• Journal of The Korean Association For Science Education
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• v.37 no.4
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• pp.553-564
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• 2017

This study investigated the change of pre-service elementary teachers' professional visions through video-based reflection on science teaching with focus on their attention and pedagogical reasoning about student learning. Specifically, we compared two reflection cycles before and after pre-service elementary teachers went through the collaborative video-based reflection process in a professional learning community. The primary data were collected from eight pre-service elementary teachers and included their science lesson plans, videotaped lessons, video-reflection papers, and transcripts from the interviews. Pre-service elementary teachers' attention was categorized in five aspects: classroom management & control, teacher's instruction, students' thinking & learning, subject knowledge, and assessment. The level of their pedagogical reasoning about student thinking and learning was determined with six levels based on the number of evidence, evidence area, and evidence type. The findings revealed that 1) individual reflection is not enough - collaborative reflection is essential to change their attention toward students learning and thinking 2) pedagogical reasoning levels increase gradually throughout the individual and collaborative video-based reflection processes. The participants not only attributed student learning solely to the characteristics of students but also connected it with their own instruction or science content knowledge and used different types of evidences as they went through two reflection cycles. Implications for using video in the teacher education program were discussed.

• Korean Journal of Child Education & Care
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• v.19 no.1
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• pp.27-43
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• 2019

Objective: The purpose of this study is to investigate how the child care teachers experience about professional vision development through participating in video clubs with their peers while watching videos about their interactions with children in the classroom. Methods: We selected three child care teachers in a day care center in Seoul area and conducted the qualitative case study. Video clubs were designed to support the quality of teacher-child interaction by developing child-care teachers' professional vision. And the video clubs used the self-reflection process and cooperative self-reflection process as an important educational method. Results: Teachers were able to experience the change of attention in watching their interaction scene through the 4-time video club participation and to have opportunity for educational (knowledge based) reasoning. Particularly, through participation in the video club, the teacher could pay attention to teachers' intention, teachers' decision making process, and child's intention. In addition, through video club participation, the teachers experienced educational interpretation based on children's thinking and interest; and reasoning through reflective thinking about the results of teaching behavior. This change of professional vision was possible through mutual scaffolding through cooperative reflection among participating teachers. Conclusion/Implications: Based on the results of this study we discussed the importance of the professional vision development of the child care teachers and the effectiveness of the video club for supporting their professional vision development.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06b
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• pp.45-50
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• 1998

Several 3 dimensional image display systems were recently developed in Korea. These are a holographic video system based on pulse laser illumination, ad 8-view 3 dimensional image system capable of displaying computer generated 3 dimensional images and multiview 3 dimensional imaging system based on moving aperture and holographic screens of both transmission and reflection types. All these systems require no special glasses to watch and works impressively.

• Journal of Broadcast Engineering
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• v.5 no.1
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• pp.102-112
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• 2000

The previous video structuring techniques are mainly limited to shot or shot group level. However, the shot level structure couldn't provide semantics within a video. So, researches on high level structuring are going on for getting over the drawbacks of shot level structure, recently. To overcome the drawbacks of shot level structure, we propose video scene segmentation technique based on color and motion features. For considering various color distribution, each shot is divided into sub-shots based on color feature. A key frame is extracted from each sub-shot. The motion feature in a shot is extracted from MPEG-1 video's motion vector. Moreover adaptive weights based on motion's property in search range are applied to color and motion features. The experiment results of proposed technique show the excellence in view of the over-segmentation and the reflection of semantics, comparing with those of previous techniques. The proposed technique decomposes video into meaningful hierarchical structure and provides video browsing or retrieval based on scene.

• Journal of Electrical Engineering and Technology
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• v.11 no.2
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• pp.519-528
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• 2016

In order to achieve fast computational speed with good visual quality of output video, we propose a frequency domain based new fractal video compression scheme. Normalized cross correlation is used to find the structural self similar domain block for the input range block. To increase the searching speed, cross correlation is implemented in the frequency domain using FFT with one computational operation for all the domain blocks instead of individual block wise calculations. The encoding time is further minimized by applying rotation and reflection DFT properties to the IFFT of zero padded range blocks. The energy of overlap small size domain blocks is pre-computed for the entire reference frame and retaining the energies of the overlapped search window portion of previous adjacent block. Quadtree decompositions are obtained by using domain block motion compensated prediction error as a threshold to control the further partitions of the block. It provides a better level of adaption to the scene contents than fixed block size approach. The result shows that, on average, the proposed method can raise the encoding speed by 48.8 % and 90 % higher than NHEXS and CPM/NCIM algorithms respectively. The compression ratio and PSNR of the proposed method is increased by 15.41 and 0.89 dB higher than that of NHEXS on average. For low bit rate videos, the proposed algorithm achieve the high compression ratio above 120 with more than 31 dB PSNR.

• Journal of the Optical Society of Korea
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• v.9 no.1
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• pp.26-31
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• 2005

We describe the design and the implementation of video-rate reflection confocal scanning microscopy (CSM) using an acousto-optical deflector (AOD) for the fast horizontal scan and a galvanometer mirror (GM) for the slow vertical scan. Design parameters of the optical system are determined for optimal resolution and contrast. The OSLO simulations show that the performances of CSM are not changed with deflection angle and the wavefront errors of the system are less than 0.012λ. To evaluate the performances of designed CSM, we do a series of tests, measuring lateral and axial resolution, real time image acquisition. Due to a higher axial resolution compared with conventional microscopy, CSM can detect the surface of sub-micrometer features. We detect 138㎚ line shape pattern with a video-rate (30 frm/sec). And 10㎚ axial resolution is archived. The lateral resolution of the topographic images will be further enhanced by differential confocal microscopy (DCM) method and computational algorithms.

• Journal of the Korean Chemical Society
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• v.66 no.6
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• pp.459-471
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• 2022

The purpose of this study is to develop the workshop to improve teachers' questions considering the context of discourse. Four pre-service science teachers in the fourth grade participated in the study. Pre-service science teachers participated in the workshop. The characteristics of their reflection on the question considering the context of discourse were analyzed. Pre-service science teachers considered the types of questions they learned in the workshop during the reflection. But the affective domains of students were rarely considered. Whether the students respond was considered as an important factor of reflection. The questions were evaluated based on the frequencies. A single question without context was reflected on. Various PCK elements were not considered comprehensively. Based on the results, the practical implications to develop a program for improving teacher expertise related to the questions considering the context of discourse were discussed.

• Journal of The Korean Association For Science Education
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• v.42 no.1
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• pp.97-109
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• 2022

In this study, we investigated pre-service teachers' reflection of questions during science instruction in teaching practicum from the perspective of productive reflection. The productive reflection used in this analysis has four aspects of learners and learning, subject matter knowledge, instruction, and assessment. Five pre-service teachers participated in this study. They reflected on their questions with one class video by using think-aloud method. Semi-constructed interviews were also conducted. The analyses of the results reveal that the aspect of 'instruction' and the 'learners and learning' were frequently included in their reflections. 'subject matter knowledge' was often included in their reflection while 'assessment' was hardly included. The integrations of the two aspects appear most often, those of three aspects appear only sometimes. However, four aspects appear very rarely. The integrations of 'learners and learning' and 'instruction' with the other aspects were most frequent, and the integrations of 'content knowledge' with the other aspects were often. However, the integration of 'assessment' was very few. There were more productive reflections from pre-service teachers who reflect on several questions in context than who reflected on questions one by one. In addition, they exhibited some difficulties in suggesting alternatives to improve their questions. They tried to modify the teaching method related to the questions rather than revise the form of questions. Based on the results, practical implications to improve expertise related to the questions of pre-service teachers were discussed.

• The Journal of the Korea Contents Association
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• v.16 no.6
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• pp.9-18
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• 2016

This paper proposes a multi-view Wyner-Ziv Video coding scheme based on spatio-temporal adaptive estimation. The proposed algorithm is designed to search for a better estimated block with joint bi-directional motion estimation by introducing weights between temporal and spatial directions, and by classifying effectively the region of interest blocks, which is based on the edge detection and the synthesis, and by selecting the reference estimation block from the effective motion vector analysis. The proposed algorithm exploits the information of a single frame viewpoint and adjacent frame viewpoints, simultaneously and then generates adaptively side information in a variety of closure, and reflection regions to have a better performance. Through several simulations with multi-view video sequences, it is shown that the proposed algorithm performs visual quality improvement as well as bit-rate reduction, compared to the conventional methods.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.25 no.2
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• pp.120-133
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• 2018

Purpose: A meta-analysis was conducted to evaluate effectiveness of education programs using video recording and feedback in the improvement of competency in clinical skills for health care majors. Methods: Six databases were searched and inclusion criteria were randomized controlled trials (RCTs) or non-randomized controlled trials (NRTs) reporting level of skill competency using numerical measurements. Data analysis and synthesis were performed using Comprehensive Meta-Analysis software and Revman program. Results: Of 1,568 records, 11 studies met inclusion criteria. Statistically significant effectiveness of education programs using video recording and feedback was identified. A low risk of bias was detected among both RCTs and NRTs. Meta-analysis showed that the intervention groups had more effective improvements in skill competency (standardized mean difference [SMD]: 0.74; 95% CI: 0.33~1.16). Results of subgroup analysis showed higher effects when interventions dealt with one skill, used self-reflection with expert feedback, and included instruction from instructor in the education programs. Conclusion: Findings suggest that schools for health care majors should actively adopt video and feedback based skill training allowing educators to design effective programs. Potential is higher for students to achieve higher competency when they train with one skill at a time, use of instruction and receive feedback from experts.