• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.1843-1846
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• 2003

In MPEG-21 Multimedia Framework, Digital Item (DI) is the minimum unit fur processing and delivering the multimedia contents. So how to process, manipulate and represent DI is a very important problem in the standpoint of interoperability for each terminal and provide., and Digital Item Processing (DIP) regarding this issue. This paper suggests technologies which are concerning how DIP should interact with other parts of MPEG-21 (Digital Item Adaptation (DIA), Intellectual Property Management and Protection (IPMP), etc.). For this concept, this paper uses the video summary contents which can describe the hierarchical structures of original multimedia contents. In MPEG-21 environment, the usage of this summary video is very useful delivery and consumption way in view of network burden, efficient accessing to contents.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8A
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• pp.879-888
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• 2004

In this paper, we propose a real time QoS(Quality of Service) guaranteed transmission mechanism for MPEG video traffic at the congested node in IP based networks. Recent spread of the Internet has increased the demands of a real time multimedia service of the quality, Because the type of Internet services can, however, offer the best effort delivery strategies, it is difficult to treat all the types of traffic with differential COS (Class of Service). Most of all, the hierarchical coding method of MPEG data utilizes the reference frame for the motion prediction. The loss of the reference frames makes QoS of the video traffic degraded because the reference frame bit error causes the consecutive packet loss. Therefore we have studied the real time QoS guaranteed mechanism for video traffic by analyzing the previous methods. Computer simulation results show that the proposed scheme has better performance than the previous one.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.113-116
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• 2007

T-DMB (Terrestrial-DMB) service is now available in the metropolitan area, but due to the bandwidth limitation, it is allowed to provide up to CIF resolution. As users' requests for high-quality mobile multimedia services are rapidly increasing and additional bandwidth can be provided by adopting the hierarchical modulation transmission technology, the research on the Advanced Terrestrial-DMB(AT-DMB) service using the SVC(Scalable Video Coding) scheme is being actively studied. In this paper, through computer simulations, first, while keeping the current T-DMB service unchanged, the visual qualities of AT-DMB services are investigated by varying the additional bandwidth. Then, by considering the cases that the overall bandwidth can be allowed to dynamically allocate to the T-DMB/AT-DMB video services, the performance characteristics between two layers are compared over the different kinds of video sequences.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.1
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• pp.10-17
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• 2007

Hierarchical modulation technology which can make the advanced T-DMB(terrestrial-digital multimedia broadcasting) system backward compatible with the conventional T-DMB system and provide high-rate and high-quality services is introduced in this paper. As additional data streams are embedded within the conventional data streams by the hierarchical modulation, the advanced T-DMB system can provide high-quality video service and more broadcasting service channels. In order to guarantee the quality of both the conventional and additional services powerful error correcting scheme is required. The error performance of advanced T-DMB system with hierarchical modulation is investigated and analyzed according to the various error correcting schemes in this paper.

• Journal of Broadcast Engineering
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• v.15 no.6
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• pp.868-875
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• 2010

AT-DMB was developed to raise the transmission rate of existing T-DMB with backward compatability. The transmission and hierarchical video service technique were legislated as Korean TTA standards, and other application service techniques including data services are being developed for the commercial service. In this paper, we consider the power of transmission power level of signals in Advanced Terrestrial Digital Multimedia System according to the constellation ratio. And we propose a new scheme for normalization of transmission signal power level in AT-DMB system. Adopting this scheme, the signal power level of hierarchical modulated signal can be uniform in AT-DMB system both for B Mode and Q Mode.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.86-88
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• 2008

지상파 방송(DMB: Digital Multimedia Broadcasting)은 음성, 영상, 데이터와 같은 다양한 멀티미디어 신호를 디지털 방식으로 변조하여 이동 중에 방송을 청취 할 수 있는 차세대 디지털방송 서비스이다. 하지만 한정된 대역폭으로 인한 비디오 전송율의 한계에 따라 최대 CIF(Common Interleaved Frame)급 화면해상도까지 서비스가 가능하다. 그러나 지상파 DMB 전송 고도화망에서는 계층 변조(Hierarchical Modulation)전송 기법을 통하여 추가의 전송대역폭을 확보할 수 있다. 또한 스케일러블 비디오 코딩(Scalable Video Coding)부호화 방식을 이용하여 고전송효율/고품질의 이동 멀티미디어 방송서비스를 제공할 수 있는 고품질 AT(Advanced Terrestrial)-DMB 시스템이 가능하다. 이러한 고품질 AT-DMB의 개발에 있어서 여러 방식들이 제시됨에 따라 시뮬레이터를 통한 다중화 시스템의 분석이 필요하다. 본 논문에서는 고품질 AT-DMB가 가능한 스케일러블 비디오 방식을 JM8.8을 사용하여 구현하였으며, 다중화 시스템의 실험을 하였다. 또한 시뮬레이터를 통하여 확보된 계층 간의 화질 차이와 엔지니어를 위해 비트스트림의 분석화면 및 PSNR을 제공 하였다.

• Journal of Satellite, Information and Communications
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• v.9 no.4
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• pp.38-41
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• 2014

Due to the diversity of device performances and the possibility of providing multimedia service through many networks, media consumption environment has been changed in various ways. In recent, mobile services and broadcasting services started to provided through IP network. According to this flow changes, there was great demand for various multimedia services through heterogenous networks. To solve this problem, MMT was suggested as a standard of multimedia transport which replaces MPEG-2 TS(Transport Stream) which is used for HD(High Definition) transport. MMT can be provided various broadcasting based on IP through terrestrial, satellite, cable broadcasting networks, and also deliver multimedia through many networks at the same time. MMT was risen as a method of servicing UHD broadcasting. In this paper, we present an implementation of service architecture for hierarchical UHD broadcasting over heterogenous networks using MMT.

• The Journal of the Korea Contents Association
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• v.18 no.12
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• pp.660-675
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• 2018

This study is designed to investigate how the perceived characteristics of the online video services affect the 'flow' as positive experience and satisfaction of users. For the study, we conducted a questionnaire survey on 289 people using YouTube, and then analyzed the relationships among variables using hierarchical regression analysis. As a result, it was confirmed that interactivity, newness of recommendation service, diversity of content, and entertainingness of contents all affect the lower level of flow experience. On the other hand, the accuracy of the recommendation service did not affect the flow experience, but positively affects the level of satisfaction. Finally, it is also confirmed that flow has a direct effect on user satisfaction, and mediates relationship between the characteristics of YouTube and satisfaction. The results of this study are helpful to understand user's perception and experience of online video platform service and suggest the discussion points to be considered by the industry to satisfy users.

• Journal of Broadcast Engineering
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• v.14 no.4
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• pp.509-517
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• 2009

This paper introduces an Advanced Terrestrial DMB (AT-DMB) system which provides higher efficiency of transmission and better quality of service than conventional T-DMB system. In AT-DMB, a hierarchical modulation method is applied to transmit more data while maintaining backward compatibility to conventional T-DMB receivers. This method can provide not only high quality video service but also lots of broadcasting channels. In this paper, the performance of the hierarchical modulation in AT-DMB system is analyzed with computer simulation in several environments compared with the performance of T-DMB system.

• Journal of Satellite, Information and Communications
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• v.2 no.2
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• pp.59-63
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• 2007

In this paper, we propose an advanced Ka-band satellite HD broadcasting system using scalable video coding technology. As already known, it is not so easy to achieve reasonable link availability on Ka-band because of the rain-attenuation effect, and in case of HD broadcasting service it's more difficult. To overcome that problem, we propose an hierarchical broadcasting system based on H.264 SVC technology. In this paper, we suggest a few types of system scenario to realize the concept. Those scenarios are including DVB-S and DVB-S2 and spatially scalable video stream is the source stream in all cases.