• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.3
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• pp.145-151
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• 2023

3D-CNN is one of the deep learning techniques for learning time series data. Such three-dimensional learning can generate many parameters, so that high-performance machine learning is required or can have a large impact on the learning rate. When learning dynamic hand-gestures in spatiotemporal domain, it is necessary for the improvement of the efficiency of dynamic hand-gesture learning with 3D-CNN to find the optimal conditions of input video data by analyzing the learning accuracy according to the spatiotemporal change of input video data without structural change of the 3D-CNN model. First, the time ratio between dynamic hand-gesture actions is adjusted by setting the learning interval of image frames in the dynamic hand-gesture video data. Second, through 2D cross-correlation analysis between classes, similarity between image frames of input video data is measured and normalized to obtain an average value between frames and analyze learning accuracy. Based on this analysis, this work proposed two methods to effectively select input video data for 3D-CNN deep learning of dynamic hand-gestures. Experimental results showed that the learning interval of image data frames and the similarity of image frames between classes can affect the accuracy of the learning model.

• Journal of KIISE:Databases
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• v.29 no.2
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• pp.119-127
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• 2002

Video server which stores video streams should serve more users with the requested streams rapidly, satisfying their time constraints. However, the number of users supported and the response times for the requested services in video server are in the oppositional relationship with viewpoint of disk throughput. In this paper, we propose new policy that can provide not only rapid responses for the service requests but also increase the number of users supported in the storage system of video server. The policy admits the random movements of disk heads for urgent service requests but maintains the sequential or restricted movements of disk heads and eliminates rewind time of disk heads for less-urgent service requests in storage system of multiple disks environment so that it can not satisfy only the QoS of users but also support more users.

• Journal of the Korea Convergence Society
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• v.10 no.2
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• pp.141-148
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• 2019

The purpose of this study is to analyze and compare the effectiveness of elementary in e-Learning video lessons. In an elementary school where the educational videos are frequently used, the learning about video materials is important but it is difficult to judge all students by a teacher in a classroom. In order to solve the problems of the field, In the fifth-grade elementary school social studies class, learning using video material was conducted by using the online learning judgment system for the experimental group, and learning using video material was conducted by the traditional method for the controlled group. As a result of the experiment, the class using the online learning judgment system was effective in enhancing the learner 's academic achievement. It also positively influenced learners' learning satisfaction. Teachers' satisfaction was not statistically significant because of the small number of teachers. However, The mean value of the teachers' satisfaction in the experimental group was high and the deviation was small.

• Journal of the Korean Society of Earth Science Education
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• v.7 no.2
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• pp.276-285
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• 2014

The purpose of this study is to investigate the pattern and characteristics of elementary school teaching and learning processes in science based classes. The study participants' class was recorded in video and instructional conversation transcription. The pattern of the observed class was analyzed using the classification frame suggested by Mogan &Saxton(2006). In result, the questioning for elicit information was most frequent and questioning for shape understanding and the questioning for press for reflection in its priority. In result, the presence of elicited questioning for the attainment of knowledge and understanding is more prominent in science-based classrooms. It was revealed that the participating teachers used the questioning sentence pattern more frequently and the self-sustained inquiry that accelerates creative thinking of the student was lacking. It was discovered that teaching elicited questioning, which accelerates creative thinking, as well as fact confirmation pattern is a necessary element of training for teachers.

• Journal of Korean Elementary Science Education
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• v.39 no.2
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• pp.268-283
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• 2020

In this study, we aimed to look at what dilemmas of science teaching elementary school teachers experience and how they cope with their dilemmas in everyday science classes. Three elementary school teachers participated and qualitative data such as class log, class video, and interview materials were analyzed in inductive ways. The main findings are as follows. First, the dilemmas were classified based on the four factors that make up the science class; teacher, student, learning content, environment. However the dilemmas appeared to be not only one factor involved, but the rest of the factors intertwined. Thus, it was interpreted how the main factors causing the dilemmas conflicted with other factors. Second, the types of teachers' coping strategies to the dilemmas could be largely divided into 'give-up', 'stick to' and 'modified'. In some cases, teachers gave up on what they valued and did not take active action ('give-up'), teachers chose what they valued and made decisions to actively realize it ('stick to'), and in others, conflicts were adjusted by introducing new methods or elements to their classes ('modified'). Based on these results, we discussed that the teacher's dilemmas could facilitate the teacher's learning or professional development.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.6
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• pp.137-144
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• 2020

As the spread of COVID-19, the demand for interactive online class is increasing. Universities are introducing various types of online classes, but many problems arise in the field. Learners complain about the quality of the lecture, and professors have difficulty in preparing and conducting online classes. This study analyzed teaching & learning situation in interactive online class and drew teacher's pain point through case studies. Also, we suggested a method to solve the problem divided into a systemic approach and an administrative approach. The stable settlement of interactive online lectures is expected to accelerate the digital transformation of universities.

• Journal of Practical Engineering Education
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• v.12 no.2
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• pp.255-264
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• 2020

In the database design course, the team project is a very important process to develop students' database design competencies. In order to carry out team projects smoothly, active interaction between students and the professor as well as collaboration among team members are very important. However, a full uncontacted class was suddenly decides in the first semester of 2020, it was questionable whether it would be possible to effectively manage this course, where team projects to construct database take up a big portion. However team projects were able to proceed without major problems through interaction using real-time video media such as zoom, and discussions, quizzes, and Q&A supported by the online education support system (LMS), and online presentations, mutual evaluations, and so on. This paper shares the experience of managing engineering team projects in uncontacted classes and based on three surveys introduces desirable improving directions of this instruction and some suggestions to improve uncontacted classes overall.

• Journal of the Korea Society of Computer and Information
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• v.27 no.10
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• pp.211-222
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• 2022

The purpose of this study is to indicate the direction of the future university classes in the post-COVID era, comparing and analyzing lecture evaluation of pre and post COVID-19. To this end, 4 yeard data were used from 2018 to 2019 for pre COVID-19 and form 2020 to 2021 data for post COVID-19. The results were as follows. In the case of liberal arts, "assignments" was the word with the highest frequency and degree centrality(DC) regardless of pre and post-COVID-19 In the major, "understanding" appeared as the most important word. The result of the ego network analysis indicated that "video lecture" and "non-face-to-face classes" were difficult and "interaction" between the professor and the students was important. As a results, it is important to reduce the weight of assignments and increase interaction with students in liberal arts classes. In the case of majors, it is necessary to operate face-to-face classes rather than non-face-to-face classes, and to organize the contents of videos without difficulty.

• Journal of KIISE:Software and Applications
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• v.27 no.5
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• pp.529-542
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• 2000

Recent years, the use of multimedia information is rapidly increasing, and the video media is the most rising one than any others, and this field Integrates all the media into a single data stream. Though the availability of digital video is raised largely, it is very difficult for users to make the effective video access, due to its length and unstructured video format. Thus, the minimal interaction of users and the explicit definition of video structure is a key requirement in the lately developing image and video management systems. This paper defines the terms and hierarchical video structure, and presents the system, which construct the clustering-based video hierarchy, which facilitate users by browsing the summary and do a random access to the video content. Instead of using a single feature and domain-specific thresholds, we use multiple features that have complementary relationship for each other and clustering-based methods that use normalization so as to interact with users minimally. The stage of shot boundary detection extracts multiple features, performs the adaptive filtering process for each features to enhance the performance by eliminating the false factors, and does k-means clustering with two classes. The shot list of a result after the proposed procedure is represented as the video hierarchy by the intelligent unsupervised clustering technique. We experimented the static and the dynamic movie videos that represent characteristics of various video types. In the result of shot boundary detection, we had almost more than 95% good performance, and had also rood result in the video hierarchy.

• ETRI Journal
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• v.29 no.6
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• pp.826-828
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• 2007

Efficient downscaling in a transcoder is important when the output should be converted to a lower resolution video. In this letter, we suggest an efficient algorithm for transcoding from MPEG-4 SP (with simple profile) to H.264/AVC with spatial downscaling. First, target image blocks are classified into monotonous, complex, and very complex regions for fast mode decision. Second, adaptive search ranges are applied to these image classes for fast motion estimation in an H.264/AVC encoder with predicted motion vectors. Simulation results show that our transcoder considerably reduces transcoding time while video quality is kept almost optimal.