• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.1B
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• pp.1-6
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• 2011

We have considered fast handoff algorithms to support seamless streaming in wireless LANs. It is impossible to provide seamless streaming service while moving within wireless LANs, In this paper, we proposed a new handoff algorithm where the critical value for handoff can be adjusted according to peripheral wireless circumstances. This algorithm can prevent an unnecessary scanning job and save handoff delay time through the active scanning procedure to the specific channel groups. Also, we evaluated the handoff performance of our proposed algorithm, and compared it with the performance of the existing wireless LAN. We can see that the performance with our proposal is better than that of the general wireless LAN.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.9
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• pp.626-636
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• 2009

In Mobile IP-enabled wireless LAN (WLAN), packet flows are corrupted due to the handoff of a mobile node (MN) at the link and network layers, which results in burst packet losses and can cause temporary buffer underflow in a streaming client at the MN. This transient behavior hurts time-sensitive streaming media applications severely. Among many suggestions to address this handoff problem, few studies are concerned with empirical issues regarding the practical validation of handoff options on the time-sensitive streaming media applications. In this paper, targeting seamless streaming over Mobile IP-enabled WLAN, we introduce a seamless media streaming framework that estimates accurate pre-buffering level to compensate the handoff latency. In addition, we propose a link-layer (L2) assisted seamless media streaming system as a preliminary version of this framework. The proposed system is designed to reduce the handoff latency and to overcome the playback disruption from an implementation viewpoint. A packet buffering and forwarding mechanism with L2 trigger is implemented to reduce the handoff latency and to eliminate burst packet losses generated during the handoff. A pre-buffering adjustment is also performed to compensate the handoff latency. The experimental results show that the proposed approach eliminates packet losses during the handoff and thus verify the feasibility of seamless media streaming over Mobile IP-enabled WLAN.

• KIISE Transactions on Computing Practices
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• v.22 no.7
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• pp.310-314
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• 2016

Currently, several research studies are looking to improve the quality of DASH (Dynamic Adaptive Streaming over HTTP) based live streaming services. However, conventional DASH based streaming schemes cannot provide seamless playback while maintaining the low buffering and it adversely affects the QoE (Quality of Experience). To address this problem, we propose the QoE driven segment scheduling scheme. The proposed scheme adaptively schedules the segment request message according to the time and variation of segment fetching. Simulation results indicate that the proposed scheme improves the QoE of live streaming service by maintaining the low buffering delay and reducing the buffer underflow events.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.131-139
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• 2007

The recent advance in wireless network technologies has enabled the streaming media service on the mobile devices such as PDAs and cellular phones. Since the wireless network has low bandwidth channels and mobile devices are actually composed of limited hardware specifications, the transcoding technology is needed to adapt streaming media to given mobile devices. Futhermore owing to the diversity of bandwidth in the wireless network by reason of mobile users' movements and environments, it is difficult to provide stable QoS. In this paper, the autonomic multimedia transcoding system is proposed in order for users to provide network adaptive QoS. Our proposed system is based on the estimation of available bandwidth in wireless network for seamless multimedia streaming service. The proposed system is designed and implemented for various mobile clients. In experiments, we evaluate its seamless multimedia streaming and the adaptation transcoding bit rate according to the changes of bandwidth in wireless network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.7
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• pp.467-476
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• 2014

Recently, various services which use the fused form of broadcasting and communication are being offered over the Internet globally. To provide various interactive services through connected smart TV on wired or wireless network, the seamless multimedia service is key feature. In this paper, Dynamic Adaptive Streaming over HTTP (DASH)is adopted to develop cost-effective adaptive streaming system for Open Hybrid TV(OHTV) service. This system can provide seamless adaptive streaming service for IP VOD, Video Clips, Ad insertion which are defined in OHTV.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.9
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• pp.2118-2135
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• 2012

With the rapid development of heterogeneous emerging wireless technologies and numerous types of mobile devices, the need to support robust mobile video streaming based on the seamless handover in Future Internet is growing. To support the seamless handover, several IP-based mobility management protocols such as Mobile IPv6 (MIPv6), fast handover for the MIPv6 (FMIPv6), Hierarchical MIPv6 (HMIPv6) and Proxy Mobile IPv6 (PMIPv6) were developed. However, MIPv6 depreciates the Quality-of-Service (QoS) and FMIPv6 is not robust for the video services in heterogeneous emerging wireless networks when the Mobile Node (MN) may move to another visited network in contrast with its anticipation. In Future Internet, the possibility of mobile video service failure is more increased because mobile users consisting of multiple wireless network interfaces (WNICs) can frequently change the access networks according to their mobility in heterogeneous wireless access networks such as 3Generation (3G), Wireless Fidelity (Wi-Fi), Worldwide Interoperability for Microwave Access (WiMax) and Bluetooth co-existed. And in this environment, seamless mobility is coupled according to user preferences, enabling mobile users to be "Always Best Connected" (ABC) so that Quality of Experience is optimised and maintained. Even though HMIPv6 and PMIPv6 are proposed for the location management, handover latency enhancement, they still have limit of local mobility region. In this paper, we propose a robust mobile video streaming in Heterogeneous Emerging Wireless Systems. In the proposed scheme, the MN selects the best-according to an appropriate metric-wireless technology for a robust video streaming service among all wireless technologies by reducing the handover latency and initiation time when handover may fail. Through performance evaluation, we show that our scheme provides more robust mechanism than other schemes.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.1335-1340
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• 2006

본 논문에서는 사용자의 상호작용에 대해서 끊김없이 재생하는 멀티미디어 스트리밍 기법을 제안한다. 제안하는 멀티미디어 스트리밍 기법은 기존 디코딩 버퍼와 스트림 버퍼 외에 스트림 백업 버퍼를 추가로 사용한다. 추가된 스트림 백업 버퍼는 사용자의 상호작용에 효율적으로 지원할 수 있도록 현재 재생 위치를 중심으로 기존 스트림 버퍼의 2배 크기만큼 미리 버퍼링하여 효율적인 탐색과 빠른 재생을 지원한다. 사용자가 요구하는 대부분의 탐색작용은 현재 재생 위치 근처에서 일어날 확률이 높으므로, 제안한 멀티미디어 스트리밍 기법을 이용하여 사용자 상호작용에서 거의 지연 없이 효율적으로 재생한다. 본 논문에서는 구현 환경으로 멀티미디어 스트리밍을 지원하기 위한 MS사의 MMS서버를 이용하여 멀티미디어 스트리밍을 송수신하고 기존 재생기들과 제시한 멀티미디어 스트리밍 기법을 적용한 재생기와의 성능을 비교 평가하였다. 제안한 스트리밍 기법의 적용 예로서는 원격 강의 및 네트워크 게임 등이 있다.

• Journal of KIISE
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• v.44 no.5
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• pp.545-552
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• 2017

Because of the explosive growth of mobile devices and development of network technologies, HTTP (Hypertext Transfer Protocol) adaptive streaming has become a new trend in video delivery to provide efficient multimedia streaming services. As interest in personalized broadcasting grows, the study of interactive multimedia has been actively pursued. The interactive multimedia service is a method of playing media according to a scenario selected by the user. Providing the interactive multimedia service with the existing HTTP adaptive streaming causes switching delay and buffer underflow according to the point in time when the user selects the scenario while the client streams the interactive multimedia and therefore decreases the user QoE (Quality of Experience). In this paper, we propose an adaptive streaming scheme for interactive multimedia service in HTTP adaptive streaming to provide seamless playback. We design the architecture and prefetching scheme for interactive multimedia streaming.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.515-517
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• 2006

Recently, there is a rapidly growing demand for efficient real-tine playback and transmission of large amounts of multimedia data. But most users' connections are not fast enough to download large chunks of multimedia data. Therefore a streaming technology is needed in which users enable the real-time playback of multimedia date without having to download the whole of the multimedia date. In this paper, we propose a personalized IP streaming system. The proposed IP streaming system enables users to got an intelligent recommendation of multimedia contents based on the user preference information stored on the streaming server or the home media server. Moreover, users are assured of seamless access of streamed content event if they switch to another client device by implementing streaming system based on user identification and device information. We evaluate our approach with simulation results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.670-672
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• 2021

The video streaming technologies are used in diverse areas including aerospace. UAV (Unmanned Aerial Vehicle) is still being developed so that we are able to use the UAV not only in military areas but also in civil areas. Remotely monitoring and observing a certain area is possible via using video streaming service based on the UAV nowadays. However, UAV is vulnerable to weather conditions, plane's weight, battery capacity and so on, which makes many restrictions of flight time and video streaming services. In order to prolong the video streaming services, we can use a number of UAVs, fly them one by one, and switch video streaming channels. In the paper, we propose the methods how to interchange UAVs' missions and their video streaming channels to provide seamless video stream services.