• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.6
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• pp.1052-1059
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• 2016

Video-on-Demand(VoD) is one of the most popular media streaming which attracted many researchers' attention. VMesh is one of the most cited works in the field of the VoD system. VMesh is proposed to solve the problem of random seeking functionality. However, a large number of the DHT(Distributed Hash Table) searches in VMesh is sill the main problem which needs to be solved. In order to reduce the number of the DHT searches, the clustered segment index(CSI) scheme is proposed. In this scheme, the video segments are divided into clusters. The segment information of the video segments, which are clustered into the same cluster, are stored in the same clustered segment index that can be searched by using the hash key. Each peer also can request the required segments by using this clustered segment index. The experiment results show that the number of the DHT searches in the proposed scheme is less than that of VMesh even in case of peers leave and join the network or peers perform the fast forward/backward operations.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.10
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• pp.87-96
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• 2004

These days, it is essential that a business-class hotel provide customers with Internet service. So the most hotels have been installing facilities actively for Internet service. Businessmen also want to use Internet service level to their own office or home in hotel room. But now TV and VoD(partial) based-on CATV in hotel is supplied, and the additional network are installed for Internet service. The existing TV also must be replaced to HDTV within 2 or 3 years. The objective of this paper is to implement the next generation hotel multimedia service system using xDSL technology, VLAN mapping technology, and QoS technology. This system can provide each room in hotel with high-quality video service and Internet service simultaneously, and can also supply Internet access service using wireless LAN for the Places, such as lobby, conference room, and coffee shop in hotel. Therefore, this system can create the new market in hotel multimedia service field by connecting xDSL technology to VLAN mapping technology for charging and QoS technology for video stream transmission.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.4
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• pp.333-341
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• 2013

In this paper, a feedback linearization control is proposed to regulate the output voltages of a three-phase four-wire inverter under the unbalanced and nonlinear load conditions. First, the nonlinear model of system including the output LC filters is derived in the d-q-0 synchronous reference frame. Then, the system is linearized by the multi-input multi-output feedback linearization. The tracking controllers for d-q-0-components of three-phase line-to-neutral load voltages are designed by linear control theory. The experimental results have shown that the proposed control method gives the good performance in response to the load conditions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.7
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• pp.879-884
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• 2020

In the conventional video file system, videos are stored in a high performance server which has mass storage hard disks or disk arrays. For 3D internet broadcasting, real time operations are required to transmit video files to many clients. This paper describes the design of the 3D internet broadcasting system which can provide realtime streaming service to many users in the 5G environment. In reality, unicast is used to transmit multimedia contents over the internet rather than IP multicast since IP multicast has its own drawbacks in deployment, security, maintenance and so on. In addition, multimedia broadcasting service system like VoD has difficulties in applying to 3D internet broadcasting system since it requires a large amount of system and network resources. In this work, we develop a 3D internet broadcasting system which can construct effective data delivery by minimizing performance-degrading factors.

• Journal of the Optical Society of Korea
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• v.11 no.3
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• pp.101-107
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• 2007

In this paper, we have presented the results of Wavelength Division Multiplexing-Passive Optical Network (WDM-PON) based fiber-to-the-home (FTTH) field trial test which was held in the city of Gwangju. We have implemented an injection locked Fabry-Perot Laser Diode (FP-LD) based WDM-PON system and reliably delivered Internet Protocol TV (IP-TV), networked Personal Video Recorder (N-PVR), High-Definition Video on Demand (HD-VoD), Education on Demand (EoD) and Internet service as FTTH service through the system during the field trial test. We have also verified that the WDM-PON system worked well to provide quality of service (QoS) guaranteed 100Mbps bandwidth per subscriber. Furthermore, we have presented network designing issues in Outside Plant (OSP) and Customer Premises Network (CPN) that should be overcome to efficiently deploy FTTH service. Finally, based on the field trial test results, we proposed FTTH service deployment strategies.

• International Journal of Contents
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• v.9 no.1
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• pp.18-25
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• 2013

Recently, augmented reality has been proved immensely useful on a day to day basis when tied with location-based technology. In this paper, we present a new method for displaying augmented reality contents on mobile devices. We add 3D models on the view of the camera and use location-based services, motion sensors to calculate the transformation of models. Instead of remaining at a fixed position on camera view while moving around a 3D model, the model rotates on display in the opposite direction that the user is walking. We also design client as a ubiquitous client to reduce constraints on disk space and memory capacity on mobile devices. Implementation results show effective use in creating GPS-based 3D view augmented reality contents for Smart Mobile Devices.

• The Transactions of the Korea Information Processing Society
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• v.5 no.8
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• pp.1960-1971
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• 1998

The researches and developments to provide multimedia communication services such as Video on Demand(VoDJ), real time video phonc and multipoint vidco conferencing on broadband ISDN environmcnts have been proceeded with activity. Specifications for Vol) services which is worked by Digital Audio-Visual Council(DAVIC) to support detail technologies including total service system that is consist of VoD server. delive[\! networl, and Set-Top Box(STB) had been already finished and ITU-T SG16 also recommended the standards of H.300 series terminal aspects for conversational multimedia services, But the architectures of multimedia tenninals recommended and specified by these organizations do not have an efficient st11lcture to provide all of retrieval, distrihution and conversational service due to a different point of view about multimedia terminals and services. In this paper, we analyzed the recornmendatio!E and the specifications of intemational public and private organizations like lTU-T, DAVIC and ATM forum. As a result of these analysis. we propose an efficient terminal architecture, and then we have designed, lmplemented the multimedia communication terminal for offering VoI) and real- time conversation ,,, functional module test according to the individual commumication service session and confirined the validiry or terminal implemented to be used on broadband ISDK environments.

• Journal of Broadcast Engineering
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• v.14 no.5
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• pp.625-637
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• 2009

With advent of TV environment and increasing of variety of program contents, users are able to experience more various and complex environment for watching TV contents. According to the change of content watching environment, users have to make more efforts to choose his/her interested TV program contents or TV channels than before. Also, the users usually watch the TV program contents with their own regular way. So, in this paper, we suggests personalized TV program schedule recommendation system based on the analyzing users' TV watching history data. And we extract the users' watched program patterns using the sequential pattern mining method. Also, we proposed a new sequential pattern mining which is suitable for TV watching environment and verify our proposed method have better performance than existing sequential pattern mining method in our application area. In the future, we will consider a VoD characteristic for extending to IPTV program schedule recommendation system.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.739-741
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• 2001

변화하는 네트웍환경에서, VoD서비스를 제공하는 방법에 대해서 맡은 연구가 이루어지고 있다. 이들 중에서 스트림 데이터의 특성을 이용하여 데이터를 제공하는 방법에 대해 활발한 연구가 진행중이다. 그러나, 이 연구들은 전송에만 초점을 많이 맞추고 있다. 따라서, 본 연구는 이러한 스트링의 저장 방법에 대해서 연구한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.11a
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• pp.102-104
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• 2013

본 논문에서는 사용자가 뉴스나 스포츠 중계 등의 라이브 방송을 제외한 녹화방송 프로그램 및 VoD콘텐츠를 시청하는 중에 화면 상의 상품에 대한 관심이 유발되었을 때, 객체의 좌표정보를 통해 사용자의 입력을 받아 객체의 부가정보를 실시간 검색하고 부가정보 데이터를 생성하는 방법을 통해 사용자에게 해당 객체의 부가 정보를 제공하는 방법을 제안한다.