• KIPS Transactions on Computer and Communication Systems
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• v.3 no.3
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• pp.81-86
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• 2014

According to the development of streaming services with P2P and mobile network technologies, researches to enhance the service quality in mobile environment have been proposed. However, streaming services considering high-speed mobile environment and characteristics of heterogenous terminals have been hindered from being provided with the required quality from user because of bandwidth congestion between selfish peers of existing P2P system. It is also prone to long delay and loss in accordance with the repeated traffic amounts because there are no optimized solution for traffic localization. The structure to enhance peer contribution for service differentiation and peer selection with clustering scheme with location information of terminal can satisfy both users and service providers with service quality and efficiency. In this paper, we propose an incentive mechanism and resource distribution scheme with user contribution and traffic cost information based on user location, which make mobile users increase the satisfaction of service quality in LTE environments.

• Journal of KIISE:Information Networking
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• v.37 no.6
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• pp.483-488
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• 2010

Due to the prevalence of various mobile devices and wireless broadband networks, there has been a significant increase in interest and demand for multimedia streaming services. Moreover, the user can service the participatory video broadcasting service in the mobile device and it can be used to deliver the real-time news and more variety information in the user side. Live multimedia service of user participation should consider not only the video quality but also the delay bounds and continuity of video playback for improving the user perceived QoS (Quality of Service) of streaming service. In this paper, we propose an adaptive rate control scheme, called DeBuG (Delay Bounds Guaranteed), to guarantee the delay bounds and continuity of video playback for the real-time streaming in mobile devices. In order to provide those, the proposed scheme has a quality adaptation function based on the transmission buffer status and network status awareness. It also has a selective frame dropper, which is based on the media priority, before the transmission video frames. The simulation results demonstrate the effectiveness of our proposed scheme.

• Journal of Korea Multimedia Society
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• v.10 no.5
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• pp.612-622
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• 2007

As compared with wired network environment, mobile VOD service in wireless network environment is difficult to guarantee the quality of VOD service due to the limitation of the system resources. Moreover, the wireless network has small bandwidth resources and short access range so that has limitations for providing the service to a large number of mobile clients. The limited battery capacity of a mobile device becomes an obstacle to mobile clients for enjoying VOD service for a long time. Therefore, these drawbacks should be considered in developing mobile VOD applications. This paper proposes a new technique for improving QoS of mobile VOD service by jointly use of broadcasting technique, which can provide VOD service to a large number of mobile clients simultaneously, and bursty communication technique, which can reduce the power consumption of a mobile device. With having these two techniques, streaming data are divided into segments, each of which is grouped into a particular packet and then transmitted at a time in the busty communication manner. In the performance evaluation, the power consumption on WNIC of a mobile device can be reduced by over 80%, and the initial service delay can be reduced in proportion to the number of channels compared with the existing staggered broadcasting technique.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.501-502
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• 2008

모바일 단말이 이종네트워크 환경에서 멀티미디어 데이터를 스트리밍 수신받으며 이동할 때, 특성이 다른 링크로 옮겨감에 따라 스트림의 전송률이 링크의 적정 대역폭을 초과하여 정상적인 전송이 되지 않거나 링크의 적정 대역폭을 미달하여 효율적인 전송이 되지 않을 수 있다. 본 논문에서는 SIP Mobility상황에서의 링크특성 정보 저달 방법을 고안하고, 전달받은 링크특성 정보를 통한 전송 조절 방법을 제안한다. 실제 RTP패킷 전송 실험을 통하여 스트리밍 전송 성능이 개선됨을 보인다.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.05a
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• pp.316-319
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• 2019

In this paper, the streaming architecture is designed by analyzing the existing real-time streaming platform, and the real-time communication and media storage are handled by accommodating multiple users. Furthermore, the Android mobile app allows users to test their behavior and provide services for deployment.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.1483-1486
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• 2013

최근 무선통신의 급격한 발전과 스마트 기기의 확산으로 인해 Tving, pooq 등 다양한 모바일 방송 서비스가 급속도로 증가하고 있다. 또한 다양한 영상처리 기법 등이 등장함에 따라 4K, 8K급의 UHD 동영상들이 속속들이 등장하고 있다. 이로 인해 트랜스코딩을 통해 가공되는 동영상의 포맷 및 해상도 또한 매우 다양해질 것으로 전망된다. 현재까지의 트랜스코딩 연구사례는 사용자의 이동환경을 고려한 안정적 QoS 보장 또는 서버의 부하를 줄이기 위한 분산처리 기법 등의 연구 위주로 진행되어 온 것이 현실이다. 하지만 상기 조건(adaptive streaming 및 서버부하 처리)들을 충족시키긴 위해선 보다 효율적인 트랜스코딩 시스템의 제공이 선행 되어야 할 것이다. 이에 따라 본 논문에서는 사용자 관점에서 보다 빨리 스트리밍 서비스를 제공 받기 위하여 우선순위 큐 알고리즘을 적용한 시스템을 설계 및 구현하였다. 검증을 위하여 4가지 콘테이너(.MOV, .FLV, .MKV, .AVI)를 실험대상으로 하였고, 비교 대상 트랜스코딩 시스템은 상용 스트리밍 서비스인 YouTube를 활용하였다. 성능 측정결과, 총 트랜스코딩 완료시간은 YouTube에 비해 41.61%로 시간이 단축되었다. 또한 모바일 TV시청자가 55%를 차지한다는 점을 고려하여 컨트롤 서버에서는 최단시간 서비스 제공을 위하여 저해상도부터 추출하여 스트리밍 서버를 통해 송출하도록 구현하였다. 본 연구결과는 트랜스코딩 성능개선 뿐만 아니라 모바일 대상자를 위한 맞춤형 서비스를 보다 빨리 제공할 수 있을 것이며, 그 수요는 점차 증대될 것으로 예상된다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.5
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• pp.47-58
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• 2011

Recently, there are several technologies for protecting information in the lightweight device, One of them, the AES[1] algorithm and CRT mode, is used for numerous services(e,g, OMA DRM, VoIP, IPTV) as encryption technique for preserving confidentiality. Although it is possible that the AES algorithm CRT mode can parallel process transmitting data, IPTV Set-top Box or Mobile Device that uses these streaming service has limited computation-ability. So optimizing crypto algorithm and enhancing its efficiency for those environment have become an important issue. In this paper, we propose implementation method that can improve efficiency of the AES-CRT Mode by improving algorithm logics. Moreover, we prove the performance of our proposal on the mobile device which has limited capability.

• Journal of KIISE
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• v.44 no.11
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• pp.1219-1230
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• 2017

Real-time streaming services over the Internet have increased with the explosive growth of the various mobile platforms, with a focus on smart phones, and the demand for them is growing. In addition, the bandwidth occupied by the streaming services over the Internet had already surpassed 50% in 2010. Because of the shortage of network bandwidth for multimedia services traffic, restrictions on quality and capacity will become more and more serious. CCN is a future Internet architecture that improves how existing host-based Internet architecture handles content-oriented structure, but it is designed for the transmission of general contents and is not suitable for transmitting real-time streaming contents. In this paper, we focus on the inefficient aspects of CCN and propose a hierarchical grade-based scheme for real-time service for a more efficient environment in real-time streaming services. Experiments have shown better performance in terms of bandwidth, network load, and reliability.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.10
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• pp.990-994
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• 2010

Mobile WiMAX does not guarantee the media qualities because it does not consider the characteristics of video coding techniques. In this paper, PC-MCA(Priority-based Combining adaptive Modulation and Coding with ARQ), a priority based channel-adaptive streaming scheme, is proposed to guarantee media qualities. PC-MCA uses QoS scheduler by scheduling priority of the media and differentially controls modulation and coding schemes according to wireless channel condition and frame priorities. It also guarantees multimedia service quality through video decoding reliability.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.228-229
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• 2012

고 해상도의 멀티미디어 영상을 모바일 기기에서 클라우드를 통해 제공 받을 때 시간적, 공간적 손실을 최소화 하고 모바일 기기에 환경에 맞는 최적의 상태로 멀티미디어를 제공함으로 시간적, 공간적 손실을 최소화하는 방안을 제안한다.