• Journal of Navigation and Port Research
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• v.28 no.10 s.96
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• pp.869-874
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• 2004

Digital TV broadcasting's resolution or tone quality is very excellent than analog broadcasting and has many advantages including various multimedia functions such as home shopping, home banking, internet search, telecommuting, VOD, etc. In this study, it is essential to analyze the regional electromagnetic environment before Digital TV broadcasting, and therefore we analyzed Busan area's limitation using ETRI propagation model. For maintaining high-quality Digital TV signals, we measure electric field intensity wide and far in Busan including mountains area and high-rise buildings. Generally, it has lower value by a standard ETRI propagation model than simulated value about standard model, but distribution pattern are similar with it. Compared theoretical values with the measured results, they have similar values for flat area but very different values for crowded city area and mountains area So we conclude that ETRI propagation model and theoretical model are not suitable for Busan in a free space.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.603-612
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• 2010

Recently, with the advance of computing and networking technique, the high speed internet becomes widespread, however, it is still hard job to do streaming the media which requires high network bandwidth over the internet. Previous VoD system researches for streaming over the internet mainly proposed techniques that controls the QoS(Quality of Service) of the media in proportion to the network status. Though, this could be the solution for the service provider while the service user who wants constant QoS may not satisfy with variable QoS. In the paper, we propose greedy precedent frame transmission technique, GPFT, for guarantee of constant QoS. In GPFT, Streaming VoD server prefetches precedent frames and transmits the frame greedily by increasing the frame transmission rate while the available network bandwidth is high. The GPFT uses the prefetched precedent frames to guarantee the QoS while the available network bandwidth is low. The experiment result shows that the proposed GPFT could guarantee the constant QoS by prefetching the frames adaptively to the network bandwidth with the characteristic of video stream.

• Journal of Broadcast Engineering
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• v.16 no.1
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• pp.23-32
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• 2011

Design and Implementation of Clipcast Service via Terrestrial DMB This paper outlines the system design and the implementation process of clipcast service that can send clips of video, mp3, text, images, etc. to terrestrial DMB terminals. To provide clipcast service in terrestrial DMB, a separate data channel needs to be allocated and this requires changes in the existing bandwidth allocation. Clipcast contents can be sent after midnight at around 3 to 4 AM, when terrestrial DMB viewship is low. If the video service bit rate is lowered to 352 Kbps and the TPEG service band is fully used, then 320 Kbps bit rate can be allocated to clipcast. To enable clipcast service, the terminals' DMB program must be executed, and this can be done through SMS and EPG. Clipcast service applies MOT protocol to transmit multimedia objects, and transmits twice in carousel format for stable transmission of files. Therefore, 72Mbyte data can be transmitted in one hour, which corresponds to about 20 minutes of full motion video service at 500Kbps data rate. When running the clip transmitted through terrestrial DMB data channel, information regarding the length of each clip is received through communication with the CMS(Content Management Server), then error-free files are displayed. The clips can be provided to the users as preview contents of the complete VOD contents. In order to use the complete content, the user needs to access the URL allocated for that specific content and download the content by completing a billing process. This paper suggests the design and implementation of terrestrial DMB system to provide clipcast service, which enables file download services as provided in MediaFLO, DVB-H, and the other mobile broadcasting systems. Unlike the other mobile broadcasting systems, the proposed system applies more reliable SMS method to activate the DMB terminals for highly stable clipcast service. This allows hybrid, i.e, both SMS and EPG activations of terminals for clipcast services.

• The Transactions of the Korea Information Processing Society
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• v.7 no.7
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• pp.2050-2059
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• 2000

In a video-on-Demand(VOD) service, a server has to return to he normal playback quickly at a certain new frame position after interactive operations such as jump or last playback. In this paper, we propose an efficient scheme to write a transmission schedule for a playback restart of a video stream at a new frame position after interactive operations. The proposed scheme is based on convergence characteristics, that is transmission schedules with different playback startup frame position in a video stream meet each other at some frame position. The scheme applies a bandwidth smoothing from a new frame position to a convergence position without considering all remaining frames of a video stream. And then the scheme transmits video dta according to the new schedule from the new frame position to the convergence position, and then transmits the remaining video data according to the reference schedule from the convergence position, and then transmits the remaining video data according to the reference schedule from the convergence position to the last frame position. In this paper, we showed that there existed the convergence position corresponding to nay frame position in a video stream through many experiments based on MPEG-1 bit trace data. With the convergence we reduced the computational overhead of a bandwidth smoothing, which was applied to find a new transmission schedule after interactive operations. Also, storage overhead is greatly reduced by storing pre-calculated schedule information up to the convergence position for each I frame position of a video stream with video data off-line. By saving information on a transmission schedule off-line along with the video data and searching the schedule corresponding to the specified restarting frame position, we expect the possibility of normal playback of a video stream with small tolerable playback startup delay.

• Journal of the Korean Society for information Management
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• v.21 no.4 s.54
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• pp.5-26
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• 2004

A literature analysis for the planning and realization of the multimedia meta database and digital library's integrated information system was carried out to establish the various oceanographic resources in the Oceanographic Information Center, the first in Korea. The study targeted from printed matter, network resources, full-text and to VOD. The focus of the analysis lies in the providing practical integrated information retrieval service for oceanographic resources based on the framework of effective MODS metadata with network resources description. The analyses included oceanographic resources, multimedia information processing, MODS metadata descriptive elements, metadata classification, system organization, and retrieval for planning and implementation of the multimedia meta database system.

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.175-178
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• 2006

1990 년대부터 본격적으로 시작된 국내 휴대폰의 역사는 불과 10 년 사이에 전체 인구 중 3600 만명 이상의 가입자가 휴대폰을 사용하고 있는 모바일 강국으로 발전하였다. 국내 이동통신사들의 다양한 서비스 전략과 단말 제조사들의 다양한 기술의 발전으로 휴대폰은 단순한 전화기능만을 담당하는 커뮤니케이션 디바이스(Communication Device)에서 다양한 VOD, AOD 서비스들의 도입으로 엔터테인먼트 디바이스(Entertainment Device)로 발전했고, DMB, TV, MP3, 카메라 등 다양한 디바이스들이 결합된 컨버전스 기능성 기기(Functional Device)로 발전해 가고 있다. 이런 과정에서 사용자들은 휴대폰에서 다양한 경험을 하게 된다. 본 연구는 다양한 매체와 디바이스가 결합 된 모바일 환경 속에서 이동통신사와 제조사의 관점에서 분석한 자료를 바탕으로 하나의 통합된 경험을 사용자들에게 제공할 수 있는 방법을 고찰해 보고자 한다. 휴대폰을 만드는 제조업체가 수행하는 경험 디자인은 이동통신사에 상관없이, 자사의 경험 통일성(identity)을 강조하게 되고, 이동통신사는 제조업체와 상관없이 자사의 경험 통일성을 강조하게 된다. 통일성 뿐만 아니라 기능이나 직무(task)의 중요성도 다르기 때문에 경험 디자인을 위한 우선순위도 다르게 된다. 이것의 결과는 모두 사용자가 떠 앉게 된다. 즉 사용자의 경험이 복잡해지게 되고 이것은 장기적으로 제조업체 및 이동통신사 모두에게 불이익을 주게 된다. 본 논문에서는 제조사와 이통사를 위한 사용자 경험 모형을 세웠고, 각 요소별로 접근 방법의 차이에 대해 논의를 하였다. 사용자가 휴대폰 경험에서 혼돈을 적게 하기 위해서는 제조사와 이통사의 인터랙션은 서로 일관성이 있어야 하고, 스타일 부문에서는 서로간의 입장차이가 좁히기 쉽지 않으므로 둘 다 사용자의 선택의 폭을 넓혀주는 방향으로 진행을 한다. 기획단계에서 부터 협력을 함으로써 양사의 갭을 줄일 수 있다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.6
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• pp.1581-1589
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• 1999

In B-ISDN(Broadband Integrated Services Digital Networks), the efficient implementation of multicast function is very important since the demand for distributed type of service such as VOD(Video On Demand) system is expected to grow. In this paper, the multicast performance characteristics of fully-interconnected switch fabric used for our research is the proper architecture for a small-sized switch element, and it uses bit addressing method for addressing scheme and thus it is easy to implement multicast function without adding a function block. To incorporate the bursty nature of traffic in ATM networks, we used IBP(Interrupted Bernoulli Process) model as an input traffic model. We presented and analyzed the simulation results in terms of the multicast operation of the switch. Based. on this study, it its analyzed that congestion avoidance may be feasible if we use a proper traffic control scheme by finding an overload point due to multicast.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2B
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• pp.137-145
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• 2006

In this paper, we propose a multicast P2Patching technique in the application layer. The P2Patching technique serves VOD stream effectively with Patching in P2P environment. The P2Patching provides multicast tree construction technique that reduces the server load and minimizes the start delay with extended multicast technique. And we provide a fast recovery technique by tree failure and dynamic buffering scheme that guarantees the continuous streaming by frequent tree disconnections. Comparing the method with that of $P2Cast^{[12]}$, we obtained the better performance by our scheme in terms of average join count, service rejection probability, tree recovery failure and buffer starvation. The average about 16$\%$ of the improvement is shown by the simulation. Most of all, the performance of buffer starvation and average join count shows a significant improvement than that of P2Cast.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.5
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• pp.213-217
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• 2001

Excessive memory buffer requirement in continuous media playback is a serious impediment of wide spread usage of on-line multimedia service. Skewed access frequency of available video files provides an opportunity of re-using the date blocks which has been loaded by one session for later usage. We present novel algorithm which minimizes the buffer requirement in multiple sessions of multimedia playbacks. In continuous media playback originated from the disk, a certain amount of memory buffer is required to synchronize asynchronous disk. Read operation and synchronous playback operation. As aggregate playback bandwodth increases, larger amount of buffer needs to be allocated for this synchronization purpose. The focus of this work is to study the asymptotic behavior of the synchronization buffer requirement and to develop an algorithm coping with this excessive buffer requirement under bandwidth congestioon. We argue that in a large scale continuous media server, it may not be necessary to read the blocks for each session directly from the disk. The beauty of our work lies in the fact that it dynamically adapts to disk utilization of the server and finds the optimal way of servicinh the individual sessions while minimizing the overall buffer space requirement. Optimality of the proposed algorithm is shown by proof. The effectiveness and performance of the proposed scheme is examined via simulation.

• The Journal of the Korea Contents Association
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• v.17 no.2
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• pp.521-534
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• 2017

In 2013 the Netflix, an OTT in USA, launched all at once 13 episodes of the House of Cards season. Binge-watching is the word which means watching continuously 2~6 episodes of a TV program with one sitting, the new normal of TV watching behavior, cultural and social currents all over the world. This study has analyzed the factors and motivations which affect to the persistent intention to use binge-watching. It conducted an online survey from 333 Quota sample from Korean age groups between 20th~60th with 81 questionnaires. The 5 groups were induced as motivation factors to binge-watching. The 3 groups which consisted of , , are affecting as positive to intention to use binge-watching. But the other 2 groups which are and doing as negative. The survey has shown that the persistent intention to binge-watching is affected by ages more younger, whom doing binge watching more frequently, whom estimating more higher to the conceived usefulness to use. As a theoretical model, expanded technology acceptance model was adopted and US drama House of Cards. This study could promote the next generation contents planning and S-VOD service industry.