• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.6
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• pp.175-185
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• 2009

In this paper, performance of OFDM systems with turbo code is analyzed and simulated in a satellite broadcasting channel. The performance is evaluated in terms of bit error probability. The satellite channel is modeled as a combination of Rayleigh fading with shadowing and Rician fading channels. As turbo decoding algorithms, MAP (maximum a posteriori), Max-Log-MAP, and SOVA (soft decision Viterbi output) algorithms are chosen and their performances are compared. From simulation results, it is demonstrated that Max-Log-MAP algorithm is promising in terms of performance and complexity. It is shown that performance is substantially improved by increasing the number of iterations and interleaver length of a turbo encoder. The results in this paper can be applied to OFDM-based satellite broadcasting systems.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2014.06a
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• pp.1-2
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• 2014

본 논문에서는 hidden Markov model (HMM) 기반의 스테레오 신호로부터 서라운드 오디오 신호를 생성하는 기법을 제안한다. 먼저 5.1 채널 오디오 훈련 데이터베이스로부터 MDCT 영역에서 전방/서라운드 채널의 서브밴드 에너지를 프레임 단위로 계산하고, 이를 특징 벡터로 하여 좌측과 우측 채널 두 개의 HMM 이 구성된다. 다음으로, 입력된 스테레오 신호에 대해 HMM decoding 을 통해 서라운드 채널의 MDCT 영역의 서브밴드 에너지가 예측된다. 이 예측된 서브밴드 에너지로부터 역 MDCT 를 통해 서라운드 오디오 신호가 생성된다. 제안된 방법의 성능평가를 위해 MUSHRA 청취 실험을 수행한 결과, 제안된 HMM 기반의 방식으로 생성된 서라운드 오디오 신호가 기존의 패시브 서라운드 디코딩 기반으로 생성된 서라운드 신호에 비해 높은 선호도를 보였다.

• Journal of Advanced Navigation Technology
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• v.13 no.5
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• pp.726-735
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• 2009

In this paper, we proposed a novel conditional access system to reduce the overhead transmission rate for messages which verify the entitlement of subscribers in bandwidth-limited system. We adapted a key update system with the tree structure which had been used for IP multicast to a group hierarchy for the subscriber groups or channel groups. We also analyzed the overhead transmission rate for periodic key update and aperiodic one for change in a subscriber. The numerical evaluations show that the proposed system can significantly reduce the overhead transmission rate for dynamic subscriber change up to several hundred thousands times for various system configuration.

• Journal of Broadcast Engineering
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• v.21 no.2
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• pp.210-218
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• 2016

In this study VOD usage patterns(VOD use and paid amount) of IPTV users were investigated reflecting the level of media use characteristics such as TV viewing time, star preference, and genre preference. Also the impact of media using characteristics and the evaluation of guide channel on the intention to use VOD was analyzed. The web survey was conducted against the respondents who have used VOD and guide channel. The results are as follows. Among the media usage characteristics, star preference has the impact on the VOD use, while genre preference has relation to the willingness to pay for VOD. Secondly, the intention to view the guide channel, entertainment of the channel, and the users' genre preference have significant impacts on the intention to use VOD. Therefore, it is necessary to raise the viewing rate of guide channel by providing the customized promotion strategy and diverse events based on the analysis of VOD usage.

• Journal of Broadcast Engineering
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• v.10 no.3
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• pp.401-412
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• 2005

We propose and design the algorithms of symbol timing recovery, carrier recovery, and equalization for the receiver of S-DMT cable modem, which supports more channels and better symmetric mutimedia services over HFC network. We evaluate the performance of the concatenated entire receiving system of 16QAM, 64QAM in the mixed noise channel of AWGN, ISI and impulse. The result of evaluation shows those algorithms work correctly and designed S-DMT receiver has good performance. We also verify the designed system has excellent immunity against impulse noise channel of practical Cable TV networks by the result of simulation with the parameters of impulse internal $\varepsilon$ and noise power $\gamma^{k}$.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.9
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• pp.1063-1070
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• 2014

Currently, The terrestrial MMS(Multi Mode Service) is considering to be adapted in the Korea. The objective and subjective video quality test was carried out to verify the current TV channel's video quality degradation by the MMS. In the objective assessment, MMS system showed better PSNR than current system. In the subjective assesment result, It's hard to find the perceive video quality degradation at overall assesment. Even though, The MMS's video quality will be improved at the documentary and entertainment genre. Comparing with the previous research at 2006 and 2008, It's the time to give the benefit of broadcasting technology to the people.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.77-85
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• 2015

This paper presents our performance evaluation after the way of minimizing waiting times between channel switching for eMBMS(evolved Multimedia Broadcast/Multicast Services) technique in LTE-Advanced systems. Existing composition of MBMS using IGMP(Internet Group Management Protocol) transfers the data with Multicast from BM-SC(Broadcast Multicast Service Center) to eNB(evolevd Node B) and with Broadcast from eNB to UE(User Equipment). Therefore, in case of channel switching, IGMP Join report should be transferred to BM-SC and then wait user's contents to be retransferred from eNB. To achieve this, Subscriber Channel technique of priorities is used for minimizing waiting times between channel switching as UE broadcasts favorite channels in advance.

• The Journal of the Korea Contents Association
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• v.8 no.3
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• pp.75-85
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• 2008

Since the first interactive broadcasting of Skylife had been launched in S. Korean it has passed over 4 years. Subsequently the new digital broadcasting platforms, such as DMB, Mobile-TV, IPTV and so forth, are appearing between the keen rivalries. At the centre of diagram for new digital platforms there is positioned the interactivity. In order to cope with the limitation of contents on television, even Korean terrestrials have resolutely carried out interactive broadcasting as of 8th of June, 2006. Although the flamed competition of digital environment there are lacking in the public understanding and interests for interactive programmes on digital television. We can be analysed that it is difficult to acquire the viewer's satisfaction for guessability in spite of our governmental efforts. Here it presents the problematic results obtained by analysing both quantitative and qualitative data from the usability test for the current interactive programme in centre of the viewer.

• The Journal of the Convergence on Culture Technology
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• v.7 no.3
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• pp.537-543
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• 2021

Under the Chapter 1, Article 3(Protection of Rights and Interests of Viewers) of the Broadcasting Act, the viewers should be able to participate in decision-making with regard to planning, programming, or production of broadcast programs. For this, the public service broadcasting, KBS is operating two kinds of system such as 'viewer-evaluation program' and 'viewer-participation program' that televises the broadcasting programs directly produced by viewers. This study presented several improvement measures by analyzing the contents of viewer-participation programs televised through the of KBS, so KBS could work as an open public platform in which the people could freely express their own thinking, ideology, opinions, and ideas.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2014.06a
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• pp.53-54
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• 2014

본 논문에서는 멀티채널 오디오 재생시스템을 구성하는 라우드스피커들이 표준위치와 상이한 위치에 존재할 경우 입력된 멀티채널 오디오 신호가 표현하는 음장감을 최대한 유지하면서 주어진 라우드스피커 배치환경에 최적으로 가상음원과 멀티채널 오디오 신호를 재생하는 방법을 제안한다. 능동잡음제어 기술에 이용되는 LSM 기술을 활용하여 원음장과 스피커를 통해 재생되는 복원음장 사이의 오차를 최소화하는 음향공간필터를 설계하여 적용하였으며, 청취평가를 통하여 음장감이 유지됨을 확인하였다.