• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.3
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• pp.493-503
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• 2024

This paper addresses the issue of continuous user authentication within the metaverse environment. Recently, the metaverse plays a vital role in personal interaction, entertainment, education, and business, bringing forth significant security concerns. Particularly, vulnerabilities related to user identity verification have emerged as a major issue. This research proposes a novel method to verify identities by analyzing users' character movements in the metaverse through a pose estimation model. This method uses only video data for authentication, allowing flexibility in limited environments, and investigates how character movements contribute to user identification through various experiments. Furthermore, it explores the potential for extending this approach to other digital platforms. This research is expected to significantly contribute to enhancing security and innovating user identity verification methods in the metaverse environment.

• Journal of Digital Contents Society
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• v.12 no.4
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• pp.485-490
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• 2011

Smoothing is a transmission plan where variable rate video data is converted to a constant bit rate stream. These smoothing algorithms include CBA, MCBA, MVBA, PCRTT and others. But, these algorithms build a transmission plan per frame unit. So, these algorithms cause frame burst or GOP burst. In order to improve it, MVBAG algorithm build a transmission plan per GOP. But this algorithm may not guarantee QoS when frame's size is abruptly larger or smaller than the computed transmission rate. In this paper, a smoothing algorithm is proposed to enhance MVBAG algorithm's problem. In order to show the proposed algorithm's performance, the proposed algorithm is compared with MVBAG algorithm using various evaluation factors such as number of frames that do not meet the QoS, average transmission rate variability per frame, average transmission rate variability per GOP. Experimental results show that the proposed algorithm outperforms MVBAG algorithm in number of frames that do not meet the QoS.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.12
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• pp.102-107
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• 2007

This paper proposes a H.264/AVC entropy decoder without embedded processor nor memory fabrication process. Many researches on H.264/AVC entropy decoders require ROM or RAM fabrication process, which is difficult to be implemented in general digital logic fabrication process. Furthermore, many researches require embedded processors for bitstream manipulation, which increases area and power consumption. This papers proposes hardwired H.264/AVC entropy decoder without embedded processor, which improves data processing speed and reduces power consumption. Furthermore, its CAVLC decoder optimizes lookup table and internal buffer without embedded memory, which reduces hardware size and can be implemented in general digital logic fabrication process without ROM or RAM fabrication process. Designed entropy decoder was embedded in H.264/AVC video decoder, and it was verified to operate correctly in the system. Synthesized in TSMC 90nm fabrication process, its maximum operation frequency is 125MHz. It supports QCIF, CIF, and QVGA image format. Under slight modification of nC register and other blocks, it also support VGA image format.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.3083-3093
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• 2010

The number of Free-Form construction projects are increased by development of 3D parametric modeling technology. The reason of Free-Form Architecture's appearance is advance of digital technology. BIM simulation decision making support is inefficient because it is used in virtual reality. In this study, we developed "AR naviX" which is the digital contents of construction management based on AR for effective decision making support to Free-Form construction project. It reflects construction site by using site picture and video, or Laser scanning data. User feel high reality and is absorbed in augmented reality. So they can reduce the time of decision.

• Journal of Digital Contents Society
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• v.3 no.1
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• pp.1-9
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• 2002

This paper is proposed to algorithm for measuring traffic information automatically, for example, volume count, speed and occupancy rate, from CCTV camera images installed on highway, add to function of image detectors which can be collected the traffic information. Recently the method of traffic informations are counted in lane one by one, but this manner is occurred critical errors by occlusion frequently in case of passing larger vehicles(bus, truck etc.) and is impossible to measure in the 8 lanes of highway. In this paper, installed the detection area include with all lanes, traffic informations are collected using tracking algorithm with passing vehicles individually in this detection area, thus possible to detect all of 8 lanes. The experiment have been conducted two different real road scenes for 20 minutes. For the experiments, the images are provided with CCTV camera which was installed at Kiheung Interchange upstream of Kyongbu highway, and video recording images at Chungkye Tunnel. For image processing, images captured by frame-grabber board 30 frames per second, $640{\times}480$ pixels resolution and 256 gray-levels to reduce the total amount of data to be interpreted.

• Journal of Digital Contents Society
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• v.15 no.4
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• pp.449-455
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• 2014

Detection of moving objects is a fundamental task in most of the computer vision applications, such as video surveillance, activity recognition and human motion analysis. This is a difficult task due to many challenges in realistic scenarios which include irregular motion in background, illumination changes, objects cast shadows, changes in scene geometry and noise, etc. In this paper, we propose an foreground extraction algorithm based on codebook, a database of information about background pixel obtained from input image sequence. Initially, we suppose a first frame as a background image and calculate difference between next input image and it to detect moving objects. The resulting difference image may contain noises as well as pure moving objects. Second, we investigate a codebook with color and brightness of a foreground pixel in the difference image. If it is matched, it is decided as a fault detected pixel and deleted from foreground. Finally, a background image is updated to process next input frame iteratively. Some pixels are estimated by input image if they are detected as background pixels. The others are duplicated from the previous background image. We apply out algorithm to PETS2009 data and compare the results with those of GMM and standard codebook algorithms.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.881-886
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• 2007

This study was to develope a vibrotactile display system using windows media player from digital audio signal. WMPlayer10SDK system which was plug-in tool by microsoft windows media player provided its video and audio signal information. The audio signal was tried to be change into vibrotactile display. Audio signal had 4 sections such as 8bit, 16bit, 24bit, and 32bit. Each section was computed its frequency and vibrato scale. And data was transferred to 38400bps network port(COM1) for vibration. Using this system was able to develop the music suit which presented tactile feeling of music beyond sound. Therefore, it may provide cross modal technology for fusion technology of human senses.

• The Journal of Advanced Prosthodontics
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• v.8 no.5
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• pp.354-362
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• 2016

PURPOSE. The trueness and precision of acquired images of intraoral digital scanners could be influenced by restoration type, preparation outline form, scanning technology and the application of power. The aim of this study is to perform the comparative evaluation of the 3-dimensional reproducibility of intraoral scanners (IOSs). MATERIALS AND METHODS. The phantom containing five prepared teeth was scanned by the reference scanner (Dental Wings) and 5 test IOSs (E4D dentist, Fastscan, iTero, Trios and Zfx Intrascan). The acquired images of the scanner groups were compared with the image from the reference scanner (trueness) and within each scanner groups (precision). Statistical analysis was performed using independent two-samples t-test and analysis of variance (${\alpha}=.05$). RESULTS. The average deviations of trueness and precision of Fastscan, iTero and Trios were significantly lower than the other scanners. According to the restoration type, significantly higher trueness was observed in crown and inlay than in bridge. However, no significant difference was observed among four sites of preparation outline form. If compared by the characteristics of IOS, high trueness was observed in the group adopting the active triangulation and using powder. However, there was no significant difference between the still image acquisition and video acquisition groups. CONCLUSION. Except for two intraoral scanners, Fastscan, iTero and Trios displayed comparable levels of trueness and precision values in tested phantom model. Difference in trueness was observed depending on the restoration type, the preparation outline form and characteristics of IOS, which should be taken into consideration when the intraoral scanning data are utilized.

• Journal of Digital Convergence
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• v.9 no.5
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• pp.225-233
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• 2011

Internet telephony is an Internet service which supports voice telephone using VoIP technology on the IP-based Internet. It has some advantages in that voice telephone services can be accompanied with multimedia services such as video communication and messaging services. Recently, the introduction of smart phones has led to a growth in social networking services and thus, the research and development of Internet telephony has been actively progressed and has the potential to become a replacement for the telephone service that is currently being used. In this paper we designed and implemented a recording system which records voice data of SIP-based Internet telephone's voice calls. It is developed on the linux system and has some features such as audio mixing of two in/out voice channels, live packet sniffing, and the ability to transfer mixed audio files to the log file server. These functions are implemented using various open source softwares. Afterwards, this VoIP recording system will be applied as a base technology to advanced services like a VoIP-based call center system.

• Journal of Digital Convergence
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• v.10 no.4
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• pp.265-270
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• 2012

The subscriber access network is cause of the bottleneck phenomenon because equipment and infrastructure were not originally designed for busty high-bandwidth traffic between MAN(Metro Area Network) and LAN(Local Area Network). Whether riding on shorter copper drops or optical fiber, Ethernet is emerging as the future broadband protocol of choice, offering plug and play simplicity, and low cost. EPON(Ethernet Passive Optical Network) combines point-to-multipoint optical infrastructure with low-cost high-bandwidth Ethernet. The future broadband access network will be a combination of point-to-point and point-to-multipoint Ethernet, optimized for transporting IP data, as well as time critical voice and video. EPON is being considered as a novel communications infrastructure for next-generation broadband access network for the convergence of low-cost Ethernet equipment and low-cost fiber infrastructure. But, EPON has a problem with duplex multimedia services. It is the insufficiency of bandwidth for upstream. Because all ONUs use a shared transmission media for upstream. In this paper, we addressed the problem of upstream bandwidth in EPONs. We presented a wavelength division EPON supporting QoS in the differentiated services framework.