• Journal of Korea Society of Industrial Information Systems
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• v.4 no.4
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• pp.32-39
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• 1999

Video-On-Demand servers have to provide timely processing guarantees and reduce the storage and reduce the storage and bandwidth requirements for continuous media However, compression techniques used in Video-On-Demand servers make the bit rates of compressed video data significantly variable from frame to frame Consequently, most pervious Video-On-Demand servers which use constant bit rate retrieval to guarantee deterministic service under-utilize the system resources and restrict the number of clients. In this paper, I propose a buffer management scheme called CAP(Caching And Prefetching) for Video-On-Demand server using variable bit rate continuous media. By caching and prefetching the data CAP reduces the variation of the compressed data and increases the number of clients simultaneously served and maximizes the utilization of system resources. Results of trace-driven simulations show the effectiveness of the scheme.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.225-228
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• 2001

We describe the implementation of MPEG-4 Systems for Video on Demand services. We discuss the issues in implementint MPEG-4 Systems, specially Object Description and Elementary stream management(Buffer control, Synchronization). The file-server pump the multiplexed streams to the client through the DMIF. Interaction between server and client is done with User Command(play, pause, stop, fast foward, ...). Stream data are multiplexed off-line. In advance, the file-server read multiplexed streams and pumps it to MPEG-4 terminal(client). Our system can be used in various application not only Video on Demand services, but also Internet broadcasting, remote surveillance, mobile communication, remote education, etc.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.4
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• pp.491-508
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• 2010

In peer-to-peer (P2P) on-demand streaming networks, the alleviation of server load depends on reciprocal stream sharing among peers. In general, on-demand video services enable clients to watch videos from beginning to end. As long as clients are able to buffer the initial part of the video they are watching, on-demand service can provide access to the video to the next clients who request to watch it. Therefore, the key challenge is how to keep the initial part of a video in a peer's buffer for as long as possible, and thus maximize the availability of a video for stream relay. In addition, to address the issues of delivering data on lossy network and providing scalable quality of services for clients, the adoption of multiple description coding (MDC) has been proven as a feasible resolution by much research work. In this paper, we propose a novel caching scheme for P2P on-demand streaming, called Dynamic Buffering. The proposed Dynamic Buffering relies on the feature of MDC to gradually reduce the number of cached descriptions held in a client's buffers, once the buffer is full. Preserving as many initial parts of descriptions in the buffer as possible, instead of losing them all at one time, effectively extends peers’ service time. In addition, this study proposes a description distribution balancing scheme to further improve the use of resources. Simulation experiments show that Dynamic Buffering can make efficient use of cache space, reduce server bandwidth consumption, and increase the number of peers being served.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.737-740
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• 1998

Under the worldwide booming internet environment, there has been increasing demand for various multimedia services. Especially the demand for effective video services has been rapidly increased. In this paper, we describe the implementation of video service system for internet use based on H/263 video compression technique and UDP socket on the TCP/IP environment. In addition, by using the plug-in-play technique, the implemented system improved user interface for correct retrieval and easy usage.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.3
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• pp.919-940
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• 2012

Video on Demand (VOD) is a multimedia service which allows a remote user to select and then view video at his convenience at any time he wants, which makes the VOD become an important technology for many applications. Numerous periodic VOD broadcasting protocols have been proposed to support a large number of receivers. Broadcasting is an efficient transmission scheme to provide on-demand service for very popular movies. This paper proposes a new broadcasting scheme called Popularity Cushion Staggered Broadcasting (PCSB). The proposed scheme improves the Periodic Broadcasting (PB) protocols in the latest mobile VOD system, which is called MobiVoD system. It also, reduces the maximum waiting time of the mobile node, by partitioning the $1^{st}$ segment of the whole video and storing it in the Local Media Forwarder (LMF) exactly in the Pool of RAM (PoR), and then transmitting them when the mobile nodes miss the $1^{st}$ broadcasted segment. The results show that the PCSB is more efficient and better than the all types of broadcasting and caching techniques in the MobiVoD system. Furthermore, these results exhibits that system performance is stable under high dynamics of the system and the viewer's waiting time are less than the previous system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.12
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• pp.2852-2859
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• 1997

Video-On-Demand system provides electronic video rental services from remote video servers on a broadband communication networks. Most of proposed VOD systems are typically designed for one-to-one conncetion between a user and video server. Therefore, video server stream services to customers individually by allocating a dedicated transmission channel and a set of video server resources for each customer. However, it is inefficiency and wxpensive way when server support multiple users who access the same video stream with a dedicated video channel. Therefore, to achieve cost-effectiveness, batching have studied method that uses multicast communication to simultaneously service all users requesting the same video with a single video with a single video stream. However, the application of the multicast communication by batching detract from the VCR-like function and on-demand nature of the system. In this paepr, we propose a scheme that can support an interactive VCR for all user requesting the same video stream with batching. To reduce a server I/O and network bandwidth requirement, dynamic buffer is allocated to access node which has variable playout poit. Consequently, it makes possible interactive VCR operation as if customer uses true VOD system. Also, this scheme can just deliver a multicast stream without delay after an initial request or VCR action occurred. The policy can guarantee acceptable services to number of users at minimum cost.

• Journal of Digital Contents Society
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• v.9 no.1
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• pp.69-75
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• 2008

Video-on-demand (VOD) service allows subscribers to view any video whenever they want. With the development of the high speed computer networks, web-based VOD services are available. To support VOD services, charging scheme is necessary. Pay-per-view is an effective charging scheme for VOD services. Pay-per-view allows the subscribers to pay for what they have viewed. Privacy is another important attribute for VOD services. The subscribers may not want to reveal what they have viewed to anyone including the VOD provider. Anonymity makes it complicated to calculate charge for the VOD service. An approach that achieves both anonymity and pay-per-view charge calculation is necessary. In this paper, anonymous web-based VOD service is proposed. The proposed approach also gives pay-per-view capability.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.4
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• pp.138-144
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• 2007

With recent proliferation of video-on-demand services, caching in a multimedia streaming server is becoming increasingly important. Previous studies have shown that request interval based caching and its extension for considering different video popularity performs well in various streaming environments. In this paper, we show that block level refinement of this existing scheme can further improve the performance of streaming servers. Trace driven simulations with real world VOD traces have shown that the proposed scheme improves the cache hit rate and the startup latency.

• Journal of Korean language education
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• v.29 no.2
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• pp.181-208
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• 2018

The aim of this study is to design a Real-time video Korean curriculum. Curriculum using real-time video, which is a variant of distance learning, teaches Korean to students studying in distant places through real-time video communication program. This is expected to supplement the lack of interaction in existing video classes and enable online simultaneous interaction, while increasing learning opportunities for Korean language students living in distance places. To find out the needs of the subjects for the curriculum design, this study conducted a one-on-one interview with 9 female married immigrants who are enrolled in the Cyber University which is opening a curriculum later. According to the survey, the students answered that they have a high intention of attending classes if the lack of interaction in existing distance classes are supplemented. Therefore, we could confirm the demand of a curriculum consisting of an overall real-time video education and multilateral individual connection. Also, we found out that there is a demand in performance rather than comprehension and a high demand for detailed feedback from the teacher. The result shows that the curriculum needs to establish performance-oriented contents to progress to an advanced level Korean Language, and include a study plain comprising of real-time interaction.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.7-10
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• 1998

In implementing real time video on demand(VOD), the increase of user on internet causes a network traffic congestion. In this paper, we programmed a CGI able to login in VOD home for limiting the number of user in solving the problem, and also applied and adaptive multimedia synchronization technique for controlling video and audio data in a network. In addition, a real time multimedia player was designed and implemented in a personal computer operating at Window95/98/NT.