• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1997년도 Proceedings International Workshop on New Video Media Technology
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• pp.43-48
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• 1997

The video transmission for real-time viewing over the Internet is a core operation for the multimedia services. However, its realization is very difficult because the Internet has two major problems, namely, very narrow endpoint-bandwidth and the network jitter. We already proposed a scalable video transmission method in [8] which used MPEG-4 video VM(Verification Model) 2.0[3] for very low bit rate coding and an adaptive temporal rate control of video objects to overcome the network jitter problem. In this paper, we present the improved adaptive temporal rate control scheme for the scalable transmission. Experimental results for three test video sequences show that the adaptive temporal rate control can transfer the video bitstream at source frame rate under variable network condition.

• 인터넷정보학회논문지
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• 제5권6호
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• pp.59-66
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• 2004

본 논문에서는 MPEG 비디오 데이터를 GoP 단위로 분할하여 장면전환 특성을 파악하고 그에 따라 칼만필터를 사용하여 비디오 데이터의 전송량을 예측하는 방법을 제안하고자 한다. 비디오 데이터의 정확한 장면전환을 파악하기 위해서 압축 도메인에서 고속으로 장면에 대한 정보를 검출하는 알고리즘을 사용하여 급진적 장면전환 유형과 점진적 장면전환 유형으로 분류하였다. 분류된 정보는 칼만필터의 세부 인자로 사용되어 비디오 데이터의 전송량을 예측한다. 본 논문에서 제안한 방법은 압축 도메인에서 장면전환 탐지와 비디오 데이터의 전송량을 예측하여 처리 시간을 감소시키고자 하였다. 세 종류의 서로 다른 비디오 데이터 911개의 1프레임을 사용한 실험에서 96.2- 97.6%로 전송량을 예측하였다.

• 한국정보처리학회논문지
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• 제7권7호
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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.

• 정보처리학회논문지A
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• 제12A권3호
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• pp.197-204
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• 2005

본 논문에서는 인터넷 상의 분산 비디오 스트리밍 서비스에서 저장된 가변 비트율 비디오의 전송에 대해 고려한다. 스트리밍 서비스에서 전송 중에 대역폭 재조정 프로토콜에 따라 대역폭 할당이 줄게 되면 흔히 재생의 끊김 현상이 발생한다. 본 논문에서는 이러한 문제점을 극복할 수 있는 가변 비트율 비디오에 대한 전송 기법을 제안한다. 이 기법에서는 저장된 가변 비트율 비디오에 대한 사전 정보를 사용하여 재생이 끊김없이 이루어질 수 있도록 전송한다. 또한 제안된 전송 기법 하에서의 수용 제어를 위해 버퍼-대역폭 관계를 근사적으로 계산할 수 있는 기법을 제안한다.

• 한국통신학회논문지
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• 제21권9호
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• pp.2328-2340
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• 1996

Until now, the transmission of data for VOD(Video on Demenad) was based on a real time modelling of video data. Markow Modulated Fluid Sources(MMFS) and Markow Modulated Poisson Sources(MMPS) are the most widely used modelling methods. But the charactersitics of the VBR(Variable Bit Rate) signal prevents modelling from actually being "real-time". Also these methods call for the use of large buffers for the abolishment of cell loss. These modelling methods are, of course, useful i case of teleconferences where a real time modelling of video traffic is inevitable, but they are insufficient in cases where the characteristic infomation of video traffic can be obtained beforehand-cases such as VOD. Video data is speial in that if one file is preprocessed all other products can simply be copied from that onepreprocessed file. This characteristic helps reduce the overhead arising from the job of drawing out characteristic information to almost zero. But still, compared to the existing real time modelling method data transmission using characteristic information succeeds in raising the efficiency of data transmission. In tis paper we will outline a method of dta transmission which use the characteristic information of each video stream, and evaluate this method through some experiments.periments.

• Journal of Communications and Networks
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• 제12권3호
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• pp.209-215
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• 2010

In an asymmetrical speed channel environment like asymmetric digital subscriber line, the up-link bandwidth is normally smaller than the down-link bandwidth, which will lead to extremely low utilization of down-link bandwidth when current P2P video transmission is applied. To overcome this, a new fast P2P video transmission method applied in an asymmetrical speed channel environment is proposed in this paper. On the basis of the many-to-one concept, the proposed method uses a new multipeer aggregation technique to enhance the utilization of down-link bandwidth. In addition, an adaptive peer assignment algorithm is also introduced in order to minimize the overall transmission time. Experimental results show that by using our proposed method, the utilization of down-link bandwidth is significantly improved, and the overall transmission time is greatly reduced.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1247-1252
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• 2004

A objective quality assessment for the evaluation performance of a video transmission system as a basic step for construction of digital video transmission system between the spots and headquarter. Due to a limit of an analog video transmission system and the developments of various digital media and digital video standards, the need of introduce of a digital system are increased gradual1y, At this points. previously performance evaluations are performed and the quality assessment is the most important thing. We can be divided quality assessment method by the subjective quality assessment and objective quality assessment. The subjective quality assessment method has some problems which are required high cost and much time to evaluate the quality, And because existing objective quality assessment method such that PSNR are based on an analog form, the correlation with subjective data is very low. Therefore we design a new objective quality assessment method using Gabor wavelet transform reflecting HVS(Human Visual System), Designed objective quality assessment method is superior to other objective method such that PSNR or EPSNR In this paper, we proposed objective quality assessment using Gabor wavelet can be used for performance evaluation and verification of video transmission system.

• 컴퓨터교육학회논문지
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• 제14권6호
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• pp.83-89
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• 2011

이 연구에서는 스마트 HDMI 스위치를 제안하는데, HDMI 플러그를 물리적으로 빼고 다시 껴는 일이 없는 상태에서 새로이 형성되는 비디오 스트림을 감지해서 자동적으로 전송 경로를 해당 포트로 전환해 주는 것이 주된 내용이다. 더 나아가 제안하는 시스템은 밀리미터 밴드 기술을 기반으로 진보된 무선 비디오 전송 구조 안에서 설계되었다. 하드웨어 실험을 통해서 제안된 시스템이 스마트 포트 전환 기능을 포함하는 가운데 풀 HD 비디오 전송 성능을 갖는 것을 보임으로써 그 유용성을 확인하였다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 추계학술대회
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• pp.1125-1126
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• 2015

네트워크 기반의 원격지휘통제를 구현하기 위하여 해상 전술영상 및 음성의 전송을 사용 중에 있으나, 전술팀과 기지국의 거리와 해상상태는 데이터 신호의 전달을 어렵게 만든다. 이에 따라 해상전술 영상 및 음성 전송에 대한 이해를 바탕으로 제한사항을 식별하고, 전송률을 높이기 위한 효율적인 방안을 제시한다.

• 디지털산업정보학회논문지
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• 제18권4호
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• pp.13-21
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• 2022

Recently, in wireless video sensor networks(WVSN), various schemes for efficient video data transmission have been studied. In this paper, a layer based cooperative relaying(LCR) algorithm is proposed for minimizing scalable video transmission distortion from packet loss in WVSN. The proposed LCR algorithm consists of two modules. In the first step, a parameter based error propagation metric is proposed to predict the effect of each scalable layer on video quality degradation at low complexity. In the second step, a layer-based cooperative relay algorithm is proposed to minimize distortion due to packet loss using the proposed error propagation metric and channel information of the video sensor node and relay node. In the experiment, the proposed algorithm showed that the improvement of peak signal-to-noise ratio (PSNR) in various channel environments, compared to the previous algorithm(Energy based Cooperative Relaying, ECR) without considering the metric of error propagation.The proposed LCR algorithm minimizes video quality degradation from packet loss using both the channel information of relaying node and the amount of layer based error propagation in scalable video.