• 한국과학교육학회지
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• 제15권4호
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• pp.429-436
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• 1995

The purpose of this study is to identify students' alternative frameworks about tide concept, to investigate some characters of them and students' understanding types with increasing grade in secondary school earth science course. The objective questionnaire method was used, and the subjects of this study are 528 students selected randomly in secondary school. The results are as follow. 1) Thirteen alternative frameworks about tide concept, related to the phase change of the moon and the motion of the earth are identified. 2) The alternative frameworks needed mechanical and causal reasoning have the trend reinforced or sophisticated with increasing the grade. And alternative frameworks needed phenomenal and mechanical, phenomenal and causal reasoning are changed little but ones needed phenomenal, variative and basic reasoning change scientifically. The rates of the alternative frameworks needed definitional, empirical, phenomenal reasoning decrease at the learning grade of that concept but increase after that grade. 3) Middle school students have the definitional, phenomenal, empirical and qualitative understanding types but high school students have the causal, analytic, quantitative and mechanical ones on tide concept.

• 한국과학교육학회지
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• 제16권1호
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• pp.61-76
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• 1996

The purpose of this study was to apply the instructional strategies for conceptual change prescribed by Posner et al(1982) to the astronomic content domain taught in the elementary and middle school and to analyze the characteristics of students' knowledge revealed in the test before, during and after the instruction. Also, it was to investigate the intercorrelation of cognitive levels, spatial ability and science achievement. The major findings of this study are as follows: 1. Students had a great variety of misconceptions related to the motion of the moon before the instruction, that is, the phases, the names of phases and the cause of changing phases by the moon's orbit about the earth, the moon's appearance and location at the given time, the relative positions of earth, moon and sun during a lunar eclipse, the cause that a full moon is not at the line of node once a month. In the analysis of students' responses concerning the cause of changing phases of the moon and a lunar eclipse, the results indicate that the great majority of students had rote learning rather than meaningful learning in the middle school. 2. Students' reponses during the instruction concerning the changing phases of the moon and the predictive knowledge about the motions of the earth and the moon were analyzed. 1) According to the results of the test given before and after experiment, after discussion, achievement score of the whole of subjects and groups in both preformal and formal cognitive levels appeared to increase linearly. 2) There was no statistically significant differences of achievement scores before and after experiment, after discussion between preformal group and formal group in cognitive levels. 3. Distribution of achievement scores according to the whole of subjects and groups in preformal and formal cognitive levels shows that there was a statistically significant difference between pretest and posttest. 4. Types of conceptual changes concerning the cause of changing phases of the moon that occurred from pretest to posttest were classified as accommodation, incomplete accommodation, assimilation, no change and no model. Six of the seven students starting instruction with alternative frameworks didn't sustain those alternative models throughout instruction. Five of these six students accommodated completely and the last one partially. Seventy-nine percentage of students taking instruction with fragmental models assimilated correct propositions at the end of the instruction. These results suggest that conceptual change model prescribed by Posner et al(1982) has promised the meaningful learning to students taking with fragmental models, especially in cases where students with misconception enter instruction. 5. High correlation between achievement score of simple-recall items and that of written items in pretest and posttest indicates that the higher students got the score in simple-recall items the better they also performed in written items. However, there was no statistically significant differences among cognitive levels, spatial ability and science achievement in the whole of subjects and groups according to the cognitive levels.

• 한국지구과학회지
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• 제40권5호
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• pp.476-486
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• 2019

This study examines the controlling role of synoptic disturbances on $PM_{10}$ spring variability in the Korean Peninsula by using empirical orthogonal function (EOF) and back trajectory analyses. Three leading EOF modes are identified, and a lead-lag analysis suggests that $PM_{10}$ variabilities be closely related to the synoptic weather systems. The first EOF shows the spatially homogeneous distribution of $PM_{10}$, which is influenced by travelling anticyclonic disturbance with negative precipitation and descending motion. The second and third modes exhibit the dipole structures of $PM_{10}$, being associated with propagating cyclones. Furthermore, the back-trajectory analysis suggests that the transport of pollutants by anomalous winds associated with synoptic disturbances also contribute to the altered $PM_{10}$ concentration. Hence, a substantial synoptic control should be considered in order to fully understand the $PM_{10}$ spatiotemporal variability.

• 한국과학교육학회지
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• 제34권8호
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• pp.703-718
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• 2014

이 연구에서는 지구, 지구 - 달 계, 태양계, 그리고 은하와 우주를 포함하는 천체의 구조와 운동을 종합한 천문 시스템(astronomical systems)의 학습 발달과정(learning progressions)을 조사하기 위하여, 순위 선다형 평가 문항을 개발하고 이를 초등/중학생들에게 적용한 검사 결과에 기반하여 학습 발달과정 해석의 타당성 검증의 근거를 제시하였다. 연구의 과정은 '구인특화, 평가문항 개발, 평가결과 기술, 측정 모델'로 이루어진 4 단계의 구인 모델링 방식(construct modeling approach)에 기반하여 진행되었다. 천문 시스템의 내용적 평가 구인으로 천체의 운동과 구조를 선정하였고, 탐구실행적 평가 구인으로 공간적 사고와 시스템 사고와 같은 천문학적 사고를 선정하였다. 이 연구에서 개발된 순위 선다형 평가 문항들은 천문 시스템에 대한 학습 발달과정을 조사하기 위한 검사 도구로서 적절하였다. 즉, item fit 분석 결과는 학생들의 문항 반응 결과가 Rasch 모델로 측정한 결과와 부합하였다. 그리고 Wright map 분석 결과는 이 연구의 평가 문항들이 천문시스템에 대한 학생들의 가설적 발달 경로를 조사하는데 매우 효과적임을 보여주었다. 학습 발달과정의 하위 정착점에서 학생들은 천체들의 위치와 운동 방향의 변화를 지구에서 보는 관점에서 2차원 평면으로 해석하는 공간적 사고 수준을 보였으며, 지구-달 계의 모델에서 천체의 위치와 변화를 부정확하게 연결하거나, 태양계 행성들과 은하수에 대한 단순한 패턴을 인식하는 시스템 사고 수준을 보였다. 학습발달과정의 중간 단계에서 학생들은 우주에서 내려다 본 지구 및 지구-달 계, 태양계의 모델을 근거로 천체의 운동을 해석하는 공간적 사고의 수준을 나타냈으며, 천체의 구조를 구성하는 요소들을 이 모델들과 연관시키는 시스템 사고를 보였다. 학습 발달과정의 상위 정착점에서 학생들은 우주에서 내려다 본 관점에서 형성된 천체의 운동 모델을 지구에서 바라 본 관점에서 얻은 자료와 서로 연관시키는 관점 전환의 공간적 사고를 지구의 운동, 지구-달 계의 운동, 태양계 행성의 운동, 은하와 우주의 운동에 적용할 수 있었다. 또한 상위 정착점에 도달한 학생들은 천문 시스템의 설명 모델을 구성하는 하위 요소들 간의 상호연관성을 파악하고 이를 설명 모델에 적용할 수 있는 시스템 사고를 나타냈다.

• Journal of Astronomy and Space Sciences
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• 제26권2호
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• pp.171-186
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• 2009

이 연구에서는 미래 한국의 달 탐사에 대비, 지구-달 천이궤적을 설계하고 분석하였다. 궤적 설계는 최소연료로 지구 주차궤도에서부터 달 임무궤도까지 도달하는 모든 단계에 대해서 실시하였으며 미래 한국의 달 탐사 개발 계획에 실질적인 도움이 되기 위해 2017년, 2020년, 2022년으로 각각 나누어 설계를 하였다. 탐사선의 운동방정식의 구현을 위하여 태양, 지구, 달의 중력에 의한 섭동력이 포함된 N체 운동 방정식을 사용하였으며 보다 실질적인 우주환경의 모사를 위하여 지구의 비대칭 중력장(Geopotential), 태양 복사압(Solar radiation pressure) 그리고 달의 J2 섭동에 의한 영향도 고려하였다. 임무 설계를 위해 가정된 추력은 순간 추력(Impulsive thrust)으로 가정하였으며 발사체의 성능은 현재 개발 예정인 KSLV-2로 가정하였다. 미래 한국의 가상 달 탐사선이 지구-달 천이 궤적(Trans Lunar trajectory)에 진입하는 방법으로는 지구 주차 궤도에서 직접 진입 하는 방법과 여러번의 타원 중개 궤도를 거친 후 지구-달 천이 궤적으로 진입하는 방법을 모두 이용하였다. 아울러 TLI(Trans Lunar Injection) 기동시 탐사선의 대전 지상국에서의 가시성에 따른 기동의 크기에 대한 영향이 분석되었다. 이 연구를 통한 임무 설계 결과는 달 탐사 임무 설계를 위한 발사 가능 시기(launch opportunity), 성공적인 임무 수행을 위한 임무 단계별 최적의 기동량 및 해당 궤도의 특성 그리고 다양한 임무 파라미터등의 해석을 포함하고 있다. 임무 설계 결과, 미래 한국이 쏘아 올릴 수 있는 달 탐사선의 전체 질량은 해당 임무의 수행시기 보다는 초기 지구 출발 궤도의 초기 고도와 발사제의 초기 궤도 투입 성능에 따라 더욱 크게 좌우됨을 확인하였다.

• 대기
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• 제26권4호
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• pp.635-647
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• 2016

The effects of sea surface temperature (SST) gradient induced by the previous typhoon on the following typhoon motion over East Asia have been investigated using Weather Research and Forecasting (WRF) model for the previous Typhoon Bolaven (1215) and following Typhoon Tembin (1214). It was observed that Typhoon Bolaven remarkably reduced SST by about $7^{\circ}C$ at Yellow Sea buoy (YSbuoy). Using the WRF experiments for the imposed cold wake over West of Tembin (WT) and over East of Tembin (ET), this study demonstrates that the effects of eastward SST gradient including cold wake over WT is much significant rather than that over ET in relation to unexpected Tembin's eastward deflection. This difference between two experiments is attributed to the fact that cold wake over WT increases the magnitude of SST gradient under the eastward SST gradient around East Asia and the resultant asymmetric flow deflects Typhoon Tembin eastward, which is mainly due to the different atmospheric response to the SST forcing between ET and WT. Therefore, it implies that the enhanced eastward SST gradient over East Asia results in larger typhoon deflection toward the region of warmer SST according to the location of the cold wake effect. This result can contribute to the improvement of track prediction for typhoons influencing the Korean Peninsula

• 대한지구과학교육학회지
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• 제8권1호
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• pp.87-97
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• 2015

This study is to find out that the effect of class applied Jigsaw cooperative learning to self-directed learning skills and task commitment. This study has been aimed at 2 class 66 students pre-service teachers who take "Science and study of teaching materials I" enrolled in B University of Education located in B city. This study targets to 2009 revision of elementary school science curriculum of changes in earth's surface(3-1), the volcano and earthquakes (4-1), the solar system and the stars (5-1), the motion of the Earth and the Moon (6-1) sections. Clarify the subject of study for implementing a research topics are as follows. First, What is the effect of class applied Jigsaw cooperative learning to self-directed learning skills? Second, what is the effect of class applied Jigsaw cooperative learning to task commitment? Third, what is awareness of class applied Jigsaw cooperative learning? Results of the study were as follows: First, class applied Jigsaw cooperative learning was effective in improving self-directed learning skills. Second, class applied Jigsaw cooperative learning was effective in improving task commitment. Third, in the course of discussion, students got consideration for others with leadership in their discussion was good in the class applied Jigsaw cooperative learning discussion. There was a response that they would like to do the class continually.

• Progress in Superconductivity
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• 제3권1호
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• pp.56-59
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• 2001

We have constructed a multi-channel SQUID magnetometer system for localization and classification of magnetic targets. Ten SQUID magnetometers were arranged to measure 5 independent components of 3 $\times$ 3 magnetic field gradient tensor. To get gradient from the difference of magnetic field measurements, we carefully balanced magnetometers. SQUIDs with slotted washer were used for operation in an unshielded laboratory environment, and noise characteristic in the laboratory was measured. With the multi-channel SQUID magnetometer system, we have successfully traced the motion of a bar magnet moving around it at a distance of about 1 m. In the urban environment, the drift of uniform magnetic field due to the irregular motion of a large magnetic body at distance and earth field causes an error in the position calculation, and this results in the distortion of the calculated trajectory. In this paper, we present the architecture and the performance of the system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1048-1049
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• 2015

The sihwa tidal power plant is the first tidal power plant in korea and the biggest of the world. The tidal power turbine is operated by tidal energy. The tidal energy is generated by the relative motion of the earth and celestial masses specially the sun and the moon, which interact via gravitational forces. The tidal power is estimated by the predicted the tidal amplitude and phase. This paper gives a process of estimate of tidal power using Matlab T-tide based on tide prediction. The proposed method is tested using actual recorded data comparing to predicted date.

• 한국지구과학회지
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• 제34권7호
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• pp.662-668
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• 2013

기후-전구대기화학모델을 이용하여 엘니뇨가 대류권 오존에 미치는 영향을 분석하였다. 40년간(1971-2010) 대류권 오존을 EOF 분석한 결과에서 열대 중앙-동태평양에서 오존의 감소가 관측과 유사하게 잘 모의되었다. 그러나 인도양-인도네시아 부근의 오존 증가는 관측에 비해 약하게 모의되었다. 엘니뇨에 의한 오존변동 과정을 이해하기 위하여 2006년 엘니뇨의 경우를 좀 더 자세히 분석하였다. 엘니뇨의 발생 시 중앙-동태평양의 오존 감소는 활발해진 상승운동과 그에 따른 수증기량 증가로 오존의 체류시간이 짧아졌음에 기인하였다. 해수면 온도 강제력으로 유도된 하강기류 편차와 수증기 감소로 인도양 대류권 상층 오존이 증가하였다.