• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.6B
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• pp.1060-1067
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• 2000

MPEG-4 visual coding is an object-based system. The current video coding standards, H.261, MPEG-1, and MPEG-2 encode frame by frame. On the other hand, MPEG-4 separately encodes several objects, such as video objects and audio objects, in the same frame. Each transmitted object is decoded and composed in one frame. Shape coding is a process of coding visual objects in a frame. In this paper we present conformance test method for MPEG-4 shape decoders. This paper reviews the basic shape decoding standard, and proposes conformance test methods for BAB type decoder, and CAE decoder for intra and inter VOPs. Our test generates all possible cases of shape motion vector difference and context.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1C
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• pp.35-44
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• 2004

In this paper, we design an efficient VLSI architecture of entropy coding algorithm in JPEG2000. Entropy coder is a context-based binary arithmetic encoder, and composed of a Context Extractor(CE) and an Arithmetic Coder(AC). We speed-up CE by skipping no-operation bits in coding passes, and AC is to be performed based on MQ coder. Because of using Qe value associated with each allowed context and probability estimation, MQ coder is a multiplication free coder that reduces computation loads and makes simple the structure of arithmetic coder. We have developed and synthesized the VHDL models of CE and AC pairs using Xilinx FPGA technology. The proposed architecture operates up to 30MHz.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.39-42
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• 2005

H.264, a recently proposed international video coding standard, has adopted context-based adaptive variable length coding (CAVLC) as the entropy coding tool in the baseline profile. By combining an adaptive variable length coding technique with context modeling, we can achieve a high degree of redundancy reduction. However, CAVLC in H.264 has weakness that the correct prediction rate of the variable length coding (VLC) table is low in a complex area, such as the boundary of an object. In this paper, we propose a VLC table prediction scheme considering multiple reference blocks; the same position block of the previous frame and the neighboring blocks of the current frame. The proposed algorithm obtains the new weighting values considering correctness of the VLC table for each reference block. Using this method, we can enhance the prediction rate of the VLC table and reduce the bit-rate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.146-150
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• 2009

Nowdays needs the new still image compression standard. JPEG2000 has been developed. JPEG2000 divide DWT and EBCOT. EBCOT is consisted of Bit Plane Coding and ARithmetic Coding algorithm. In this paper, we proposed BPC algorithm that is efficient context-based generation. Proposed BPC Algorithm forecasted coding pass using SigStage, column, mpass value. BPC designed using Verilog HDL. H/W implemenates using Xillinx FPGA technology.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5C
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• pp.464-471
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• 2010

The demand for high quality of multimedia applications, which far surpasses the rapid evolution of transmission and storage technologies, makes better compression coding capabilities ever increasingly more important. In order to provide enhanced video coding performance, this paper proposes an efficient competition-based motion vector coding scheme. The proposed algorithm adaptively forms the motion vector predictors based on the contexts of scene characteristics such as camera motion and nearby motion vectors, providing more efficient candidate predictors than the previous competition-based motion vector coding schemes which resort to the fixed candidates optimized by extensive simulations. Up to 200% of compression gain was observed in the experimental results for the proposed scheme applied to the motion vector selection for skip mode processing.

• Broadcasting and Media Magazine
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• v.24 no.4
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• pp.102-108
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• 2019

VVC(Versatile Video Coding)는 H.264/AVC(Advanced Video Coding)와 H.265/HEVC(High Efficiency Video Coding)의 엔트로피 코딩 기술로 사용되었던 CABAC(Context-based Adaptive Binary Arithmetic Coding)을 기반으로하여 압축율과 처리율을 향상시킬 수 있는 다양한 기술들이 채택되어 현재 CD(Committee Draft)가 완성되었고 참조 모델인 VTM6.0이 정식으로 배포되었다. 본 논문에서는 VVC Draft 6에 채택된 엔트로피 코딩 관련 기술들과 H.265/HEVC의 엔트로피 코딩의 차이점을 설명하고 엔트로피 코딩의 압축 성능과 엔트로피 코딩의 복잡도를 분석한다.

• Korean Journal of Child Studies
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• v.24 no.6
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• pp.15-31
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• 2003

This study examined the effects of emotion inducing contexts on types of infants smiling. Facial expressions of forty-five 11-to 15-month-old infants were videotaped in an experimental lab with positive and negative emotional contests. Infants' smiling was identified as the Duchenne smile or non-Duchenne smile based on FACS(Facial Action Coding System, Ekman & Friesen, 1978). Duration of smiling types was analyzed. Overall, infants showed more smiling in the positive than in the negative emotional context. Occurrence of Duchenne smiling was more likely in the positive than in the negative context and in the peek-a-boo than in the melody toy condition within the same positive context. Non-Duchenne smiling did not differ by context.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.3
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• pp.141-145
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• 2009

In this paper, we propose an efficient lossless compression algorithm using spatial and temporal information. The proposed method obtains higher lossless compression of images than other lossless compression techniques. It is divided into two parts, a motion adaptation based predictor part and a residual error coding part. The proposed nonlinear predictor can reduce prediction error by learning from its past prediction errors. The predictor decides the proper selection of the spatial and temporal prediction values according to each past prediction error. The reduced error is coded by existing context coding method. Experimental results show that the proposed algorithm has better performance than those of existing context modeling methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.9B
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• pp.1098-1107
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• 2011

As recent integration of wire and wireless networks and the convergence of telecommunications and broadcasting, uniform and standardized by the broadcasting operators of existing stations to provide 4A(Any-time, Any-where, Any-device, Any-contents) services for the next-generation of multimedia services research is being progressed. Demand for theses next-generation multimedia services to ensure video compression coding technology, as well as mobility, ability to operation a variety of devices, characteristics and performance of user network and the status and conditiion, user preferences and context-awareness based on the technology has an interest in technical studies. In this paper, the current internet environment, SVC(Scalable Video Coding) encoded by a mixture of multicast and overlay multicast transmission technology for broadcasting services by designing and efficient multimedia broadcasting system is proposed. In addition, ACK-Aow Optimization by overlay multicast scheme existing tree-based overlay multicast, and by comparing the effectiveness of the proposed algorithm is demonstrated.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.2
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• pp.125-131
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• 2010

This paper presents the implementation of a EBCOT TIER-1 for JPEG2000 Encoder. JPEG2000 is new standard for the compression of still image for overcome the artifact of JPEG. JPEG2000 standard is based on DWT(Discrete Wavelet Transform) and EBCOT Entropy coding technology. EBCOT(Embedded block coding with optimized truncation) is the most important technology that is compressed the image data in the JPEG2000. However, EBCOT has the artifact because the operations are bit-level processing and occupy the harf of the computation time of JPEG2000 Compression. Therefore, in this paper, we present modified context extraction method for enhance EBCOT computational efficiency and implemented MQ- Coder as arithmetic coder. The proposed system is implemented by Verilog-HDL, under the condition of TSMC 0.25um ASIC library, gate counts are 30,511EA and satisfied the 50MHz operating condition.