• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.6
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• pp.1052-1059
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• 2016

Video-on-Demand(VoD) is one of the most popular media streaming which attracted many researchers' attention. VMesh is one of the most cited works in the field of the VoD system. VMesh is proposed to solve the problem of random seeking functionality. However, a large number of the DHT(Distributed Hash Table) searches in VMesh is sill the main problem which needs to be solved. In order to reduce the number of the DHT searches, the clustered segment index(CSI) scheme is proposed. In this scheme, the video segments are divided into clusters. The segment information of the video segments, which are clustered into the same cluster, are stored in the same clustered segment index that can be searched by using the hash key. Each peer also can request the required segments by using this clustered segment index. The experiment results show that the number of the DHT searches in the proposed scheme is less than that of VMesh even in case of peers leave and join the network or peers perform the fast forward/backward operations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.10
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• pp.5013-5034
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• 2019

In the Peer-to-Peer (P2P) streaming systems, peers randomly form a network overlay to share video resources with a data scheduling scheme. A data scheduling scheme can have a great impact on system performance, which should achieve two optimal objectives at the same time ideally. The two optimization objectives are to improve the perceived video quality and maximize the network throughput, respectively. Maximizing network throughput means improving the utilization of peer's upload bandwidth. However, maximizing network throughput will result in a reduction in the perceived video quality, and vice versa. Therefore, to achieve the above two objects simultaneously, we proposed a new data scheduling scheme based on multi-objective particle swarm optimization data scheduling scheme, called MOPSO-DS scheme. To design the MOPSO-DS scheme, we first formulated the data scheduling optimization problem as a multi-objective optimization problem. Then, a multi-objective particle swarm optimization algorithm is proposed by encoding the neighbors of peers as the position vector of the particles. Through extensive simulations, we demonstrated the MOPSO-DS scheme could improve the system performance effectively.

• Proceedings of the Korea Contents Association Conference
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• 2010.05a
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• pp.411-413
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• 2010

오버레이 멀티캐스트 트리 구성 알고리즘과 멀티미디어 스트림 중계 전송 모듈 설계하고 방송 소스 획득 및 멀티미디어 스트림을 렌더하기 위해 VLC(Video Lan Client) API를 이용하여 초고속 광 인터넷망에서 오버레이 멀티캐스트 기반 실시간 HDTV급 방송 서비스 시스템을 구현하였다.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1998.03a
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• pp.89-92
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• 1998

압연철판의 생산라인에 있는 카메라에 입력되는 영상정보를 Image Frame Grabber를 이용하지 않고 Video Overlay Board를 사용하여 라인에 입력되는 압연철판을 분석하여 외곽선을 가로지른 선분의 길이가 기준에 준할 때 정확한 절단정보를 발생시킴으로 기존에 사용해온 작업자의 대략적인 지식을 이용한 절단에서 발생되는 압연 철판의 손실을 최소화시키며 불량률을 줄인다. 그리고 발생되는 정보를 DB화시킴으로 생산품의 정확한 재고량을 관리하는 시스템을 개발한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11C
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• pp.929-939
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• 2010

The growth of multimedia technology forces the development of video detection for large database management and illegal copy detection. To meet this demand, this paper proposes a fast video detection method to apply to a large database. The fast video detection algorithm uses spatial features using the gray value distribution from frames and temporal features using the temporal similarity map. We form the video signature using the extracted spatial feature and temporal feature, and carry out a stepwise matching method. The performance was evaluated by accuracy, extraction and matching time, and signature size using the original videos and their modified versions such as brightness change, lossy compression, text/logo overlay. We show empirical parameter selection and the experimental results for the simple matching method using only spatial feature and compare the results with existing algorithms. According to the experimental results, the proposed method has good performance in accuracy, processing time, and signature size. Therefore, the proposed fast detection algorithm is suitable for video detection with the large database.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.2
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• pp.227-232
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• 2001

IPresented is a small and handy remotely piloted vehicle(RPV) that can be used for military and non-military surveillance operations. The RPV is equipped with an on-board high resolution color camera to transmit the analog video images and on-board electronics to provide real-time flight information to the pilot, thereby enabling him/her to remotely pilot within the range of 5 km radius. This paper describes the RPV system including its design, manufacturing and flight test results which manifest the stability of on-board mission and flight equipment as well as the remote piloting capability. A future plan for necessary improvements identified from the flight tests are also discussed.

• ETRI Journal
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• v.44 no.1
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• pp.62-72
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• 2022

In this study, we propose a multi-GPU-based 8KVR stitching system that operates in real time on both local and cloud machine environments. The proposed system first obtains multiple 4 K video inputs, decodes them, and generates a stitched 8KVR video stream in real time. The generated 8KVR video stream can be downloaded and rendered omnidirectionally in player apps on smartphones, tablets, and head-mounted displays. To speed up processing, we adopt group-of-pictures-based distributed decoding/encoding and buffering with the NV12 format, along with multi-GPU-based parallel processing. Furthermore, we develop several algorithms such as equirectangular projection-based color correction, real-time CG overlay, and object motion-based seam estimation and correction, to improve the stitching quality. From experiments in both local and cloud machine environments, we confirm the feasibility of the proposed 8KVR stitching system with stitching speed of up to 83.7 fps for six-channel and 62.7 fps for eight-channel inputs. In addition, in an 8KVR live streaming test on the 5G MEC/cloud, the proposed system achieves stable performances with 8 K@30 fps in both indoor and outdoor environments, even during motion.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.685-686
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• 2006

Recently, various AR-based product design methodologies have been introduced. In this paper, we propose technologies for enhancing robust augmentation and immersive realization of virtual objects. A robust augmentation technology is developed for various lighting conditions and a partial solution is proposed for the hand occlusion problem that occurs when the virtual objects overlay the user' hands. It provides more immersive or natural images to the users. Finally, vibratory haptic cues by page motors as well as button clicking force feedback by modulating pneumatic pressures are proposed while interacting with virtual widgets. Also our system reduces gabs between modeling spaces and user spaces. An immersive game-phone model is selected to demonstrate that the users can control the direction of the car in the racing game by tilting a tangible object with the proposed augmented haptic and robust non-occluded visual feedback. The proposed methodologies will be contributed to the immersive realization of the conventional AR system.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.2
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• pp.243-248
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• 2001

The present work is described the design factors and separation mechanism of ridge-cut explosive bolt in order to optimize the stage separation characteristics. Characteristics of test samples would differ depend on the detonating devices, the shape and size of bolt body, the amount of loading explosives, and the confinment conditions of bolt. Based on the results from these experimental factors, it appears to optimal condition of ridge-cut explosive that the amount of loading explosive seems to be near 110mg of RDX, the height of loading explosive is 3.5mm, the thickness of bolt is 3.9mm, and the degree of ridge is approximately $120^{\circ}$

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.119-124
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• 1999

This paper presents new approach to technology pattern recognition of camera back cover and test of soldering. In real-time implementing of pattern recognition camera back cover and test of soldering, the MVB-03 vision board has been used. Image can be captured from standard CCD monochrome camera in resolutions up to 640$\times$480 pixels. Various options re available for color cameras, a synchronous camera reset, and linescan cameras. Image processing os performed using Texas Instruments TMS320C31 digital signal processors. Image display is via a standard composite video monitor and supports non-destructive color overlay. System processing is possible using c30 machine code. Application software can be written in Borland C++ or Visual C++