• Journal of the Korean earth science society
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• v.24 no.2
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• pp.93-99
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• 2003

The purpose of this study was to develop a new test instrument based on AAAS Benchmarks for Science Literacy, to assess k-12 students' progress in understanding nature of science (NOS). A total of 276 items were developed including 33 items for grade k-2, 36 items for grade 3-5, 78 items for grade 6-8 and 129 items for grade 9-12 and they were reviewed for validity and reliability. Key ideas that were the foundation of test items were extended, sophisticated and enriched according to the grade level. The general score of this test represents a student's cognitive state about an understanding of NOS. The result of this test can be expected to give some useful information for follow-up investigations, improving instructional design, and conducting further studies.

• Journal of the Korean earth science society
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• v.24 no.2
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• pp.100-107
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• 2003

The purpose of this study is to assess gifted students' conceptions about nature of science (NOS). Scientifically gifted students who are expected to be professionals in the future should possess an adequate understanding of NOS that if firm foundation for scientific career. 47 volunteers from the 8th grade gifted science program in Seoul National University Gifted Education Center participated to answer questions inquiring NOS conceptions. Their answers were analyzed and compared to different groups such as non-gifted students and younger gifted students. As a result, gifted students' understanding of NOS appeared to surpass that of non-gifted students in many aspects and it seemed that gifted students formed their NOS view in early ages. The relative weakness in their NOS conceptions was found in understanding of scientific enterprise. Their strong misunderstanding about obstacles that minority people would face in scientific enterprise was noticed, too. They admitted that there has been discrimination in scientific enterprise, but they wrongly believed that outstanding scientists cannot be affected by it. Further studies will be required to probe more.

• Analytical Science and Technology
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• v.8 no.4
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• pp.553-559
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• 1995

An extraction chromatographic method of separating rare earth impurities from high purity $Nd_2O_3$, $Sm_2O_3$, $Gd_2O_3$, $Er_2O_3$, $Dy_2O_3$ and $Yb_2O_3$ was studied by using $HCl-NH_4Cl$ as moving phase and P507 as stationary phase. After the impurities were enriched from the eluate by chelant-activated carbon, the active carbon was ashed and the ignited residue was used to prepare the sample electrode for spark source mass spectrometric determination. The impurities in 99.9999% rare earth oxide can be determined by the proposed method with recovery over 80%.

• Journal of the Korean earth science society
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• v.28 no.5
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• pp.556-562
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• 2007

The interdecadal variation of wintertime blocking frequency over the Siberia ($60^{\circ}E-140^{\circ}E$) is examined using the ECMWF/NCEP-NCAR re-analysis data for the period 1958-2006. The wintertime blocking frequency over the Siberia significantly decreased for the period 1986-2006, compared to the period 1958-1985, which is mainly due to the anomalous circulation of 500-hPa geopotential height field. During the period 1986-2006, there was enhancement in both the anomalous cyclonic flow over the western Siberia and the anomalous anticyclonic flow over the east Asia. These anomalous circulation patterns, which might be associated with changes in surface temperatures over the Asian continent, are suspected to playa possibly important role as an obstacle to the formation of blocking flow over the Siberia.

• Journal of the Korean earth science society
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• v.42 no.4
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• pp.383-389
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• 2021

Several studies investigating the behavior and environmental distribution of rare earth elements (REEs) have been reviewed to determine the geochemical processes that may affect their concentrations and fractionation patterns in groundwater and whether these elements can be used as tracers for groundwater-rock interactions and groundwater flow paths in small catchments. Inductively coupled plasma-mass spectrometry (ICP-MS), equipped with an ultrasonic nebulizer and active-film multiplier detector, is routinely used as an analytical technique to measure REEs in groundwater, facilitating the analysis of dissolved REE geochemistry. This review focuses on the distribution of REEs in groundwater and their application as tracers for groundwater geochemistry. Our review of existing literature suggests that REEs in ice cores can be used as effective tracers for atmospheric particles, aiding the identification of source regions.

• Journal of the Korean Society of Earth Science Education
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• v.7 no.2
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• pp.266-275
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• 2014

The purpose of this study was to examine the effect of Earth System Education using multimedia on the elementary school students' environmental sensitivity and pro-environmental behavior. To verify this research problem, the subject of this study was fifth-grade students selected from two classes of M elementary school located in Busan city. For three months, the experimental group of 25 students was taught using multimedia. The comparison group also of 26 students was taught in normal classes which used a text-book. All students were given pre and post test to verify the effects of Earth System Education using multimedia on elementary school student's environmental sensitivity and pro-environmental behavior. The results from this study are as the following. First, Earth System Education using multimedia were effective on elementary school student's environmental sensitivity. Second, Earth System Education using multimedia were effective on elementary school student's pro-environmental behavior. Third, All most all experimental students were satisfied with Earth System Education using multimedia. In conclusion, Earth System Education using multimedia showed very positive effects on improvement of elementary school students' environmental sensitivity and pro-environmental behavior.

• Journal of Korean Elementary Science Education
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• v.34 no.3
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• pp.288-296
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• 2015

This study aimed to analysis of concepts and inquiry activities related to the 'Earth Science' area in the South Korean elementary school textbooks to the current and to seek the improvement of future textbook. For the study, we were collected South Korean elementary school textbooks to the current. After the collection had been made, we were analyzed related to the 'Earth' area in the South Korean elementary school textbooks and were extracted central concepts and inquiry activities. The result of this study: First, there were 'A change in the land', 'Strata and Fossil', 'Volcanoes and Earthquakes', 'Earth and Moon', 'The weather', 'The Solar system and the Star', and 'Seasonal Change' in the central concepts related to the 'Earth' area in the South Korean elementary school textbooks to the current. Second, central concepts were almost the same but the curriculum was changed. Third, inquiry activities also were confirmed to be maintained with little change. This result was believed that it can provide a variety of suggestions at this point in changing the curriculum.

• Journal of The Korean Association For Science Education
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• v.13 no.2
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• pp.257-271
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• 1993

Four science concepts were selected from high school earth science textbook to investigate the differences in students knowledges activated in laboratory and earth environmemtal contexts. Two items, one is for laboratory and the other for earth environmental contexts, were develped for each selected concept. Students' responses were analyzed in terms of 'Common Activated Knowledges' (CAK), 'Specific Activated Knowledges'(SAK) across students' cognitive frames, grades and sexes. As contextual differences of the problems increased, gender contributed more than other variables to the frequencies of activating CAK and SAK. Context effects were also reported across cognitive frames for CAK, but SAK became more avtivated when the contextual differences of the items become smaller. As a whole, students with laboratory cognitive frames showed more significant context effects than others. Students in 11th grade, with scientific frames and with earth science cognitive frames showed relatively small context effects. The results of the study showed that sciene concepts learned in a laboratory context are not usually transferred spontaneously to earth environmental contexts. Special instructional strategies should developed to overcome the context effects.

• Journal of the Korean earth science society
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• v.42 no.4
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• pp.445-458
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• 2021

Gravity Recovery and Climate Experiment (GRACE) gravimeter satellites observed the Earth gravity field with unprecedented accuracy since 2002. After the termination of GRACE mission, GRACE Follow-on (GFO) satellites successively observe global gravity field, but there is missing period between GRACE and GFO about one year. Many previous studies estimated terrestrial water storage (TWS) changes using hydrological models, vertical displacements from global navigation satellite system observations, altimetry, and satellite laser ranging for a continuity of GRACE and GFO data. Recently, in order to predict TWS changes, various machine learning methods are developed such as artificial neural network and multi-linear regression. Previous studies used hydrological and climate data simultaneously as input data of the learning process. Further, they excluded linear trends in input data and GRACE/GFO data because the trend components obtained from GRACE/GFO data were assumed to be the same for other periods. However, hydrological models include high uncertainties, and observational period of GRACE/GFO is not long enough to estimate reliable TWS trends. In this study, we used convolutional neural networks (CNN) method incorporating only climate data set (temperature, evaporation, and precipitation) to predict TWS variations in the missing period of GRACE/GFO. We also make CNN model learn the linear trend of GRACE/GFO data. In most river basins considered in this study, our CNN model successfully predicts seasonal and long-term variations of TWS change.

• Korean Journal of Remote Sensing
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• v.35 no.1
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• pp.195-201
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• 2019

The Outgoing Longwave Radiation (OLR) is an important satellite-driven variable for understanding the Earth's energy budget balance. The geostationary OLR retrievals require angular and spectral integration using an empirical equation for irradiance flux-to-OLR from a regression analysis, which determines the accuracy of the narrowband satellite-based OLR. We selected homogeneous pixels which is satisfied less temporal-spatial variability of cloud, on three infrared channels (6.7, 10.8, $12.0{\mu}m$) of the first multipurpose geostationary satellite in Korea, namely the Communication, Ocean and Meteorological Satellite/Meteorological Imager (COMS/MI). Multiple regression analysis was performed to retrieve OLR with improved accuracy using selected parameters based on theoretical and physical significance. This algorithm yielded retrieval with higher accuracy than broadband-based OLR retrieval: RMSE of 10.54 to $3.81W\;m^{-2}$, and bias of -8.49 to $-0.07W\;m^{-2}$.