• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.38 no.6
• /
• pp.93-105
• /
• 2001

In the lossless step of Lattice Vector Quantization(LVQ), the lattice codewords produced at quantization step are enumerated into radius sequence and index sequence. The radius sequence is run-length coded and then entropy coded, and the index sequence is represented by fixed length binary bits. As bit rate increases, the index bit linearly increases and deteriorates the coding performances. To reduce the index bits across the wide range of bit rates, we developed a novel lattice enumeration algorithm adopting the set partitioning method. The proposed enumeration method shifts down large index values to smaller ones and so reduces the index bits. When the proposed lossless coding scheme is applied to a wavelet based image coding, the proposed scheme achieves more than 10% at bit rates higher than 0.3 bits/pixel over the conventional lossless coding method, and yields more improvement as bit rate becomes higher.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.8
• /
• pp.1500-1506
• /
• 2015

In this paper, en efficient broadcast scheme with acknowledged mode is proposed. Specifically, based on stochastic pattern of ACK/NACK across all users and index coding, adaptive coding scheme with XOR operation is used at the transmitter. At each receiver, packets are decoded using layered decoding method with already successfully decoded packets. From numerical results, proposed index coded broadcast scheme is shown to be more efficient than naive broadcast scheme in the sense of average total number of transmitted packets.

• MALSORI
• /
• no.53
• /
• pp.157-169
• /
• 2005

This paper proposes an efficiently representing method of spatial cues on multichannel spatial audio coding. The Binaural Cue Coding (BCC) method introduced recently represents multichannel audio signals by means of Inter Channel Level Difference (ICLD) or Source Index (SI). We tried to express more efficiently ICLD and SI information based on Inter Channel Correlation in this paper. We adopt different spatial cues according to ICC and propose a compensation method of empty spectrums created by using SI. We performed a MOS test and measuring spectral distortion. The results show that the proposed method can reduce the bitrate of side information without large degradation of the audio quality.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.54 no.8
• /
• pp.501-503
• /
• 2005

In this paper, using ranks of co-occurrence frequency about indices in pairs of neighboring pixels, we introduce a new re-indexing algorithm for efficiency of index color image lossless compression. The proposed algorithm is suitable for arithmetic coding because it has concentrated distributions of small variance. Experimental results proved that the proposed algorithm reduces the bit rates than other coding schemes, more specifically $15\%$, $54\%$ and $12\%$ for LZW algorithm of GIF, the plain arithmetic coding method and Zeng's scheme, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.4 no.5
• /
• pp.1005-1015
• /
• 2000

In this paper, the performance of Hybrid CDU MFSK system has been analyzed in the environment that narrowband Class-A impulsive noise include Gaussian noise in wireless communication channel and Nakagami fading. The performance of system improved to adopting both of technique MRC diversity and BCH channel coding. The results show that there is substantial degraded in Hybrid CDMA system performance by impulse index is stronger and the fading index is smaller. But also improvement can be obtained when BCH coding techniques are adopted. Additional MRC diversity techniques is more improvement than BCH coding techniques when degraded environment with the low fading index. But BCH coding techniques is more improvement than MRC diversity techniques when fading index has been increased. The Hybrid CDMA MFSK system is incomplete to voice communication standard BER$(10^{-3})$ in Rayleigh fading by independent each adopting techniques BCH coding and MRC diversity. But it's satisfy(improvement can be obtained) to voice communication standard BER in strong impulse noise(24dB over) by adopting techniques BCH coding and MRC diversity at a time. Additional it's a substantial enhancement $(10^{-3})$satisfaction) in fading index (m=3, 22dB) in addition to strong impulse noise and 24dB over with data service standard $(10^{-5})$ BER satisfaction. This result show that there is error performance improved by diversity branch and coding advantage.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.1C
• /
• pp.35-43
• /
• 2005

This paper introduces a new algorithm to improve compression performance of 256 color images called palette-based or indexed images. The proposed scheme counts each frequency of index values after present index value and determines each rank for every index value by sorting them in descending order. Then, the scheme makes ranked index image instead of original indexed image using the way to replace index values with ranks. In the ranked index image's distribution produced as a result of this algorithm, the higher ranked index value, the more present same values. Therefore, data redundancy will be raised and more efficient performance of compression can be expected. Simulation results verify that because of higher compression ratio by up to 22.5, this newly designed algorithm shows a much better performance of compression in comparison with the arithmetic coding, intensity-based JPEG-LS and palette-based GIF.

• Proceedings of the KIEE Conference
• /
• 2005.05a
• /
• pp.164-166
• /
• 2005

In this paper, using ranks of co-occurrence frequency about indices in neighboring pixels, we introduce a new re-indexing scheme for efficiency of index color image lossless compression. The proposed method is suitable for arithmetic coding because it has skewed distributions of small variance. Experimental results proved that the proposed method reduces the bit rates than other coding schemes, more specifically 15%, 54% and 12% for LZW algorithm of GIF, the plain arithmetic coding method and Zeng's scheme.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2019.07a
• /
• pp.423-425
• /
• 2019

본 논문에서는 2015 개정 교육과정에 따른 SW교육을 전면 시행함에 따라 공교육 및 최근 늘어나고 있는 전국의 학원 및 교습소 현황을 살펴보았다. 학생 수 규모가 큰 서울과 경기 지역에 학원 및 교습소가 많이 분포되어 있었으며 코딩교육시간 역시 서울과 경기지역이 지방에 비해 많은 것으로 나타났다. 그러나 코딩교육열지수를 살펴보면 제주와 세종이 높은 것으로 나타났다. 4차 산업 시대에 꼭 필요한 정보 컴퓨터 교육분야의 코딩교육은 컴퓨터 과학의 기초 원리나 핵심 개념, 컴퓨팅 사고력 향상 등을 위한 교육으로의 방향전환이 필요하며 창의력을 높이기 위한 교육, 융합교육을 위한 코딩 교육 등 다양한 연구가 필요하다.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.2 no.3
• /
• pp.129-137
• /
• 2007

MPEG-4 FGS is one of scalable video coding schemes specified In ISO/IEC 14496-2 Amendment 2, and particularly standardized as a scheme for providing fine granular quality and temporal scalabilities. In this paper, we propose a sign-bit reduction technique in embedded bit-plane coding to enhance the coding efficiency of MPEG-4 FGS system. The general structure of the FGS system for the proposed scheme is based on the standard MPEG-4 FGS system. The proposed FGS enhancement-layer encoder takes as input the difference between the original DCT coefficient and the decision level of the quantizer instead of the difference between the original DCT coefficient and its reconstruction level. By this approach, the sign information of the enhancement-layer DCT coefficients can be the same as that of the base-layer ones at the same frequency index in DCT domain. Thus, overhead bits required for coding a lot of sign information of the enhancement-layer DCT coefficients in embedded bit-plane coding can be removed from the generated bitstream. It is shown by simulations that the proposed FGS coding system provides better coding performance, compared to the MPEG-4 FGS system in terms of compression efficiency.

• The Journal of the Acoustical Society of Korea
• /
• v.31 no.7
• /
• pp.435-440
• /
• 2012

We propose optimal contexts for context-adaptive coding of stereo parameters in parametric stereo (PS) of enhanced aacPlus. For the quantized indexes of stereo parameters, 8 context candidates were proposed based on the index values and their combinations adjacent to a source index in the time-stereo band domain, where the time-stereo band region was further divided into 4 regions based on refresh/non-refresh frames and stereo bands. The optimal contexts for each region were proposed by experiments, which are expected to be used for context-adaptive coding of PS for improved performance.