• Journal of the Microelectronics and Packaging Society
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• v.29 no.2
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• pp.49-52
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• 2022

As the difficulty of flip chip products increase, interest in stable PKG material technology from the viewpoint of reliability is increasing. Currently, the representative of poor reliability that are mainly occurring in flip chip PKG are Sn bridge and Cu dendrite. Two type defects are caused by void generated by the flux residue around the bump. In order to essentially minimize the risk of this type of reliability failure, the linkage between the composition of Molded Under-fill (MUF) and flux, which is related material, was reviewed. In this study, the correlation between base resin and filler, which is the main component of MUF, and flux, was defined, and the material composition design was carried out by refer to lesson learn. With the current material composition, it was confirmed that moisture absorption reliability 85%/85%/24hrs pass result and void did not occur during destructive analysis, and developed MUF has shown flux immunity improving result in flip Chip PKG. We think this study can be used in yield enhancement of flip chip process and give insights to study in compatibility between MUF and flux.

• Journal of Korean Elementary Science Education
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• v.42 no.1
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• pp.47-63
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• 2023

In this study, we analyzed the PCK components in the materials units of the third and fourth grades of the Korean government-authorized teacher's guides for elementary school, developed in the 2015 revised national curriculum. The results showed that the PCK components were presented in a relatively balanced manner compared to the teacher's guides for middle school. Knowledge of the subject matter accounted for the highest proportion, and knowledge of instructional strategies in science accounted for a higher proportion than knowledge of the science curriculum. The knowledge of assessment in science showed the greatest deviation among publishers, and knowledge of students tended to show the lowest. By subcomponents, experiments and inquiries had a higher proportion than concepts and theories. The ratio of horizontal articulation was lower than that of vertical articulation or lesson objectives, and lesson objectives were presented in various ways, such as in core competencies and achievement standards for science. As questioning was emphasized, teaching strategies and questioning appeared at a similar rate. Motivation and interest, misconceptions were linked to teaching strategies and questioning. In some cases, assessment items and assessment criteria were presented at each level, and various PCK components were linked to these two components. Components with relatively large differences among publishers were supplementary or in-depth concepts, inquiry in textbooks, instruction sequence and method, subject-specific strategies, and assessment items. From the results, the implications for the development of teacher's guides were discussed.

• Journal of Science Education
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• v.47 no.1
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• pp.11-23
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• 2023

In this study, we examined the effect of socioscientific issue (SSI) based science lessons on underachieving 9th-grade students. A total of seven lessons centered on two SSIs related to the national science curriculum were developed and implemented during the first semester of 2021. Data were collected from 185 9th-grade students in one middle school in a mid-sized city of South Korea. Among them, 37 were identified as achieving far below the standards (underachieving students hereafter). Quantitative data were collected from pre- and post-tests on basic science content and attitudes and competency measures. To supplement quantitative data, lesson observation notes were recorded, and student interviews with a selected number of students were conducted. The analysis of quantitative data was conducted through the Wilcoxon Signed Rank Test and paired t-tests. Qualitative data were analyzed to find reasons for changing attitudes. The findings showed that the SSI-based lessons were more effective on underachieving students than the others in enhancing basic academic achievement, while there was no significant effect on all in attitudes and competency. Lesson observation data showed that underachieving students were more engaged in SSI-based lessons than before. Student interviews demonstrated several reasons why they were engaged, suggesting the aspects of SSI-based lessons that facilitated underachieving students' learning. Further research topics are suggested.

• The Mathematical Education
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• v.62 no.4
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• pp.531-549
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• 2023

Despite the significance of mathematics teacher guidebooks as a support for teacher learning, there are few studies that address how elementary mathematics teacher guidebooks support teacher learning. The purpose of this study was to analyze the educative features of elementary mathematics teacher guidebooks for grades 3 and 4. For this, six units from each of ten kinds of teacher guidebooks were analyzed in terms of seven dimensions of Teacher Learning Opportunities in Korean Mathematics Curriculum Materials (TLO-KMath). The results of this study showed that mathematics content knowledge for teaching was richly provided and well organized. Teacher guidebooks provided teacher knowledge to anticipate and understand student errors and misconceptions, but were not enough. Sample dialogues between a teacher and students were offered in the teacher guidebooks, making it easier for teachers to identify the overall lesson flow and key points of classroom discourse. Formative assessment was emphasized in the teacher guidebooks, including lesson-specific student responses and their concomitant feedback examples per main activity. Supplementary activities and worksheets were provided, but it lacked rationales for differentiated instruction in mathematics. Teacher knowledge of manipulative materials and technology use in mathematics was provided only in specific units and was generally insufficient. Teacher knowledge in building a mathematical community was mainly provided in terms of mathematical competency, mathematical classroom culture, and motivation. This paper finally presented implications for improving teacher guidebooks to actively support teacher learning.

• Journal of Korean Elementary Science Education
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• v.43 no.1
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• pp.185-200
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• 2024

This study explored the changes in the elementary science teaching expertise of teachers who participated in an in-school professional learning community for elementary science instructional research. Six elementary school teachers from grades 4, 5, and 6 at an 18-class S elementary school in a medium-sized city in Chungcheongbuk-do conducted collaborative instructional research on elementary science lessons as part of an in-school professional learning community, which was held 26 times over 7 months in 2020. During the professional learning community, video and audio recordings of the activities, research lessons, course materials, and professional learning community reflection activities were collected for analysis. The collected data were analyzed using qualitative research methods; data processing, reading, note-taking, description, classification, interpretation, reporting, and visualization; and the instructional professionalism elements were extracted based on the instructional professionalism framework. In the early professional learning community activity stages, the participating teachers first discussed their teaching perspectives, their experiences, and their goals for teaching science, which resulted in a selection of research questions. The teachers then collaboratively designed and implemented research lessons for each grade level, after which lesson reflections were conducted. The teachers' abilities to engage in qualitative reflection on the research questions improved after each reflection iteration. It was found that this professional learning community collaborative lesson study experience positively contributed to teaching expertise development. Based on the study findings, the implications for using professional learning communities to improve elementary teachers' science teaching expertise are given.

• Journal of The Korean Association For Science Education
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• v.29 no.6
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• pp.693-711
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• 2009

One of the most important objectives in science education is to develop students' science literacy. The purpose of this study is to analyze the relevance between biology instructional objectives in the 7th curriculum taught in elementary and secondary schools. For this study, 7 major parts in each grade were analyzed including cell, the form and function of plants, the form and function of animals, genetics, diversity, evolution, ecology, and environment. The strand map of instructional objectives is completed that represents the relation between the objectives. The summary of the results from this study is as follows. First, the concept about cells is not fully covered in lower grades including elementary schools. While the concept of energy metabolism is repeatedly covered, there is no concept of energy covered in learning the concept of energy metabolism in elementary schools. Second, the textbooks in elementary and middle schools have main concepts about the form and function of plants while those in high schools don't. The concept related to the part of the form and function of animals is repeatedly involved in the curriculum throughout the elementary, middle, and high schools. Third, the concepts such as genetics and evolution are involved in higher grades since these concepts are abstract ones. The part of genetics and evolution as well as diversity has no connection between grades in schools, so the development of "notion between" is necessary to relate these concepts with each other. Fourth, the 4 parts of diversity, ecology and environment, evolution, and the form and function of plants are covered in limited grade levels. The results of the relevance of gene in lesson goals will play an important rein as the primary material in developing the connection between textbooks in which lesson goals are closely related to each other throughout all grade levels in elementary, middle and high schools.

• Journal of The Korean Association For Science Education
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• v.44 no.5
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• pp.361-378
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• 2024

This study explores elementary teachers' PCK change through the knowledge exchange between ePCK (enacted PCK) and pPCK (personal PCK) during modeling-based science inquiry instruction. For this purpose, three elementary school teachers were selected as research participants, and the CoRes(content representations) written by the participants before and after the lessons. The CoRes were, then, analyzed using qualitative content analysis to explore changes in pPCK, and the data related to the modeling-based science inquiry instruction (such as lesson plan, lesson videos, in-depth interviews) were analyzed using grounded theory research methods. The research indicated that the pPCK of elementary teachers who enacted modeling-based science inquiry instruction changed in regard to curricular knowledge, knowledge of students, pedagogical knowledge, and assessment knowledge. The data from the modeling-based science inquiry instruction showed that the changes of the teachers' pPCK was influenced by the knowledge exchange between ePCK and pPCK during the process of planning, teaching, and reflecting on the lessons. Based on the findings, this study discussed the need to identify personal factors that influence elementary teachers' knowledge exchange between PCK realms and suggested the need to develop effective modeling-based science inquiry teaching methods.

• Journal of the Korean School Mathematics Society
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• v.9 no.4
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• pp.425-457
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• 2006

The purpose of this paper was to analyze a teacher's questioning in the learner-centered mathematics lessons and investigate its effects on the construction of learner's knowledge. For this study, it is analysed that the teacher's questioning in the 3 observed learner-centered lessons concerning elementary division topic. The study results showed that the characteristics of the teacher's questioning were respecting of learner's informal mathematical thinking, open-ended questioning for divergent thinking, appropriate questioning at every group, and respecting classroom norm. Teacher's questioning affects the quality of learner's mathematical thinking and his or her attitude toward mathematics.

• Journal of the Korean Society of Earth Science Education
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• v.4 no.2
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• pp.126-133
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• 2011

This study explored different concepts by handing out the questionnaires asking the 6 students of the second year of junior high school who had no lesson on cycle "which words related to cycle are suggested?" In regard to the stimulation of the word 'cycle', students relate it to different fields that they learn at school such as biology, environmentology, and earth science. The analyzed results from the answers by students are as follows. First, it resulted in from analysis on the questionnaire and the half-structured interviews that students were unable to expand the concept of cycle to the scientific concept, and perceived it fragmentarily. Secondly, their understanding on the system of the earth was low and they understood the concept of cycle with a unilinear thought rather than a systematic thought. Therefore, we need to synthesize the students' unilinear thoughts on cycle shown through this study and an effective educational strategy for their continuous, systematic thoughts, is essential.

• The Korean Journal of Community Living Science
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• v.28 no.3
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• pp.429-446
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• 2017

The current study aims to identify factors associated with private tutoring of college students in Korea. For this purpose, this study used the Korean Education and Employment Panel survey, which contains items regarding whether or not college students receive private tutoring as well as the monthly costs of private lessons. The current study focuses on private English lessons due to the very low response rates of other types of private tutoring. For the analysis, the 5th wave of KEEP collected in 2008 was selected, and a Heckman selection model was employed, including three categories of variables: individual, school, and parent/household factors. The results have revealed that for the selection model (receiving private English tutoring or not), having received private lessons in high school, gender, and level of satisfaction regarding the respondent's current university were significant. In terms of the outcome model (cost for private English tutoring in college), university admission type (rolling vs. regular), living with parents, school type (4-yr university vs. others), being in debt to cover private lesson fees in high school, and monthly household income had significant effects. This article also discusses the results and implications for future research and policy makers.