• The Transactions of the Korea Information Processing Society
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• v.7 no.12
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• pp.3794-3803
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• 2000

In a Video-on-Demand system, admission control that is used to serve multimedia data efficiently has to be perfonned by an accurate grasp of the condition of surplus resources. Most of all. we need to adaptable admission control mechanism because the disk has irregular response time caused by external elements of disk, and also has high deviation of amount demanded. In previous admission control schemes, they determined whether a new user is granted or not through a theoretical value. Although they based on the measurement, they left much to be desired in dealing with the service state. Measurement ~based statistical admission control scheme, as we su~~ested in this research, perfonns 2 processes of off-line process and on-line process in real service environment. Through this processes, we can grasp the accurate resource state of system and adaptive!y detennine the admission according to circumstances. Therefore, it can guarantee both maximum resource utilization and QoS(Quality of Service). On performance evaluations, we show that the video server can utilize maximum resource utilization with QoS guarantee through precision of perfonnance by measurement and adaptable admission control according to the requested bandwidth.

• The KIPS Transactions:PartB
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• v.8B no.5
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• pp.507-514
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• 2001

In VOD(Video-on-Demand) system, the real-time interactive service is one of the most important factor to determine the degree of QoS(Quality of Service). In this paper, we propose the head-end system consisted of switching agent and head-end node, which needs to receive the only video stream for multiple users which have requested the same video, to serve the unlimited interactive service which has no service delay and block. The unlimited VCR services can be served by storing the video stream with buffer at client and head-end node. And the proposed algorithm presents the method to enhance the efficiency by buffer, offer the true interactive VOD services to users because all of service requested by clients are processed immediately. In this paper, we implemented the VOD system which has the VCR functions without service delay and block. Simulation results indicate that the proposed algorithm has better performance in the number of service request and time interval.

• IE interfaces
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• v.11 no.2
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• pp.39-48
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• 1998

It is strongly believed that Video on Demand(VOD) will become one of the most promising services for Broadband Integrated Services Digital Network(B-ISDN). VOD service can be classified into two types of services: Near VOD(NVOD) and Interactive VOD(IVOD). Although VOD network requires many kinds of resources, we only consider video servers, programs. and storages. In the network. some video servers should be installed at some nodes(especially, at the root node for NVOD service). so that each node with video server stores video programs and distributes stored programs to customers. We take into account three kinds of costs related with the above resources: a program transmission cost, a program storage cost, and a video server installation cost. There exists a trade-off relationship among those three costs according to the locations of video servers and the kinds of programs stored at each video server. Given a multi-level VOD network and the total number of programs being served in the network. the resource. optimization problem for providing both IVOD and NVOD services is to determine where to install video servers, and which and how many programs should be stored at each video server, in order to minimize the total cost. In this paper we develop an efficient dynamic programming algorithm to solve the problem. We also implement the algorithm based on two different service policies assumed in this paper.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.979-982
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• 2000

In this paper we suggest the adaptive QoS-based VOD system design, which can diagnose and reflect the variable network situation. This system is based on the changeable Forward Error Correction(FEC) coding and re-transmission to enhance system quality by using the measured real-time network value such as loss, delay and jitter.

• 한국IT서비스학회:학술대회논문집
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• 2006.11a
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• pp.360-365
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• 2006

VoD (Video-on-Demand) 서비스는 가입자가 원하는 컨텐츠를 실시간으로 전송하는 서비스의 형태이다. 오늘날은 방대한 양의 멀티미디어 데이터를 효율적으로 압축하고 보다 빠르게 전송할 수 있는 시스템의 발달이 가속화되고 있고 이는 VoD 서비스의 증가로도 이어지고 있다. 그러므로 가입자가 원하는 컨텐츠를 보다 효과적으로 제공할 수 있는 VoD 서비스의 방법을 찾는 것은 중요한 일이다. 본 논문에서는 기존의 NVoD (Near-VoD) 서비스 또는 TVoD (True-VoD) 서비스 만을 제공함으로서 생길 수 있는 단점을 없애고 장점만 살릴 수 있는 방법을 제안하였다. 이는 기존의 가입자단에 Buffer를 제공하여 NVoD를 TVoD화 함으로서 가능하게 하였다. 또한, 본 논문에서 제안한 방법이 필요한 버퍼의 크기를 제시하고 전체적인 알고리즘을 제시하여 이를 구체화 하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.821-835
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• 1998

The Digital Audio-Visual Council(DAVIC) that was established to develop useful multimedia communication services has completed the specifications for providing on-demand services such as Movie on Demand(MoD), Teleshopping and accepting Internet service. And then they are proceeding the works to suport converstional communcation services like Plain Old Telecphone Service(POTS), Video telephone, Video teleconferencing. In this paper, we prpose an efficient terminal architecture which can provide conversational multimedia communication services on DAVIC Set-Top Box (STB) environments. To apply the implemented conversational terminal to the multipoint communication environment, we considered the factors of Qurlity of Services(QoS) that determine grade of conversational communication service. We also present the inter-working scheme and that system structure to satisfy QoS by using new MPEG video bridge which gurantees end to end delay requirements as major element of QoS for achieving the real time communication and does not accompany visual quality degradation.

• The Transactions of the Korea Information Processing Society
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• v.7 no.2S
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• pp.656-665
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• 2000

A critical issue in the performance of a video-on-demand system is the I/O bandwidth required in order to satisfy client requests. Several approaches: batching, bridging, piggybacking are used ot reduce the I/O demand on the video server through sharing. Piggybacking is the policy for altering display rates of requests in progress fro the same object, for the purpose of merging their corresponding I/O streams into a single stream, which can serve the entire group of merged requests. In this paper, we propose a new policy called an adaptive reservation-based piggybacking that dynamically reserves the I/O stream capacity of video server for popular videos according to video server loads to immediately schedule the requests for popular videos. The performance of the proposed policy is evaluated through simulations, and is compared with that of simple piggybacking. As the result, we know that the adaptive reservation-based piggybacking provides better service probability, average waiting time and percentages saving in frames than simple piggybacking.

• The Journal of Society for e-Business Studies
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• v.12 no.4
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• pp.85-98
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• 2007

This study uses conjoint analysis technique to calculate relative importance of each attribute of a specific online content: video-on-demand (VoD) services of TV soap operas. A series of interviews were conducted to identify and derive critical attributes for VoD services. Conjoint instrument was constructed using attributes identified and administered among actual viewers. Price, genre, additional service, and actors were found to be the most highly valued attributes of the VoD services. While price was the most valued attribute for female viewers, it was genre for male viewers. The result suggests that these attribute differentiation would lead to more profitable pricing scheme, and development of additional services may be critical for online content business' success.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.5
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• pp.236-239
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• 2006

A wireless MAC scheduler that provides a high level of quality-of-service (QoS) for video-on-demand (VOD) applications while achieving a reasonable level of system throughput is proposed. The proposed scheduler considers both channel qualities of mobiles and the urgency of real-time packets coming from VOD applications in a cross-layer approach between application and MAC layers.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.331-333
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• 2000

최근 VOD(Video On Demand)나 AOD(Audio On Demand) 서비스가 급증하면서 멀티미디어 스트리밍 기술에 대한 관심이 커지고 있다. 기존의 스트리밍 서비스는 정적으로 멀티미디어를 전송하므로 네트워크 환경의 대역폭(bandwidth) 변화에 대처하는데 한계가 있다. 이러한 문제점을 해결하기 위하여 본 논문에서는 적응형 스트리밍 서비스(ASS; Adaptive Streaming Service) 시스템을 제안한다. ASS 시스템은 가변 비트율을 통한 미디어 스케일링방식을 이용하여 멀티미디어 데이터를 동적으로 전송한다. 또한 프레임 조정방식과 화질 조정방식을 동시에 채택하여 적용함으로써 고화질이 보장되는 전송환경과 느린 회선에서도 끊김없이 안정적인 스트리밍 서비스를 제공받을 수 있도록 한다.