• Proceedings of the Korea Information Processing Society Conference
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• 2004.11a
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• pp.191-194
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• 2004

차세대 인터넷 서버는 인터넷을 통하여 여러 사용자에게 HDTV 급 고품질 멀티미디어 서비스를 제공하고자 개발된 시스템이며, 이를 위하여 디스크 연결 및 네트워크 기능을 정합 시킨 특화된 NS 카드를 개발하였다. Contents Container 파일 시스템은 NS 카드 전용으로 개발된 멀티미디어 파일 시스템이며, 본 논문에서는 Contents Container 파일 시스템에 대한 개발 내용을 기술하고, 개발 시스템의 장단점을 파악하고자 EXT3 파일 시스템과 비교 분석하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.3
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• pp.458-468
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• 2009

The patching technique has been used for removing initial waiting time of NVOD. The technique was applicable only to time segmented NVOD services. However, data segmented NVOD methods have been known to have less initial waiting time or use less server's bandwidths than the time segmented NVODs. Therefore, we expect that if patching is applied to a data segmented NVOD, a more efficient NVOD service will be possible. But there has not been such approach. In this paper, we propose a new VOD scheduling algorithm that combines the patching technique with a data segmented NVOD, thus it uses less server's bandwidths and removes initial waiting time, hence makes a true VOD service possible. The proposed technique also absorbs the storage overhead necessary for client buffering incurred by patching into the data segmentation policy of the NVOD scheduling, hence does not need any extra overhead of the client's resource. Therefore, it is also applicable to the case that the client has resource limits.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1105-1108
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• 2005

Media service model is divided into 3 models that are Client Pull, Server Push, and IPP(Interleaving Pull & Push) model. In most single VOD(Video On Demand) environment, Client Pull model was sufficient to play the movie Because most media contents has a low bitrate and resolution. But according to an increment of the demand of the high definition media, Client Pull model is not sufficient. Parallel VOD environment is made of several of VOD servers and provides the parallel media stream simultaneously for one client. We compared and analyzed the performance of service models with respect to network delay and data size in buffer in the single and parallel VOD environment and we found that IPP service model keeps the least network delay and stable client buffer state in the parallel VOD environment.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05a
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• pp.145-148
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• 2003

본 논문은 단일 VOD 환경에서의 서버/클라이언트 간 데이터 서비스 모델을 분석하고 이를 병렬 VOD 환경에 적용함으로써 보다 나은 사용자 QoS(Quality of Service)를 제공하고자 한다. 이를 위해 단일 VOD 환경에서는 클라이언트가 데이터를 요청하고 서버가 전달해주는 Client Pull 모델과 서버 측에서 일방적으로 데이터를 전달해주는 Server Push 모델을 네트워크상 전달지연 측면에서 분석하고 위 두 모델.을 통합한 IPP(Interleaving Pull & Push) 서비스 모델과 Client Pull 모델을 전달지연과 클라이언트 버퍼 내 데이터 잔여량 측면에서 병렬 VOD 환경에서 적용 및 비교하였다. 시뮬레이션을 통해 병렬 VOD 환경에서 IPP 서비스 모델이 가장 적은 전달지연과 보다 안정적인 클라이언트 버퍼를 유지함을 알 수 있으며 이를 동해 사용자에게 보다 나은 서비스를 제공할 수 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.10-12
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• 2004

초고속망의 급속한 보급은 인터넷 사용자로 하여금 다양한 형태의 멀티미디어 서비스에 대한 요구를 증가시키고 있다. 하지만 데이터 용량의 기하급수적인 증가는 VOD(Video On Demand) 서비스에 많은 문제를 야기하고 있다. 따라서 이와 같은 문제점을 지닌 병렬 VOD 서버를 개선, 보완할 수 있는 새로운 형태의 P2P 기반 VOD 서버를 본 논문에서 제안하고자 한다. P2P 기반 VOD 서버는 병렬 VOD 서버에 비해 저렴한 구축비용과 용이한 확장성을 제공하며 계층화된 멀티미디어 데이터 서비스를 제공함으로써 다양한 대역폭을 갖고 있는 통신망 환경에서 실시간 멀티미디어 서비스가 가능한 장점을 가지고 있다.

• The KIPS Transactions:PartA
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• v.9A no.2
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• pp.137-146
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• 2002

In VOD server, in order to guarantee playback of continuous media, such as video, without hiccups for multiusers, the server has to manage its buffer sophisticatedly by prefeching a part of the data into the buffer As the continuous media data buffered by one user can be used again by the others, the number of disk accesses is reduced and then the latency time far the users is also reduced. In this paper, we propose a new buffer management technique for continuous media in VOD server. Our basic algorithm partitions the buffer into groups and then a group of buffer which has the lowest utilization is chosen and partitioned again for a new user. The basic algorithm is extended for supporting multiple streams and clip data and for providing VCR functions. Our proposed technique is able to increase in the number of concurrent users as increasing the utilization of the buffer and to minimize the average waiting time for multiuser accesses as the bandwidth of storage is slowly reached to the limit. In the simulation study for comparing the performance of our technique with that of the existing techniques, we show that the average waiting time is reduced mere than 50% and the number of concurrent users increases by 1 ∼5% as compared with those of the exiting techniques.

• Journal of The Korean Association of Information Education
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• v.3 no.1
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• pp.22-32
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• 1999

In this paper, a von system which is based on current computer technologies is implemented. This von system organizes many personal computers in a local network into a configuration server, storage servers, and clients. To provide reliability, the data is stored using software RAID technology. Also, multimedia services are client-based for efficiency. The software components of this von system are the von configuration software, the von configuration service software, the von management software, and the von service software. Only the von service software runs in the client, while all the others run in the configuration server. The operating system on which the configuration server is run is the Windows NT such that the software executes like the UNIX-daemon process in the Windows NT service manager.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.5
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• pp.942-947
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• 2008

A cluster server usually consists of a front end node and multiple backend nodes. Though increasing the number of bookend nodes can result in the more QoS(Quality of Service) streams for clients, the possibility of failures in backend nodes is proportionally increased. The failure causes not only the stop of all streaming service but also the loss of the current playing positions. In this paper, when a backend node becomes a failed state, the recovery mechanisms are studied to support the unceasing streaming service. The basic techniques are hewn as providing very high speed data transfer rates suitable for the video streaming. However, without considering the architecture of cluster-based VOD server, the application of these basic techniques causes the performance bottleneck of the internal network for recovery and also results in the inefficiency CPU usage of backend nodes. To resolve these problems, we propose a new failure recovery mechanism based on the pipeline computing concept.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.576-578
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• 2000

현재의 대부분의 VOD System에서는 Single Server System의 제약인 확장성과 안정적 서비스를 제공하기 위해 Multi-Server System을 사용하고 있다. Multiple Server에 Video Data를 Striping한 구조를 Parallel Video Server Architecture라 한다. 본 연구에서는 Parallel Video Server System 상에서 Data의 Striping Policy에 대해 고찰해보고 이때 발생하는 load balancing과 redundancy 문제의 해결책을 제시하였다. 또한 이를 실제 local Network 시스템에 적용하여 구현하였다.

• The Transactions of the Korea Information Processing Society
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• v.4 no.5
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• pp.1172-1181
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• 1997

A militimedia data is a data mixed of formatted data like an audio and video. Multimedia data has characteristics that it need large amount of storage,wide network bandwith andreal time responsibolity. Because of these characteristocs, the VOD server and continous media storage server have a disk stripe structure or disk stripe sructure or disk array structure(RAID).In the parallel disk access system,high-speed play-back of continous media using segment interleavung may not ensure Qos pf other cioents because of the concentrated load within some disks. The load concentration of disks is related to both the number of disks in the system and playback rate of contimous media.In this paper. we describe that high-speed playback scheme,which is independent of the number of disk and plyback rate can be achieved by technique of changing the in-teval of access to segnent location.We show the experimental result of this technique in this pater.