• Journal of Korea Multimedia Society
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• v.21 no.3
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• pp.400-414
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• 2018

It is required for today's video contents to interact with a viewer in order to provide more personalized experience to viewer(s) than before. In order to do so by providing friendly experience to a viewer from video contents' systemic perspective, understanding and analyzing the situation of the viewer have to be preferentially considered. For this purpose, it is effective to analyze the situation of a viewer by understanding the state of the viewer based on the viewer' s behavior(s) in the process of watching the video contents, and classifying the behavior(s) into the viewer's emotion and state during the flow. The term 'Flow-emotion-state' presented in this study is the state of the viewer to be assumed based on the emotions that occur subsequently in relation to the target video content in a situation which the viewer of the video content is already engaged in the viewing behavior. This Flow-emotion-state of a viewer can be expected to be utilized to identify characteristics of the viewer's Flow-situation by observing and analyzing the gesture and the facial expression that serve as the input modality of the viewer to the video content.

• Journal of Korea Multimedia Society
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• v.20 no.1
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• pp.1-9
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• 2017

Explosive deployment of smart mobile devices such as smart phones, and tablets along with expansion of wireless internet bandwidth have enabled the deployment of mobile video streaming such that video traffic becomes the most important service in wireless networks. Recently, for more efficient video streaming services, the ISO MPEG group standardized a protocol called DASH (Dynamic Adaptive Streaming over HTTP) and the standard has been quickly adopted by many service providers such as YouTube and Netflix. Despite of the convenience of mobile streaming services, users also suffer from low QoE(Quality of Experience) due to dynamic channel fluctuations and unnecessary downloading due to high churning rates. This paper proposes a noble efficient video rate selection algorithm considering user buffer level, channel condition and churning rate. Computer simulation based performance study showed that the proposed algorithm improved the QoE significantly compared to a method that determines the video rate based on current channel conditions. Especially, the proposed method reduced the rebuffering rate, one of the most important performance factors of the QoE, to a nonnegligible level.

• The Korean Journal of Emergency Medical Services
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• v.23 no.1
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• pp.87-99
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• 2019

Purpose: The aim of this study was conducted to assess the proficiency of both direct laryngoscopy and video laryngoscopy and the usefulness of each laryngoscope, thereby provide basic data for further education using video laryngoscopy. Methods: Forty one paramedic subjects participated in this study. Usability was measured with the System usability scale. The Macintosh direct laryngoscope and $C-MAC^{(R)}$ video laryngoscope were two instruments evaluated in the study. Results: Training with video laryngoscopy showed significantly better results within the categories of dental injury (p=.004), esophageal intubation (p=.001), and proper depth placement of intubation tubes (p=.019). The results of the System usability scale questionnaire and the degrees of visibility based on the Cormack & Lehane classification were also found to be better achieved with the video laryngoscopy (p=.000). Conclusion: This study suggests enhancing education with video laryngoscopy, which could reduce the risk of complications and duration of intubation while increasing the success rate among students and emergency medical technicians with little experience, rather than the existing method of only using direct laryngoscope, which requires considerable experience and skills.

• Korean Journal of Human Ecology
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• v.10 no.2
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• pp.19-35
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• 2007

The purpose of this study was to examine the awareness and experience of extramarital relations across individual and familial variables of married men and women. Data for this study were 600 married men and women who were recruited the respondents through internet site. Results of this study were as follows; 1) Most of married men and women were regarded extramarital relations types(emotional connections, short-term relationship such as prostitution, sexual intercourse except a prostitution, one-night stands, physical connections, letter chatting with multimedia, video chatting with multimedia), By gender men had more permissiveness attitudes about extramarital relations type than women, 2) There were significant differences in the awareness and experience of extramarital relations types across variables(sex, age, education level, income, occupation, religion, marriage duration). 3) Married men reported that they experience(emotional connections, sexual intercourse, physical connections, letter chatting with multimedia, video chatting with multimedia, infidelity ideation, infidelity attempts) more extramarrital relations types than married women. There were significant differences in the experience extramarital relations types across variables.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.2
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• pp.427-434
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• 2018

Video services have been widely generalized thanks to the progress in compression streaming technologies. In spite of the innate difficulties in guaranteeing quality of service(QoS) of the Internet, the quality of service that is experienced by users have been improved considerably with overall bandwidth growth over the Internet and new compression and streaming technologies. For further sophisticated management scheme from the current homogeneous one, it should consider the characteristics of video contents. This paper investigates that the Quality of Experience(: QoE) for video services can vary according to the characteristics of video contents for the same compression method and transmission environments. It is expected that this result contributes to establish a new and advanced scheme to manage QoE for video services over the Internet.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.1
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• pp.308-324
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• 2018

HTTP adaptive streaming (HAS) is a promising technology for delivering video content over the Internet. HAS-based video streaming solutions rely on bandwidth estimation to select the appropriate video bitrate. Video streaming solutions that consider network conditions provide users with seamless video playback. However, when multiple clients compete for a common bottleneck link, conventional bandwidth estimation schemes that consider only one client overestimate the network bandwidth due to the ON-OFF traffic pattern. The bandwidth overestimation can cause Quality of Experience (QoE) degradation, such as unnecessary changes in video quality, and unfairness of video quality. In this paper, we propose a client-side bandwidth estimation scheme to obtain a better QoE of HAS in the multiple-client environment. The proposed scheme differentiates the client buffer status according to the buffer occupancy, and then estimates the available network bandwidth based on the buffer status and segment throughput. We evaluate the performance of HAS implemented in the ns-3 network simulator. Simulation results show that compared with the conventional schemes, the proposed scheme can enhance the QoE.

• Journal of KIISE
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• v.44 no.4
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• pp.423-432
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• 2017

Recently, the video quality control schemes for the improvement of the QoE (Quality of Experience) of video streaming services that are based on DASH (Dynamic Adaptive Streaming over HTTP), which is a standard of HTTP adaptive streaming (HAS) services, have been studied. However, the problem of the existing schemes is the degradation that is due to unnecessary quality changes because the VBR (Variable Bitrate) characteristics of the video are not considered. In this paper, we propose a SC-DASH (Segment Characteristics-based DASH) which controls the video quality based on the segment characteristics. The SC-DASH can prevent the occurrence of the unnecessary quality changes by controlling the video quality based on the size of the next segment, the segment throughput, and the buffer occupancy. The experiment results showed that the SC-DASH improves the QoE by reducing the unnecessary quality changes compared with the existing quality control schemes.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.12
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• pp.1811-1818
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• 2013

As the broadband network are being deployed recently, the IPTV (Internet Protocol TV) has appeared and become a most representative service that incorporates audio, video, etc. In spite of the long-period efforts, however, no standardized method exists to measure and evaluate the quality of video that is experienced through TV in the customer's premises. Therefore, before developing a method to measure and evaluate the quality of experience (QoE) for video that is the ultimate goal, this paper reviews the outcomes from the past standardization activities and drive a few important implications that would be reflected to the method to measure and evaluate QoE for video.

• Korean Journal of Child Studies
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• v.18 no.2
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• pp.105-120
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• 1997

The purpose of this study was to investigate children's abilities of self-control and visual information processing based on their experience with video games. Participants, divided by prior exposure to video games, were 44 seven-year-old and 48 eleven-year-old boys. The impulsive tendency of children was measured through the MFFT and The delayed satisfaction test. Visual information processing ability was assessed through perceptual speed, mental rotation, and spatial visualization tasks. No differences were found between more-and less-video-game-experienced boys. Significant differences, however, were found in visual information processing abilities. More experienced boys performed better in mental rotation and spatial visualization tasks than less experienced boys.

• Journal of Broadcast Engineering
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• v.24 no.7
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• pp.1209-1220
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• 2019

The demand for virtual reality (VR) is rapidly increasing. Providing the immersive experience requires much operation and many data to transmit. For example, a 360-degree video (360 video) with at least 4K resolution is needed to offer an immersive experience to users. Moreover, the MPEG-I group defined three degrees of freedom plus (3DoF+), and it requires the transmission of multiview 360 videos simultaneoulsy. This could be a burden for the VR streaming system. Accordingly, in this work, a bitrate-saving method using projection conversion is introduced, along with experimental results for streaming 3DoF+ 360 video. The results show that projection conversion of 360 video with 360lib shows a Bjontegaard delta bitrate gain of as much as 11.4%.