• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.97-99
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• 2021

Edge caching can provide high QoE by reducing traffic in the backhaul network and reducing latency in video streaming services. But due to the limited capacity of edge cache, large amounts of content cannot be cached. In this paper, we propose an edge-fog prefix caching that reduces playback delay by caching prefixes of video content on edges and storing the rest in fog cache.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.3
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• pp.873-889
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• 2014

IP address lookup is very crucial in performance of routers. Several works have been done on prefix caching to enhance the performance of IP address lookup. Since a prefix represents a range of IP addresses, a prefix cache shows better performance than an IP address cache. However, not every prefix is cacheable in itself. In a prefix cache it causes false hit to cache a non-leaf prefix because there is possibly the longer matching prefix in the routing table. Prefix expansion techniques such as complete prefix tree expansion (CPTE) make it possible to cache the non-leaf prefixes as the expanded forms, but it is hard to manage the expanded prefixes. The expanded prefixes sometimes incur a great deal of update overhead in a routing table. We propose a bitmap-based prefix cache (BMCache) to provide low update overhead as well as low cache miss ratio. The proposed scheme does not have any expanded prefixes in the routing table, but it can expand a non-leaf prefix using a bitmap on caching time. The trace-driven simulation shows that BMCache has very low miss ratio in spite of its low update overhead compared to other schemes.

• Journal of Computing Science and Engineering
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• v.9 no.3
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• pp.134-141
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• 2015

In on-demand multimedia streaming systems, streaming techniques are usually combined with proxy caching to obtain better performance. The patch streaming technique has no start-up latency inherent to it, but requires extra bandwidth to deliver the media data in patch streams. This paper proposes a proxy caching technique which aims at reducing the bandwidth cost of the patch streaming technique. The proposed approach determines media prefixes with high patching cost and caches the appropriate media prefix at the proxy/local server. Herein the scheme is evaluated using a synthetically generated media access workload and its performance is compared with that of the popularity and prefix-aware interval caching scheme (the prefix part) and with that of patch streaming with no caching. The bandwidth saving, hit ratio and concurrent number of clients are used to compare the performance, and the proposed scheme is found to perform better for different caching capacities of the proxy server.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.586-588
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• 2004

트랜스코딩에 관련된 연구들은 비디오 스트리밍에 대한 품질관련 연산들을 제공해 주었으나 트랜스코딩 과정에서 발생하는 연산지연과 전송지연에 대한 고려가 부족하였다. 또한 비디오 스트리밍에 대한 캐슁기법과 관련된 연구들은 비디오 스트리밍 서버와 클라이언트 사이의 전송지연을 줄여주는 장점을 제공하는 반면, 트랜스코딩과의 협업을 위한 연동들은 드물었다. 본 논문에서는 대역폭이 유선망에 비해 상대적으로 빈약한 무선망 채널을 통해 연속적인 비디오 스트리밍 서비스를 제공하는 과정 중에 발생하는 전송지연과 연산지연을 동시에 극복할 수 있도록 해주는 통합 시스템 아키텍처와 캐슁 알고리즘을 제안한다.

• Journal of Advanced Navigation Technology
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• v.16 no.3
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• pp.455-462
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• 2012

The loss due to caching replacement in the wireless mobile proxy caching structure has a significant effect on streaming QoS. This paper proposes a similarity-based caching loss minimization (SCLM) for minimizing the loss caused by the caching replacement. The proposed scheme divides object segments, and then it performs the similarity relation about them. Segments that perform the similarity relation generates similarity relation tree (SRT). The similarity is an important metric for deciding a relevance feedback, and segments that satisfy these requirements in the cache block for caching replacement. Simulation results show that the proposed scheme has better performance than the existing prefix caching scheme, segment-based caching scheme, and bi-directional proxy scheme in terms of QoS, average delayed startup ratio, cache throughput, and cache response ratio.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.7B
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• pp.431-437
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• 2007

Web proxy caching provides an effective way to reduce access latency and bandwidth requirement. In particular, prefix caching is considered as an alternative for improving video delivery over wide area networks because video objects are usually too large to be cached in their entirety. Nevertheless, many studies have pointed that the user-perceived latency is often not dominated by object transmission time, but rather by setup process such as TCP connection time that precedes it. We propose pre-connecting techniques and show that the techniques can be used efficiently in TCP splicing. Our analysis shows the pre-connection significantly reduces start-up latency and TCP connection time in simple analytical model. The deployment of the proposed pre-connection does not require protocol modification or the cooperation of other entities.

• Journal of Industrial Technology
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• v.24 no.B
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• pp.177-186
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• 2004

The main bottleneck for a VOD system is bandwidth of storage or network I/O due to the high bandwidth requirements and long-lived nature of digital video. Patching is one of the most efficient techniques to overcome the bottleneck of the VOD system through the use of multicast scheme. In this paper, we propose a new patching scheme, P2P proxy patching, for improving the typical patching technique by jointly using the proxy prefix caching scheme and the P2P proxy. In our proposed scheme, each client play a role in a proxy for multicasting a regular stream to other clients that request the same stream. Due the use of the P2P proxy and the prefix caching, the server bandwidth is required significantly less than that of the typical patching technique. In the performance study, we show that our patching scheme can reduce the server bandwidth requirements compared with the existing patching techniques.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.178-180
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• 2003

이동 컴퓨팅 환경에서의 프록시는 트랜스코딩과 캐슁 등의 방법으로 미디어 스트림을 재가공하여 멀티미디어 스트리밍의 연속성을 보장해 준다. 프록시에 대한 기존의 접근들은 대체로 트랜스코딩과 캐슁을 별개의 주제로 다루었었다. 따라서 본 논문에서는 트랜스코딩과 캐슁을 통할하여 연동시킨 프록시 시스템 아키텍처를 구현하였다. 또한 서버와 프록시 사이의 전송 지연. 프록시에서의 미디어 스트림 재가공에 걸리는 지연, 프록시와 클라이언트 사이의 bandwidth 자원 등을 창조하여 adaptive한 트랜스코딩 및 캐슁을 할 수 있도록 해주는 transco-prefix caching에 대해 제안하였다. 그 결과 transco-prefix caching을 통하여 트랜스코딩과 캐슁의 장점들을 동시에 살필 수 있었다.

• Journal of the Korea Society of Computer and Information
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• v.20 no.12
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• pp.45-52
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• 2015

We propose a hybrid prefix caching scheme to enable high speed IP address lookup. All prefixes loaded in a prefix cache should not be overlapped in address range for correct IP lookup. So, every non-leaf prefix needs to be expanded not so as to be overlapped. The shorter expanded prefix is more preferable because it can cover wider address range just as an single entry in a prefix cache. We exploits advantages of two dynamic prefix expansion techniques, bounded prefix expansion technique and bitmap-based prefix expansion technique. The proposed scheme uses dual bound values whereas just one bound value is used in bounded prefix expansion. Our elaborated technique make the dual bound values be associated with several subtries flexibly using bitmap information, rather than with fixed subtries. We evaluate the performance of the proposed scheme in terms of the average length of the expanded prefixes and cache miss ratio. The experiment results show the proposed scheme has lower cache miss ratio than other previous schemes including both bounded prefix expansion and bitmap-based expansion irrespective of the cache size.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.355-357
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• 2003

본 논문은 기존에 제시되었던 협동적 캐슁 프록시 서버의 구조에 프록시 서버에 독립적인 prefix 배치와 프록시 서버간의 suffix 공유라는 동작을 추가하여, 무선 상에서의 효율적인 멀티미디어 콘텐츠 스트리밍이 가능하도록 하였다. 제안한 구조에 적합한 동작방법과 알고리즘 및 이에 따른 prefix의 특성을 제시하며, 콘텐츠 초기 지연 시간의 감소와 서버저장 능력 향상에 대한 성능 개선 효과를 기술한다.