• Journal of Advanced Navigation Technology
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• v.16 no.3
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• pp.463-470
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• 2012

This paper proposes a new profit popularity-based segment caching control mechanism for assuring a consecutive streaming QoS (Quality of Service) in the wireless channel. Then, the proposed mechanism operates SSCP (Single Segment Caching Profit) and MSCP (Multiple Segment Caching Profit) for assuring a QoS. SSCP and MSCP is to optimize the cache performance when is performed the streaming in the proxy. The proposed mechanism simulated to evaluate such mechanisms as fixed-partition mechanism, weight-based mechanism, SSCP, and MSCP. Simulation results show that the proposed mechanism has superior performance compared to other mechanisms.

• 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.

• 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.

• Journal of Korea Multimedia Society
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• v.8 no.7
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• pp.943-952
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• 2005

This paper proposes a user's mobility based cooperative proxy caching policy for effective resource management of continuous media objects in mobile environments. This policy is different from the existing proxy caching policies in terms of how to exploit users' mobility. In other words, existing caching policies work based on the information about objects by referring to users' requests within a specified domain whereas the proposed caching policy runs by utilizing a number of users' requests across several domains. So, the proposed policy is applicable to random requests in mobile environments. Moreover, we also propose a replacement policy based on weights and playback time. To check the efficiency of the proposed caching policy, the proposed replacement policy is run with different size of caching unit: object or segment. The result of performance evaluation tells that segment sizes, ratio of users' mobility and weights are major factors for the efficient operation of the cooperative caching.

• Journal of the Korea Society for Simulation
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• v.12 no.2
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• pp.25-34
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• 2003

Because of explosive growth in demand for web-based multimedia applications, proper proxy caching for large multimedia object (especially video) has become needed. For a video object which is much larger in size and has different access characteristics than the traditional web object such as image and text, caching the whole video file as a single web object is not efficient for the proxy cache. In this paper, we propose a proxy caching strategy with the constant-sized segment for video file and an improved proxy cache replacement policy. Through the event-driven simulation under various conditions, we show that our proposal is more efficient than the variable-sized segment strategy which has been proven to have higher hit ratio than other traditional proxy cache strategies.

• The KIPS Transactions:PartA
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• v.15A no.1
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• pp.53-60
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• 2008

Streaming media has contributed to a significant amount of today's Internet Traffic. Like traditional web objects, rich media objects can benefit from proxy caching, but caching streaming media is more of challenging than caching simple web objects, because the streaming media have features such as huge size and high bandwidth. And to support various bandwidth requirements for the heterogeneous ubiquitous devices, a transcoding proxy is usually necessary to provide not only adapting multimedia streams to the client by transcoding, but also caching them for later use. The traditional proxy considers only a single version of the objects, whether they are to be cached or not. However the transcoding proxy has to evaluate the aggregate effect from caching multiple versions of the same object to determine an optimal set of cache objects. And recent researches about multimedia caching frequently store initial parts of videos on the proxy to reduce playback latency and archive better performance. Also lots of researches manage the contents with segments for efficient storage management. In this paper, we define the 9-events of transcoding proxy using 4-atomic events. According to these events, the transcoding proxy can define the next actions. Then, we also propose the segment-based caching policy for the transcoding proxy system. The performance results show that the proposing policy have a low delayed start time, high byte-hit ratio and less transcoding data.

• The KIPS Transactions:PartB
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• v.11B no.6
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• pp.691-700
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• 2004

This paper proposes a user's mobility based cooperative proxy caching policy for effective resource management of continuous media objects in mobile environments. This policy is different from the existing proxy caching policies in terms of how to exploit users' mobility. In other words, existing caching policies work based on the information about objects by referring to user's requests within a specified domain whereas the proposed caching policy runs by utilizing a number of user's requests across several domains. So, the proposed policy is applicable to random requests in mobile environments Moreover, we also propose a replacement policy based on weights and playback time. To check the efficiency of the proposed caching policy, the proposed replacement policy is run with different size of caching unit object or segment. The result of performance analyze tells what a ratio of user's mobility is are major factors for the efficient operation of the cooperative caching.

• Journal of Communications and Networks
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• v.7 no.4
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• pp.478-488
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• 2005

To conserve the usage of energy, indexing techniques have been developed in a wireless mobile environment. However, the use of interleaved index segments in a broadcast cycle increases the average access latency for the clients. In this paper, we present the broadcast-based location dependent data delivery scheme (BBS) for dynamic range queries. In the BBS, broadcasted data objects are sorted sequentially based on their locations, and the server broadcasts the location dependent data along with an index segment. Then, we present a data prefetching and caching scheme, designed to reduce the query response time. The performance of this scheme is investigated in relation to various environmental variables, such as the distributions of the data objects, the average speed of the clients, and the size of the service area.

• Journal of Broadcast Engineering
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• v.10 no.3
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• pp.313-320
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• 2005

The increasing popularity of multimedia streaming services introduces new challenges in content distribution. Especially, it is important to provide the QoS guarantees as they are increasingly expected to support the multimedia applications. Multimedia streams typically experience the high start-up delay due to the large protocol overhead, the delay, and the loss properties of the wireless networks. The service providers can improve the performance of multimedia streaming by caching the initial segment (prefix) of the popular streams at proxies near the requesting clients. The proxy can initiate transmission to the client while requesting the remainder of the stream from the server. In this paper, we propose the traffic based caching algorithm (TSLRU) to improve the performance of caching proxy. TSLRU classifies the traffic into three types, and improve the performance of caching proxy by reflecting the several elements such as traffic types, recency, frequency, object size when performing the replacement decision. In simulation, TSLRU performs better than the existing schemes in terms of byte hit rate, hit rate, startup latency, and throughput.

• Journal of Korea Multimedia Society
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• v.21 no.8
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• pp.942-951
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• 2018

In these days, 360 degree videos, which is provided via VR, have high resolution and quality of 8K. These kinds of videos inevitably require streaming technology which guarantees QoS. Therefore, we suggest MPEG DASH HTTP protocol which stably provides streaming services of high quality videos in 8K, which are 360 degree tile-encoded, on low-spec devices such as OTT and IPTV Settop and Tile Segment Cache management structure for servers operating streaming services.