• School Mathematics
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• v.17 no.4
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• pp.613-632
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• 2015

In this study, we hope to reveal teacher knowledge necessary to address student errors and difficulties about ratio and rate. The instruments and interview were administered to 3 in-service primary teachers with various education background and teaching experiments. The results of this study are as follows. Specialized content knowledge(SCK) consists of profound knowledge about ratio and rate beyond multiplicative comparison of two quantities and professional knowledge about the definitions of textbook. Knowledge of content and students(KCS) is the ability to recognize students' understanding the concept and the representation about ratio and rate. Knowledge of content and teaching(KCT) is made up of knowledge about various context and visual models for understanding ratio and rate.

• Research in Mathematical Education
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• v.6 no.1
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• pp.39-51
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• 2002

This study described an elementary teacher's practical knowledge of selecting and using mathematical tasks for promoting students' understanding and discourse. The informant of this ethnographic inquiry was a third grade teacher and has 10 years of teaching experience. According to the analysis of multiple data sources, this study showed that based on his beliefs about the development of understanding of mathematics and discourse, he continually employed two different types of tasks: open-ended tasks and tasks from students' mistakes and comments during discourse. Teachers' practical knowledge of teaching mathematics and the classroom norms for students' understanding and discourse are suggested to be given attention for further research on this area.

• Communications for Statistical Applications and Methods
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• v.30 no.5
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• pp.501-516
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• 2023

Knowledge distillation (KD) refers to extracting knowledge from a large and complex model (teacher) and transferring it to a relatively small model (student). This can be done by training the teacher model to obtain the activation function values of the hidden or the output layers and then retraining the student model using the same training data with the obtained values. Recently, relational KD (RKD) has been proposed to extract knowledge about relative differences in training data. This method improved the performance of the student model compared to conventional KDs. In this paper, we propose a new method for RKD by introducing a new loss function for RKD. The proposed loss function is defined using the area difference between the teacher model and the student model in a specific hidden layer, and it is shown that the model can be successfully compressed, and the generalization performance of the model can be improved. We demonstrate that the accuracy of the model applying the method proposed in the study of model compression of audio data is up to 1.8% higher than that of the existing method. For the study of model generalization, we demonstrate that the model has up to 0.5% better performance in accuracy when introducing the RKD method to self-KD using image data.

• Journal of the Korean School Mathematics Society
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• v.16 no.1
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• pp.157-185
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• 2013

This study was to investigate novice teachers' Specialized Content Knowledge for Teaching in High School Calculus Lessons. The lessons of two novice teachers in Kyunggi Do were observed from July, 2011 to Feb. 2012. All observed lessons were audeotaped and transcribed into word files. Their calculus lessons were analyzed into three kinds of knowledge consisting of SCKT. Their SCKT just copied the contents of the textbook and other additional SCKT were not found for teaching. Even though students asked a question that they did not understand, the teacher just repeated the previous contents that already he used. But this study included possible contents of SCKT within the areas these teachers covered so that teachers in school may use for teaching of Calculus. The novice teacher do not have sufficient experience, the program of the college of education and the contents of the teacher certificate-examination should include multi-dimensional approaches in SCKT to pre-service teachers in order to raise better specialized teachers in mathematics.

• IEMEK Journal of Embedded Systems and Applications
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• v.17 no.4
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• pp.209-215
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• 2022

This paper proposes a novel approach for training an unsupervised depth estimation algorithm. The objective of unsupervised depth estimation is to estimate pixel-wise distances from camera without external supervision. While most previous works focus on model architectures, loss functions, and masking methods for considering dynamic objects, this paper focuses on the training framework to effectively use depth cue. The main loss function of unsupervised depth estimation algorithms is known as the photometric error. In this paper, we claim that direct depth cue is more effective than the photometric error. To obtain the direct depth cue, we adopt the technique of knowledge distillation which is a teacher-student learning framework. We train a teacher network based on a previous unsupervised method, and its depth predictions are utilized as pseudo labels. The pseudo labels are employed to train a student network. In experiments, our proposed algorithm shows a comparable performance with the state-of-the-art algorithm, and we demonstrate that our teacher-student framework is effective in the problem of unsupervised depth estimation.

• Journal of Korean Elementary Science Education
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• v.39 no.1
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• pp.100-116
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• 2020

The purpose of this study was to investigate the interaction of science PCK between two elementary school teachers by the teacher collaboration within the school. We chose the case that two teachers collaborated spontaneously in the 5th-grade science classes. Even though they had similar teaching experiences, one of them had the science PCK while the other did not. As a result of this study, two teachers began to collaborate to avoid comparisons of science classes between them. They shared the same teaching plan but practiced science teaching individually. During they taught science, they usually collaborated on the instructional sequences, student's activities, and the content of assessments. They had an in-depth collaboration when the teacher who lacked the science PCK asked help to teach problem-centered learning by science inquiry. During the collaboration, their science PCK components, especially the knowledge of instructional strategies for teaching science, shared and it affected the teacher's science practices who lacked the science PCK. However, they did not usually share the knowledge of teaching for their everyday science classes because two teachers had the perception of noninterference about their science classes. This case has the limitation that it is hard to generalize the results but teacher collaboration shows the possibility to develop the elementary school teachers' science professionalism by having peers in the school who can help them in science classes.

• The Journal of the Korea Contents Association
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• v.20 no.10
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• pp.353-368
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• 2020

This research investigates how pre-service music teachers demonstrated pedagogical content knowledge (PCK) and self-efficacy during a 16-week Music Education Course. 37 pre-service music teachers underwent peer mentoring, and prepared teaching guides and class teaching demonstrations. At the end of the course, the 37 participants' teacher self-efficacy and PCK components (namely pedagogical knowledge, representational knowledge, subject matter knowledge, assessment knowledge, student characteristics knowledge, curriculum knowledge, and context and social knowledge) were assessed. Data on their self-efficacy and PCK were gathered through a group interview and their self-reflection journals, and analyzed as phenomenological experience research. Analyses of the data show that pre-service music teachers acquired diverse knowledge. It also showed that peer mentoring enhanced the pre-service music teachers' self-efficacy, enabling them to prepare teaching guides and confidently demonstrate classes. Thus, diverse opportunities in research and practical class demonstrations contributed to pre-service music teachers' PCK and self-efficacy.

• Journal of Educational Research in Mathematics
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• v.25 no.4
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• pp.691-715
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• 2015

This study explored preservice secondary mathematics teachers' mathematical knowledge for teaching [MKT]. In order to measure preservice teachers' MKT, we developed items according to Ball, Thames & Phelps (2008)'s domains and conducted to 53 preservice teachers. Also, we interviewed 1 preservice teacher with the items and a set of interview questions. The findings from the data analysis suggested as follows: a) overall, the preservice teachers scored average 30.2 out of 100; b) the preservice teachers appeared to be unable to explain students' difficulties in learning a specific mathematical idea and how they would respond to and resolve such difficulties.

• Journal of the Korean School Mathematics Society
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• v.13 no.4
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• pp.619-633
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• 2010

To offer insights in organizing professional development programs to promote teachers' substantial ongoing learning, this paper provides an overview of situative perspectives in terms of cognition as situated, cognition as social, and cognition as distributed. Then, it describes research findings on how mathematics teachers can enhance their knowledge and thus improve their instructional practices through participation in a professional development program that mainly provides opportunities to learn and analyze students' mathematical thinking and to perform mathematical tasks through which they interpret the understanding of students' mathematical thinking. Further, it shows that a knowledge of students' mathematical thinking is a powerful tool for teacher learning. In addition, it suggests that teacher-researcher and teacher-teacher collaborative activities influence considerably teachers' understanding and practice as such collaborations help teachers understand new ideas of teaching and develop innovative instructional practices.

• Research in Mathematical Education
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• v.17 no.4
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• pp.221-241
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• 2013

The data for the present paper was a part of a large research project conducted to assess preservice teachers' knowledge related to fractions and place value at a southwestern public university in 2007. The study utilized convenience sampling, consisting of 150 elementary preservice teachers who were enrolled in a mathematics methods course before their student teaching. The results demonstrated preservice teachers' knowledge of teaching comparison, addition, subtraction, and multiplication of fractions was insufficient even though these should be basic knowledge. Teacher preparation programs should emphasize profound knowledge for teaching fractions using representations.