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[Author] Taegeun OH(3hit)

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  • Device-Aware Visual Quality Adaptation for Wireless N-Screen Multicast Systems

    Inwoong LEE  Jincheol PARK  Seonghyun KIM  Taegeun OH  Sanghoon LEE  

     
    PAPER-Terrestrial Wireless Communication/Broadcasting Technologies

      Vol:
    E96-B No:12
      Page(s):
    3181-3189

    We seek a resource allocation algorithm through carrier allocation and modulation mode selection for improving the quality of service (QoS) that can adapt to various screen sizes and dynamic channel variations. In terms of visual quality, the expected visual entropy (EVE) is defined to quantify the visual information of being contained in each layer of the scalable video coding (SVC). Fairness optimization is conducted to maximize the EVE using an objective function for given constraints of radio resources. To conduct the fairness optimization, we propose a novel approximation algorithm for resource allocation for the maximal EVE. Simulations confirm that the QoS in terms of the EVE or peak signal to noise ratio (PSNR) is significantly improved by using the novel algorithm.

  • Implementation of Multimode-Multilevel Block Truncation Coding for LCD Overdrive

    Taegeun OH  Sanghoon LEE  

     
    PAPER-Digital Signal Processing

      Vol:
    E95-A No:5
      Page(s):
    867-875

    The Liquid-crystal display (LCD) overdrive technique has been utilized to reduce motion blur on a display via a reduction in the response time. However, to measure the variation of the pixel amplitudes, it is necessary to store the previous frame using a large frame memory. To downscale the frame memory, block truncation coding (BTC) is commonly employed due to the simplicity of its implementation, even if some visual artifacts may occur for image blocks with high frequency components. In this paper, we present a multimode-multilevel BTC (MBTC) technique that improves performance while maintaining simplicity. To improve the visual quality, we uniquely determine the quantization level and coding mode of each block according to the distribution of the luminance and chrominance amplitudes. For a compression ratio of 6:1, the proposed method demonstrates higher coding efficiency and overdrive performance by up to 3.81 dB in the PSNR compared to other methods.

  • Increasing Throughput and QoS Using Bandwidth and Region Division with Frequency Overlay over Multicell Environments

    Taegeun OH  Sanghoon LEE  Gye-Tae GIL  

     
    PAPER

      Vol:
    E92-B No:1
      Page(s):
    85-92

    A cell planning and resource allocation scheme called EBRD (Enhanced Bandwidth and Region Division) is presented for improving channel capacity and for maintaining a proper QoS (Quality of Service) over the downlink OFDMA (Orthogonal Frequency Division Multiple Access) system. Through an optimal combination of sectorization and frequency overlay, the EBRD scheme improves both channel capacity and outage probability. In order to analyze the performance of the proposed algorithm, the outage probability is obtained as a closed numerical form. In the simulation, the EBRD scheme outperforms 3-sectorization in terms of throughput and outage probability.