• Broadcasting and Media Magazine
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• v.12 no.3
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• pp.37-52
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• 2007

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.275-280
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• 2013

With rapidly growing mobile wireless services, the existing copper-based mobile backhaul technologies suffer from reaching the capacity limits. PON technologies is drawing attention as a key solution to replace the existing mobile backhaul technologies due to not only providing innovative network capacity but also cost-effective maintenance caused by the bandwidth gain from optical fibers. With a PON-based mobile backhaul, broadband wireless multimedia services such as a video conference and IPTV can be seamlessly provided. In this paper, we first introduce overview of the PON-based mobile backhaul technology. For a example of practical integration, three types of EPON-WiMAX integrated architectures are proposed and comparatively analyzed in term of costs and network performance. Then, applicable plan and anticipated effects are presented when applying network coding on the PON-based mobile backhaul to improve the performance of delivering multicast traffic.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.86-96
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• 2013

Unified Speech and Audio Coding (USAC) is the speech/audio codec with the best quality, approved on Final Draft International Standard (FDIS) at MPEG meeting in 2011. Since MPEG conventionally standardizes only the decoder, it is not easy to study on the encoder technologies. Furthermore, Reference Model(RM) shows extremely poor performance. To solve these problems, the open source project(JAME) proposes the methods to make the improved performance of main encoder technologies in USAC. Especially, this paper introduces the encoder modules: the signal classifier for selective operation between two coders, the psychoacoustic model in frequency domain, and window transition technology. Finally, the results of verification test for FDIS and the performance of Common Encoder are appended.

• Journal of Broadcast Engineering
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• v.12 no.6
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• pp.542-554
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• 2007

Seamless streaming of multimedia content via heterogeneous networks to viewers using a variety of devices has been a desire for many multimedia services, for which the multimedia contents should be adapted to usage environments such as network characteristics, terminal capabilities, and user preferences. Scalability in video coding is one of attractive features to meet dynamically changing requirements of heterogeneous networks. Currently a new scalable video coding (SVC) is standardizing in the Joint Video Team (JVT) of the ISO/IEC Moving Picture Experts Group (MPEG) and the ITU-T Video Coding Experts Group (VCEG), which will be released as Extension 3 of H.264/MPEG-4 AVC. In this paper, we introduce new technologies of SVC and evaluate performance of it especially regarding on overhead bit-rate and coding efficiency to support spatial, temporal, and quality scalability.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.39-45
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• 2020

The fifth generation (5G) mobile communication has been more commercialized worldwide. One of the promising 5G technologies is non-orthogonal multiple access (NOMA). We present the achievable sum rate of non-orthogonal multiple access (NOMA) with correlated superposition coding (SC). Then this paper investigates the impacts of correlation on the achievable sum rate of correlated SC NOMA. It is shown that the achievable sum rate of correlated SC NOMA is greater than that of standard independent SC NOMA, for the most of the values of the power allocation factor over the meaningful range of the user fairness. In result, correlated SC could be a promising scheme for NOMA.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.6
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• pp.2554-2575
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• 2020

Data hiding technology hides secret information into the carrier, so that when the carrier is transmitted over network, it will not attract any malicious attention. Using data compression, it is possible to reduce the data size into a small compressed code, which can effectively reduce the time when transmitting compressed code on the network. In this paper, the main objective is to effectively combine these two technologies. We designed a data hiding scheme based on two techniques which are turtle-shell information hiding scheme and absolute moment block truncation coding. The experimental results showed that the proposed scheme provided higher embedding capacity and better image quality than other hiding schemes which were based on absolute moment block truncation coding.

• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.2899-2908
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• 2021

The laser transport system of the high power laser facility is mainly composed of large-aperture laser transport mirrors (TMs). Obtaining the high-resolution online damage images during the operation, which is of great significance for operating safely of the mirrors and the facility. Based on wavefront coding, pan-tilt scanning and image stitching technologies, an online laser-damage images detection system is designed, and it can achieve high-precision detection of surface characteristics of large-aperture laser transport mirrors. The preliminary simulation proves that the system can solve the depth of field matching problem caused by pan-tilt tilt imaging and achieve higher resolution.

• Journal of Broadcast Engineering
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• v.27 no.3
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• pp.332-340
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• 2022

Recently, with the development of deep learning and artificial neural network technologies, research on the application of neural network has been actively conducted in the field of video coding. In particular, deep learning-based intra prediction is being studied as a way to overcome the performance limitations of the existing intra prediction techniques. This paper presents a method of context-adaptive neural network-based intra prediction model training and its coding performance analysis. In other words, in this paper, we implement and train a known intra prediction model based on convolutional neural network (CNN) that predicts a current block using contextual information from reference blocks. Then, we integrate the trained model into HM16.19 as an additional intra prediction mode and evaluate the coding performance of the trained model. Experimental results show that the trained model gives 0.28% BD-rate bit saving over HEVC in All Intra (AI) coding mode. In addition, the coding performance change of training considering block partition is also presented.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.4
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• pp.1128-1139
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• 2012

With the development of three-dimensional display and related technologies, depth video coding becomes a new topic and attracts great attention from industries and research institutes. Because (1) the depth video is not a sequence of images for final viewing by end users but an aid for rendering, and (2) depth video is simpler than the corresponding color video, fast algorithm for depth video is necessary and possible to reduce the computational burden of the encoder. This paper proposes a fast mode decision algorithm for depth video coding based on depth segmentation. Firstly, based on depth perception, the depth video is segmented into three regions: edge, foreground and background. Then, different mode candidates are searched to decide the encoding macroblock mode. Finally, encoding time, bit rate and video quality of virtual view of the proposed algorithm are tested. Experimental results show that the proposed algorithm save encoding time ranging from 82.49% to 93.21% with negligible quality degradation of rendered virtual view image and bit rate increment.

• Journal of Broadcast Engineering
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• v.26 no.2
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• pp.208-220
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• 2021

This paper evaluates the performance of multilayer VVC and SHVC. Multilayer VVC supports a multi-layer coding and many coding technologies have been added and extended compared to SHVC. For this reason, it is necessary to evaluate the multi-layer coding performance of VVC and the coding performance for inter-layer reference prediction. Multilayer VVC provides significant BD-rate improvement of AI 24.4%, RA 29.4%, LDB 29.4%, LDP 32.6% on average when compared to SHVC, so that it is shown that VVC can provide scalability more efficiently. On the other hand, the complexity of the encoding time increases by an average of 14 times and decoding time by an average of 1.8 times, which requires efforts to reduce the complexity.