• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.2
• /
• pp.260-268
• /
• 2008

This raper discusses improvement of MCVoD System by changing the channel allocation of VoD Server. And we analyzed performance of MCVoD System. Using simulation, we compare MCVoD with another VoD server using same channel allocation. In case of average channel allocation, MCVoD System using interchange agent, represents three times better than previous VoD server.

• Proceedings of the Korean Information Science Society Conference
• /
• 1999.10c
• /
• pp.105-107
• /
• 1999

최근 컴퓨터와 제반 기술들의 눈부신 발달로 인해 대용량의 멀티미디어 데이터를 다루는 서비스들이 많이 등장하고 있다. 주문형 비디오 서비스(Video on Demand)가 가장 대표적인 예라고 할 수 있으며, 이를 구현하기 위한 많은 방법들이 제안되고 있다. 본 논문에서는 현재까지 개발되어 있는 VoD 시스템에 관하여 살펴보고, 이를 기반으로 PASS(Parallel and Scalable Server) VoD 시스템을 제안한다. PASS VoD 시스템은 병렬 비디오 서버로서 SAN(System Area Network)로 연결된 independent proxy 구조와 비슷한 구조를 가지는 시스템이다. 본 논문에서는 PASS VoD 시스템에 대하여 설명하고 PASS VoD 시스템이 scalable 함을 시뮬레이션을 통하여 확인하였다.

• The Transactions of the Korea Information Processing Society
• /
• v.6 no.10
• /
• pp.2642-2648
• /
• 1999

This paper describes a DAVIC based VoD service system that allows access via the Web, taking advantage of the wide availability of Web browsers. A simple access mechanism of a DAVIC based VoD system, using a Web browser is adopted on the proposed system. The client and VoD server are compliant with DAVIC, a user can access the VoD server simply by selecting the Web server's address via a Web browser. A menu enables the user to select VCR-like buttons, to establish an S2 control flow and to send the commands contained in the buttons to the VoD server. A simple implementation shows the feasibility of the proposed approach.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.3 no.5
• /
• pp.444-460
• /
• 2009

In this paper, we propose an expanded patching technique in order to reduce the server network bandwidth requirements to support true VoD services in VoD Systems. Double Patching, which is a typical multicast technique, ensures that a long patching stream delivers not only essential video data for the current client but also extra video data for future clients. Since the extra data may include useless data, it results in server network bandwidth wastage. In order to prevent a server from transmitting useless data, the proposed patching technique uses a new kind of stream called a linking stream. A linking stream is transmitted to clients that have received short patching streams, and it plays a linking role between a patching stream and a regular stream. The linking stream enables a server to avoid transmitting unnecessary data delivered by a long patching stream in Double Patching, so the server never wastes its network bandwidth. Mathematical analysis shows that the proposed technique requires less server network bandwidth to support true VoD services than Double Patching. Moreover, simulation results show that it has better average service latency and client defection rate compared with Double Patching.

• The KIPS Transactions:PartD
• /
• v.14D no.5
• /
• pp.565-572
• /
• 2007

In this paper, we developed a VoWLAN(Voice over WLAN) system based on an open source software. The system aims to provide VoIP service over wireless LAN with an IP-PBX server. The features of system presented in this paper are as follows. First, the initial cost for the development is reduced since the system is developed based on open source software. Second, the system provides various additional services such as Voice Mail, Conference Call, and Interactive Voice Response with a software IP-PBX server. Third, the VoWLAN terminal provides high-level user applications with minimal system resources using lightweight open software solutions. Finally, it is highly scalable since it is based on the open source software.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.25 no.6A
• /
• pp.918-926
• /
• 2000

A huge storage and broad bandwidth are required to provide subscribers with VoD services. Hence, there is a huge amount of cost in establishing networks for VoD services. To determine how to reduce the cost, a number of studies involving such as distributed server systems, multicasting, program caching, stream sharing, are currently in progress. In this paper, a request criterion for multicast service and the ratio of required bandwidth for unicast to multicast are generated. The effect of multicast service on network bandwidth, server bandwidth, and buffer size was analyzed and validated through computer simulation. The results of this study could be applied to efficient designing networks for VoD services.

• The KIPS Transactions:PartA
• /
• v.11A no.3
• /
• pp.207-212
• /
• 2004

This paper provides the higher user QoS(Quality of Service) by analyzing media service model between server and client in single VoD(Video on Demand) environment and applying it to parallel VoD environment. Media service model is divided into the Client Pull, Server Push, and IPP(Interleaving Pull & Push) model. A server sends data based on client's request in the Client Pull Model. A server one-sidedly sends data without client's request in the Server Pull model. And the WP model unites above two models. For a parallel VoD environment, We built the PMSS system which provides the parallel media streaming services that one client is simultaneously served by several servers. In the single and parallel VoD environment, We compare and analyze the performance of service models with respect to network delay and data size in buffer. In this experiment, we found that IPP service model keeps the least network delay and stable client buffer in the parallel VoD environment. This result shows that PMSS can provide the more quality of service.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.2S
• /
• pp.577-593
• /
• 2000

A distributed video-on-demand (VoD) system is one where collection of video data is located at dispersed sites across a computer network. In a single site environment, a local video server retrieves video data from its local storage device. However, in the setting of a distributed VoD system, when a customer requests a movie from the local server, the server may need to interact with other servers located across the network. In this paper, we present three types of presentation plans that a local server must construct in order to satisfy the customer request. Informally speaking, a presentation plan is a temporally synchronized detailed sequence of steps that the local server must perform for presenting the requested movie to the customer. This involves obtaining commitments from other video servers, obtaining commitments from the network service provider, as well as making commitments of local resources, within the limitations of available bandwidth, available buffer, and customer data consumption rates. Furthermore, for evaluating the goodness of a presentation plan, we introduce two measures of optimality for presentation plans: minimizing wait time for a customer, and minimizing access bandwidth is used. We develop algorithms to compute optimal presentation plans for all three types, and carry out extensive experiments to compare their performance. We have also mathematically proved certain results for the presentation plans that had previously been verified experimentally in the literature.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.65-65
• /
• 2000

For Video on Demand(VoD) servers, a design of an efficient scheduler is important to the support a large number of clients having various playback speeds and receiving rates. In this paper, we propose the scheduling algorithm to handle establishing deadlines and selection using the earliest deadline first. To establish deadlines and selections, the period of the receiving rates for each client is located between the over-max receiving rate and the over-playback rate. To avoid video starvation and the buffer overflow of each client, the proposed algorithm guarantees providing the admission control. Because of establishing deadlines and selection, period of each client receiving is between one over max receiving rate and one over play back rate. Using Virtual Buffer in server, scheduling load is reduced. The efficiency of the proposed algorithm is verified using a Petri Net_Based simulation tool, Exspect.

• Journal of Korea Society of Industrial Information Systems
• /
• v.15 no.2
• /
• pp.31-39
• /
• 2010

VoD(Video-on-Demand) servers have to provide timely processing guarantees for continuous media and reduce the storage and bandwidth requirements for continuous media. The compression techniques make the bit rates of compressed video data significantly variable from frame to frame. A VoD system should be able to provide the client with interactive operations such as fast forward and fast rewind in addition to normal playback of movie. However, interactive operations require additional resources such as storage space, disk bandwidth, memory and network bandwidth. In a stored video application such as VoD system, it is possible that a priori disk access patterns can be used to reserve the system resources in advance. In addition, clients of VoD server spend most of their time in playback mode and the period of time spent in interactive mode is relatively small. In this paper, I present the new buffer management scheme that provides efficient support for interactive operations in a VoD server using variable bit rate continuous media. Simulation results show that our strategy achieves 34% increase of the number of accepted clients over the LRU strategy.