• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.609-614
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• 1999

Our present ability to work with video has not been confined to wired communication environment. This paper describes the new technological trend of wireless video communication. In wireless video communication, unlike wired network, several techniques are needed. At first, error robust video coding is essential. Due to characteristics of wireless channel, the system is exposed to more error prone environment. In addition, encoded video bit streams are vulnerable to the error because of the entropy coding. Recently many frameworks are developed to cope with this problem. We just explore the numerous robust video coding approaches with the viewing of error control. And more we discuss other on going research topics in this wireless video communication fields like low-power assumption design, trans-codec technique, and rate control schemes in brief.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.884-889
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• 2003

Based on the reinterpretation of the well-known relationship between shear and the rate of change of bending moment in a reinforced concrete beam subject to combined shear and moment loads, the shortcomings of present truss models are discussed. The core of the theory is that a new perspective on the shear strength can be gained by viewing the internal stress filed in terms of the superposition of two base components of shear resistance; arch action and beam action. The arch action can be designed using the simple truss having curved compression chord, while the beam action between the two chords can be modeled using a parallel chord truss with MCFT or RA-STM. The compatibility of deformation associated to the two action is taken into account by employing a characteristic factor a. The new model was examined by the Stuttgart beam shear tests, and the results show that the present approach provides good estimates of stirrup contribution and concrete contributions.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.571-574
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• 2005

We demonstrated a high speed liquid crystal (LC) display mode based on a nonchiral smectic C LC in an antiparallel planar geometry. In this antiparallel planar nonchiral smectic C (APNSC) LC mode, analog gray scales and wide viewing properties are achieved using a stepwise thermal annealing process (STAP). Because of an initially stable LC alignment in large area through the STAP, the APNSC LC mode exhibits the characteristics of fast response and high contrast ratio. This new APNSC mode is suitable for processing the dynamic image at a video rate in the next-generation LCDs.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.198.1-198.1
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• 2016

Organic light-emitting diode (OLED) displays have promising potential to replace liquid crystal displays (LCDs) due to their advantages of low power consumption, fast response time, broad viewing angle and flexibility. Organic light emitting materials are vulnerable to moisture and oxygen, so inorganic thin films are required for barrier substrates and encapsulations.[1-2]. In this work, the silicon-based inorganic thin films are deposited on plastic substrates by plasma-enhanced chemical vapor deposition (PECVD) at low temperature. It is necessary to deposit thin film at low temperature. Because the heat gives damage to flexible plastic substrates. As one of the transparent diffusion barrier materials, silicon oxides have been investigated. $SiO_x$ have less toxic, so it is one of the more widely examined materials as a diffusion barrier in addition to the dielectric materials in solid-state electronics [3-4]. The $SiO_x$ thin films are deposited by a PECVD process in low temperature below $100^{\circ}C$. Water vapor transmission rate (WVTR) was determined by a calcium resistance test, and the rate less than $10.^{-2}g/m^2{\cdot}day$ was achieved. And then, flexibility of the film was also evaluated.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4585-4603
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• 2015

Video streaming services make up a large proportion of Internet traffic on both fixed and mobile access throughout the world. Adaptive streaming allows for dynamical adaptation of the bitrate with varying network conditions, to guarantee the best user experience. Adaptive bitrate algorithms face a significant challenge in correctly estimating the throughput as it varies widely over time. In this paper, we first evaluate the throughput estimation techniques and show that the method that we have used offers stable response to throughput fluctuations while maintaining a stable playback buffer. Then, we propose an adaptive bitrate scheme that intelligently selects the video bitrates based on the estimated throughput and buffer occupancy. We show that the proposed scheme improves viewing experience by achieving a high video rate without taking unnecessary risks and by minimizing the frequency of changes in the video quality. Furthermore, we show that it offers a stable response to short-term fluctuations and responds swiftly to large fluctuations. We evaluate our algorithm for both constant bitrate (CBR) and variable bitrate (VBR) video content by taking into account the segment sizes and show that it significantly improves the quality of video streaming.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.4
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• pp.1128-1139
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• 2012

With the development of three-dimensional display and related technologies, depth video coding becomes a new topic and attracts great attention from industries and research institutes. Because (1) the depth video is not a sequence of images for final viewing by end users but an aid for rendering, and (2) depth video is simpler than the corresponding color video, fast algorithm for depth video is necessary and possible to reduce the computational burden of the encoder. This paper proposes a fast mode decision algorithm for depth video coding based on depth segmentation. Firstly, based on depth perception, the depth video is segmented into three regions: edge, foreground and background. Then, different mode candidates are searched to decide the encoding macroblock mode. Finally, encoding time, bit rate and video quality of virtual view of the proposed algorithm are tested. Experimental results show that the proposed algorithm save encoding time ranging from 82.49% to 93.21% with negligible quality degradation of rendered virtual view image and bit rate increment.

• Journal of Information Display
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• v.11 no.2
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• pp.76-83
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• 2010

This paper presents the multi-user autostereoscopic 3D display system constructed and operated by the authors using the time-multiplexing approach. This prototype has three main advantages over the previous versions developed by the authors: its hardware was simplified as only one optical array is used to create viewing regions in space, a lenticular multiplexing screen is not necessary as images can be produced sequentially on a fast 120Hz LCD with full resolution, and the holographic projector was replaced with a high-frame-rate digital micromirror device (DMD) projector. The whole system in this prototype consists of four major parts: a 120Hz high-frame-rate DMD projector, a 49-element optical array, a 120Hz screen assembly, and a multi-user head tracker. The display images for the left/right eyes are produced alternatively on a 120Hz direct-view LCD and are synchronized with the output of the projector, which acts as a backlight of the LCD. The novel steering optics controlled by the multiuser head tracker system directs the projector output to regions referred to as exit pupils, which are located in the viewers’eyes. The display can be developed in the "hang-on-the-wall"form.

• Journal of People, Plants, and Environment
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• v.24 no.6
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• pp.639-649
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• 2021

Background and objective: Various images from visual display terminals (VDTs) as well as living lighting are important parts of our daily life; thus, properly controlling the lighting environment - that is, illuminance, color temperature and good images from VDTs - can have a substantial effect on improving the mental health and work efficiency in everyday life. We examined electroencephalography (EEG) and heart rate variability (HRV) responses to various lighting conditions in 25 university students as they viewed images of a green landscape or traffic congestion. Methods: EEG was performed in darkness and when the room was illuminated with 10 different light-emitting diode (LED) color temperatures, while the EEG and HRV responses to green landscape or traffic congestion image stimuli were measured in darkness and during room illumination with three different LED color temperatures. Results: We found a significant difference between darkness and high LED illumination (400 lx) at 7 (CZ, F4, FZ, O1, O2, OZ, and T6) of 30 channels, while the alpha wave activity increased during darkness. In the second experiment, the green landscape image stimuli in the 30 lx-2600 K lighting condition elicited theta wave activity on the EEG, whereas the traffic congestion image stimuli under high LED illumination elicited high beta and gamma wave activities. Moreover, the subjects exhibited better stress coping ability and heart rate stability in response to green landscape image stimuli under illuminated conditions, according to their HRV. Conclusion: These results suggest that lower color temperatures and illumination levels alleviate tension, and that viewing green landscape image stimuli at low illumination, or in darkness, is effective for reducing stress. Conversely, high illumination levels and color temperatures are likely to increase tension and stress in response to traffic congestion image stimuli.

• Journal of Korean Society of Forest Science
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• v.108 no.3
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• pp.440-453
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• 2019

This study was carried out to investigate the effect of watching a two-dimensional (2D) forest video and a virtual reality (VR) forest video on stress reduction in adults. Experiments were conducted in an artificial climate room, and 40 subjects participated. After inducing stress in the subjects, subjects watched a 2D gray video, 2D forest video, or VR forest video for 5 mins. The autonomic nervous system activity was evaluated continuously in terms of measured heart rate variability during the experiment. After each experiment, the subject's psychological state was evaluated using a questionnaire. The 2D forest video decreased the viewer's stress index, increased HF, and reduced heart rate compared with the 2D gray video. The VR forest video had a greater stress index reduction effect, LF/HF increase effect, and heart rate reduction effect than the 2D gray video. Psychological measurements showed that subjects felt more comfortable, natural, and calm when watching the 2D gray video, 2D forest video or VR forest video. We also found that the 2D forest video and VR forest video increased positive emotions and reduced negative emotions compared to the 2D gray video. Based on these results, it can be concluded that watching the 2D forest and VR forest videos reduces the stress index and heart rate compared with watching the 2D gray video. Thus, it is considered that the 2D forest video increases the activity of the parasympathetic nervous system, and the VR forest video increases the activity of the sympathetic nervous system. The increased activity of the sympathetic nervous system upon watching the VR forest video is judged to be positive sympathetic nerve activity, such as novelty and curiosity, and not negative sympathetic activity, such as stress and tension. The results of this study are expected to be the basis for examining the visual effects of forest healing, with hope that the utilization of VR, the technology of the fourth industrial revolution in the forestry field, will broaden.

• International journal of advanced smart convergence
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• v.8 no.4
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• pp.9-15
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• 2019

The government has defined domestic violence as one of the four major social evils and tried to prepare laws and systems to prevent it. Nevertheless, domestic violence has emerged as a serious social issue, and compare to the number of domestic violence cases that are constantly increasing, the report rate of domestic violence is significantly lower. This suggests the need to improve citizens' perception of domestic violence as the issue to solve it together in society, not as a private matter at home. Most of existing contents for preventing domestic violence and improving awareness are simple viewing forms of video contents, which have little effect on recognition. We aim to confirm the possibility of improving social awareness about domestic violence by producing Virtual Reality (VR) contents that have great features of user's immersion and empathy. In this VR content, the user can interact with various objects in the virtual reality of domestic violence and directly or indirectly experience the victim's position. Users who view the violent environment from the victim's point of view can have a subjective empathy for the problem, which is expected to induce more active awareness about domestic violence.