• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.114-117
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• 2017

Scalable Video Coding(SVC)은 효율적인 스트리밍을 제공하기 위해 제안된 비디오 코딩 방식으로 비디오 파일을 계층적으로 구분을 하여 기초 계층에 향상 계층을 추가하여 비디오의 해상도, 프레임 재생율 그리고 화질을 개선시킬 수 있다. 현재 Software Defined Networing(SDN) 환경에서 SVC를 이용한 다양한 라우팅 기법 연구가 진행되고 있다. 본 논문은 SDN 환경에서 네트워크 상태에 따라 하나 또는 여러 개의 경로로 전송을 하는 하이브리드 비디오 스트리밍을 제안한다. 제안 기법에서 경로의 선택은 SVC의 계층별로 진행한다. 제안 기법을 통해 비디오 세그먼트의 손실율을 줄여 높은 QoE를 제공할 수 있고 비디오의 끊김 현상을 최소화 할 수 있다.

• Journal of Korea Multimedia Society
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• v.3 no.2
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• pp.164-173
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• 2000

This paper presents an efficient bandwidth allocation method for multiple source in the two-layer video coding of different spatial resolution. We first investigate the model of bitrate distortion in the MPEG-2 spacial scalable coding,. By using approximated model parameters, than we propose an efficient bitrate control method in order to keep the same distortion level among coders and the constant quality ratio between layers. Simulation results show that the proposed method can satify the user requirement in comparison to the conventional method.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.4
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• pp.67-75
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• 2009

Multi-layered video coding that provides scalability across the visual content has emerged for easily adaptive service over current heterogeneous network. However, the network is still error prone environment so that video service may suffer packet loss or erroneous decoding of the video. Especially distortion caused by the burst error may propagate to several pictures until intra refreshing, which will raise a terrific degradation of picture quality. To overcome the problem at terminal independently, we propose a new error concealment algorithm for the multi-layered video coding. The proposed method uses the similarity of between layers in the multi-layered video coding and POCS (Projections Onto Convex Sets) which is a powerful error concealment tool, but heavily dependent on initial values. To find adequate initial value which can reduce iteration times as well as achieve high performance, we took consideration into both features of layered approach coding and the correlation in neighbor blocks. The simulation results show that the proposed concealment method works well.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.5
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• pp.1187-1193
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• 2014

This paper presents an effective motion estimation to improve the performance of the motion compensated temporal filtering (MCTF) which is a core part of the wavelet-based scalable video coding. The proposed scheme makes the motion vector field uniform by the modified median operation and the search strategies using adjacent motion vectors, in order to enhance the pixel connectivity which is significantly relevant to the performance of the MCTF. Moreover, the motion estimation with variable block sizes that reflects the features of frames is introduced for further correlation improvement of the motion vector field. Experimental results illustrate that the proposed method reduces the decomposed energy on the temporal high frequency subband frame up to 30.33% in terms of variance compared to the case of the full search with fixed block sizes.

• Journal of Korea Multimedia Society
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• v.13 no.4
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• pp.575-581
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• 2010

With widespread use of the Internet and improvements in streaming media and compression technology, digital music, video, and image can be distributed instantaneously across the Internet to end-users. However, most conventional Digital Right Management are often not secure and not fast enough to process the vast amount of data generated by the multimedia applications to meet the real-time constraints. The SVC offers temporal, spatial, and SNR scalability to varying network bandwidth and different application needs. Meanwhile, for many multimedia services, security is an important component to restrict unauthorized content access and distribution. This suggests the need for new cryptography system implementations that can operate at SVC. In this paper, we propose a new scrambling encryption for reserving the characteristic of scalability in MPEG4-SVC. In the base layer, the proposed algorithm is applied and performed the selective scambling. And it encrypts various MVS and intra-mode scrambling in the enhancement layer. In the decryption, it decrypts each encrypted layers by using another encrypted keys. Throughout the experimental results, the proposed algorithms have low complexity in encryption and the robustness of communication errors.

• Journal of the Korea Society of Computer and Information
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• v.17 no.7
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• pp.97-106
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• 2012

Management of biosignal data in mobile devices causes many problems in real-time transmission of large volume of multimedia data or storage devices. Therefore, this research paper intends to suggest an m-Health system, a clinical data processing system using mobile in order to provide quick medical service. This system deployed health system on IP network, compounded outputs from many bio sensing in remote sites and performed integrated data processing electronically on various bio sensors. The m-health system measures and monitors various biosignals and sends them to data servers of remote hospitals. It is an Android-based mobile application which patients and their family and medical staff can use anywhere anytime. Medical staff access patient data from hospital data servers and provide feedback on medical diagnosis and prescription to patients or users. Video stream for patient monitoring uses a scalable transcoding technique to decides data size appropriate for network traffic and sends video stream, remarkably reducing loads of mobile systems and networks.

• Journal of Broadcast Engineering
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• v.12 no.3
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• pp.250-265
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• 2007

In this paper, a fast intermode decision scheme is introduced by efficiently performing the mode decision using statistical hypothesis testing for hierarchical B-picture coding of SVC, in which much computational power is expensed for combined variable block sizes and hierarchical B-pictures. The hypothesis testing in the proposed method is performed on $16{\times}16\;and\;8{\times}8$ blocks to have early termination for RD computation of all possible modes. The early termination in intermode decision is performed by comparing the pixel values of current blocks and corresponding motion-compensated blocks. The proposed scheme exhibits effective early termination behavior in intermode decision and leads to a significant reduction up to 69% in computational complexity with slight increment in bit amounts. The degradation of visual quality turns out to be negligible in terms of PSNR values.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.8B
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• pp.535-540
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• 2005

This paper presents a scalable caching algorithm of proxy server with the finite storage size minimizing client's buffer size and constant-bit-rate channel bandwidth. Under the general video traffic condition, it is observed that the amount of decreased client's buffer size and channel bandwidth after caching a video frame depends on the relative frame position in the time axis as the frame size. Based on this fact, we propose an effective caching algorithm to select the cached frames by using the normalized buffer size. Finally, experimental results are provided to show the superior performance of the proposed alghrithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.12C
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• pp.1173-1183
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• 2006

In this paper, we propose an efficient method for improving visual quality of AR-FGS (Adaptive Reference FGS) which is adopted as a key scheme for SVC (Scalable Video Coding) or H.264 scalable extension. The standard FGS (Fine Granularity Scalability) adopts AR-FGS that introduces temporal prediction into FGS layer by using a high quality reference signal which is constructed by the weighted average between the base layer reconstructed imageand enhancement reference to improve the coding efficiency in the FGS layer. However, when the enhancement stream is truncated at certain bitstream position in transmission, the rest of the data of the FGS layer will not be available at the FGS decoder. Thus the most noticeable problem of using the enhancement layer in prediction is the degraded visual quality caused by drifting because of the mismatch between the reference frame used by the FGS encoder and that by the decoder. To solve this problem, we exploit the principle of cyclical block coding that is used to encode quantized transform coefficients in a cyclical manner in the FGS layer. Encoding block coefficients in a cyclical manner places 'higher-value' bits earlier in the bitstream. The quantized transform coefficients included in the ealry coding cycle of cyclical block coding have higher probability to be correctly received and decoded than the others included in the later cycle of the cyclical block coding. Therefore, we can minimize visual quality degradation caused by bitstream truncation by adjusting weighting factor to control the contribution of the bitstream produced in each coding cycle of cyclical block coding when constructing the enhancement layer reference frame. It is shown by simulations that the improved AR-FGS scheme outperforms the standard AR-FGS by about 1 dB in maximum in the reconstructed visual quality.

• KIISE Transactions on Computing Practices
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• v.20 no.11
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• pp.604-609
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• 2014

Decoding processes in portable media players have a high computational cost, resulting in high power consumption by the CPU. If decoding computations are reduced, the power consumed by the CPU is also be reduced, but such a choice generally results in a degradation of the video quality for the users, so it is essential to address this tradeoff. We proposed a new CPU power management scheme that can make use of the scalability property available in the H.164/SVC standard. We first proposed a new video quality model that makes use of a video quality metric(VQM) in order to efficiently take into account the different quantization factors in the SVC. We then propose a new dynamic voltage scaling(DVS) scheme that can selectively combine the previous decoding times and frame sizes in order to accurately predict the next decoding time. We then implemented a scheme on a commercial smartphone and performed a user test in order to examine how users react to the VQM difference. Real measurements show that the proposed scheme uses up to 34% fewer energy than the Linux DVFS governor, and user tests confirm that the degradation in the quality is quite tolerable.