• Journal of the Korean earth science society
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• v.33 no.7
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• pp.672-682
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• 2012

The purpose of this study is to investigate elementary school science gifted students' perceptions about Earth systems and environmental problems. A total of 28 students in the attached center for science gifted education to the university participated in this study. Through the survey, participating students were asked to respond to their self-reported knowledge level, the perceived danger levels, certainty, and tangibility of the selected 13 Earth environmental problems. The DAET (Draw-An-Earth Test)-Checklist were developed and used to analyze the images of the Earth drawn by students. Additional interviews were conducted to clarify the meanings and components of students' image. Results indicated that a total of 80 components regarding Earth systems, 11 components of Earth systems interaction, and 4 components related to Earth systems literacy were identified through the DAET-Checklist and additional interviews. Regarding the students' self-reported knowledge level, they reported that they were most knowledgeable about air pollution, global warming, and water pollution. and they also recognized global warming, air pollution, and water pollution as the most dangerous problem. Results indicated that participants were certain that acid rain, air pollution, and water pollution were problematic, and that acid rain, air pollution, and forest desertification were tangible issues. It is anticipated that this study contributes to understanding the elementary school science gifted students' perceptions toward the selected Earth systems and environmental problems.

• Journal of the Korean earth science society
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• v.32 no.5
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• pp.494-503
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• 2011

During the last three decades, earth science has been re-conceptualized as an interdisciplinary discipline entitled Earth System Science (ESS), which is based on knowledge of the physical earth system and human impact on the earth. While there is increasing effort to teach earth as a system in K-12 education, teachers' preparedness of to teach earth system is still in its infancy. This article focuses on reviewing the literature of teachers' knowledge of earth systems and of how teachers' knowledge of subject matter affects their teaching practice and pedagogical content knowledge (PCK). First, the study investigated a literature of PCK in general as well as in science teaching. Then this study duscuss what teachers' subject matter knowledge (SMK) is and what it means to be in teaching earth system science. Third, a literature of teachers' knowledge of earth system was reviewed. Finally, a number of suggestions and implications are made as to what teacher education program should do to better prepare future teachers to teach earth systems.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.10a
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• pp.494-495
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• 2008

• Proceedings of the Petrological Society of Korea Conference
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• 2009.05a
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• pp.4-6
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• 2009

• Journal of the Korean earth science society
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• v.28 no.6
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• pp.673-685
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• 2007

The purpose of this study was to investigate Earth Systems Understandings (Mayer, 1991) and Earth Systems meaning generation reported by science-talented students who participated in a geological field trip. The eight (4 female and 4 male students) field trip reports were randomly selected among all the reports written by twenty eighth-grade students who joined Shiwha-Lake field trip in Korea. The three-step program, including preparation, field trip, and summary, was provided to the students in order to facilitate meaningful learning through outdoor teaming activities. Seven Earth Systems Understandings and thematic types (Keys, 1999) were used to analyze the reports. The results of this study indicated thai aesthetic views and stewardship toward the Earth, which were the most distinguishing characteristics in Earth Systems Education, were reflected on most of the reports. The results also showed that the students tried to represent their understandings in such a type as meaning extension, meaning enhancement, or meaning elaboration. Overall, many students used 'knowledge-telling' process with a long list of observations and facts, whereas a few students used higher-order 'knowledge-transforming' process by coordinating their findings with interpretations and reasoning in their writings.

• Proceedings of the Korean Geotechical Society Conference
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• 1994.09a
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• pp.129-138
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• 1994

It is well recognized that accurate analysis of lateral earth pressure is very signficant factor which determines the design amount of braced cut walls and braced systems. Many researchers, Peck, Terzaghi-Peck and so on, make a study about lateral earth pressure to act on the flexible walls. But these studies trouble accurate to multy layered systems like inland areas in Korea. This study is compared with the field messurement data to estimate the earth pressure distributions in multy layered areas and the empirical earth pressure distributions. The conclusions are as follows : At final excavation depth, the lateral earth pressure which messured by field instrument is smaller than the empirical earth pressure. (About 1.85~5.32 times). In the case of considering the soft rock layer to the final excavation depth, the messured earth pressure is safe to be compared with empirical earth pressure. The messured earth pressure distributions are like that the upper soil layer is small the middle soil layer is large, the rock mass layer is very small.

• Journal of Astronomy and Space Sciences
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• v.40 no.4
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• pp.149-171
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• 2023

ShadowCam is a National Aeronautics and Space Administration Advanced Exploration Systems funded instrument hosted onboard the Korea Aerospace Research Institute (KARI) Korea Pathfinder Lunar Orbiter (KPLO) satellite. By collecting high-resolution images of permanently shadowed regions (PSRs), ShadowCam will provide critical information about the distribution and accessibility of water ice and other volatiles at spatial scales (1.7 m/pixel) required to mitigate risks and maximize the results of future exploration activities. The PSRs never see direct sunlight and are illuminated only by light reflected from nearby topographic highs. Since secondary illumination is very dim, ShadowCam was designed to be over 200 times more sensitive than previous imagers like the Lunar Reconnaissance Orbiter Camera Narrow Angle Camera (LROC NAC). ShadowCam images thus allow for unprecedented views into the shadows, but saturate while imaging sunlit terrain.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.2
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• pp.141-147
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• 2013

Permanent magnet (PM) motors that employ rare-earth magnets containing dysprosium (Dy) are used in electric and hybrid electric vehicles. However, it is desirable to reduce the amount of Dy used since it is expensive. This study investigates the rotor structure of a PM synchronous motor with a Dy-free rare-earth magnet. Flux barrier shapes and PM thicknesses that enhance the irreversible demagnetization are investigated. In addition, a rotor structure that improves the irreversible demagnetization is proposed. We demonstrate that the proposed rotor structure without Dy improves the irreversible demagnetization.

• International journal of advanced smart convergence
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• v.9 no.3
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• pp.97-104
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• 2020

In this paper, we propose a method to derive the kernel function directly from the measured apparent earth resistivity. At this time, the kernel function is obtained through the process of solving a nonlinear system. Nonlinear systems with many variables are difficult to solve. This paper also introduces a method for converting nonlinear derived systems to linear systems. The kernel function is a function of the depth and resistance of the Earth's layer. Being able to derive an accurate kernel function means that we can estimate the earth parameters i.e. layer depth and resistivity. We also use various Earth models as simulation examples to validate the proposed method.

• Journal of Astronomy and Space Sciences
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• v.28 no.4
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• pp.345-354
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• 2011

Earth acquisition is to solve when earth can be visible from satellite after Sun acquisition during launch and early operation period or on-station satellite anomaly. In this paper, the algorithm and test result of the Communication, Ocean and Meteorological Satellite (COMS) Earth acquisition are presented in case of on-station satellite anomaly status. The algorithms for the calculation of Earth-pointing attitude control parameters including those attitude direction vector, rotation matrix, and maneuver time and duration are based on COMS configuration (Eurostar 3000 bus). The coordinate system uses the reference initial frame. The constraint calculating available time-slot to perform the earth acquisition considers eclipse, angular separation, solar local time, and infra-red earth sensor blinding conditions. The results of Electronics and Telecommunications Research Institute (ETRI) are compared with that of the Astrium software to validate the implemented ETRI software.