• Journal of Astronomy and Space Sciences
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• v.18 no.2
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• pp.129-136
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• 2001

The accuracy of GPS applications is heavily dependent on the satellite ephemeris and earth orientation parameter. Specially applications like as the real time monitoring of troposphere and ionosphere require real time or predicted ephemeris arid earth orientation parameter with very high quality. IGS is producing IGS ultra rapid product called IGU for real time applications which includes the information of ephemeris and earth orientation. IGU is being made available twice everyday at 3:00 and 15:00 UTC arid covers 48 hours. The first 24 hours of it are based on actual GPS observations and the second 24 hours extrapolated. We will construct the processing strategy for yielding ultra rapid product and demonstrate the propriety through producing it using 48 hours data of 32 stations.

• Journal of the Korean earth science society
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• v.25 no.7
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• pp.519-531
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• 2004

The purpose of this study was to ascertain high school student ideas on the motion of the Earth and moon by cognitive level. For this study, five students determined to be of high, middle and low cognitive level selected from 73 10th-grade students at a high school located in Suwon, Gyeonggido. The results of this study were as follows: first, students at the high cognitive level had comparatively more logical and scientific conception on the revolution and rotation of the Earth and moon. second, students at the middle cognitive level, generally had a passive learning attitude to unconditionally memorize learned contents, so they were apt to forget learned contents, also their recognized conception was not enlarged. In addition, they had native theories, intuitive ideas and misconceptions as well as made logical errors in the course of explanation for the motion of the Earth and moon. In the course of explanation for the phases of the moon and the cause of change of season, because of their scientific conception, the students made more and more errors in conception. finally students at the low cognitive level were not willing to think logically and positively and were very passive in the attitude to recognize conception. In addition, they have learned helplessness on the grounds that they have low scholastic achievement specially in science.

• Journal of the Korean Regional Science Association
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• v.34 no.3
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• pp.29-42
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• 2018

Population growth in Korea is slowing down, and the ratio of 1~2 person households has exceeded 53.3% of the total. And in the future, it is becoming more important how to accommodate as proper planning in residential areas. In this paper, we examine whether the existing district unit plans respond appropriately to the trend of the increase in small-sized housing, and we propose improvement plans for elements of the district unit plan and measures to enhance its applicability in response to small-sized housing. To do this, we analyzed the guidelines and contents of the district unit plans related to small-sized housing in recent 6 residential sites, and derived problems and improvements through literature review and expert consultation. As a result of the study, we proposed the items that need to be reflected in the district unit plan related to various housing type for one person household. And planning elements related to households, housing site, building layout, and architectural shape and appearance were also proposed, which were suitable for single-person households, such as small-sized communal housing, share-house, and single-person housing. It also suggested that single-person households should be considered for housing characteristics, including introduction of auxiliary welfare facilities such as unmanned delivery box and guest houses, and exclusion of low-demand auxiliary welfare facilities such as kindergartens. The suggested content can be used to make guidelines for small-sized housing in district unit plan.

• Journal of Astronomy and Space Sciences
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• v.20 no.4
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• pp.299-312
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• 2003

Earth to Mars ballistic mission opportunities from Naro Space Center are studied. Determining ballistic mission opportunities can be divided into two major parts, i.e. the launch window and the daily launch window determination. At the launch window determination parts, Porkchop diagrams of Earth launch C3 magnitude, total mission duration, declination of $V_{\infty}$ vector at the Earth launch, and declination & right ascension of $V_{\infty}$ vector at the Mars arrival are examined. The location of launch site and rotation effects of the Earth are considered during the daily launch window determination parts. Using Lambert method, various Porkchop diagrams of launching in 2027 are examined for example. The daily launch window of Naro Space Center at that year was checked to verify the launch possibility by comparing with the Kennedy Space Center.

• Journal of the Korean earth science society
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• v.32 no.1
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• pp.73-83
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• 2011

A new method was developed to better understand the principle of Coriolis force. We also investigated the understanding of 5 10th grade students and analyzed their responses. Since no clear explanation about the nature of a rotating disk is provided in school textbooks, it tends to be misunderstood as the earth surface revolving on its axis pointing to the North Pole. This study was carried out focusing on the fact that a rotating disk is the tangential plane at arbitrary latitude. Results showed that there are changes in students' conceptions on the principle of Coriolis force with a new understanding of the rotating disk. In conclusion, a new method used in this study helped students better understand the link between Coriolis force and rotating disk. The method would be helpful to clarify the principle of Coriolis force in school science.

• Journal of The Korean Association For Science Education
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• v.22 no.1
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• pp.40-53
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• 2002

This study was based on the analysis of earth and environmental science items in PISA 2000 data. The purpose of this study was to identify i) gender differences in scientific literacy, ii) item characteristics that favored either female or male, and iii) misconceptions that 15-years-old Korean students have in the field of earth and environmental science. The results revealed significant gender differences. Overall, male students demonstrated higher level of achievement than female students. On the other hand, amongst high ability students, female students outperformed male students in open-constructed items. Female students tended to score higher on items that required long answers or items related to scientific processes, whereas male students outperformed female students in science knowledge or items that required data interpretation. The study also revealed that a majority of Korean students had misconceptions in fundamental earth and environmental science knowledge, such as the direction of earth's axis and equator, and the causes of Greenhouse Effect.

• Journal of The Korean Association For Science Education
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• v.37 no.1
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• pp.9-16
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• 2017

The result of TIMSS 2015 was announced at the end of 2016. In this research, we conducted test-curriculum matching analysis for 8th grade earth science and analyzed Korean students' percentage of correct answers and responses for TIMSS earth science test items. According to the results, Korean students showed high percentage of correct answers when the item topics are covered in the 2009 revised science curriculum, and Korean students revealed their weakness in constructed response items since the percentage for correct answers on constructed response items is half that of multiple choice items. Depending on the earth science topic, for 'solid earth' area, which includes earth's structure and physical features, as well as earth's processes and history, students showed high percentage of correct answers for multiple choice items. Students, however, showed low percentage of correct answers for items that require applying knowledge to everyday situations and connecting with other areas of science such as biology. For 'atmosphere and ocean' areas, which include earth's processes and cycles, students showed low percentage of scores for climate comparison between regions, features of global warming, etc. For the area of 'universe', students showed high percentage of scores for the earth's rotation and revolution, the moon's gravity, and so on because they have learned these topics since primary school. Discussed in the conclusion are ways to secure content connection between the primary and middle school earth science curriculums, ways to develop students' science-inquiry related competencies, and so on to improve middle school earth science curriculum as well as teaching and learning.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.4
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• pp.324-331
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• 2018

The thermal environment on lunar surface is more severe than that of earth's surface or low earth orbit because of the long daytime and nighttime due to 28 days of rotation cycle of moon. Thus, analyzing heat flux on lunar lander at potential landing sites is important to determine the landing site in its initial design phase. In this study, thermal model of lunar regolith that can simulate lunar surface temperature was constructed for analyzing thermal characteristics according to the potential landing sites of lunar lander. The heat flux analyses were performed various latitudes of equator, mid-latitude, polar regions, lunar mare and highland. In addition, we also investigated the heat flux of lunar lander when it is landed on adjacent area to hill.

• Development and Reproduction
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• v.7 no.1
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• pp.1-7
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• 2003

Most animals, including human beings, live in a cyclic pattern of lift that is influenced by the ambient changes of environment. The regular changes occurred by rotation of the Earth itself its revolving around the Sun, and the local environment, are reflected by the distinct behavior in the living organisms. These regular changes of environment have been imprinted into the genes within the living organisms through the evolutionary process over a long period of time. The genes are expressed by rhythms during the process of fetal development followed by growth. The environmental modifications ultimately are settled in genes, serving as a biological clock that is located putatively in the hypothalamus. Thus the biological clock governs a large number of rhythms and affects the time of birth and death lift expectancy, behavior, physiology, cell division, biochemical reaction, etc. The rhythms are readjusted to the changes of environmental cues. The biological clock has the great advantage of predicting and preparing the regular changes of environment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.9
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• pp.821-827
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• 2015

Electromagnetic waves which are emitted from the Sun due to solar flare explosion can cause failures in HF radio communications in the day-side area of the Earth, that is so-call as Radio Blackouts. The international scale representing the severity of the Radio Blackouts is determined by the solar X-ray flux which is measured by United States Geostationary Operational Environmental Satellite. However, the scale is not always applicable to HF communication users in the different area on the Earth, because the HF communication effects depend not only on the X-ray strength but also on the subsolar point location. To solve this problem, we developed a HF radio spectrum monitoring system utilizing a spectrum analyzer. This system conducts a real-time measure of the HF spectrum, and automatically calculates signal to noise ratios and the occurrences of the HF blackouts as comparing with the interference level which is described from the ITU recommendation.