• Journal of Science Education
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• v.33 no.2
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• pp.290-303
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• 2009

The purpose of this study was to analyze communication, problem solving and self-directed learning of elementary and secondary scientific gifted students. In addition, this study investigated correlation on the subdomains of communication, problem solving and self-directed learning. The subjects of this study were 252 students(97 elementary students and 155 secondary students) who had been enrolled at Center for Science Gifted and Talented Education. Elementary and secondary scientific gifted students' self-directed learning skill was the highest score among core abilities. The result of analysis on self-directed learning subdomain presented the highest score in basic self control of elementary students. The secondary scientific gifted students showed the highest score in effort attribution to result. Subdomains of core capacity has very high correlation. This fact shows very high correlation among core abilities. The results of this study are suggesting that the systematical life skills education based on concrete factors is effective to improve communication, problem solving and self-directed learning of scientific gifted students.

• Journal of Science Education
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• v.44 no.2
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• pp.157-166
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• 2020

In this study, we analyzed the reflection degree of science core competencies, which is presented in second grade middle school science textbooks, and the perception of science core competencies of second year middle school students. To do this, we analyzed the frequency of presentation of science core competencies in middle school second grade textbooks, and surveyed 400 students from three schools in Chungnam area to find out their perception of science core competency. The survey consisted of 15 questions consisting of a five-step Likert scale and 5 ranking questions. The survey analyzed the responses of 327 people who responded faithfully and conducted a post-interview survey to interpret the survey results. The main findings are as follows: First, in the second grade middle school science textbook, the proportion of 'scientific thinking', 'scientific inquiry,' and 'scientific communication' is large, and the students are perceived to have a high proportion of 'scientific thinking,' 'scientific inquiry,' and 'scientific problem solving' in the textbook. Second, students recognize that the proportion of 'scientific inquiry' and 'scientific problem solving' in the evaluation conducted in school was high, and the proportion of 'scientific communication' and 'scientific participation and lifelong learning' was very low. Third, the most important competency in science that students perceive is the 'scientific problem solving,' the competency they wanted most from science is the 'scientific inquiry,' and the competency most needed to live in future society is the 'scientific communication.' Fourth, in the case of 'scientific participation and lifelong learning,' it is an important element of science literacy, but the proportion of consisting science textbooks is low, and students are not aware of the importance or necessity in science.

• Nuclear Engineering and Technology
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• v.33 no.3
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• pp.298-306
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• 2001

As fuel burnup proceeds, thermal gradients, differential swelling, and inter-assembly loading may induce assembly duct bowing. Since duct bowing affects the reactivity, such as long or short term power-reactivity-decrement variations, handling problem, caused by top end deflection of the bowed assembly duct, and the integrity of the assembly duct itself. Assembly duct bowing were first observed at EBR-ll in 1965, and then several designs of assembly ducts and core restraint system were used to accommodate this problem. In this study, NUBOW-2D KMOD was used to analyze the bowing behavior of the assembly duct under the KALIMER(Korea Advanced Liquid MEtal Reactor) core restraint system conditions. The mechanical behavior of assembly ducts related to several design parameters are evaluated. ACLP(Above Core Load Pad) positions, the gap distance between the ducts, and the gap distance between the duct and restraint ring were selected as the sensitivity parameter for the evaluation of duct deflection.

• Korean Institute of Interior Design Journal
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• v.26 no.6
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• pp.24-32
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• 2017

STEAM education is an effective teaching method to develop self-problem-solving skills through creative thinking. In order to revitalize STEAM education, various program models are being developed recently. The purpose of this study is to develop a STEAM education program based on the project-based learing method that includes the process of solving global environmental problems. The STEAM element was extracted by linking the zero energy house design with the middle school curriculum, and the STEAM education program was developed considering career activities. It was analyzed whether the developed program can improve STEAM core competence and job preparation ability. The education program was conducted for middle school students and the program was evaluated through questionnaires. In order to strengthen the STEAM competency, project-based learning method was applied and it was able to enhance the active problem solving ability of learners. In addition, opportunities for career experience could be provided through career exploration programs and various activities. Through this STEAM education program, it is expected to contribute to cultivating human resources with convergence knowledge and core competency.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.4
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• pp.466-477
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• 2005

Statement of problem : Problem of matching the appearance of porcelain restorations with the patient's natural dentition has always been a concern to dental clinicians. Recently, demands for esthetics, even in restorations requiring strength, has brought a revolution to dentistry and increased use of zirconia. Among the various factors, shade and translucency or the core can significantly affect the overall esthetics of the restoration and should be considered when selecting an all-ceramic system. Purpose : The purpose of this study was to spectrophotometrically evaluate the influence of different zirconia systems and core thickness on the final shade of all-ceramic restorations using the CIEL$^*a^*b^*$ system. Material and Methods: Core specimens (n : 20 per group) of In-Ceram Alumina, In-Ceram Zirconia, Digident CAD/CAM Zirconia, Cercon Zirconia were fabricated 20mm in diameter. 10 specimens of each group were fabricated at core thickness of 0.5mm and 0.7mm. These core specimens were veneered with shade Al & A3 porcelain of the recommended manufacturer. CIEL$^*a^*b^*$ coordinates were recorded for each specimen with a spectrophotometer (Model CM-2600d, Minolta, Japan). Color differences were calculated using the equation ${\Delta}E^*=[({\Delta}L^*)^2+({\Delta}a^*)^2+({\Delta}b^*)^2]^{\frac{1}{2}}$. Results : 1. Specimens of core thickness 0.5mm and 0.7mm did not exhibit clinically perceived color difference. 2. Regarding shade reproducibility, In-Ceram Alumina and In-Ceram Zirconia showed significant difference within each group. 3. Cercon Zirconia group showed the highest $L^*$ value and Digident Zirconia group showed lowest $a^*$ & $b^*$ value. 4. Generally the shade difference between materials was higher in the A3 shade group than in the Al shade group. Conclusion: Within the limitations of this study, there was no color difference after increase in core thickness and every all-ceramic system has color characteristics that clinicians have to consider when selecting materials. Also, manufacturers of different porcelain systems must make every effort to achieve color reproducibility.

• Journal of the Korean Society for Library and Information Science
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• v.46 no.3
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• pp.79-102
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• 2012

Higher educational institutions face an increasing demand for developing a renewed set of competencies of college students who will live in the knowledge-based society. However, relatively little is known about what constitutes the core competencies that college students need to develop and how we can improve them. Nine categories of core competencies required for college graduates were drawn from the previous research and examples of core competencies developed by other institutions. They are analytic thinking skills, problem-solving skills, communicating skills, collaborative working skills, and etc. A reading guidance course for strengthening core competencies, developed based on the teaching and learning methods was adapted to students of LIS for one semester. Implications of these and related findings are discussed.

• Journal of Korean Elementary Science Education
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• v.36 no.4
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• pp.346-355
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• 2017

The 2015 revised national science curriculum encourages students to cultivate the science core competencies such as scientific thinking, science process skills, scientific problem-solving ability, scientific communication skill, scientific participation and lifelong learning ability. To fill this purpose, we practiced science writing classes based on core competencies and examined the effect of its application. The target unit was 'weather and our life', 'acid and base', 'speed of an object', and 'structure and function of our body' in the fifth grade of elementary school. The results were as follows. First, it was proven that science writing activities based on core competencies did not help improving science process skills of learners. Second, it had a significant effect on the improvement of the learner's self-directed learning ability, in particular, owner spirit, meta cognition and information search. Third, this strategy for science writing changed learners' scientific attitude positively. The above-mentioned results show that this science writing classes can be applicable as one of effective methods in cultivating science core competencies.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.11
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• pp.893-898
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• 2016

Plastic array lens are cheap to manufacture; however, plastic is not resistant to high temperatures and moisture. Optical glass represents a better solution but is a more-expensive alternative. Glass array lens can be produced using lithography or precision-molding techniques. The lithography process is commonly used, for instance, in the semiconductor industry; however, the manufacturing costs are high, the processing time is quite long, and spherical aberration is a problem. To obtain high-order aspherical shapes, mold-core manufacturing is conducted through ultra-precision grinding machining. In this paper, a $4{\times}1$ mold core was manufactured using an ultra-precision machine with a jig for the injection molding of an aspherical array lens. The machined mold core was measured using the Form TalySurf PGI 2+ contact-stylus profilometer. The measurement data of the mold core are suitable for the design criterion of below 0.5 um.

• KIEE International Transactions on Electrophysics and Applications
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• v.3C no.5
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• pp.165-170
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• 2003

This paper presents development of solid core suspension disc insulators (cap and cap suspension disc insulator) for replacing cap and pin suspension disc insulators in overhead transmission and distribution lines which expose to lightning discharges. By this means the punctured problem caused by steep front surge voltage created by lightning discharge on the lines can be solved. The solid core suspension insulator was designed and constructed based on the dimensions of conventional suspension disc insulators (cap and pin insulators). The insulators are made of alumina porcelain. The electrical and mechanical characteristics of the solid core suspension insulators were carried out. The puncture test was performed in the air by applying steep front impulse voltage with amplitude about 2.5 per unit of 50% flashover (CFO) of the insulator unit at negative standard lightning impulse $1.2/50\;\mu\textrm{s}$ with steepness up to $9200\;kV/\mu\textrm{s}$. The testing results show that solid core suspension disc insulators are not punctured eventhough the steepness of the steep front impulse voltage was increased up to $9200\;kV/\mu\textrm{s}$.

• Journal of the Optical Society of Korea
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• v.12 no.2
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• pp.112-117
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• 2008

Single-mode propagation conditions of X-ray waveguides are investigated by numerical calculations in order to understand the importance of waveguide design parameters, such as core thickness and the optical constants of waveguide materials, on the transmission and coherence properties of the waveguide. The simulation code for mode analyzing is developed based on a numerical solution of the parabolic wave equation. The initial boundary value problem is solved numerically using a finite-difference scheme based on the Crank-Nicolson scheme. The E-field intensities in a core layer are calculated at an X-ray energy of 8.0 keV for air and beryllium(Be) core waveguides with different cladding layers such as Pt, Au, W, Ni and Si to determine the dependence on waveguide materials. The highest E-field intensity radiated at the exit of the waveguide is obtained from the Pt cladded beryllium core with a thickness of 20 nm. However, the intensity from the air core waveguide with Pt cladding reaches 64% of the Be-Pt waveguide. The dependence on the core thickness, which is the major parameter used to generate a single mode in the waveguide, is investigated for the air-Pt, and Be-Pt waveguides at an X-ray energy of 8.0 keV. The mode profiles at the exit are shown for the single mode at a thickness of up to 20 nm for the air-Pt and the Be-Pt waveguides.