The results are as follows. In the problem solving processes, science gifted students are 'changes of the sunlight by water layer', 'changes of the Earth's temperature', 'changes of the air pressure', ' change of the wind and weather' were represented in order. On other hand, regard to earth system thinking for climate changes, while science gifted students were used sub components related to atmospheres frequently, they were used sub components related to biosphere, geosphere, and hydrosphere a little. But, the analytical results of the structural relationship between the sub components related to earth system, they were recognised that biosphere, geosphere, and hydrosphere used very important in network structures. In conclusion, science gifted students were understood well that components of the earth system are influencing each other.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.380-383
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• 2004

Heavy metal release from wastewater is a serious environmental problem, and therefore, various wastewater treatment techniques have been developed. Among the techniques, sorption technique is most attractive. Considerable researches have been recently focused on finding out inexpensive sorbents, especially from various natural materials. In order to evaluate the applicability of the scoria taken from the Jeju Island, Korea to remove heavy metals (Pb, Cu, Zn, Cd) from aqueous solutions, equilibrium sorption experiments were conducted in this study. In equilibrium tests, powdered activated carbon (PAC), one of the most commonly used sorbents, was also tested to compare the effectiveness of the Jeju scoria with that of PAC. The Jeju scoria had larger adsorption capacity and affinity for metal ions (Pb(II), Cu(II), Zn(II), Cd(II)) than PAC. The sorption parameters of the two sorbents were evaluated by using both the Langmuir and Freundlich isotherms, and the sorption data were better fitted to the Freundlich isotherm. In addition, the sorption behavior of metal ions (Pb(II), Cu(II), Zn(II), Cd(II)) onto the scoria displayed a typical characteristic of the cation sorption. The removal of metal ions decreased at a lower pH condition due to competition with hydrogen ions for the sorption sites of Jeju scoria, while the removal increased at a high pH condition due to hydroxide precipitation.

• Proceedings of the KSRS Conference
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• 2007.03a
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• pp.49-54
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• 2007

고분해능복사계(AVHRR) 자료로부터 산출한 아시아지역 지면피복 분류자료들 (United States Geological Survey: USGS, International Geosphere Biosphere Programme: IGBP, University of Maryland: UMd)의 분류특성을 분석하였으며 이를 근거로 하여 이 지역에 대한 지면피복의 분류를 시도하였다. 서로 다른 지면피복 분류 자료들의 비교를 위하여 지도 투영법을 일치시켰으며 지면피복 정의가 유사한 유형들만 비교하였다. 세 지면피복 자료에서 분류가 모두 일치하는 비율은 33.57%이고 3 자료 중 두 자료에서 분류가 일치하는 비율은 49.69%로 나타났다. 전체적으로 나대지(사막)， 도시 및 혼합림과 같이 식생의 생물리적 특성이 뚜렷한 유형들에서는 분류의 일치율이 높게 나타났다. 반면에 농지， 낙엽활엽수림， 및 낙엽침엽수렴과 같이 식생의 생물리적 특성이 유사한 유형에서는 일치율이 낮게 나타났다. 분류에 사용된 기본 입력자료수， 지면피복 유형수，분류기법 및 입력 자료의 전처리 수준 등이 지면피복 분류 결과에 차이를 유발한 것으로 판단된다. 지면피복 자료들의 비교결과와 각 유형별 식생지수의 평균 계절변동 특성을 이용하여 이 지역에 대한 지면피복 분류자료를 보완하였다.

• Journal of the Korean Society of Earth Science Education
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• v.3 no.1
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• pp.1-8
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• 2010

The purpose of this study was to analysis the 6th students' conceptions of the nature phenomenon focused on the systematic characteristics. For this study, 12 students of the 6th grades participated in special class for testing their conceptions about the water cycle in the earth system. And we analyzed the outcomes of students' conceptions based on SBF conceptual representation. The results indicate that most of the subjects perceived that the water cycle in earth system wasn't complex system maintaining its existence and functions as a whole through the interaction of its parts but simple system maintaining some actions between atmosphere and hydrosphere, geosphere, biosphere(biological world). And they didn't perceive the characteristics of the water cycle whose all parts must be presented the change of volume between vapor and water, glacier proposing the total hydro-volume are established in the earth system. Based on the results, it was suggested that the main goals of the schools' science education should be to provide students who understand the water cycle system as attaching importance to form with the skills needed to coherent understanding of the essential qualities for the nature phenomenon system.

• Nuclear Engineering and Technology
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• v.22 no.1
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• pp.36-44
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• 1990

A safety assessment computer code CALM (Computer program of Assessment for LILW Management) is developed for the theoretical prediction of long-term safety of low-and intermediate-level radioactive waste disposal. CALM is composed of three submodels, which are the resaturation model, the geosphere migration model, and the radiation dose model. For the verification of its usefulness, the safety assessment of an assumed waste repository is performed. The results show that the computer code, CALM developed through this study can be a useful tool for the safety assessment of low- and intermediate-level radioactive waste repository.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.21 no.1
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• pp.149-164
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• 2023

As part of the safety case development for generic disposal sites in Korea, it is necessary to develop generic assessment models using various geosphere-biosphere interfaces (GBIs) and potentially exposed groups (PEGs) that reflect the natural environmental characteristics and the lifestyles of people in Korea. In this study, a unique modeling strategy was developed to systematically construct and select Korean generic biosphere assessment models. The strategy includes three process steps (combination, screening, and experts' scoring) for the biosphere system conditions. First, various conditions, such as climate, topography, GBIs, and PEGs, were combined in the biosphere system. Second, the combined calculation cases were configured into interrelation matrices to screen out some calculation cases that were highly unlikely or less significant in terms of the exposure dose. Finally, the selected calculation cases were prioritized based on expert judgment by scoring the knowledge, probability, and importance. The results of this study can be implemented in the development of biosphere assessment models for Korean generic sites. It is believed that this systematic methodology for selecting the candidate calculation cases can contribute to increasing the confidence of future site-specific biosphere assessment models.