• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1264-1265
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• 2006

Study about the feasibility and effect of high-energy ball milling on a specific Mg alloy under protection medium of alcohol was presented via comparing with conventional vacuum milling. More fine particles with wider powder size distribution but more irregular shape were shown of the powder milled under alcohol. No obvious oxide was revealed from the two kinds of Mg alloy powders with limited milling time. And since slip induced in a preferential direction, the (002) texture was formed in the Mg alloy powders at the initial stage of alcohol milling. More O and Fe contaminants were introduced into the powders milled under alcohol according to the EDS analysis.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.7
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• pp.2589-2609
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• 2021

Segment routing (SR) is a highly implementable approach for traffic engineering (TE) with high flexibility, high scalability, and high stability, which can be established upon existing network infrastructure. Thus, when a network failure occurs, it can leverage the existing rerouting methods, such as rerouting based on Interior Gateway Protocol (IGP) and fast rerouting with loop-free alternates. To better exploit these features, we propose a high-performance and easy-to-deploy method SRUF (Segment Routing under Uncertain Failures). The method is inspired by the Value-at-Risk (VaR) theory in finance. Just as each investment risk is considered in financial investment, SRUF also considers each traffic distribution scheme's risk when forwarding traffic to achieve optimal traffic distribution. Specifically, SRUF takes into account that every link may fail and therefore has inherent robustness and high availability. Also, SRUF considers that a single link failure is a low-probability event; hence it can achieve high performance. We perform experiments on real topologies to validate the flexibility, high-availability, and load balancing of SRUF. The results show that when given an availability requirement, SRUF has greater load balancing performance under uncertain failures and that when given a demand requirement, SRUF can achieve higher availability.

• Macromolecular Research
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• v.16 no.7
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• pp.663-665
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• 2008

• Journal of The Korean Association For Science Education
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• v.24 no.1
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• pp.157-170
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• 2004

Students experience science not only through school science lessons but also through various other channels. Science-related facilities, including science museums and centers, are important channels for informal science education. Korea has a number of governmental and private facilities in which young people can experience various aspects of scientific activities, and many of them also provide the programs supporting out-of-school science activities. However, there has been no systematic survey study on those facilities providing out-of-school activities, thus they have not been used effectively as well as their social utility is not fully realized. To this end, in 2002 researchers of this study carried out surveys (1) of the facilities supporting out-of-school science activities and (2) of science programs provided by these facilities. The surveys show that there are approximately 180 facilities supporting science activities in Korea. More than 40% of them are located in Seoul and Gyeonggi areas. Among them, the proportion of special theme science museums was the greatest (37.9%). The facilities supporting out-of-school science activities usually do not target the specific age groups but are intended for all people. The proportion of governmental facilities exceeds that of private ones. 41.8% of the facilities examined in this study run their own science activity programs. Among the 10 categories of the programs, 'science class' type programs were the most common. There were more programs for elementary and middle school students than preschoolers, high school students and adults. The contents of the programs were more related to astronomy and meteorology, the observation of living things and field trips. Despite their high practical potential, the special theme science museums were found to be lacking in relevant programs, which could fulfill their values for informal science education.

• Communications of Mathematical Education
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• v.20 no.1 s.25
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• pp.33-59
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• 2006

This study is intended to reconsider the meaning of the education for gifted/talented children, the foundation object of science high school by examining the behavior characteristics between gifted students and talented students in open-end mathematical problem solving and to provide the basis for realization of 'meaningful teaming' tailored to the learner's level, the essential of school education. For the study, 8 students (4 gifted students and 4 talented students) were selected out of the 1 st grade students in science high school through the distinction procedure of 3 steps and the behavior characteristics between these two groups were analyzed according to the basis established through the literature survey. As the results of this study, the following were founded. (1) It must be recognized that the constituent members of science high school were not the same excellent group and divided into the two groups, gifted students who showed excellence in overall field of mathematical behavior characteristics and talented students who had excellence in learning ability of mathematics. (2) The behavior characteristics between gifted students and talented students, members of science high school is understood and a curriculum of science high school must include a lesson for improving the creativity as the educational institutions for gifted/talented students, unlike general high school. Based on these results, it is necessary to try to find a support plan that it reduces the case which gifted students are generalized with common talented students by the same curriculum and induces the meaningful loaming to learners, the essential of school education.

• Journal of the Korean earth science society
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• v.43 no.3
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• pp.446-463
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• 2022

This study suggests the need for polar literacy education as an effective conceptual system to explain climate change in terms of science education in line with the common effort of humankind to respond to global environmental changes. To this end, we investigated the status of polar literacy in high school students through quantitative tests and qualitative interviews and discussed the resulting implications. A total of 329 high school sophomore students from two high schools participated in a test consisting of 25 true and false questions developed by referring to the Polar Literacy Principles, while 13 students agreed to be interviewed. The results showed that a somewhat insufficient understanding and conceptual gaps appeared regarding several areas of the Polar Literacy Principles. Knowledge of the geographic features of the polar regions was weak, and little was known about the components and key characteristics of the cryosphere. The lack of understanding of these concepts results in the inability of students to link the operational mechanisms of polar and global climate change sufficiently. While accepting unsatisfactory concepts in the school curriculum without criticism from outside media, students perceived the mechanism of climate change as somewhat monotonous or distorted. Moreover, linguistic information, analogies, and visual observation were used as cognitive strategies to compensate for the ambiguous understanding of polar and climate change. Based on the abovementioned results, we argue that polar literacy education should be introduced as a new knowledge system that can be used to aid a systematic and comprehensive understanding of climate change within the school science curriculum. Additionally, we suggest the following implications: review the consistency of knowledge related to polar literacy in other subjects, provide critical standards for out-of-school media information related to climate change, examine students' misconceptions, and identify improved thinking strategies.

• Journal of The Korean Association For Science Education
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• v.31 no.6
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• pp.920-930
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• 2011

This research was executed in order to analyze the factors and strengths of learning difficulties that science-gifted high-school students experienced in Korea Science Academy. The subjects are 284 gifted high-school students from Korea Science Academy who responded to a paper-and-pencil questionnaire survey. The questionnaire used in this research was developed by focusing on the difficulties in the learning situations of science-gifted highschool students based on Rhodes' 4P theory of creative achievement. The data was analyzed using cross-tabulation analysis, frequency analysis, MANOVA by the SPSS 12.0 program. The analysis of the questionnaire survey on the learning difficulties showed (i) a grade difference in interpersonal relationship and (ii) gender differences in learning ability and learning strategies. Also, it was observed that the students tried to solve their learning difficulties most frequently by meeting their school peers except for methods of 'the others' such as relying on religious power.

• Proceedings of The KACE
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• 2017.08a
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• pp.113-116
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• 2017

현대 사회는 4차 산업혁명을 통해 빠르게 발달하고 있다. 이러한 사회에서는 새로운 지식과 기술이 끊임없이 만들어지고 기존의 지식과 기술이 도태되고 지식과 기술의 생명주기가 점차적으로 빨라지고 있다. 이에 따라 새롭게 제시되는 지식과 기술을 적합한 문제에 적용하여 문제를 해결하는 능력의 중요성이 커지고 있다. 특히 차세대 기술로 평가받는 인공지능, 로봇, 자율 자동차, 사물 인터넷 등의 기술과 연관된 문제를 해결하는 방법은 컴퓨터를 활용한 문제 해결방법과 밀접하게 연관돼있기 때문에 컴퓨터를 활용하여 주어진 문제를 표현하고 해결하는 능력은 매우 중요하다. 본 연구에서는 운영체제에서 기본적으로 제공되는 파일 관리 프로그램에 대한 문제점을 제기하고 문제 해결을 위해 컴퓨팅 사고력을 활용해서 문제에 대한 조사 단계, 분석 단계, 그리고 자동화 단계를 거쳐 문제를 해결한다.

• Journal of agricultural medicine and community health
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• v.32 no.2
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• pp.63-73
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• 2007

Objectives: The purpose of this study was to obtain basal information to establish a proper birth-encouraging policy in the future through the survey of the attitude towards childbirth and its related factors among female students in junior, senior high school, and university. Methods: A survey was performed for 2 weeks in June, 2006, for a total of 688 female students which included 185 ones in a girls' junior high school and 242 ones in a girls' senior high school in Sacheon, and 261 ones in two universities in Jinju. The selfadministered questionnaires developed by the authors included the socio-demographic characteristics, the attitude towards childbirth, the preference of a son for their future child, the belief on relative importance of family or work after marriage, the seriousness perception of low birth rate in Korea, frequencies of education in school about low birth rate. The attitude was measured by an answer to the question of 'To what degree do you think you are going to have a child(or children)?' Results: The proportion of positive attitude towards their future childbirth was 76.2% in junior high school, 63.9% in high school, and 82.8% in university students (p<0.01). In the logistic regression analysis, the significant factors related with positive attitude towards future childbirth were school grade, preference of a son for their future children, and belief on relative importance of family or work after marriage. Conclusions: It suggests that the related factors with positive attitude towards future childbirth need to be considered to make a proper birth policy.

• Journal of The Korean Association For Science Education
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• v.29 no.7
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• pp.767-782
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• 2009

The researchers who are studying biology and teachers who are teaching biology think that the genetics-related concepts are highly significant than other concepts in biology. With such background, researches on the identification of major concepts have been under way to guide in biology class. Minimal research has been carried out, however, on what concepts should be taught to achieve the specific objectives of the class in relation to the unit of genetics in middle and high school. Accordingly this study was designed to determine the concepts of genetics that should be taught to achieve the objectives of the genetics unit in secondary school. For this purpose 5 instructional objectives of the genetics unit on the 9th grade and 4 instructional objectives of Biology I were selected and the concepts that were taught to achieve class objectives. The survey was conducted among 114 science teachers from middle schools and 85 biology teachers from high schools. The results indicated that 9.1 and 10.2 concepts on average were taught in the 9th grade and in Biology I respectively. Moreover statistical difference in the number of concepts that were taught according to the teachers' teaching experiences appeared among the middle school teachers (p<.05). But such statistical difference did not appear among the high school teachers (p>.05). Furthermore the concepts for the 9th grade consist of the basic genetics concepts although Biology I concepts were integrated and advanced contents for same concepts. Thus this finding suggests that concepts of genetics units to be taught in middle and high school were in linkage.