• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.2
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• pp.20-28
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• 2003

Recently we need a faster and more accurate motion vector search algorithm for ASIC(Application Specific IC) or small systems. Block motion estimation using Full Search(FS) algorithm provides the best visual quality and PSNR, but it requires intensive computations. The previously proposed fast algorithms reduced the number of computations by limiting the number of searching locations. This is accomplished at the expense of less accuracy of motion estimation and gives rise to an appreciably higher SAD(Sum of Absolute Difference) for motion compensated images. In this paper we exploit the spatial correlation of motion vectors and present a fast motion estimation scheme which uses the predicted motion vector(PMV). The PMV scheme is more clear and simpler than the previously proposed algorithms which also use adjacent motion vectors. Simulation results with standard video sequences show that the PMV scheme is faster and more accurate than other algorithms such as Nearest-Neighbors Search(NNS) algorithm.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.5
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• pp.477-485
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• 2002

In this paper, we present an efficient hardware architecture for the H.263 video codec and its VLSI implementation. This architecture is based on the unified interface by which internal hardware engines and an internal RISC processor are connected one another. The unified interface enables the modular design of internal blocks, efficient hardware/software partitioning, and pipelined paralled operations. The developed VLSI supports the H.263 version 2 profile 3 @ level 10, and moreover, both the control protocol H.245 and the multiplexing protocol H.223. Therefore, it can be used for the complete ITU-T H.324 or 3GPP 3G 324M multimedia processor with the help of an external audio codec. Simultaneous encoding and decoding of QCIF format images at a rate greater than 15 frames per second is achieved at 40 MHz clock frequency.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.1
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• pp.81-92
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• 1999

In this paper, we propose a new image segmentation algorithm which can be use din object-based image coding applications such as MPGA-4. Since the conventional objet segmentation methods based on mathematical morphology tend to yield oversegmented results, they normally need a postprocess which merges small regions to obtain a larger one. To solve this oversegmentation problem, in this paper, we prosed a block-based segmentation algorithm that can identify large texture regions in the image. Also, by applying the watershed algorithm to the image blocks between the homogeneous regions, we can obtain the exact pixel-based contour. Experimental results show that the proposed algorithm yields larger segments, particularly in the textural area, and reduces the computational complexities.

• Journal of IKEEE
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• v.24 no.1
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• pp.46-51
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• 2020

With Wi-Fi and Bluetooth connectivity becoming more common in today's handheld mobile devices, single-chip multi-radio combo-modules, which integrate two or more heterogeneous wireless radios on a single chip, are becoming more and more popular. The key requirement for combo solutions is that the quality of the user experience (QoE) must not be compromised by degrading connectivity performance. Therefore, characterizing and understanding the behaviour of combo-module is of vital importance to ensure this requirement in various environments. In this paper, we investigate the impact of the use of combo-modules on the performance of mobile video streaming over a Wi-Fi network. Our study reveals that the use of combo-modules incurs considerable side effects on QoE for mobile video streaming applications when the Wi-Fi and Bluetooth operate at the same time in the 2.4GHz ISM band. We reveal that rate-based adaptive algorithms, including the most popular adaptive bitrate streaming MPEG-DASH, is more severely affected by this phenomenon than buffer-based adaptive algorithms.

• The KIPS Transactions:PartC
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• v.10C no.7
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• pp.835-842
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• 2003

The technical advancement in and the widespread expansion of use of the internet has recently led to an increase in high bandwidth multimedia data usage. This is largely due to an unfettered access to the internet. The intrinsic merit of the internet, however, brings about a side effect：multimedia date can easily be duplicated recklessly. This invokes the problem of intellectual property right violation. Focusing on this matter, multi-faceted studies are being conducted now. This paper aims to provide, by applying steganography and encryption methods into the SMIL files which supply subtitle data, the intellectual property protection of both motion picture and its subtitle data, as well as the integrity of the contents in question. In order to achieve the above goal, the authors show a particular method how to safely embed subtitle data into the given frames, after they separate subtitle data to encrypt them. By doing this, the authors suggests, the intellectual property right to the subtitle data as well as their integrity can be protected and achieved respectively. Besides, an integrity service for motion picture can be made.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.3C
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• pp.239-247
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• 2003

This paper presents a dual-rate (2.4/4.0 kbps) Improved Harmonic-CELP(IHC) speech coder based on the EHC(Efficient Harmonic-CELP) which was presented by the authors. The proposed IHC employs the harmonic coding for voiced and the CELP for unvoiced segments. In the IHC, an initial voiced/unvoiced estimate is obtained by the pitch gain and energy. Then, the final V/UV mode is decided by using the frame energy contour. A new harmonic estimation combining peak picking and delta adjustment provides a more reliable harmonic estimation than that in the EHC. In addition, a noise mixing scheme in conjunction with an improved band voicing measurement provides the naturalness of the synthesized speech. To demonstrate the performance of the proposed IHC coder, the coder has been implemented and compared with the 2.0/4.0 kbps HVXC(Harmonic excitation Vector Coding) standardized by MPEG-4. Results of subjective evaluation showed that the proposed IHC coder and produce better speech quality than the HVXC, with only 40% complexity of the HVXC.

• Journal of Digital Convergence
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• v.12 no.3
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• pp.269-275
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• 2014

The DAB system was designed to provide CD quality audio and data services for fixed, portable and mobile applications with the required BER below $10^{-4}$. However for the T-DMB system with the video service of MPEG-4 stream, BER should go down $10^{-8}$ by adding FEC blocks which consist of the Reed-Solomon (RS) encoder/decoder and convolutional interleaver/deinterleaver. In this paper we propose two types of turbo coded T-DMB system without altering the puncturing procedure and puncturing vectors defined in the standard T-DMB system for compatibility. One(Type 1) can replace the existing RS code, convolutional interleaver and RCPC code by a turbo code and the other one (Type 2) can substitute the existing RCPC code by a turbo code. Simulation results show that two new turbo coded systems are able to yield considerable performance gain after just 2 iterations. Type 2 system is better than type 1 but the amount of performance improvement is small.

• Polymer(Korea)
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• v.37 no.1
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• pp.94-99
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• 2013

Polydiacetylene (PDA) is made by photopolymerization of self-assembled diacetylene monomers. If diacetylene monomers are arranged systematically and close enough with distance of atoms, 1,4-addition polymerization will occur by the irradiation of 254 nm ultraviolet rays and then PDA will have alternated ene-yne polymer chains at the main structure. Aqueous solutions of diffused PDA is tinged with blue which shows ${\lambda}_{max}$ 640 nm. Visible color changes from blue to red occurs in response to a variety of environmental perturbations, such as temperature, pH, and ligand-receptor interactions. In this study, we synthesized cationic peptides - PCDA(10,12-pentacosadyinoic acid) liposome using a solid phase peptide synthesis (SPPS) method and prepared liposome solutions at various molar ratios using MPEG-PCDA. When mammalian cells were treated with the liposomes, high transfection efficiency and low toxicity were observed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.12C
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• pp.1669-1676
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• 2004

In H.264, 7 modes {16${\times}$16, 16${\times}$8, 8${\times}$16, 8${\times}$8, 8${\times}$4, 4${\times}$8, 4${\times}$4) are used to enhance the coding efficiency. The motion vector estimation with 7 modes may require huge computing time. In this paper, to speed up the motion vector estimation procedure while the high image quality remains, we propose a motion vector refinement scheme using the temporary motion vector generated with little computation. The proposed estimation process consists of three phases: Mode decision for a 16${\times}$16 macroblock, Composing a temporary motion vector, Refinement of the temporary motion vector. We demonstrate the effectiveness of the proposed method by computer simulation. In the results, the encoding time consumed by the proposed scheme has been reduced significantly while the encoded video quality remains unchanged.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.1
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• pp.3-10
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• 1998

In this paper, a new superimposition scheme using a computer vision system was proposed with 7 pairs of skull and ante-mortem photographs, which were already identified through other tests and DNA fingerprints at the Korea National Institute of Scientific Investigation. At this computer vision system, an unidentified skull was caught by video-camcoder with the MPEG and a ante-mortem photograph was scanned by scanner. These two images were processed and superimposed using pixel processing. Recognition of the individual identification by anatomical references was performed on the two superimposed images. This image processing techniques for the superimposition of skull and ante-morterm photographs simplify used the previous approach taking skull photographs and developing it to the same size as the ante-mortem Photographs. This system using various image Processing techniques on computer screen, a more precise and time-saving superimposition technique could be able to be applied in the area of computer individual identification.