• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.9
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• pp.4446-4462
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• 2019

In this paper, we focus on interference cancellation for three-hop cognitive radio networks (CRNs) over Rayleigh fading channels. In CRNs, secondary users (SUs) are allowed to opportunistically utilize the licensed spectrum during the idle time of primary users (PUs) to achieve spectrum sharing. However, the SUs maybe power constrained to avoid interference and cover a very short transmission range. We here propose an interference cancellation scheme (ICS) for three-hop CRNs to prolong the transmission range of SUs and improve their transmission efficiency. In the proposed scheme, a flexible transmission protocol is adopted to cancel the interference at both secondary relays and destinations at the same time. And a closed-form expression for the secondary outage probability over Rayleigh fading channels is derived to measure the system performance. Simulation results show that the proposed scheme can significantly reduce the secondary outage probability and increase the secondary diversity in comparison with the traditional cases.

• Journal of Korean Elementary Science Education
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• v.32 no.4
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• pp.393-403
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• 2013

The purpose of this study was to investigate the perception of school teachers in science research ethics and perception of science research ethics education. A survey was administered for this study and a total 167 elementary and secondary teachers studying in K University graduate school participated. The survey was organized to examine participants' 1) science research ethics awareness, 2) status of science research ethics education, and 3) needs for science research ethics education, and 4) the perception of the direction of the science research ethics education in school. Each item was responded using either 1 to 5 Likert type scale, multiple choices questionnaires. The results were as follows: both of elementary and secondary school teachers showed above average interest in science research ethics and secondary school teachers showed significantly higher interest than elementary school teachers(p<0.05). In degree of awareness of science research ethics, plagiarism (M=3.98) was the highest, followed by free-riding(M=3.78), the scientist's social responsibility(M=3.71), and forge(M=3.61). In response science research ethics problem occurs in science education activities more than the average(M=3.39). Teacher's response on the teaching of science research ethics ranges from 3.02 to 4.47, but each science research ethics elements was showed a large deviation. Elementary and secondary school teachers responded that science research ethics education needed(M=4.34). Science research ethics education should be included in the school curriculum. Eighty-five percent of the teachers responded that the science research ethics education should be started from elementary school. 'Discussion-type classes with examples' was preferred as an effective teaching. And teachers needed 'instructional materials' and 'teachers training' for science research ethics education.

• 한국과학교육학회:학술대회논문집
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• 2008.08a
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• pp.47-56
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• 2008

This article presents how in China mainland a school and a school district find their science teachers. Based on studying relevant materials and years of intensive involvement in teacher education and recruitment practices the authors draw three features of the current secondary science teachers' employment system in China mainland: certification control conducted very loosely selection criteria and process vary with schools and school districts due to the remarkable difference existed among them the normal universities/colleges established originally only for secondary science teacher education still play a vital role in shaping effecting quality of teacher candidates although no one of them for a long time have focused on only doing what they were supposed to do. For further development, changes and essential reform are expected duo to the increasing promotion toward the internal quality of education and therefore high quality of teachers and teacher candidates.

• Journal of the Korean earth science society
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• v.38 no.5
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• pp.367-377
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• 2017

The purpose of this research is to investigate characteristics of science content knowledge and pedagogical content knowledge shown in the primary school science classes. Through analysis of classroom teaching, explore the features and differences between primary and secondary school science PCK. Using open-ended interviews with the teachers and group discussions on a regular basis to analyze and compare classes of five primary school teachers, the relationship between CK and PCK. Regardless of the school level the teacher's PCK and professionalism is required with varying focus and emphasis. The features of the primary school teacher's PCK are as follows: Firstly, elementary teach secondary teach content, teachers value pedagogical knowledge (PK) content knowledge (CK). The primary school PCK requires more of understanding of students and teaching methods that to subject areas. PCK be without content knowledge, and the teacher's PCK is subject-specific In addition to the characteristics of PCK in the primary school science teaching, ways to set up professional exchange or collaboration between primary and secondary teachers, and to provide supplementary in-service training focused on content knowledge for primary school teachers.

• BMB Reports
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• v.44 no.2
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• pp.118-122
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• 2011

Most widely used secondary structure assignment methods such as DSSP identify structural elements based on N-H and C=O hydrogen bonding patterns from X-ray or NMR-determined coordinates. Secondary structure assignment algorithms using limited $C{\alpha}$ information have been under development as well, but their accuracy is only ~80% compared to DSSP. We have hereby developed SABA (Secondary Structure Assignment Program Based on only Alpha Carbons) with ~90% accuracy. SABA defines a novel geometrical parameter, termed a pseudo center, which is the midpoint of two continuous $C{\alpha}s$. SABA is capable of identifying $\alpha$-helices, $3_{10}$-helices, and $\beta$-strands with high accuracy by using cut-off criteria on distances and dihedral angles between two or more pseudo centers. In addition to assigning secondary structures to $C{\alpha}$-only structures, algorithms using limited $C{\alpha}$ information with high accuracy have the potential to enhance the speed of calculations for high capacity structure comparison.

• Journal of The Korean Association For Science Education
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• v.21 no.5
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• pp.944-967
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• 2001

The purpose of this study is to compare and analyze secondary school chemistry education in Korea and China in order to identify implications for the improvement of Korean chemistry education. The school systems, curricula, and teacher education related to secondary chemistry education of both countries were compared and analyzed. The 6-3-3-4 school system is used in both countries, and national school curricula are formulated by the Ministries of Education in both countries. The 1996 chemistry curricular standard for advanced middle schools in China, and 1997 chemistry curriculum for Korean high schools were compared in several aspects, followed by comparisons of chemistry teacher education in both countries. Based on the comparative analysis of chemistry education, some ideas and issues which provide implications for improving Korean high school chemistry education were identified. Chemistry teaching in the junior secondary schools, tentative implementation of curricula, required course work in chemistry, structure of curricula, oral assessments, probation of teachers and other issues are identified and discussed in this study.

• Journal of the Korean Chemical Society
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• v.46 no.6
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• pp.561-568
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• 2002

This study examined secondary school science teachers' thinking on physical and chemical change. For this research, we analysed the answers of 80 secondary school science teachers. According to the result of the analysis,teachers had various opinions when they classified phenomena of dissolving ionic compound or diluting acid into phys-ical change and chemical change. Many teachers tended to classify similar phenomena into different change when those were represented with different focus. It means that teachers' opinions were not consistent.

• Journal of Engineering Education Research
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• v.20 no.4
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• pp.21-27
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• 2017

The purpose of this study is to provide basic data and guideline to STEM(Science, Technology, Engineering, Mathematics) educators who prepare engineering education in elementary and secondary school. For this, this study develops a composition model for engineering education program of elementary and secondary school. To do this, a literature research, experts interview and Delphi survey were conducted. Through the literature research, we extracted the components of model for engineering education program of elementary and secondary school and then made a first draft of the model. The draft was revised by experts while Delphi survey was used to validate the model based on Delphi panels' opinions. The panels for the Delphi survey consisted of 51 experts in the STEM education field. The survey was conducted three different times and importance survey was included in the third stage. The conclusions of this study were as follows: First, the model consist of definition, 4 directions, 4 characteristics, 3 educational goals according to school level, educational contents area and element, teaching and learning method and evaluation method. The educational contents area and element consist of 2 major areas, 7 areas and 18 elements. Second, all components of the developed model were valid in most of the statistics such as mean, standard deviation, the degree of consensus and convergence, and CVR(Content Validity Ratio). Third, importance for education contents area and element according to the school level are analyzed.

• Journal of The Korean Association For Science Education
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• v.32 no.1
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• pp.182-200
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• 2012

There is growing recognition that secondary students must be given the opportunity to write in their science classrooms as well as in scientific inquiry based learning situations, yet the development of writing education standards for secondary school science teachers still needs to be addressed. The primary objective of this research was to explore the writing education standard for secondary school science teachers. The research objective was attained through the use of literature analyses. Drawing upon those results of the related literature analyses, this study suggests a list of writing education standards for secondary school science teachers. The list consists of 17 education standards and includes 42 sub-standards in total across four education areas.

• Journal of the Korean earth science society
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• v.30 no.6
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• pp.773-786
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• 2009

Recently, the connection between science museum and school science curriculum has been emphasized, but the frameworks for evaluating school science curricula are insufficient in terms of how much of school science curriculum was reflected and attained. The purposes of this study are to develop a framework that can be utilized to evaluate levels of curriculum that are reflected and attained in the texts of exhibition panels displayed in science museums. We developed an evaluation tool based on the frameworks used to assess students' achievement in the secondary school curriculum, and we used the tool to measure the reflection and attainment levels demonstrated in the texts of exhibition panels about earth science contents of secondary school curriculum in three science museums located in Chungcheong-do, central part of Korea. Findings showed that the levels of reflection and attainment of secondary school curriculum in exhibition panels about earth science contents in science museums were measured 38.7% and 2.82 points out of 5.0respectively. We hope that the evaluation tool used in this study could be utilized to measure the levels of reflection and attainment of secondary school science curriculum demonstrated in the text of each of exhibition panels in science museums.