• 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 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.

• Journal of the Korean earth science society
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• v.31 no.1
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• pp.71-87
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• 2010

The purpose of this study was to explore 8th-grade students' imageries of the Earth. We analyzed the middle school students' imageries about the Earth represented with words and drawings in Earth Systems Understanding (ESU, hereafter) framework. The students' imageries about 'the Earth' are vary by their experiences and prior-knowledge, which significantly impacts their imagery construction. Especially, the students' ESU were characterized into two aspects: One is a macroscopic view point based on full-objects of the Earth by indirect experiences and the other is everyday view point based on scene of the Earth surface and environment by direct experiences. Results revealed students' imageries about the Earth were impacted by visual experiences and those students' ESU were more represented by drawing as visual imagery than by words, formal language. The negative imageries were mainly represented through interactions of the Earth subsystems.

• Journal of the Korean earth science society
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• v.26 no.2
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• pp.160-165
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• 2005

A series of high resolution spectra of CH Cygni obtained at the Bohyunsan Optical Astronomy Observatory (BOAO) in April 2004 has been analyzed. The emission components of the [O I] 6300 A lines are de-convoluted and fitted with Gaussian functions in order to investigate the characteristics and the structure of CH Cygni system along with the analysis for $H{\alpha}$ and [O III] lines. A present geometrical structure of the components of CH Cygni system is suggested.

• Journal of Positioning, Navigation, and Timing
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• v.3 no.4
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• pp.149-154
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• 2014

The BeiDou is a satellite-based positioning and navigation system, which is under construction by the China Satellite Navigation Office. Until the June of 2014, the constellation of BeiDou navigation satellite system consists of 14 satellites including five geostationary earth orbit (GEO), five inclined geosynchronous earth orbit (IGSO) and four medium earth orbit (MEO). In this paper, we present the positioning results using BeiDou B1 code measurements obtained from three GNSS reference stations (BHAO, SKMA, MKPO). Combined Beidou/GPS positioning results are also compared to BeiDou and GPS only. BeiDou-only positioning errors for the east-west and north-south direction had less than 2 meter with root mean square (RMS) value. However, the positioning error for the up-down direction had larger than 10 meter at a 95% confidence level. Our results also suggest that the position precision is improved by combined BeiDou/GPS compared to BeiDou-only.

• Journal of the Korean earth science society
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• v.28 no.4
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• pp.431-444
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• 2007

An automatic system of 36 cm telescope for the Web Based astronomy education was developed. The tracking accuracy of this system was about 1"/min. The pointing accuracy was ${\pm}10"$ in the right ascension direction, ${\pm}20"$ in the declination direction. These results will be improved continuously. The results of IRAF image analysis for the pilot observation data were stable, which means that this remote astronomical observation system is suitable f3r the education of astronomical observation.

• Korean Journal of Remote Sensing
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• v.39 no.5_3
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• pp.949-965
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• 2023

In this study, we propose a method to monitor the surface area of agricultural reservoirs in South Korea using Sentinel-1 synthetic aperture radar images and the deep learning model, Swin Transformer. Utilizing the Google Earth Engine platform, datasets from 2017 to 2021 were constructed for seven agricultural reservoirs, categorized into 700 K-ton, 900 K-ton, and 1.5 M-ton capacities. For four of the reservoirs, a total of 1,283 images were used for model training through shuffling and 5-fold cross-validation techniques. Upon evaluation, the Swin Transformer Large model, configured with a window size of 12, demonstrated superior semantic segmentation performance, showing an average accuracy of 99.54% and a mean intersection over union (mIoU) of 95.15% for all folds. When the best-performing model was applied to the datasets of the remaining three reservoirsfor validation, it achieved an accuracy of over 99% and mIoU of over 94% for all reservoirs. These results indicate that the Swin Transformer model can effectively monitor the surface area of agricultural reservoirs in South Korea.

• Journal of Photoscience
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• v.9 no.2
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• pp.267-268
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• 2002

A vertebrate retina is an organ belonging to the central nerve system (CNS), and is usually difficult to regenerate except at an embryonic stage in life. However, certain species of urodele amphibians, such as newts and salamanders, possess the ability to regenerate a functional retina from retinal pigment epithelial (RPE) cells even as adults. After surgical removal of neural retinas from adult newt eyes, the remaining RPE cells lose their pigment granules, transdifferentiate into retinal progenitor cells, which further differentiate into various retinal neurons, and then finally reform a functional neural network. To understand the molecular mechanisms of CNS regeneration, we attempted to investigate the genes expressing in regenerating newt retina. mRNAs were isolated from regenerating retinas at 18-19 days after the surgical removal of the normal retina, and a cDNA library (regenerating retinal cDNA library) were constructed. Our EST analysis of 112 clones in the regenerating cDNA library revealed that about 70% clones are closely related to the genes previously identified. About 40% clones are housekeeping genes, and about 15% clones encode proteins related to the regulation of gene expression and to the proliferation of the cells. Sequences similar to neural retina- and RPE-specific genes were not detected at all. These results led us to suppose that the regenerating retinal cells are in a state considerably different from those of neither neural retina nor RPE cells.

• Journal of the Optical Society of Korea
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• v.16 no.2
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• pp.141-144
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• 2012

A mobile Rayleigh Doppler wind LIDAR at an eye-safe wavelength of 355 nm incorporating double-edge technique with triple-channel Fabry-Perot etalon is developed for wind measurement from 5 to 40km. The structure of this LIDAR system is described. An intercomparsion experiment with rawinsonde is made, showing good agreement with expected measurement accuracy. A continuous observation of stratosphere wind field for several days with temporal resolution of 15 min and spatial resolution of 200 m from 5 to 40 km is presented, demonstrating the stability and robustness of the LIDAR. A stratospheric quasi-zero wind layer can be found at around 20 km with a direction change from east to west evident in the continuous observation.

• Journal of the Korean earth science society
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• v.27 no.5
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• pp.528-538
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• 2006

Main aspect of this study is to clarify the petrochemistry and petrogenesis of intermediated-basic plutons located in the southwestern part of the Korean peninsula. These Intermediated-basic plutons consist of Pre-Cambrian anorthosite-gabbro, Triassic hornblende gabbro (Jirisan area), Jurassic diorite-syente (Jirisan and north area) and Cretaceous gabbro-diorite (south area). The Massif type anorthosite has multi intrusions, where each one intruded by gabbroic rocks, composed of gabbro, norite, troctolite and leucogabbro. In the variation diagram of the major-minor composition, AMF and Pl-Px-Ol diagrams, we suggest that intermediated-basic plutons in the southwestern part of the Korea show a trend consistent to Daly's value and calc-alkaline rock series. Accoding to REE (La/Yb)cw and Eu/Sm, these plutons are enriched with LREE than HREE, and emplaced by the tectonic setting in continent and/or continental margin.