• 한국정보통신설비학회:학술대회논문집
• /
• 2005.08a
• /
• pp.417-421
• /
• 2005

In the recent digital communication systems, the performance of Turbo Code using the error correction coding depends on the interleaver influencing the free distance determination and the recursive decoding algorithms that is executed in the turbo decoder. However, performance depends on the interleaver depth that needs many delays over the reception process. Moreover, turbo code has been known as the robust coding methods with the confidence over the fading channel. International Telecommunication Union(ITU) has recently adopted it as the standardization of the channel coding over the third generation mobile communications(IMT-2000). Therefore, in this paper, we proposed the interleaver that has the better performance than existing block interleaver, and modified turbo decoder that has the parallel concatenated structure using MAP algorithm. In the real-time voice and video service over third generation mobile communications, the performance of the proposed two methods was analyzed and compared with the existing methods by computer simulation in terms of reduced decoding delay using the variable decoding method over AWGN and fading channels for CDMA environments.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.43 no.5
• /
• pp.649-665
• /
• 2019

This study presents a conceptual framework for the growth process as a manager based on data gathered from the sales experiences and careers of fashion brand managers. The study participants were seven managers with over 15 years of sales experience in a women's clothing brand in Gwangju. Data were collected through in-depth interviews from January 2018 to September 2018 and analyzed using open coding, axis coding, and selective coding according to Strauss and Corbin's grounded theory method. The study results are as follows. First, this study found six categories and 17 sub-categories based on the shop manager's sales experiences and careers. Second, we found the central job category as well as categories with causality, interaction, moderating and outcome relationships. Third, we developed a paradigm model that links the main phenomena, causal conditions, contextual conditions, intervening conditions, action/interaction strategies, and consequence categories. Fourth, the process of growing as a fashion brand manager was described by an integrated story.

• The Journal of Information Systems
• /
• v.30 no.4
• /
• pp.153-171
• /
• 2021

Purpose This study is to phenomenologically discover key antecedents and outcomes of behavioral process of SNS users who have multiple SNS sub-accounts. Unlike previous studies that focused on user behavior in the context of a specific SNS platform, this study attempts to describe how and why individual manages their multiple sub-accounts across a variety of SNS platforms. Design/methodology/approach By applying the grounded theory methodology (GTM) to elucidate the unique behavior in SNS platforms, this study has conducted in-depth interview with 14 respondents who handle multiple accounts across the SNS platforms. As a results of analyzing the interview manuscripts, this study has extracted 47 concepts, 10 sub-categories and 6 main categories by conducting open coding, axis coding, and selective coding. Findings By analyzing interview data, this study has derived main categories such as account management, impression management, self-categorization, authority to determine the relationship, digital shadow work, and portfolio SNS accounts from qualitative interview data. This study has also conducted a process analysis that represents how main categories could be inter-related. Based on findings, this study provides a new phenomenological perspective to understand the behavioral process of SNS users' sub-account usage experience.

• Journal of the Korea Society of Computer and Information
• /
• v.29 no.9
• /
• pp.61-68
• /
• 2024

In this paper, Generative AI is a technology that creates various forms of content such as text, images, and music, and is being utilized across different fields. In the security sector, generative AI is poised to open up new possibilities in various areas including security vulnerability analysis, malware detection and analysis, and the creation and improvement of security policies. This paper presents a guide for identifying vulnerabilities and secure coding using ChatGPT for security vulnerability analysis and prediction, considering the application of generative AI in the security domain. While generative AI offers innovative possibilities in the security field, it is essential to continuously pursue research and development to ensure safe and effective utilization of generative AI through in-depth consideration of ethical and legal issues accompanying technological advancements.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2009.11a
• /
• pp.213-215
• /
• 2009

본 논문에서는 비트평면 부호화를 이용한 적응적 깊이정보 맵 부호화에서 블록 단위 비트율 조절 방법을 제안한다. 기존 방법에서는 깊이정보 맵에 대한 비트율 조절을 위해 양자화 변수를 이용하여 분리된 비트평면의 이진 영상들 중 특정 비트평면의 이진 영상만 부호화하는 방법을 통해 비트율을 조절할 수 있었다. 본 논문에서는 비트율-왜곡 최적화 방법을 이용하여 블록 단위로 부호화할 비트평면의 이진영상을 결정하는 방법을 제안한다. 실험 결과 제안하는 방법이 기존 방법보다 BD-PSNR이 0.2 dB 향상되었고 BD-rate가 2.97% 감소되어 제안하는 방법의 우수함을 확인할 수 있었다.

• Proceedings of the IEEK Conference
• /
• 2001.06a
• /
• pp.205-208
• /
• 2001

According to the IMT-2000 specification of 3GPP(3rd Generation Partnership Project) and 3GPP2, Turbo codes is selected as a FEC(forward error correction) code for even higher reliable data communication. In 3GPP complied IMT-2000 system, channel coding under consideration is the selective use of convolutional coding and Turbo codes of 1/3 code rate with 4 constraint length. Suggesting a new path metric normalization method, we achieved a low complexity and high performance SOVA decoder for Turbo Codes, Further more, we analyze the decoding performance with respect to update depth and find out the optimal value of it by using computer simulation. Based on the simulation result, we designed a SOVA decoder using VHDL and implemented it into the Altera EPF10K100GC503FPGA.

• ETRI Journal
• /
• v.36 no.2
• /
• pp.242-252
• /
• 2014

Since July of 2012, the 3D video extension of H.264/AVC has been under development to support the multi-view video plus depth format. In 3D video applications such as multi-view and free-view point applications, synthesized views are generated using coded texture video and coded depth video. Such synthesized views can be distorted by quantization noise and inaccuracy of 3D wrapping positions, thus it is important to improve their quality where possible. To achieve this, the relationship among the depth video, texture video, and synthesized view is investigated herein. Based on this investigation, an edge noise suppression filtering process to preserve the edges of the depth video and a method based on a total variation approach to maximum a posteriori probability estimates for reducing the quantization noise of the coded texture video. The experiment results show that the proposed methods improve the peak signal-to-noise ratio and visual quality of a synthesized view compared to a synthesized view without post processing methods.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.12
• /
• pp.2525-2532
• /
• 2009

In this paper, a fast sphere decoder is proposed for the joint detection of phase-shift keying (PSK) signals in uncoded Vertical Bell Laboratories Layered Space Time (V-BLAST) systems. The proposed decoder, PSD, consists of preprocessing stage and search stage. The search stage of PSD relies on the depth-first branch-and-bound (BB) algorithm with "best-first" orders stored in lookup tables. Simulation results show that the PSD is able to provide the system with the maximum likelihood (ML) performance at low complexity.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.8C
• /
• pp.651-660
• /
• 2010

In this paper, we implement an efficient histogram-based prefiltering to compensate the illumination mismatches in regions between neighboring views. In multi-view video, such illumination disharmony can primarily occur on account of different camera location and orientation and an imperfect camera calibration. This discrepancy can cause the performance decrease of multi-view video coding(MVC) algorithm. A histogram matching algorithm can be exploited to make up for these differences in a prefiltering step. Once all camera frames of a multi-view sequence are adjusted to a predefined reference through the histogram matching, the coding efficiency of MVC is improved. However general frames of multi-view video sequence are composed of several regions with different color composition and their histogram distribution which are mutually independent of each other. In addition, the location and depth of these objects from sequeuces captured from different cameras can be different with different frames. Thus we propose a new algorithm which classify a image into several subpartitions by its depth information first and then histogram matching is performed for each region individually. Experimental results show that the compression ratio for the proposed algorithm is improved comparing with the conventional image-based algorithms.

• Journal of Broadcast Engineering
• /
• v.22 no.1
• /
• pp.28-41
• /
• 2017

In this paper, the fast encoding algorithm in High Efficiency Video Coding (HEVC) encoder was studied. For the encoding efficiency, the current HEVC reference software is divided the input image into Coding Tree Unit (CTU). then, it should be re-divided into CU up to maximum depth in form of quad-tree for RDO (Rate-Distortion Optimization) in encoding precess. But, it is one of the reason why complexity is high in the encoding precess. In this paper, to reduce the high complexity in the encoding process, it proposed the method by determining the maximum depth of the CU using a hierarchical clustering at the pre-processing. The hierarchical clustering results represented an average combination of motion vectors (MV) on neighboring blocks. Experimental results showed that the proposed method could achieve an average of 16% time saving with minimal BD-rate loss at 1080p video resolution. When combined the previous fast algorithm, the proposed method could achieve an average 45.13% time saving with 1.84% BD-rate loss.