• Journal of Korea Multimedia Society
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• v.8 no.4
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• pp.502-508
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• 2005

This paper proposes a dynamic hybrid patching technique that can improve the performance of VOD systems by adopting the advantages of both greedy patching and grace patching to use a VOD server's limited network-I/O bandwidth. The proposed technique uses grace patching to the requests for the videos, arrival intervals of which are smaller than the size of patching window, and uses greedy patching to the rest requests. In addition, proposed patching technique expands the latest particular patching multicast into a regular multicast for a new request. In result, the patching multicast data for the new request can be the data from the beginning to the skew point of the video and the holding time of a dispatched channel can exceedingly decrease. Simulation results confirm that the proposed technique is better than grace patching in terms of defection rate and average service latency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7B
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• pp.679-689
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• 2006

Delivering multicast stream is one of the cost-saving approach in the large scale VOD environment. Because implementing VCR-like interactions for user's convenience in the multicast streaming system involves complex problems, we need the proper solutions for them. In this paper, we propose a hybrid scheme which uses the general P2P and the patching scheme with the Collaborative Interaction Streaming Scheme(CISS). CISS provides jumping functionability to the appropriate multicast session after VCR-like interaction in the environment in which multiple peers transmit VCR-like interaction streams to the VCR-like functionability request node to reduce the loads generated by frequent join or departure of peers at the multicast tree during providing VCR-like functionability. Therefore, with the proposed scheme we can distribute network traffic and reduce control overhead and latency. And to evaluate the performance of proposed scheme we compare it in the aspect of the performance of streaming delivery topology, control overhead and streaming quality with P2Cast[10] and DSL[11]. The simulation result shows that proposed P2Patching reduces about 30% of process overhead and enhances about $25{\sim}30%$ of streaming quality compared with DSL.

• ETRI Journal
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• v.37 no.4
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• pp.685-695
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• 2015

This paper proposes a novel video delivery scheme that reduces the bandwidth consumption cost from a video server to terminals in Long-Term Evolution networks. This proposed scheme combines optimized hybrid multicast with a segment-based caching strategy for use in environments where the maximum number of multicast channels is limited. The optimized hybrid multicast, allocation of multicast channels, and cache allocation are determined on the basis of a video's request rate, the related video's length, and the variable cost per unit size of a segment belonging to the related video. Performance evaluation results show that the proposed scheme reduces a video's delivery costs. This work is applicable to on-demand TV services that feature asynchronous video content requests.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.05b
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• pp.279-282
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• 2003

패칭은 새로운 비디오 요청들에 대하여 이미 전송중인 동일 비디오 스트림을 공유함으로써 비디오 서버의 네트워크 대역폭 요구를 감소시키며 true VOD를 지원하는 멀티캐스트 기법이다. 본 논문에서는 탐욕 패칭과 점진 패칭의 성능을 향상시키기 위해 두 가지 방법의 장점을 취할 수 있는 혼성 패칭 방법을 제안한다. 혼성 패칭은 탐욕 패칭을 기본으로 하고 있으나 새로운 요청과 동일 비디오에 대한 최근의 정규 멀티캐스트간의 스큐가 패칭 윈도우보다는 크지만 최근의 패칭 멀티캐스트와의 스큐가 패칭 윈도우보다 작은 경우에는 최근의 패칭 멀티캐스트를 정규 멀티캐스트가 되도록 확장함으로써 새로운 요청을 위한 패칭 채널의 시간을 대폭 감소시켜 VOD 시스템의 성능을 향상시키고자 한다.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.27 no.3
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• pp.24-29
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• 2019

The paste-type adhesive can be stored for a certain period of time and can be cured at room temperature. So it is mainly used for crack patching repair of aircraft airframe structures. This study analysed the influence of environmental factors and evaluated the adherence strength characteristics according to the adherence delay time of the paste-type adhesive. The test specimens were made of aluminum alloy(AL 2024-T3) with reference to ASTM D1002 which is generally performed to measure the adherence strength of the adhesive used for metal bonding. As a result of analysing the influence of temperature and humidity, it was found that the optimal temperature range is $24.5{\pm}0.5^{\circ}C$ and the optimal humidity range is $71{\pm}1%$ for maintenance work of the aircraft using EA-9320 adhesive. In addition, the adherence strength did not decrease with the inherent application time of the EA-9320, but it was found that the adherence strength dropped rapidly when the applied time exceeded the inherent application time of it.