• Journal of Broadcast Engineering
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• v.18 no.1
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• pp.88-97
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• 2013

Collaborative filtering(CF) for the personalized recommendation is a successful and popular method in recommender systems. But the mainly researched and implemented cases focus on dealing with independent items with explicit feedback by users. For the domain of TV program recommendation in VOD service platform, we need to consider the unique characteristic and constraints of the domain. In this paper, we studied on the way to convert the viewing history of each TV program episodes to the TV program preference by considering the series structure of TV program. The former is implicit for personalized preference, but the latter tells quite explicitly about the persistent preference. Collaborative filtering is done by the unit of series while data gathering and final recommendation is done by the unit of episodes. As a result, we modified CF to make it more suitable for the domain of TV program VOD recommendation. Our experimental study shows that it is more precise in performance, yet more compact in calculation compared to the plain CF approaches. It can be combined with other existing CF techniques as an algorithm module.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.7
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• pp.467-476
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• 2014

Recently, various services which use the fused form of broadcasting and communication are being offered over the Internet globally. To provide various interactive services through connected smart TV on wired or wireless network, the seamless multimedia service is key feature. In this paper, Dynamic Adaptive Streaming over HTTP (DASH)is adopted to develop cost-effective adaptive streaming system for Open Hybrid TV(OHTV) service. This system can provide seamless adaptive streaming service for IP VOD, Video Clips, Ad insertion which are defined in OHTV.

• 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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• 2000.04a
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• pp.199-201
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• 2000

본 논문에서는 클러스터에 기반한 주문형 비디오 (VOD: Video On Demand) 시스템에서의 QoS (Quality of Service) 아키텍처를 제안한다. 제안하는 QoS 아키텍처는 IP 네트웍상에서 사용자에게 다양한 서비스 질의 선택과, 선택한 질의 보장을 제공하며, 클러스트 시스템의 자원관리를 통해 서버의 효율을 극대화 시킨다. 클러스터 VOD 시스템의 QoS 아키텍처는 사용자 요구의 협상을 위한 Weighted Price 함수와 요구분배 기법인 Max-min 함수를 이용하여 사용자에게 제공하는 QoS의 수준을 높여주고, 저장 서버들간의 부하균등을 통해 효율성을 높인다. QoS 아키텍처 내의 핵심 모듈인 QoS Mapper와 QoS Manager의 성능을 확인 하는 실험을 통하여 사용자에게 서비스되는 QoS 수준이 증가하였음을 확인할 수가 있었고, 저장서버들간의 부하를 효과적으로 분산시켜 VOD 시스템의 동시 사용자수를 증가 시키고, 안정적인 서비스를 할 수 있음을 확인하였다.

• Journal of the Korea Computer Industry Society
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• v.3 no.5
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• pp.529-546
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• 2002

A VOD server, which is the central component for constructing VOD systems, requires to provide high bandwidth and continuous real-time delivery. It is also necessary to the sophisticated disk scheduling and data placement schemes in VOD sewers. One of the most common problem facing in such a system is the high initial latency time to service multiple users concurrently. In this paper, we propose a dynamic stream merging scheme for reducing the initial latency time in VOD servers. The proposed scheme allows clients to merge streams on a request as long as their requests fall within the reasonable time interval. The basic idea behind the dynamic stream merging is to merge multiple streams into one by increasing the frame rate of each stream. In the performance study, the proposed scheme can reduce the initial latency time under the minimum buffer use and also can enhance the performance of the VOD server with respect to the capacity of user admission.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.6
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• pp.435-447
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• 2004

For VOD systems, it is important to provide QoS to more users under the limited resources. To analyze QoS issues in real environment, we implement clustered VOD server and embedded client system based on the Linux open source platform. The parallel processing of MPEG data, load balancing for nodes and VCR like functions are implemented in the server side. To provide more user friendly interface, the general TV is used for a VOD client's terminal and the embedded board is used supporting for VCR functions. In this paper, we measure the performance of the implemented VOD system under the various user requirement features and evaluate the sources of performance limitations. From these analyses, we propose the dynamic admission control method based on the availability memory and network bandwidth. The proposed method enhances the utilization of the system resource for the more QoS media streams.

• Proceedings of the Korea Multimedia Society Conference
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• 2000.04a
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• pp.269-272
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• 2000

컴퓨터와 인터넷 기술의 비약적인 발전으로 인해 인터넷 상에서의 실시간 (real time) 멀티미디어 데이터서비스가 가능해짐에 따라 생겨난 주문형 미디오 (Video On Demand ; VOD) 서비스는 현재 양질의 비디오화면을 실시간으로 서비스하기위한 서비스의 연구에만 집중되어 있을뿐 정작 사용자를 위한 서비스형태에 대한 개발은 전혀 이루어지지않고 있다. 따라서 사용자의 다양한 요구 및 최신의 컴퓨터기술을 충분히 활용한 새로운 On-Demand 서비스 체계로의 변호가 시급히 요구됨에 따라, 본 논문에서는 VOD 서비스를 위해 사용자 측면에서의 보다 적극적인 정보서비스를 위한 AVOD(Active -VOD) 서비스 시스템을 설계하고 구현하였다.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05c
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• pp.377-380
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• 2002

인터넷 기반의 VOD(Video On Demand) 서비스 시스템이 사용자에게 QoS (Quality of Service)를 보장하기 위한 방법으로 네트워크 흐름제어 기능을 갖춘 브로커를 개발하고자 한다. 네트워크 상태에 따라 흐름제어를 하는 브로커는 멀티-레이어 데이터를 이용하여 VOD 서비스를 제공한다. 이로써 사용자는 최소한의 버퍼와 버퍼 교환 알고리즘에 따른 복잡도를 줄일 수 있다는 장점을 가진다. 본 논문에서는 네트워크 상태를 파악하여 VOD 서비스를 제공할 수 있는 브로커를 설계하고 구현 결과에 대해 기술하겠다.

• Journal of Advanced Navigation Technology
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• v.16 no.3
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• pp.504-509
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• 2012

Multiple CAS (Conditional Access System) could be safely downloaded and implemented in IPTV environment. Domestic standard of iCAS (Interchangeable CAS) which is providing device compatibility and mobility, can only defines CAS replacement for protecting Real-Time Streaming broadcast. CAS, however has limitations in IPTV's two-way communication environment where it needs to fulfill contents protection requirements of various broadcasting service. In order to supplement the limit of CAS, DRM protection technology should be required. Contents for real time broadcasting service or real time VOD service could be protected by CAS technology whereas services such as PVR, download VOD service or downloaded contents sharing could be protected by DRM technology. Therefore, a flexible IPTV device service environment could be constructed by mutual protection of CAS and DRM. This essay is going to research on the method of applying DRM based on iCAS standard, as well as proposing a system configuration applied with iCAS/DRM in commercialization.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.207-210
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• 1998

Providing the connectivity interworking between the lightweight signaling function using in VOD set-top box and the broadband signaling function In the access node system, it can diminish the cost-burden of user about set-top box and we shall use efficiently the network resources. Therefore, In this paper, we shall design the signaling brokerage agent function for the connectivityinterworking in access node system and discuss the result applied its function to the real-time VOD service.