• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.719-727
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• 2021

In the field of architecture, retractable devices capable of responding flexibly to the environment have been applied widely to large structures. Among these devices, the aesthetically pleasing retractable membrane is lightweight so that the membrane can be opened easily using only a traction device. On the other hand, because the towed membrane moves as it is connected to the main cable by a trolley, the number of trolleys needed increases in proportion to the roof's area. This study proposes an optimal model for an open-type trolley (OTT), which is used widely in these devices, using topology optimization. The analysis used the ANSYS program. A new model was proposed based on the results and reviewed through the feedback. Through this process, it was possible to develop a prototype with increased durability and reduced weight. For OTT, optimization was performed based on static analysis and the boundary conditions, so three prototypes were designed. A comparison of the proposed trolley with the conventional one under the same conditions revealed an up to 71.04% decrease in volume while the yield-strength reached 8.67 to 11.43%. In conclusion, the optimal trolley proposed was found to be reliable in terms of economy and stability.

• Korean Journal of Ichthyology
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• v.22 no.2
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• pp.90-95
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• 2010

Blue devil (Pomacentrus caeruleus, also called Chrysiptera cyanea) is widespread in the Indo-Pacific Ocean and very popular all over the world as an aquarium fish because it is so easy to keep in a marine aquarium. However, tank-breeding techniques are not completely known. In this study, we reared blue devil and investigated its spawning ecology, as a necessary precursor for successful artificial-tank breeding. We investigated the spawning volume according to time with two types of calendars: solar and lunar. Rearing conditions were set at 30 ppt salinity, $27^{\circ}C$ water temperature, in two aquariums with water volumes of 80 and 125 L. We successfully bred P. caeruleus in this artificial-tank system. The aquarium fish formed a spawning harem with one male and more than two females. We harvested about 113,580 eggs in 44 spawning episodes by two spawning harems during the 11-month period from December to October. They showed a peak season of spawning volume and time in May and June. We confirmed the two peak points in spawning volumes and times, which coincided with the first quarter and last (third) quarter of the lunar phases of the moon.

• Journal of the Korean Society of Earth Science Education
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• v.12 no.3
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• pp.198-207
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• 2019

The purpose of this study is to investigate the effect of jigsaw cooperative learning class of elementary pre-service teacher on task commitment and creative personality. This study established an twelve-week period of experimental treatment from september to november 2019, and the students who participated in the study formed a research group of 121 students in 2nd grade of their advanced classes who are attending the second semester of b university of education and taking courses in 'teaching research 2'. B university of education is singleness class that doesn't have compare group, so this study is constituted only study group. Applying based-jigsaw cooperative learning class to study group, before and after concept of task commitment test and creative personality test is performed. The results of the study were as follows. First, the study group applied jigsaw cooperative learning-based science class had statistically significant differences in task commitment (p<.05). Second, the study group applied jigsaw cooperative learning-based science class had statistically significant differences in creative personality efficacy(p<.05). Third, jigsaw cooperative learning-based science class of pre-service teachers have a very good feeling. Through such study results, the study could figure out that the class applying jigsaw cooperative learningbased science class has positive effect on concept of task commitment and creative personality efficacy.

• Journal of the Korean earth science society
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• v.34 no.7
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• pp.727-737
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• 2013

The purpose of this study was to investigate the middle school students' perception and their learning satisfaction in SMART learning based science instruction. Three types of modules on the solar system and lunar phases unit at the middle school level were developed and lessons on each module were taught to 207 student participants. All participants were provided with tabletPC(iPad2) with iOS5 installed, and using astronomy app Solar Walk, mirroring function, QR code, and Google Presentation, the lessons were carried out both in classroom and at home. The instrument for assessing students' perception on the SMART learning-based instruction was developed based on 4 factors including Self-directed, Motivation, Adaptiveness, and Technology Embedded, with a Likert scale from 1-5 on 20 items. The learning satisfaction survey instrument was originally from Keller's work (1987), and its test items were adapted and modified. To reveal the perception and learning satisfaction about SMART learning-based science lessons, the participants were comparatively analyzed by gender and science achievement levels. Results indicated that male students showed positive perception for the SMART learning-based instruction. Group with higher science achievement scores showed more positive perception of the SMART learning-based instruction in terms of Self-directed and Motivation factor. Also, the learning satisfaction of male students was higher than female students and group with higher academic ability more satisfied with the SMART learning-based instruction than the low group. The results provide implications for future development of programs and help set a direction of increasing the use of a SMART learning-based science in school.

• Sijohaknonchong
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• v.30
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• pp.53-90
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• 2009

This study discusses the aspects of Korean-American Sjjo writers' consciousness of sijo and its significance, focusing primarily on the Sijo-Anthologies of Korean-American authors, "The Moon of the Desert" (1989), "The Dandelion of the Desert" (1994), and The Stars of the Desert" (1996) published by the Sijo Society of America. For this purpose, I thoroughly examined "Notes of Writing Sijo' attached to the authors' works and some other sijos added at the end of the paper. They started writing sijos quite early. Sijo has been recognized as a typical traditional genre of literature, and even foreigners came to write them in English. The following is the summary of the view on sijo propounded by Korean-American authors. Firstly, they follow traditional view on the theory of sijo in terms of its nature and utility, and at the same time they emphasize the utility of katharsis through self expressions. Secondly, their recognition of the value of sijo boils down to its formal patterns. Lastly, they develop the idea of national literature through their significance of writing sijos. They think that they can contribute to the development of national literature as well as the expression of patriotism through writing sijos. Therefore, they recognize themselves as spreaders of Korean culture to the local residents, and as the main stream enhancing the status of Korean culture through the competition with other nations.

• Journal of Gifted/Talented Education
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• v.22 no.2
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• pp.265-290
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• 2012

This study try to analyze the effect that personal and social factors affects the interactions among science gifted students. For this, I analyze the interacting role of science gifted students in social co-construction and scientific model constructing class for phase change and rising-sinking time of moon and categorize according to type. I analyze aspects of interaction and association of each elements in the students after I understand character type self conception friendship a parents-children relationship relation with teachers derived from advanced research through questionnaire and depth interview. After analyzing, I find the following-close friendship form or not and usual school class participation appear important factors that have strong connection with the aspect of the interactions. Also, character type, self conception and relation of parents affect the interactions relatively lower. Through this study, We identify two things. Firstly, We must consider individual's inside factors for making animatedly the interaction among the students. Secondly, We get considering factors that devise the strategies for making the interaction animatedly.

• Korean Journal of Remote Sensing
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• v.35 no.2
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• pp.265-278
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• 2019

Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) data help to enable rapid emergency responses through detection of the artificial and natural disasters occurring at night. The DNB data without correction of lunar irradiance effect distributed by Korea Ocean Science Center (KOSC) has advantage for rapid change detection because of direct receiving. In this study, radiance differences according to the phase of the moon was analyzed for urban and mountain areas in Korean Peninsula using the DNB data directly receiving to KOSC. Lunar irradiance correction algorithm was proposed for the change detection. Relative correction was performed by regression analysis between the selected pixels considering the land cover classification in the reference DNB image during the new moon and the input DNB image. As a result of daily difference image analysis, the brightness value change in urban area and mountain area was ${\pm}30$ radiance and below ${\pm}1$ radiance respectively. The object based change detection was performed after the extraction of the main object of interest based on the average image of time series data in order to reduce the matching and geometric error between DNB images. The changes in brightness occurring in mountainous areas were effectively detected after the calibration of lunar irradiance effect, and it showed that the developed technology could be used for real time change detection.

• Journal of the Korean earth science society
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• v.44 no.1
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• pp.62-78
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• 2023

The purpose of this study is to analyze the field of Earth science at a science fair. For this purpose, 566 pieces of data spanning 21 years (2000 to 2020), acquired from entries in the Earth Science section on the science fair website, were analyzed using the semantic network method. As a result, geoscience topics have been actively explored in works submitted for the Earth Science section of the science fair. Fossils from the Cretaceous period of the Mesozoic Era were particularly predominant. Together with these, keywords corresponding to astronomy, space science, and atmospheric science formed a small-scale network. Astronomy and space science mainly dealt with the dynamic characteristics of asteroids, Venus, and Jupiter. Other subjects included the solar system, sunspots, and lunar phases. Atmospheric science has focused on atmospheric physics, atmospheric observation and analysis technology, atmospheric dynamics, air quality monitoring, while marine science has been limited to physical oceanography and geologic oceanography. This study, is expected to help select Earth Science topics and conduct inquiry activities in schools.

• Journal of the Korean association of regional geographers
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• v.12 no.6
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• pp.656-670
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• 2006

In Gcochang-Gun, the population decrease, due to a rural exodus phenomenon, has led to the absolute decline in the numbers of both primary and secondary schools and students. However, the high schools in Geochang-Gun show an unusual characteristic that the students from other areas outside Geochang-Gun cover about 25% of the total students studying in Geochang-Gun. This is quite contrary to the contention that one of the major factors hindering the development of rural areas is generally the inferior condition of education. In this context, this paper aims to explore the spatio-temporal changes in the sphere of influence of the secondary education with special reference to Geochang-Gun, Gyeongnam. Most importantly Geochang High School and Geochang Daesung High School account for over 98% of the students coming from other areas outside Geochang-Gun's cross-border counties. This means that the sphere of influence of the Geochang's secondary education is dependent largely upon the two private academic high schools.

• Journal of Astronomy and Space Sciences
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• v.19 no.2
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• pp.163-172
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• 2002

This article investigates the problem of data preprocessing for the precision orbit determination (POD) of low earth orbit satellite using GPS .aw data. Several data preprocessing algorithms have been developed to edit the GPS data automatically such that outlier deletion, cycle slip identification and correction, and time tag error correction. The GPS data are precisely edited for the accuracy of POD. Some methods of data preprocessing are restricted to the rate of the collections of the pseudorange and carrier phase measurements. This study considers the preprocessing efficiency varied with the rate, the quality of receiver and the altitude of the satellite's orbit. We also propose the proper methods in accordance with the rate for single frequency and dual frequency receivers.