• International Journal of Internet, Broadcasting and Communication
• /
• v.13 no.4
• /
• pp.39-47
• /
• 2021

Lempel-Ziv coding is one of the most famous source coding schemes. The output of this source coding is usually a non-uniform code, which requires additional source coding, such as arithmetic coding, to reduce a redundancy. However, this additional source code increases complexity and decoding latency. Thus, this paper proposes the optimal maximum a-posteriori (MAP) receiver for non-uniform source non-orthogonal multiple access (NOMA) with symmetric superposition coding (SSC). First, we derive an analytical expression of the bit-error rate (BER) for non-uniform source NOMA with SSC. Then, Monte Carlo simulations demonstrate that the BER of the optimal MAP receiver for the non-uniform source improves slightly, compared to that of the conventional receiver for the uniform source. Moreover, we also show that the BER of an approximate analytical expression is in a good agreement with the BER of Monte Carlo simulation. As a result, the proposed optimal MAP receiver for non-uniform source could be a promising scheme for NOMA with SSC, to reduce complexity and decoding latency due to additional source coding.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.16 no.1
• /
• pp.44-57
• /
• 2016

Rectification is used as a preprocessing to reduce the computation complexity of disparity estimation. However, rectification also requires a complex computation. To minimize the computing complexity, rectification using a lookup-table (R-LUT) has been introduced. However, since, the R-LUT consumes large amount of memory, rectification with compressed LUT (R-CLUT) has been introduced. However, the more we reduce the memory consumption, the more we need decoding overhead. Therefore, we need to attain an acceptable trade-off between the size of LUT and decoding overhead. In this paper, we present such a trade-off by adaptively combining simple coding methods, such as differential coding, modified run-length coding (MRLE), and Huffman coding. Differential coding is applied to transform coordinate data into a differential form in order to further improve the coding efficiency along with Huffman coding for better stability and MRLE for better performance. Our experimental results verified that our coding scheme yields high performance with maintaining robustness. Our method showed about ranging from 1 % to 16 % lower average inverse of compression ratio than the existing methods. Moreover, we maintained low latency with tolerable hardware overhead for real-time implementation.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.9
• /
• pp.4205-4227
• /
• 2018

Network Coding (NC) is an approach recently investigated for increasing the network throughput and thus enhancing the performance of wireless mesh networks. The benefits of NC can further be improved when routing decisions are made with the awareness of coding capabilities and opportunities. Typically, the goal of such routing is to find and exploit routes with new coding opportunities and thus further increase the network throughput. As shown in this paper, in case of proactive routing the coding awareness along with the information of the measured traffic coding success can also be efficiently used to support the congestion avoidance and enable more encoded packets, thus indirectly further increasing the network throughput. To this end, a new proactive routing procedure called Congestion-Avoidance Network Coding-Aware Routing (CANCAR) is proposed. It detects the currently most highly-loaded node and prevents it from saturation by diverting some of the least coded traffic flows to alternative routes, thus achieving even higher coding gain by the remaining well-coded traffic flows on the node. The simulation results confirm that the proposed proactive routing procedure combined with the well-known COPE NC avoids network congestion and provides higher coding gains, thus achieving significantly higher throughput and enabling higher traffic loads both in a representative regular network topology as well as in two synthetically generated random network topologies.

• Journal of Korea Game Society
• /
• v.18 no.1
• /
• pp.7-18
• /
• 2018

As coding education is ubiquitous in elementary or higher school curriculum, puzzle-based coding platforms such as Scratch or Entry have been popularly deployed and employed by many Korean coding educational institutions. In this article, we propose a quantitative students' coding assessment methodology and discuss several issues of the method. Besides, we show its usefulness through case studies shown in our proprietary coding platform called "CodingPuzzle" system. Additionally, we describe detailed design and implementation issues of our coding assessment system that has already been ported to the CodingPuzzle system and is currently under operation.

• Journal of the Korea Society of Computer and Information
• /
• v.13 no.2
• /
• pp.31-40
• /
• 2008

Various coding styles for C language have been proposed so far but there has been a lack of synthetic review about them. In this paper, I propose a new C coding style by analyzing coding rules that are included in the representative C coding styles and by adding new coding rules besides them. In addition, I designed an automated C coding style checker named CStyler which was implemented using Lex and Yacc. It is designed to be able to verify unpreprocessed source code as well as preprocessed source code. And I improved its flexibility by being able to add a new coding rule by end user. I think that the new C coding style and coding style checker, CStyler, can be utilized for education and for future research to develop and extend a static analysis tool.

• Journal of Microbiology and Biotechnology
• /
• v.26 no.8
• /
• pp.1473-1480
• /
• 2016

This study focused on the variations in the non-coding sequences between ctxB and rstR of various CTX phages. The non-coding sequences of CTX-1 and CTX-cla are phage type-specific. The length of the non-coding region of CTX-1 and CTX-cla is 601 and 730 nucleotides, respectively. The non-coding sequence of CTX phage could be divided into three regions. There is a phage type-specific Variable region between two homologous Common regions (Common regions 1 and 2). The non-coding sequence of RS1 element is similar to CTX-1 except that Common region 1 is replaced by a short RS1-specific sequence. The non-coding sequences of CTX-2 and CTX-cla are homologous, indicating the non-coding sequence of CTX-2 is derived from CTX-cla. The non-coding region of CTX-O139 is similar to CTX-cla and CTX-2; however, it contains an extra phage type-specific sequence between Common region 2 and rstR. The variations in the non-coding sequences of CTX phages might be associated with the difference in the replication efficiency and the directionality in the integration into the V. cholerae chromosome.

• Korean Journal of Childcare and Education
• /
• v.17 no.5
• /
• pp.25-41
• /
• 2021

Objective: The purpose of this study was to analyze the effect of a director's support for coding education perceived by childcare teachers on the participation of teachers in the learning community and the intention to implement coding education. Methods: The participants of this study were 312 early childhood teachers working at daycare centers in Seoul, Gyeong-gi, and In-cheon area. The data were collected through the survey questionnaires and analyzed using a structural model to explore the relationship between variables. Results: Verifying the mediating effect of infant teacher participation in the learning community between a director's support and infant teacher's intention to implement coding education positively mediates the director's support and infant teacher's intention to implement coding education. In particular, it was discovered that the intention to participate in coding-related learning communities had the greatest impact on infant teachers' intentions to implement coding education based on total effectiveness. Conclusion/Implications: The above analysis results suggest that in order to enhance the intention of infant teachers to implement coding education, it is necessary to support the learning community related to coding education and encourage participation from infant teachers.

• Journal of Broadcast Engineering
• /
• v.19 no.2
• /
• pp.250-256
• /
• 2014

Non-reference P frame coding is used to enhance coding efficiency in low-delay encoding configuration of Internet Video Coding (IVC), which is being standardized as a royalty-free video codec in MPEG. The existing method of non-reference P frame coding which was adopted in the reference Test Model of IVC (ITM) 4.0 adaptively applies a non-reference P frame with a fixed coding structure based on the magnitude of motion vectors (MVs), however, which unexpectedly degrades the coding efficiency for some sequences. In this paper, the existing non-reference P frame coding is improved by changing non-reference P frame coding structure and applying a new adaptive method using the ratio of the amount of generated bits of non-reference frames to that of reference frames as well as MVs. Experimental results show that the proposed non-reference P frame coding gives 6.6% BD-rate bit saving in average over ITM 7.0.

• Journal of Broadcast Engineering
• /
• v.23 no.4
• /
• pp.495-502
• /
• 2018

JVET (Joint Video Exploration Team) which explored evolving technologies of video coding with capabilities beyond HEVC (High Efficiency Video Coding), released a references software codec named the Joint Exploration Model (JEM) for performance verification of coding technologies. JEM has 67 intra prediction modes that extend the 35 modes of HEVC for intra prediction. Therefore, the enhancement of the coding performance is limited due to the overhead of prediction mode coding. In this paper, we analyze the probabilities of prediction modes selections, and then we propose a more efficient intra prediction mode coding based on the results of analyzed mode occurrence. In addition, we propose a context modeling for CABAC (Context-Adaptive Binary Arithmetic Coding) of the proposed mode coding. Experimental results show that the BD-rate gain is 0.02% on the AI (All Intra) coding structure compared to JEM 7.0. We need to optimize context modeling for additional coding performance enhancement.

• The Journal of the Acoustical Society of Korea
• /
• v.19 no.3
• /
• pp.26-34
• /
• 2000

In this paper, we propose a 4kbps speech coder that combines the harmonic vector excitation coding with time-separated transition coding. The harmonic vector excitation coding uses the harmonic excitation coding in the voiced frame and uses the vector excitation coding with the structure of analysis-by-synthesis in the unvoiced frame, respectively. But two mode coding method is not effective for transition frame mixed in voiced and unvoiced signal and a new method beyond using unvoiced/voiced mode coding is needed. Thus, we designed a time-separated transition coding method for transition frame in which a voiced/unvoiced decision algorithm separates unvoiced and voiced duration in a frame, and harmonic-harmonic excitation coding and vector-harmonic excitation coding method is selectively used depending on the previous frame U/V decision. In the decoder, the voiced excitation signals are generated efficiently through the inverse FFT of harmonic magnitudes and the unvoiced excitation signals are made by the inverse vector quantization. The reconstructed speech signal are synthesized by the Overlap/Add method.