• Journal of the Korean Chemical Society
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• v.66 no.6
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• pp.472-492
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• 2022

The purpose of this study was to investigate secondary science teachers' PCK components and subcomponents that are specific to online and offline learning environment. Data collection consisted of survey, class observation, and individual interviews of twelve science teachers. This study used a theoretical framework of PCK for deductive data analysis and articulated codes and themes through the following inductive analysis. Data analysis revealed that each of PCK components showed different specificity to the online and offline learning environment. And subcomponents of each PCK component were different according to the specificity of the online and offline learning environment. Teaching orientation toward science had a specific orientation for the online learning environment, i.e., 'learning science concept' and 'lecture centered instruction.' Knowledge of the science curriculum had online-offline mixed learning environment specific knowledge, i.e., 'reorganization of curriculum' and online learning environment specific knowledge, i.e., 'development of learning goal' and 'science curricular materials.' Knowledge of science teaching strategies had online learning environment specific knowledge, i.e., 'topic-specific strategy', 'subject-specific strategy', and 'interaction strategy' and COVID-19 offline learning environment specific knowledge, i.e., 'topic-specific strategy' and 'interaction strategy'. Knowledge of student science understanding had online learning environment specific knowledge, i.e., 'student preconception', 'student learning difficulty', 'student motivation and interest', and 'student diversity' and COVID-19 offline learning environment specific knowledge, i.e., student learning difficulty'. Knowledge of science assessment had online-offline mixed learning environment specific knowledge and online learning environment specific knowledge, i.e., assessment contents and assessment methods for each.

• Journal of The Korean Association For Science Education
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• v.40 no.5
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• pp.543-563
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• 2020

This study explores how the teaching practices of two teachers changed during scientific modeling classes. It also aims to understand these changes in terms of the teachers' modeling pedagogical content knowledge (PCK) development. The study participants were two elementary school teachers and their fifth-grade students. The teachers taught eight lessons of scientific modeling classes about the human body. The data analysis was conducted for lessons 1-2 and 7-8, which best showed the change in teaching practice. The two teachers' teaching practices were analyzed in terms of feedback frequency, feedback content, and the time allocated for each stage of model generation, evaluation, and modification. Teacher A led the evaluation and modification stages in a teacher-driven way throughout the classes. In terms of feedback, teacher A mainly used answer evaluation feedback in lesson 1-2; however, in lesson 7-8, the feedback content changed to thought-provoking feedback. Meanwhile, teacher B mostly led a teacher-driven model evaluation and modification in lesson 1-2; however, in lesson 7-8, she let her students lead the model evaluation and modification stages and helped them develop models through various feedbacks. The analysis shows that these teaching changes were related to the development of modeling PCK components. Furthermore, the two teachers' modeling PCK differed in teaching orientation, in understanding the modeling stages, and in recognizing the value of modeling, suggesting the importance of these in modeling teaching practice. This study can help improve the understanding of modeling classes by revealing the relationship between teaching practices and modeling PCK.

• The Journal of Korean Association of Computer Education
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• v.4 no.2
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• pp.135-143
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• 2001

Teachers' cognitive understanding of subject matter content have direct impact on the quality of students learning. In order to understand this, we need to investigate the relationships between the teachers' level of knowledge about the content and the instruction teacher provide for students. Professional development programs for computer education teachers include courses in computer science, curriculum studies, and the application of computers in the classroom. Effective teachers, however, have expertise in the subject matter content, know curriculum, and understand contextual knowledge for teaching computers in the classrooms. Although computer education have evolved for last 20 years, we have not yet made significant progress on researching "what" is the professional knowledge of computer teachers, and "how" they could be trained. Teacher's knowledge includes pedagogical and contextual knowledge of teaching the specific subject. The purpose of this paper is to understand the professional knowledge of computer teachers, and the adoption of PCK (pedagogical content knowledge). As a result of this paper, I hope to initiate further discussions and researches on PCK and its' implication for computer teachers and teacher preparation programs in Korea.

• Journal of The Korean Association of Information Education
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• v.15 no.1
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• pp.23-30
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• 2011

The purpose of this study is to obtain the basic data as a part of the knowledge-base to improve the expertise of the informatics teacher in the secondary school by investigating the perception level of the Pedagogical content knowledge (PCK) of the incumbent informatics teacher in the secondary school. For achieving this purpose, the subcategory of the Pedagogical content knowledge(PCK) was divided into 6 fields based on its theoretical background and the developed questions were modified to 31 questions by the experts'checking their contents validity, the survey was carried out targeting 34 incumbent informatics teachers in the secondary school and the result was analyzed. As a result of the measurement of the perception level of the Pedagogical content knowledge of the informatics teacher in the secondary school, the average score in the whole range of PCK was 3.87. Additionally, between two groups of under 10-year-experienced teachers and over 10-year-experienced teachers, the difference about the perception level of the Pedagogical content knowledge of the informatics teacher in the secondary school by work experience was came out as a 0.05 significance level in the educational process knowledge.

• Journal of Korean Elementary Science Education
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• v.31 no.1
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• pp.109-124
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• 2012

Developing pedagogical content knowledge (PCK) has been emphasized for teacher's professionalism and it should be done from systematic teacher training courses. In this study, we investigated changes of elementary pre-service teachers' PCK of science teaching and motivational strategies before and after a training course. For the analysis of pre-service teachers' PCK, their lesson plans, surveys, and interviews were collected. According to the results, in the beginning of the semester, pre-service teachers in the experimental group usually used didactic or combination of didactic and inquiry teaching strategies and a few pre-service teachers used inquiry or discovery teaching strategies when making lesson plans. However, at the end of the semester many pre-service teachers used inquiry teaching strategies in their lessons which included activities of asking students' prior knowledge, conducing experiments, finding conclusion, and comparing teachers' explanations with students' explanations. Regarding motivational strategies, in the beginning of the semester they focused using activities to create student's emotional interest in science lesson but at the end they used other strategies to create positive atmosphere for learning, capture intellectual interest in science, and connect science to students' everyday lives. The changes in pre-service teachers' PCK in the experimental group was meaningful because there was less change in pre-service teachers' PCK in the control group. This study implies the need for effective professional development programs for developing pre-service teachers' PCK.

• Journal of the Korean Chemical Society
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• v.56 no.2
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• pp.274-289
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• 2012

The purposes of this study were to analyze instructional strategies of science teachers, science teachers' orientations toward science teaching by the reason which instructional strategies was used in middle school science classes, and the relations among PCK elements for suggesting a direction of improvement of PKC models. For this purpose, we selected three of middle school teachers as participants who had various teaching experience periods. Semi-structured interviews and classroom observations were gathered for data. From the data collected, we analyzed the type of instructional strategies of science teachers. On the base of these, we identified characteristics of the teachers' orientations toward teaching science. From the reason that instructional strategies was used, we could ascertain that knowledge of science curriculum and knowledge of students' learning which was component of PCK crucially affected instructional strategies of science teachers. Therefore we assured that analysis of practical instructional strategies of science teachers that showed through science instruction was the most effective method that could find out science teacher's orientation of teaching science internalized, and that knowledge of science curriculum and knowledge of students' learning was the basic component of PCK that formed instructional strategies of science teachers. On the basis of the result, a necessity for improvement of PCK models was presented.

• Journal of Microbiology and Biotechnology
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• v.26 no.8
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• pp.1452-1456
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• 2016

Overexpression of the genes encoding phosphoeneolpyruvate carboxykinase (pckA) and NAD-dependent malic enzyme (maeA) facilitates higher intracellular ATP and NAD(P)H concentrations, respectively, under aerobic conditions in Escherichia coli. To verify a hypothesis that higher intracellular energy reserves might contribute to H₂ fermentation, wild-type E. coli strains overexpressing pckA and maeA were cultured under anaerobic conditions in a glucose minimal medium. Overexpression of pckA and maeA enabled E. coli to produce 3-times and 4-times greater H₂ (193 and 284 nmol, respectively) than the wild type (66 nmol H₂). The pckA and maeA genes were further overexpressed in a hydrogenase-3-enhanced E. coli strain. The hydrogenase-3-enhanced strain (W3110+fhlA) produced 322 nmol H₂, whereas the ATP-enhanced strain (W3110+fhlA+pckA) produced 50% increased H₂ (443 nmol). Total H₂ in the NAD(P)H-enhanced strain (W3110+fhlA+maeA) was similar to that in the control strain at 319 nmol H₂. Possible explanations for the contribution of the increased cellular energy reserves to the enhanced hydrogen fermentation observed are discussed based on the viewpoint of metabolic engineering strategy.

• 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 Korean Elementary Science Education
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• v.30 no.3
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• pp.315-329
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• 2011

The purpose of this study is to examine the characteristics and the relationships of PCK components of elementary school teacher in the chapter of electric circuit unit. The subjects of this study were two teachers serving as main teachers in the 5th grade and data were collected through qualitative research methods such as questionnaires for teachers, classroom observations and teacher interviews. The collected data were transcribed and then analyzed. Results of analysis showed that teacher A thought that science was a class to explore and study the principles of nature phenomena and scientific knowledge by themselves In addition, teacher A helped students to understand the content by using strategies of analogy. The teacher B conveyed the contents of text without any reconstruction. But teacher B understood the standards of curriculum, and didn't want to teach students over the standards. Based on the analysis, we could conclude that PCK is formed on the basis of knowledge and belief about curriculum and knowledge and belief about learners.

• Communications of Mathematical Education
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• v.32 no.3
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• pp.297-314
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• 2018

This article aims at providing implication for teacher preparation program through interpreting pre-service teachers' knowledge by using Shulman-Fischbein framework. Shulman-Fischbein framework combines two dimensions (SMK and PCK) from Shulman with three components of mathematical knowledge (algorithmic, formal, and intuitive) from Fischbein, which results in six cells about teachers' knowledge (mathematical algorithmic-, formal-, intuitive- SMK and mathematical algorithmic-, formal-, intuitive- PCK). To accomplish the purpose, five pre-service teachers participated in this research and they performed a series of tasks that were designed to investigate their SMK and PCK with regard to students' misconception in the area of geometry. The analysis revealed that pre-service teachers had fairly strong SMK in that they could solve the problems of tasks and suggest prerequisite knowledge to solve the problems. They tended to emphasize formal aspect of mathematics, especially logic, mathematical rigor, rather than algorithmic and intuitive knowledge. When they analyzed students' misconception, pre-service teachers did not deeply consider the levels of students' thinking in that they asked 4-6 grade students to show abstract and formal thinking. When they suggested instructional strategies to correct students' misconception, pre-service teachers provided superficial answers. In order to enhance their knowledge of students, these findings imply that pre-service teachers need to be provided with opportunity to investigate students' conception and misconception.