• Korean Journal of Optics and Photonics
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• v.34 no.6
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• pp.248-260
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• 2023

A 0.5-numerical-aperture (NA) refractive-reflective objective, composed of a low-NA refractive and a reflective focal reducer, is designed. A 0.25-NA Lister objective is used for the refractive. A two-spherical-mirror system, corrected for spherical aberration, coma, and astigmatism is used for the reflective focal reducer. In spite of high NA, the refractive-reflective objective has an 18-mm working distance and improved imaging performance, compared to the 0.25-NA Lister objective.

• Current Optics and Photonics
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• v.4 no.4
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• pp.353-360
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• 2020

Adopting an elaborately designed reflective objective consisting of four mirrors, we have developed a rotating-polarizer-type microspot spectroscopic ellipsometer (SE) with an ultra-small spot size. The diameter of the focused beam, whether evaluated using a direct-image method or a knife-edge method, is less than 8.4 ㎛. After proper correction for the polarizing effect of the mirrors in the reflective objective, we unambiguously determine the dispersion of the complex refractive index and the thickness of monolayer MoS₂ using the measured microspot-spectroellipsometric data. The measured ellipsometric spectra are sensitive enough to identify small variations in thickness of MoS₂ flakes, which ranged from 0.48 nm to 0.67 nm.

• Korean Journal of Childcare and Education
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• v.16 no.5
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• pp.127-154
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• 2020

Objective: This study aimed to show and analyze the flow, content, and meaning of (prospective) early childhood educators reflective thoughts entailed in the process of planning, implementing and evaluating storybook reading by analyzing reflective journals written by technical college students enrolled in an advanced major curriculum after they completed a storybook reading assignment. Methods: The subjects of this study were 39 technical college students enrolled in an advanced major curriculum that participated in a 15-week-long 'storybook seminar' course. This study analyzed journals on storybook reading written by the students as an assignment for the storybook seminar course. Results: As a result, four categories of selecting a storybook, planning the reading of the selected storybook, actual reading of the storybook and subsequent activities were extracted according to the implementation process of storybook reading. Through this series of experiences, (prospective) early childhood educators had a childt-centered view of reading picture books, changed the method of reading picture books, re-recognized the importance of early childhood literature education, and developed a will to develop professionalism through reflective thinking. Conclusion/Implications: This study finds its meaning in showing the reflective thinking that occur within early childhood educators that plan, implement and evaluate storybook reading.

• Korean Journal of Childcare and Education
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• v.20 no.1
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• pp.1-19
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• 2024

Objective: The purpose of this study was to verify the mediating effect of reflective thinking in the relationship between early childhood teachers' play-based curriculum implementation competences and their digital competences. Methods: An online survey was conducted targeting 330 early childhood teachers. Descriptive statistical analysis, correlation analysis, and The Process macro model 4 were performed using SPSS 28.0 and The Process macro 4.1. Results: The main results of this study are outlined as follows: first, a significant positive correlation was observed between overall play-based curriculum implementation competences, reflective thinking, and digital competences, including each of their respective sub-factors. Second, the study revealed that reflective thinking played a partial mediating role in the relationship between early childhood teachers' play-based curriculum implementation competences and digital competences. Conclusion/Implications: Through this study, it was confirmed that when reflective thinking mediated play-based curriculum implementation competences, digital competences were further increased. The findings suggest that not only positive play-based curriculum implementation competences of teachers but also reflective thinking should be considered to enhance digital competences.

• Korean Journal of Childcare and Education
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• v.17 no.2
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• pp.89-101
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• 2021

Objective: The purpose of this study is to verify the effect of directors' coaching leadership on teachers' play implementation competencies and the mediation effects of teachers' reflective thinking and creative job performance by conducting a structural relationship analysis. Methods: The subjects of this study were child care teachers who were purposefully sampled from the metropolitan area which includes Seoul, Incheon, and Gyeonggi Province. A total of 267 questionnaires were analyzed after excluding poor or incomplete questionnaires by use of SPSS Statistics 25.0 and the AMOS 21.0. Results: Directors' coaching leadership was positively correlated with teachers' reflective thinking, creative job performance, and their play implementation competencies. Directors' coaching leaderships directly and indirectly influenced teachers' play implementation competencies, which was mediated by teachers' reflective thinking and their creative job performance. Conclusion/Implications: Directors' coaching leadership has a significant implication for teachers' play implementation competencies which became more important after the national curriculum standards had been revised.

• Journal of Information Technology Services
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• v.21 no.3
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• pp.89-103
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• 2022

The purpose of this study is to explore professors' perception of blended learning. For this purpose, the reflective journals written by 56 university professors was analyzed using the keyword network analysis method. The results of this study are as follows: First, as a result of keyword frequency analysis for the blended learning, the keywords showed the highest frequency in the order of (1) 'instructional design', 'student', 'instructional method', 'learning objective' in the area of learning, (2) 'importance', 'instruction', 'feeling', 'student' in the area of feeling, and (3) 'semester', 'plan', 'weekly', and 'instruction' in the area of action plan. Second, the results of analyzing the degree, closeness centrality, and betweenness centrality of network connection are as follows. (1) The keywords 'instruction', 'instructional method', 'instructional design', and 'learning objective' in the area of learning, (2) the keywords 'instruction', 'importance', and 'necessity' in the area of feeling, and (3) 'instruction', 'plan', and 'semester' in the area of action plan showed high values in degree, closeness centrality, and betweenness centrality. Based on the research results, implications for blended learning and professors' perception were discussed.

• Korean Journal of Childcare and Education
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• v.15 no.6
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• pp.189-206
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• 2019

Objective: The objective of this study was to develop and apply a Teacher Learning Community Program in order to improve the specialization of infant daycare center teachers and explore the changes in the learning attitudes of teachers. Methods: To develop the program, the requirements were analyzed by surveying 500 teachers of infant classes. The developed program was provided to 25 infant daycare center teachers for a total of 14 sessions. A total of 75 sets of collected journal writing materials were analyzed qualitatively. Results: First, the Teacher Learning Community Program for infant daycare center teachers was developed. Second, the Teacher Learning Community Program was found to bring a shift in the learning attitudes among the teachers of infant classes towards reflective and communal learning. Conclusion/Implications: The Teacher Learning Community Program brought a shift in the learning attitude towards reflective and communal learning. Thus, the Teacher Learning Community Program can be applied as a teacher education program for improvement of the specialization of infant daycare center teachers.

• Journal of Navigation and Port Research
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• v.34 no.9
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• pp.711-718
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• 2010

Redevelopment of the domestic small fishing ports is being started in earnest by applying the environmentally friendly technology in order to attract tourists. For the purpose of improving water quality in the harbor, selection of breakwater type might have the priority to secure calmness and stability. Therefore, this study is to determine the hydraulic characteristics of reflective ratio, installation efficiency and stability of the special type of blocks through the hydraulic model experiment. The results were introduced to analyze for the effect of infield construction work through numerical analysis. Gujora, a small fishing port in southern Korea, is affected by the waves of SSE, S, SSW direction and strong tidal currents. The results of applying cylindrical slit block show that stability of the blocks and harbor calmness were secured. Considering that the pass rate of a long period wave is still excellent, the primary objective of wave control and the secondary objective of improving water exchange are satisfied simultaneously.

• Journal of Educational Research in Mathematics
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• v.8 no.1
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• pp.299-312
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• 1998

In this study, we have investigated the meaning and mechanism of the 'construction' in the operational constructivism and the social constructivism. According to Piaget, a mathematical concept is the operational sch me, which is constructed through the reflective abstraction from a general coordination of activities and operations. The process of the reflective abstraction consists of 'reflechissement'and 'reflexion'. The reflechissement starting from 'intriorisation' concludes with 'thematisation', and the reflexion consists in the 'equilibration' of the result of reflechissement. The 'construction' in the social constructivism includes two process. One is the process from the individual, subjective knowledge of mathematics to the social, objective knowledge of mathematics, and the other is vice versa. The emphases is placed on the 'social interaction' and the 'representation' in this two processes. In this context, if we want to apply the social constructivism, we should clarify the meaning of 'society', and consider the difference between the society of mathematicians and the society of students.

• Korean Journal of Child Education & Care
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• v.19 no.3
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• pp.13-30
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• 2019

Objective: The purpose of this study is to analyze the annual operational status in the filed of art shown in daily teaching plan for 2-year old, provide the analysis results helping the reflective cognition and to provide the basic data for relevant researches. Methods: This study analyzed the 1 year portion of daily teaching plan of 6 edu care teachers, provided the analysis results to the teacher in charge and promote the reflective cognition. Results: First, the operational status of the art area shown in the daily teaching plan for 2-year old was analyzed by dividing it into arts experience, expression type, art supplies, basic planar material, planar painting material, three-dimensional expression material. Second, The reflective cognition in the teacher on the analysis results of operational status in the field of art for 2-year old was shown as limits such as the infant art missing art appreciation, concentration on art supplies, ambiguity of infant art and the uniformed art activity. Conclusion/Implications: The implications of this study are the facts that it identified the operational concentration in the field of art for 2-year old, it utilized the analysis data of the teacher's daily teaching plan as reflective cognition tell, it showed the diverse teacher's cognitions on the infant-oriented art education not the uniformed art activity application.