• Research in Mathematical Education
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• v.26 no.2
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• pp.45-61
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• 2023

Number talks as a brief instructional routine benefits students and teachers. In general, the routines consist of four steps- introducing, posing questions, collecting answers, sharing ideas. This paper focuses on the sharing ideas step in which multiple strategies are shared by students because teachers sometimes do not know what to do with these multiple ideas. One way is to support students to engage in comparison given that teachers are expected to support students to compare strategies in number talks. This paper explores whether and how 15 prospective teachers supported students in their practicum classroom to compare different strategies in their enacted number talk. In this paper, 15 videos of number talks enacted by the prospective teachers were collected. Analyzing the videos produced multiple episodes in relation to comparing strategies, including 1) where prospective teachers created pre-conditions for comparison, 2) where they invited students for comparison, 3) where they pressed students to compare, and 4) where they offered their own way to compare. There were two patterns that might limit the potential of having multiple strategies as conditions for comparison. Additionally, this paper found that even though the prospective teachers missed opportunities to support students to compare different strategies, there were two ways for teachers to support students to engage in comparison. These findings can be used for mathematics teacher educators to support prospective teachers.

• Electronics and Telecommunications Trends
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• v.39 no.2
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• pp.33-42
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• 2024

With the recent rapid development of artificial intelligence (AI) technology, its use is gradually expanding to include creative areas and building new content using generative AI solutions, reaching beyond existing data analysis and reasoning applications. Content creation using generative AI faces challenges owing to technical limitations and other aspects such as copyright compliance. Nevertheless, generative AI may increase the productivity of experts and overcome barriers to creative work by allowing users to easily express their ideas as digital content. Thus, various types of applications will continue to emerge. As images and videos can be created using text input on a prompt, generative AI allows to create and edit digital assets quickly. We present trends in generative AI technology for images, videos, three-dimensional (3D) assets and scenes, digital humans, interactive content, and interfaces. In addition, the prospects for future technological development in this field are discussed.

• International Journal of Advanced Culture Technology
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• v.12 no.2
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• pp.375-385
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• 2024

In the context of contemporary digital media, virtual influencers have become an increasingly important form of socialization and entertainment, in which emotional expression is a key factor in attracting viewers. In this study, we take Luo Tianyi, a Chinese virtual influencer, as an example to explore how emotions are expressed and perceived through facial expressions in different types of videos. Using Paul Ekman's Facial Action Coding System (FACS) and six basic emotion classifications, the study systematically analyzes Luo Tianyi's emotional expressions in three types of videos, namely Music show, Festivals and Brand Cooperation. During the study, Luo Tianyi's facial expressions and emotional expressions were analyzed through rigorous coding and categorization, as well as matching the context of the video content. The results show that Enjoyment is the most frequently expressed emotion by Luo Tianyi, reflecting the centrality of positive emotions in content creation. Meanwhile, the presence of other emotion types reveals the virtual influencer's efforts to create emotionally rich and authentic experiences. The frequency and variety of emotions expressed in different video genres indicate Luo Tianyi's diverse strategies for communicating and connecting with viewers in different contexts. The study provides an empirical basis for understanding and utilizing virtual influencers' emotional expressions, and offers valuable insights for digital media content creators to design emotional expression strategies. Overall, this study is valuable for understanding the complexity of virtual influencer emotional expression and its importance in digital media strategy.

• Journal of Broadcast Engineering
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• v.17 no.4
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• pp.640-658
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• 2012

One of the existing terrestrial multi-channel DTV service frameworks, called KoreaView, provides four programs, composed of MPEG-2 based one HD video and H.264/AVC based three SD videos within one single 6MHz frequency bandwidth. However the additional 3 SD videos can not provide enough quality due to its reduced spatial resolution and low target bitrates. In this paper, we propose a framework, which is called a terrestrial multi-channel high quality hybrid DTV service, to overcome such a weakness of KoreaView services. In the proposed framework, the three additional SD videos are encoded based on an H.264/SVC Spatial Base layer, which is compliant with H.264/AVC, and are delivered via broadcasting networks. On the other hand, and the corresponding three additional HD videos are encoded based on an H.264/SVC Spatial Enhancement layer, which are transmitted over broadband networks such as Internet, thus allowing the three additional videos for users with better quality of experience. In order to verify the effectiveness of the proposed framework, various experimental results are provided for real video contents being used for DTV services. First, the experimental results show that, when the SD sequences are encoded by the H.264/SVC Spatial Base layer at a target bitrate of 1.5Mbps, the resulting PSNR values are ranged from 34.5dB to 42.9dB, which is a sufficient level of service quality. Also it is noted that 690kbps-8,200kbps are needed for the HD test sequences when they are encoded in the H.264/SVC Spatial Enhancement layer at similar PSNR values for the same HD sequences encoded by MPEG-2 at a target bitrate of 12 Mbps.

• Journal of Broadcast Engineering
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• v.19 no.2
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• pp.148-157
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• 2014

Various techniques have been developed for efficient compression of stereoscopic 3D videos. Mixed-resolution based approach is one representative bit-rate saving method based on the characteristics of human visual system that the mixed-resolution stereoscopic videos are perceived close to the higher resolution. However, when the difference between the left and right image resolutions is bigger than a certain threshold level, it causes the perceived quality degradation of the 3D images. Subsequently, several researches tried to find the correlation between the difference in resolution and the level of the perceived quality degradation, but they conducted the experiments just considering the difference in resolution without considering the viewing distances, so thereby different results were retrieved from test to test. In this work, we calculated the optimal viewing distance based on the human visual system, and conducted the subjective tests with the calculated viewing distance. With the results, we demonstrate that the fixed and mobile hybrid 3DTV, which is based on mixed-resolution stereoscopic images, can provide the high quality 3D services.

• Journal of Digital Convergence
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• v.18 no.6
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• pp.45-52
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• 2020

This study ranked the degree to which flipped learning contributes to each learning area and, in contrast, to quantitatively examine how effectively these learning methods are used in flipped learning, had four-year university computer majors receive flipped learning. Existing flipped learning experiments have proven effectiveness, while there are also negative effects on effectiveness, which has led to a lot of debate. Effective experiments and classes therefore require more research and an accurate understanding of flipped learning. Analysis of the 123 samples recruited shows that flipped learning contributes to learning is in order of self-directing, collaboration, watching videos, and learning by teachers. Regression analysis of the degree to which learning method affects flipped learning effectiveness resulted in order of self-directed learning, lecture videos, and collaborative learning. This shows that flipped learning not only has the greatest influence on self-directed learning, but also self-directed learning has the greatest influence on flipped learning. It can also see that a collaborative learning and the role of video to prior learning tool is important. Through this study, we hope to understand flipped learning correctly and set learning methods and achievement goals. It is necessary to analyze the interaction between flipped learning and subdivided classroom activities.

• Journal of the HCI Society of Korea
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• v.9 no.1
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• pp.11-21
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• 2014

We present an experimental framework to analyze the physical reactions and causal factors of Visually Induced Motion Sickness (VIMS) using electroencephalography (EEG) signals and vital signs. We studied eleven subjects who are voluntarily participated in the experiments and conducted online and offline surveys. In order to simulate videos including global motions that could cause the motion sickness, we extracted global motions by optical flow estimation method from hand-held captured video recordings containing intense motions. Then, we applied the extracted global motions to our test videos with action movies and texts. Each genre of video includes three levels of different motions depending on its intensity. EEG signal and vital sign that were measured by a portable electrocorticography device and an electronic monometer in real time while the subjects watch the videos including ones with the extracted motions. We perform an analysis of the EEG signals using Distance Map(DM) calculated by correlation among each channel of brain signal. Analysis using the vital signs and the survey results is also performed to obtain relationship between the VIMS and causal factors. As a result, we clustered subjects into three groups based on the analysis of the physical reaction using the DM and the correlation between vital sign and survey results, which shows high relationships between the VIMS and the intensity of motions.

• The KIPS Transactions:PartB
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• v.9B no.6
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• pp.835-844
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• 2002

The number of channels available to a video server is limited since the number of channels a video server can support is determined by its communication bandwidth. Several approaches such as batching, piggybacking and patching have been proposed to reduce I/O demand on the video server by sharing multicast data. Patching has been shown to be efficient in the matter of the cost for VOD systems. Unlike conventional multicast techniques, patching is a dynamic multicast scheme which enables a new request to join an ongoing multicast. In addition, true VOD can be achieved since a new request can be served immediately without having to wait for the next multicast. In this paper. we propose two types of channel reservation patching algorithm : a fixed channel reservation patching and a variable channel reservation patching. To immediately schedule the requests for popular videos, these algorithms reserve the channels of video server for the fixed number of popular videos or for the variable number of popular videos which is determined dynamically according to the load of video server. The performance of the proposed algorithms is evaluated through simulations, and compared with that of simple patching. Our performance measures are average defection rate, average latency, service fairness and the amount of buffered data according to video server loads. Simulation results show that the proposed channel reservation patching algorithms provide better performance compared to simple patching algorithm.

• The Journal of the Korea Contents Association
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• v.20 no.10
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• pp.119-133
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• 2020

Recently, as famous YouTubers produce and broadcast videos that receive sponsorship and advertising such as indirect advertising (PPL), a so-called 'back advertising' controversy continues, and not only famous YouTubers but also entertainers are caught up in the issue. It is causing confusion among the public in Korea. This study attempts to find out the public's reaction before and after the controversy of 'back advertising' by YouTubers through comment analysis. Specifically, among text analysis using R programs, we intend to analyze the issue through various methods such as word cloud, qgraph analysis, LDA, and word2vec analysis, a deep learning technique. The target of the analysis was to analyze the channels of three YouTubers who belonged to the controversy of the 'back advertising' YouTuber and uploaded the 'Apology video'. The 5 most recent videos of Muk-bang YouTuber Moon Bok-hee, who has a similar content disposition to SussTV's Han Hye-yeon stylist, which was controversial, and Yang Pang, a YouTuber who showed various contents (August 09, 2020) Criterion and her first 5 videos uploaded were reviewed. As a result of the study, most of the comments that showed positive reactions before the controversy, but after the controversy, it was found that negative reactions accounted for most of the comments. Therefore, this study examines the degree of change of the public about influencers through comments after the controversy over 'back advertising' through various analysis using R program. This research also devises various measures to prevent the occurrence of back advertising of influencers in the future.

• Journal of the Korea Society of Computer and Information
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• v.19 no.7
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• pp.141-149
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• 2014

This paper describes a method to insert and detect watermark or fingerprint to/from videos in low-computing powered system as Android platforms. Fingerprint, which is a kind of watermark, has features such as patterns that contain information. The inserting frame numbers in video-stream and the positions in a picture were chosen from the encrypted user ID to insert the watermarks. The used encrypt algorithm is the HIGHT algorithm which was developed for low-computing powered systems by KISA(Korean Internet & Security Agency). Subtracting an inferred picture from the previous picture was used to extract a candidate feature. Median filtering was used to get rid of noise and stabilize the candidate feature. New algorithm that reduces calculating steps of the median filtering was developed and applied for low-specification systems. The stabilized features were accumulated over 150 times and calculated by correlation coefficient method to recognize the patterns. We examined 22 videos and successfully detected the patterns from 21 videos. The correlation coefficient r values that we examined through this study exceeded over 0.79 more than the threshold (0.7).