• Journal of KIISE:Computing Practices and Letters
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• v.6 no.3
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• pp.299-310
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• 2000

In this paper, we designed and implemented a personal VOD server using multi-thread for the real-time services of video data to the users. The system consists of service manager, disk manager, and network manager. The service manager controls the user admission to the system using the VBR(Variable Bit Rate) characteristics of MPEG (Moving Picture Experts Group) video data. The disk manager provides the functions for VCR-like operations. The disk manager reads blocks from the disk by the size of GOP(Group of Pictures) and buffers the data to the user's thread. The network manager uses TCP/IP for the communication between the server and the client. The communication starts from the client and the VOD server must respond to this request. The implemented personal VOD system shows an acceptable performance.

• Journal of Korea Multimedia Society
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• v.2 no.3
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• pp.265-276
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• 1999

Video on Demand (VOD) system is definitely one of main applications in upcoming multimedia era. In this research, we have designed and implemented a host-based scalable VOD system (SVOD) which is composed of low cost PC servers and runs on Linux kernel that is currently spotlighted in enterprise and research domains. Our contribution is as follows: first, the previous Ext2 file system was modified to efficiently support continuous media like MPEG stream. Second, the storage server features a host-based scalable architecture. Third, a software MPEG decoder was implemented using Microsoft's DirectShow$\circledR$COM. Finally, flow control between client and server is provided to suppress overflow and underflow of client circular buffer and supports FF VCR operation. We have known that it is possible to develop a thread-based and scalable VOD system on low cost PC servers and free Linux kernel.

• 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.

• Explosives and Blasting
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• v.33 no.3
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• pp.21-28
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• 2015

The objective of this study is to develop a method for monitoring continuously the combustion propagation behavior of commercial thermite reaction mixtures using conventional continuous VOD (velocity of detonation) system. In order to monitor the combustion front propagation with elapsed time during thermite reaction, the VOD system employs two types of commercial VOD probes and one self-made probe: VOD PROBEROD-OS, VOD PROBEROD-HS and VOD PROBEROD-ES, respectively. Among the probes, the only self made VOD PROBEROD-ES successfully demonstrates the velocity of combustion propagation (VOC) with elapsed time. It was found that VOC of the thermite reaction mixture inside a steel tube has been reached around 200m/s within 100mm distance from the ignition and dramatically increased up to about twice the speed of sound in the range between 100mm and 300mm distance. Finally the VOC reached up to around 800m/s. This results imply that it is necessary to use over 300mm long cartridge of thermite reaction mixture in order to achieve normal VOC of the mixture.

• Journal of Broadcast Engineering
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• v.1 no.2
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• pp.133-141
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• 1996

In this paper, a VOD(Video -on-Demand) system is implemented using LAN(Local Area Network). The use of LAN causes the time-delay problem due to its narrow channel limitation, as a result, the service using the conventional LAN used not to be popular. In this paper, to solve these problems, we develop the modified topology, the selection methodology of the network equipment, and the dedicated(improved) protocol. Consequently, we can serve at most 3 or 4 clients at the same time, and we conclude it is necessary to optimize the network buffer size depending on the size of video data.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.277-279
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• 2001

VOD 서비스를 원활히 제공하기 위해서는, 대용량의 멀티미디어 데이터를 전송할 수 있는 고속의 네트워크의 구축과 더불어, 날로 증가하는 사용자들의 요구를 수용할 수 있는 서버가 요구된다. 그러나 단일서버의 VOD 시스템은 고장 발생 시, 서비스를 중단해야 할 뿐만 아니라, 늘어나는 서비스 요청에 효과적으로 대응할 수 있는 확장성 또한 유연하지 않아서, 클러스터링 기술을 적용한 VOD 서버가 그 대안으로 인식되고 있다. 본 논문에서는 리눅스를 이용한 클러스터링 VOD 서버와 관련하여, 미디어 스트라이핑 방법과 서버 설계 및 구현 과정에 대하여 기술한다.

• Journal of Digital Convergence
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• v.12 no.2
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• pp.315-320
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• 2014

Recently, although the requirement of quality of VOD content has been transferred upto the class of HD, conventional management systems characterized by OS dependency are truly limited in quality of video image, stability, and compatibility of network environments. In addition most of the content management systems realize very limited capabilities for the real affairs of content management and distribution services in such an OS dependent environment. In this paper, we propose a new scheme of HD-Class VOD Content Management System to solve these problems. We design and implement the proposed system based on open sources by using H.264 video compression method. The proposed system offers high quality content management method based on opened systems and independent on-line distribution method so that it can be realized as an integrated management scheme for VOD contents. Moreover, our system solves the problems of occasional cutting-down video, small screen, and poor image quality that exist in the conventional wmv-type CMS. According to the result of performance evaluation, our system maintains sufficient performance and tolerence for the case of large scale HD content operations or fabrications. We expect that the proposed integrated DB scheme will especially be effective when the content management applications are changed from Internet Web environments to mobile terminal environments.

• The Journal of the Korea Contents Association
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• v.9 no.9
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• pp.18-30
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• 2009

Recently, although the requirement of quality of VOD content has been transferred upto the class of HD, conventional management systems characterized by OS dependency are truly limited in quality of video image, stability, and compatibility of network environments. In addition most of the content management systems realize very limited capabilities for the real affairs of content management and distribution services in such an OS dependent environment. In this paper, we propose a new scheme of HD-Class VOD Content Management System to solve these problems. We design and implement the proposed system based on open sources by using H.264 video compression method. The proposed system offers high quality content management method based on opened systems and independent on-line distribution method so that it can be realized as an integrated management scheme for VOD contents. Moreover, our system solves the problems of occasional cutting-down video, small screen, and poor image quality that exist in the conventional wmv-type CMS. According to the result of performance evaluation, our system maintains sufficient performance and tolerence for the case of large scale HD content operations or fabrications. We expect that the proposed integrated DB scheme will especially be effective when the content management applications are changed from Internet Web environments to mobile terminal environments.

• Journal of KIISE:Information Networking
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• v.28 no.3
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• pp.426-434
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• 2001

Striping is a scheme that partitions data into blocks and distributes the blocks on different servers in a well defined order and thus could improve system capacity through load balance. In this paper, we propose a parallel VOD server and striping policies for load balancing when extra storage nodes are attached to a parallel VOD server for insufficient disk space in that VOD server. When new video data is stored on the attached storage node, the node may be overloaded. Since it decreases the system bandwidth, appropriate striping policies are required. We therefore present three striping policies that move some block of data o existing nodes into the new node and distribute the new data across all the storage nodes including the new node. Our experiment result shows that FSM bi-direction is the most effective technique.

• Journal of Internet Computing and Services
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• v.6 no.6
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• pp.127-137
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• 2005

This paper presents implementation of client-based VOD service using multicast delivery, Conventional system provide server-based system in multicast delivery but implemented system provides on-demand client-based multicast system. The Multicast Agent Scheduler aggregates clients' request and it generate multicast group addresses and port numbers according to requested video items and service request time. Then it transmits immediately multicast address to VOD server and client who request service. And then VOD server transmits requested streams with a multicast group address and the client joins the group automatically. The Multicast Agent Scheduler assigns the same multicast group address when other clients request an identical video within the same scheduling duration. The proposed system can reduce load of server and support many clients at the same time and applies it to WMT(window media technology) of Microsoft.