• Structural Engineering and Mechanics
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• v.82 no.3
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• pp.271-282
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• 2022

The active learning surrogate model based on adaptive sampling strategy is increasingly popular in reliability analysis. However, most of the existing sampling strategies adopt the trial and error method to determine the size of the Monte Carlo (MC) candidate sample pool which satisfies the requirement of variation coefficient of failure probability. It will lead to a reduction in the calculation efficiency of reliability analysis. To avoid this defect, a new method for determining the optimal size of the MC candidate sample pool is proposed, and a new structural reliability analysis method combining polynomial chaos-based Kriging model (PC-Kriging) with adaptive sampling region is also proposed (PCK-ASR). Firstly, based on the lower limit of the confidence interval, a new method for estimating the optimal size of the MC candidate sample pool is proposed. Secondly, based on the upper limit of the confidence interval, an adaptive sampling region strategy similar to the radial centralized sampling method is developed. Then, the k-means++ clustering technique and the learning function LIF are used to complete the adaptive design of experiments (DoE). Finally, the effectiveness and accuracy of the PCK-ASR method are verified by three numerical examples and one practical engineering example.

• The Mathematical Education
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• v.55 no.4
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• pp.523-538
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• 2016

The purpose of this study is to explore the secondary mathematics teachers' technology integration self-efficacy with respect to geometry classes which they had experienced during last 1 year, 2015. For this study, we developed and validated the questionnaires based on TPACK framework in secondary geometry context. The questionnaires contained 28 items examining the secondary mathematics teachers' TPACK. We conducted the item analysis with 28 items and then the exploring factor analysis. As a result, 28 items was categorized into 5 constructs, TPCK, TCK, TK, PCK, PK, different from Mishra and Koehler's categorization. We analyzed the secondary mathematics teachers' technology integration self-efficacy with respect to geometry classes based on 5 TPACK constructs. The results indicated that there were no significant differences in technology integration self-efficacy according to gender. But technology integration self-efficacy according to the years of teaching experience differed significantly. The more years of teaching experiences teachers have, the lower level of TPCK and TK they have and the more years of teaching experiences teachers have, the higher level of PCK they have. The results also showed that there ware significant difference in TPCK according to the existence and non-existence of taking the technology courses during the time at university. Furthermore, we provide the implication for the professional preparation program for the mathematics teachers in middle schools.

• Journal of The Korean Association For Science Education
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• v.29 no.1
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• pp.54-67
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• 2009

This study dealt with two case studies of the development of beginning science teachers' pedagogical content knowledge (PCK). This study was grounded on the idea that teacher thinking and classroom behavior are related to each other in a reciprocal way. Teachers' PCK influences teaching practices, while in a reverse way teaching activities influence teachers' practical knowledge. Two beginning science teachers participated in this study. Data collection consisted of classroom observation, interviews, reflective journals and lesson plans. For data analysis, we conceptualize pedagogical content knowledge for science teaching as consisting of four components: (a) knowledge about science matter, (b) knowledge about students' understanding of science topics, (c) knowledge about instructional strategies for teaching science, (d) knowledge about assessment in science. The outcomes of this study revealed that there was a large gap between beginning science teachers' intentions for teaching science and their practice. To give beginning teachers more opportunities to incorporate their knowledge base for teaching, we propose that they need to be involved in a real teaching situation at schools rather than in the university.

• Journal of The Korean Association For Science Education
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• v.33 no.1
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• pp.63-78
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• 2013

Purposes of this study were to explore the process of experience that science teachers go through when participating in peer coaching meetings to improve teaching ability and to find out factors that affect each process of experience. The data were collected through recording of peer coaching meetings, videotapes of science class, and interviews. All the data were analyzed after transcription. The results of the study showed that even though Teacher K broke the ice and formed consensus among the peers by developing Content Representation (CoRe) at the beginning of the meetings, he became self-defensive rather than receptive of peers' opinions on the recorded class at the discussion session. But as the peer coaching went on, he realized that peer coaching was not about evaluation but rather on improving his teaching ability. In turn, he was able to look at his teaching in a more objective point of view and accepted suggestions from peer coaching discussion. The self-reflection of Teacher K acted as the key factor in the efforts to improve his teaching ability. He sought the concrete alternatives through the class analysis with fellow teachers and showed major changes in his teaching practice from the language habits, pronunciation, and speed of his speech to the interaction with students and class design. However, there was little change in knowledge of curriculum and assessment due to his strong orientation to improve students' grades as an academic high school teacher. Likewise, it was found that while peer coaching exert a strong influence on instructional methods and strategies of Teacher K, his strong orientation to improve students' grades hinders a balanced development of subcomponents of PCK.

• Journal of The Korean Association For Science Education
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• v.39 no.3
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• pp.405-414
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• 2019

As a case study, we analyzed the professor's teaching professionalism in college of science-engineering based on pedagogical content knowledge. Two professors from the college of science-engineering located in Chungcheongbuk-do participated in this study. After collecting their syllabi, we observed their classes and conducted semi-structured interview before and after the classes. Analysis were conducted on their syllabi, taped videos, field notes and transcripts of the interview. As a result, both professors' orientation to teaching was not only related to learning subject matter knowledge, but also developing job competencies or communication skills. Their orientations were transformed according to the educational situation. After establishing the final learning goals, the professors organized weekly plan by listing the topics. However, they were unaware that the goals of each topic should be presented in detail in the class. Also, one of them presented a lack of understanding of the students' prior knowledge and showed low understanding of what aspects of the topics make students difficult to learn. In addition, the two professors applied various teaching strategies such as giving examples, questioning, and problem solving, but the degree of students' participation was not enough in the process of teaching. In the aspect of assessment, the professors had low understanding in students' achievement or feedback. Based on the results of the analysis, this study proposed methods and strategies for improving the teaching professionalism of science-engineering professors.

• Journal of The Korean Association For Science Education
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• v.38 no.4
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• pp.587-598
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• 2018

In this study, we investigated the characteristics of pre-service science teachers' curriculum design for lessons using self-generated analogy. Three pre-service science teachers at a college of education in Seoul participated in this study. After a workshop on lessons using self-generated analogy, they planned and demonstrated lessons. All of the teaching-learning materials were collected, and their lessons were observed and videotaped. Semi-structured interviews were also conducted before and after their lessons. The characteristics of lessons using self-generated analogy were analyzed in the perspectives of PCK. The analyses of the results revealed that they used various strategies to promote students' generating analogies. They lacked understanding of the stages of the lessons and the role of teachers. Although all of them considered assessment, they used limited assessment methods and assessment dimensions. Some actively considered students' misconceptions, and specifically anticipated analogies that students could generate. They determined topics for lessons considering various aspects such as the level of self-generated analogy and the characteristics of scientific conceptions. On the bases of the results, we suggest some educational implications for pre-service science teacher education.

• Journal of The Korean Association For Science Education
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• v.35 no.4
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• pp.665-676
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• 2015

In this case study, we analyzed the processes of STEAM lessons conducted by preservice secondary science teachers. Three preservice science teachers at a college of education in Seoul participated in this study. After the workshop for STEAM education, they planned and practiced STEAM lessons. All of the teaching-learning materials were collected before lessons, and their lessons were observed and videotaped. Semi-structured interviews were also conducted before and after their lessons. The processes of STEAM lessons were analyzed while focusing on PCK and PDC. Their difficulties, needs, and views on STEAM education were also studied. It was found that they have taken much efforts to reflect the objectives and characteristics of STEAM education, and prepared teaching-learning materials by searching on the internet and arranging creative contents. Their great difficulty was to determine topics for STEAM lessons. While one preservice teacher satisfied with her lesson perceived STEAM education positively, the others perceived that it would be very difficult to practice STEAM lessons in school. For their STEAM lessons to be successful, the workshop needs to include some specific information on grades, proper topics for each grade, ways of making materials, and tips for effective STEAM lessons. In addition, it will be effective if the workshop is carried out after their study on constructivist learning theory and if they experience successful STEAM lessons.

• The Mathematical Education
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• v.57 no.1
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• pp.1-36
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• 2018

The purpose of this study is to examine the relationship between utilization of technology and TPACK in mathematics teachers, and to analyze needs and retentions, difference between needs and retentions, and educational needs of TPACK in mathematics teachers. Furthermore, we will prioritize TPACK items that mathematics teachers want to change, and provide implications for teacher education related to TPACK in the future. To do this, we analyzed 328 mathematics teachers nationwide by using survey on the utilization of technology, averages of TPACK's needs and retentions, t-test of two averages, Borich's educational needs analysis, and the Locus for Focus model. The results are as follows. Firstly, the actual utilization rate was lower than the positive recognition of utilization of technology by mathematics teachers, and many mathematics teachers mentioned the lack of knowledge related to TPACK. Secondly, the characteristics of in-service mathematics teacher's needs and retentions for TPACK were clear, and TPACK's starting line of in-service mathematics teacher can be different from pre-mathematics teacher's. The retentions was high in the order of CK, PCK and PK, and the needs was higher in the order of TPACK, TCK, TK and TPK. All of the higher retentions were knowledge related to PCK, and the value of CK was extremely high among them. In addition, mathematics teachers recognized needs for integrated knowledge related to technology, and they needed more TCK than TPK. The difference between needs and retentions showed that all items except two items in the PK were significant. Retentions of all items in CK was higher than needs, needs of all items in TK, TCK, TPK and TPACK was higher than retentions, PK and PCK were mixed. Thirdly, based on the analysis of Borich's educational needs and the Locus for Focus model, teacher education on TPACK for mathematics teachers needs to focus on TPACK, TK, TCK, and TPK. Specifically, TPACK needs to combine technology in terms of creativity-convergence, mathematical connections, communication, improvement of evaluation quality, and TK needs to new technology acquisition, function of utilizing technology, troubleshoot problems with technology, TCK needs to mathematical value(esthetic, practical) with technology, and TPK needs to consider technology in terms of evaluation methods, teaching and learning methods, improvement of pedagogy. Therefore, when determining the direction of teacher education related to TPACK in the future, if they try to reflect these items in detail, the teachers could participate more actively and receive practical help.

• Journal of the Korean Society of Earth Science Education
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• v.6 no.1
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• pp.69-77
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• 2013

The study aims to figure out pre-service elementary teachers' knowledge understanding on 'stratum and rock' as well as teaching-learning types on the same topic. A total of 65 seniors in an advanced science education course at B University of Education joined the research to fulfill the purpose above. With PCK classification framework, the study examined pre-service teachers' knowledge understanding on 'stratum and rock' while it analyzed how the teachers would teach the given topic to students. The results of the study are presented as follows. First, it was observed that the pre-service elementary teachers have a great understanding on 'stratum and rock' that would be taught via a science textbook for elementary fourth graders. However, regarding terms in 'shale and limestone', they appeared to have a relatively short understanding. Second, PCK elements of the pre-service teachers related to 'stratum and rock' were analyzed and according to the results, the teachers would be interested in teaching model selecting in the teaching-learning strategy field while they would be well aware of how important it is for them to perform an experiment in a teaching process. The teachers also appeared to understand that the teacher question can be mutual complementary during class. However, it turned out that the teachers would have a very much low understanding on learners' prior knowledge as they particularly believe that learning could be significantly affected by the learners' perception level as well as their learning interest and motive. Third, the pre-service elementary teachers were told to design teaching plans on 'stratum and rock' so that the study could find out what learning-teaching methods the teachers would adopt to teach the topic. It was learned that the teachers would proceed with the class basically by giving the learners a descriptive explanation on the topic and also by using pictures and drawings to enhance the learners' understanding during the class.

• Journal of the Korea Society of Computer and Information
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• v.25 no.7
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• pp.225-237
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• 2020

This study verified the effects that a programming-based TPACK education program, through design-based research on TPACK, had on pre-service teachers. The research subjects were pre-service teachers attending teacher training at a university in Korea, and 129 control groups and 126 experimental groups were recruited through lectures. The treatment used a TPACK educational program developed in a design-based study (Kim & Lee, 2019). A TPACK test tool developed by Park and Kang (2014) was used. The test results were analyzed via independent sample t-test and paired sample t-test. The results show that the programming-based TPACK education program (first cycle) was only effective in improving TPK and TPACK, but an effective educational program was developed to improve PCK, TCK, TK (second cycle), PK (third cycle), and CK (final cycle). This design-based research therefore confirmed the development of a programming-based TPACK education program that was effective for improving the TPACK of pre-service teachers.