• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.4
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• pp.321-328
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• 2014

The performance characteristics of a subscale diffuser under non-reacting conditions for high-altitude simulation were numerically investigated with respect to different lengths of the secondary throat diffuser. The ratio of the length of the diffuser entrance to the nozzle exit diameter was set to 0, 50, and 100%. In addition, flow characteristics were studied for a range of length-to-diameter ratios of the secondary throat diffuser. An insufficient diffuser entrance length caused contraction of the plume immediately after the nozzle exit. When the length-to-diameter ratio was less than 8, a strong Mach disk was formed inside the diffuser, resulting in a sharp increase in pressure. In addition, flow characteristics in the diverging part of the diffuser were investigated for a range of diverging part lengths. A short diverging part may lead to abrupt pressure recovery, resulting in the possible application of mechanical load to the diffuser.

• Journal of KIISE:Databases
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• v.33 no.3
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• pp.251-260
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• 2006

Homology searching on the primary structure (i.e., amino acid arrangement) of protein sequences is an essential part in predicting the functions and evolutionary histories of proteins. However, proteins distant in an evolutionary history do not conserve amino acid residue arrangements, while preserving their structures. Therefore, homology searching on proteins' secondary structure is quite important in finding out distant homology. In this manuscript, we propose an indexing scheme for efficient approximate searching on the secondary structure of protein sequences which can be easily implemented in RDBMS. Exploiting the concept of clustering and lookahead, the proposed indexing scheme processes three types of secondary structure queries (i.e., exact match, range match, and wildcard match) very quickly. To evaluate the performance of the proposed method, we conducted extensive experiments using a set of actual protein sequences. CSI was proved to be faster than the existing indexing methods up to 6.3 times in exact match, 3.3 times in range match, and 1.5 times in wildcard match, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.573-583
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• 2017

The purpose of this study is to ascertain the effect of both educational satisfaction and relational support on the self-efficacy of secondary school students and then eventually on their entrepreneurship. Testing self-efficacy as a mediator is another aim of this study. The findings indicated that both educational satisfaction and relational support have positive relationships with the self-efficacy of students. Self-efficacy also had a positive impact on entrepreneurship. The core part of this study focuses on the role of both educational satisfaction and relational support in fostering the self-efficacy and entrepreneurship of secondary school students. These results can serve as practical guidance when making decisions regarding the adequate pedagogy for secondary school students in order to promote entrepreneurship among the adolescents.

• Journal of the Korean Home Economics Association
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• v.18 no.4
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• pp.47-63
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• 1980

In order to investigate the current curriculum activities of home economics education secondary schools and the satisfaction and consciousness of teachers in home economic education, 158 teachers I Youngnam district were randomly selected for a series of questionnaire concerning home economics education in the secondary schools. The conclusion obtained from the data based on the questionnaire are; (1) Most of the teachers were considering that the subjects of home economics education are essential parts in developing the fundamental ability of human beings and that the subjects, therefor, should be extended to boy students as well as girls students; (2) Most of the subjects in home economics education were controlled and taught by a teacher on the school-year basis and very few subject were taught by specialists having majored in the university; (3) One of the most prominent difficulties in teaching career was lack of facilities followed by lack of the most prominent difficulties in teaching career was lack of facilities followed by lack of finances, lack of understanding of principals' with the subjects; Lack of students(interest to the subject due to the current entrance examination system for colleges/universities, excessive number of students in class, and inability of student sand teachers for the subjects concerned about; (4) Most secondary school teachers of home economics education were comprehensively taking part in the education of sexual morality of students; (5) Most teachers of home economics education in secondary schools had the satisfaction of being successful in life due to the fitness of their interest, the contribution to the society with their ability and the economic independence resulted form the improved relationships of human beings and the better visions; (6) Teaching careers of housewives were considered a pride of the family and supported by their children and husbands; (7) The most concerned problem for the women in teaching careers was an educational work for their children and lastly (8) The women in teaching careers were considered to be respectable in the comprehensive society being included by children, senior staffs and colleagues.

• Journal of The Korean Association For Science Education
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• v.37 no.4
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• pp.705-717
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• 2017

The purpose of the study is to explore secondary science teachers' emotional display rules, types of emotional labor, science-specific emotional display rules and the episodes of emotional labor. For this purpose, the survey to measure emotional labor of science teachers (The Emotional Labor of Science Teaching Scale: TELSTS) was developed and the participants were 145 secondary science teachers in Korea. Results showed that first, secondary science teachers recognized the emotional display rules defined by their schools, especially, positive display rules. Second, secondary science teachers showed that they were carrying out emotional labor in order to keep their emotional display rules in check. The mean value of responses to deep acting was high. Also, there were statistically significant differences in emotional labor depending on whether they were full-time or part-time teachers and their teaching career. Third, as a result of analyzing the specificity of science teachers, it was mainly related to the objective and logical image of science, and experimental instruction. Seventy-four percent (74%) of responses were negative or neutral emotional display rules. Finally, implications for science education are discussed.

• Research in Mathematical Education
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• v.23 no.4
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• pp.235-254
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• 2020

Through this study, we aimed to capture the nature of a mathematics method course, called "the Curriculum Development and Teaching Methods in Mathematics Education" which is a pedagogy course for teaching for secondary school mathematics taught at a university located in a south eastern part of South Korea. The research participants include three junior students who took the methods course and a local high school math teacher with two professors. The research has three parts. First, we designed a method course to prepare the junior or senior students for a teaching practicum. The individual students gave a mini lecture about a secondary mathematical topic as a course requirement. Second, the three students watched a classroom video-clip of the high school teacher and analyzed his instruction before the actual classroom visits. Furthermore, by "Let's Learn" program for students, the course was associated with a local community through the students and so that they could visit the teacher's classroom three times to observe his math classroom teaching. The students discussed the difference between their own mini lectures and the actual math classroom teaching to develop an understanding of what it entails to teach an actual math class. Third, the first author supervised the students' activities in the program including their report for it to bring out their findings to the class of the method course. We found out this method course provided the students with the experience of various aspects of actual math lesson as well as learning theories about the pedagogy for teaching for secondary school mathematics. We conclude that this course gives a model for the method course in mathematics education for secondary school mathematics.

• Journal of Ecology and Environment
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• v.32 no.3
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• pp.183-189
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• 2009

This research focused on the effects of fragmentation on moth diversity in an agricultural land-scape by comparing moth species richness and abundance between hillocks and young secondary forests. We examined five sites from the southwestern part of South Korea: three sites from hillock forest and two from secondary forest. We collected moths bi-weekly from April to October for a 2-year period (2006-2007) with a UV light trap that usually attracts moths within 30 meters. Tree species richness and abundance in $20m{\times}20m$ plots at each moth sampling site showed a substantial difference in tree diversity between the two types of forest habitats. The total abundance and richness of moth species were higher in secondary forests (541 species with 4,998 individuals) than in hillock forests (423 species with 3,913 individuals), irrespective of the distance among the sites. An ordination analysis with NMDS showed that habitat is the most important factor of grouping sites. The food preferences of the dominant moth species i,n each habitat were closely related to the habitat type.

• Carbon letters
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• v.25
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• pp.84-88
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• 2018

At present, an important research area is the search for materials that are compatible with CMOS technology and achieve a satisfactory response rate and modulation efficiency. A strong local field of graphene surface plasmon polariton (SPP) can increase the interaction between light and graphene, reduce device size, and facilitate the integration of materials with CMOS. In this study, we design a new modulator of SPP-based cycle branch graphene waveguide. The structure comprises a primary waveguide of graphene-$LiNbO_3$-graphene, and a secondary cycle branch waveguide is etched on the surface of $LiNbO_3$. Part of the incident light in the primary waveguide enters the secondary waveguide, thus leading to a phase difference with the primary waveguide as reflected at the end of the branch and interaction coupling to enhance output light intensity. Through feature analysis, we discover that the area of the secondary waveguide shows significant localized fields and SPPs. Moreover, the cycle branch graphene waveguide can realize gain compensation, reduce transmission loss, and increase transmission distance. Numerical simulations show that the minimum effective mode field area is about $0.0130{\lambda}^2$, the gain coefficient is about $700cm^{-1}$, and the quality factor can reach 150. The structure can realize the mode field limits of deep subwavelength and achieve a good comprehensive performance.

• Journal of The Korean Association For Science Education
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• v.9 no.1
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• pp.75-89
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• 1989

Secondary schools in Korea have been faced with several critical problems with regard to science education. Among them one of the most fundamental problems is associated with laboratory-based science education. There fore as a part of research project for the improvement of science education in secondary schools, this study had its abjectives to inquire into the following areas related to laboratory experiment. ${\circ}$Survey and analysis of theoretical backgrounds for science teaching focused on laboratory experiments. ${\circ}$Status survey of experiment-based science teaching in high schools. ${\circ}$Development of model for improving experiment-based science teaching. In order to fulfill these objectives this study used methods of eiterature review, survey, and interviews. The major finding are as follows : ${\circ}$Some topic for laboratory experiments as oppeared in the textbooks are not appropriate in the light of sience curricular operations in high schools. ${\circ}$In some schools equipments and facilities of school laboratories are for from sufficiency. ${\circ}$Laboratory experiments are not financially supportel for ideal science teach in both middle schools and high schools. These are not on exhaustive list of findings from this study More finding and teaching model for improvement of science education are also described in this paper.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.3
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• pp.261-272
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• 2014

Home appliances go through a couple of packaging stages from the plant to consumers. The primary packaging, inner packaging for each part, happens for protection after products leave the plant. The secondary packaging happens in the unit of product, ensuring cushioning packaging to protect products from movement. The final tertiary packaging is for transportation and delivery. Each stage of product packaging, however, costs a lot of money because of disposable packaging materials used in each stage including vinyl, tapes, Styrofoam, and corrugated cardboards. Discarded packaging materials also cause environmental problems. In an effort to come up with a measure to solve those problems, this study proposed a plan to minimize logistics costs with semi-permanent packaging materials to replace disposable ones including Styrofoam, vinyl, and corrugated cardboards in the stages of inner packaging, cushioning packaging, product unit-based packaging, and transportation. The study also developed a model to cut down logistics costs by reducing various packaging stages including the primary, secondary, and tertiary stage only to the secondary one through module-type products instead of the transportation- and delivery-type ones, as well as demonstrated the excellence of the study through numerical analysis.