• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.666-669
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• 2013

2012년 고시된 '정보시스템 구축 운영 지침'에 따라 행정안전부에서는 '전자정부 SW 개발 운영자를 위한 시큐어 코딩 가이드'를 배포하고 있다. 시큐어 코딩 기법을 예제 위주로 제시함으로써, 개발 실무에 활용도를 높이기 위하여 배포된 시큐어 코딩 가이드는 유용한 지침서임에는 틀림이 없으나, 개발자 개개인이 그 내용을 모두 숙지하기 위해서는 많은 시간과 노력을 필요로 한다. 특히 입력 데이터 검증 및 표현에 관한 시큐어 코딩은 시스템 아키텍쳐 차원의 중앙집중적인 관점이 아닌 개발자 개개인이 구현한 기능 단위 수준에서 수행되고 있는 필드의 현실상, 이를 중앙집중적인 관점에서의 입력 데이터 검증을 통하여, 보다 안전한 소프트웨어를 제작하기 위한 방법을 코드 중심의 사례로 설명하고자 한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.11a
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• pp.143-144
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• 2020

VVC (Versatile Video Coding)는 HEVC이후 차세대 표준 비디오 코딩으로 JVET(Joint Video Exploration)에 의해 2018년 표준화를 시작하였다. VVC에는 복원픽쳐의 변환-양자화에러에 의해 발생한 블로어, 블로킹, 링잉 아티팩트를 감소시키기 위하여 deblocking filter (DF), sample adaptive offset (SAO), adaptive loop filter(ALF)와 같은 모듈을 사용한다. 한편 CNN (Convolutional Neural Network)은 최근 이미지와 비디오 복원에 높은 성능을 보이고 있다. VVC에서 픽쳐는 CTU (Coding Tree Unit)으로 분할되고 각 CTU는 다시 CU (Coding Unit)으로 분할된다. 그리고 인코딩을 위한 중요한 정보들이 Picture, CTU, CU단위로 디코더에 전송된다. 이 논문에서는 화면 간 예측으로 인코딩 된 픽처에서 블록과 픽처정보를 이용한 딥러닝 기반의 인루프 필터 모델을 제안한다. 제안하는 모델은 화면 간 예측에서 QP, 4×4 블록단위의 모션벡터, 참조블록과의 시간적거리, CU의 깊이를 모델에 추가적인 정보로 이용한다.

• The KIPS Transactions:PartB
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• v.13B no.3 s.106
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• pp.301-308
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• 2006

Currently, the preferred processing of a user-centered ROI(Region-of-Interest) or a specific region of image than the transmission and decompression of a full image is needed in different applications. This preferred processing has been actively studied about from the ROI coding methods in JPEG2000 standards to the new methods complementing them. But, there does not exist an ROI coding method suitable for all applications. Therefore, this study shows a criterion of selection according to the application requirements for applying an adequate ROI coding method in JPEG2000 applications, and shows the experimental results deciding efficient parameters in the selected methods.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.8
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• pp.104-113
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• 2014

The existing rough mode decision (RMD) algorithm, used in HEVC standard loses the coding efficiency and wastes encoding time when encoding using transform skip mode (TSM) because the RMD algorithm in HEVC uses a selection method that is designed for DCT, not for TSM. This paper proposes a new RMD algorithm for TSM in HEVC. Our proposed RMD algorithm enhances the coding efficiency by employing a new cost function to increase the probability of selecting the best intra prediction mode for TSM. In addition, it reduces the encoding time by skipping the encoding process of least feasible TSM based on a newly proposed threshold value. The experiment results show that the proposed method achieves coding gains of -0.3% for screen contents with a 10% reduction in encoding time compared to those of the HEVC standard.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.12
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• pp.1281-1288
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• 2012

This paper presents the design and implementation of a multi-mode mobile broadcasting Emergency Warning System (EWS) transmission and reception system which enables the propagation of disaster information using the encoding and transmission, reception and decoding methods specified in diverse mobile broadcasting standards. The implemented system supports global mobile broadcasting standards such as Terrestrial Digital Multimedia Broadcasting (T-DMB), Digital Video Broadcasting-Handheld (DVB-H), Integrated Services Digital Broadcasting-Terrestrial (ISDB-T), and the Digital Radio Mondiale (DRM) digital radio standard. The system consists of two key part: an encoding/transmission part and a reception/decoding part. The multi-mode mobile broadcasting EWS encoding and transmission system generates EWS data according to each broadcasting specification. The generated EWS data is then transmitted through a channel interface which meets the commercial broadcasting equipment specification. The receiver system receives and decodes the EWS data on a single hardware platform and can display the results on screen. Verification and conformity testing has been carried out on the implemented system by transmitting emergency data for each mode in real-time and displaying the received information in text on the receiver display.

• The Journal of the Acoustical Society of Korea
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• v.28 no.7
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• pp.599-609
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• 2009

An overview of the recently finalized multi-channel audio coding standard MPEG Surround is provided. This audio coding standard downmixes multi-channel signals to mono or stereo signals and, simultaneously, extracts spatial parameters for its encoding process. In its decoding process, it reconstructs multi-channel signals based on the downmix signals and spatial parameters. Since the downmix signals are coded in conventional audio coding format such as AAC and MP3 and the spatial parameters require a small amount of information MPEG Surround guarantees high sound quality multi-channel audio at low bit rates. Besides, it is backward-compatible to conventional audio coding techniques because the downmix signals can be played on portable audio devices ignoring the spatial parameter information. In this paper, Part 1 presents an overview of the basic structure of MPEG Surround and Part 2 describes various modes and tools including the binaural mode which supports the virtual 5.1-channel playback via headphones or earphones. The listening test results by various companies and organizations are also presented.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11C
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• pp.1049-1058
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• 2009

After the efficiency of H.264 video compression has been announced, it replaced MPEG-2 standard in several applications. So transcoding methods of MPEG-2 to H.264 have been studying because there are variety devices and contents followed by MPEG-2. Although H.264 supported various service such as IPTV, DMB, digital broadcasting etc, but users using MPEG-2 devices cannot accessible to them. This paper propose H.264 to MPEG-2 transcoding for users of MPEG-2 devices without displacement H.264. The proposed method predicted a motion vector for MPEG-2 encoder after it extracted from motion vectors of variable blocks in H.264 to improve processing time. Also it predicted a optimal motion vector using modified boundary matching algorithm after grasped a special character for boundary and background of object. The experimental results from proposed method show a considerable reduction in processing time, as much as 65% averagely, with a small objective quality reduction in PSNR.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.5
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• pp.973-983
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• 2019

The importance of information security has been increasingly emphasized at the national, organizational, and individual levels due to the widespread adoption of software applications. High-safety software, which includes embedded software, should run without errors, similar to software used in the airline and nuclear energy sectors. Software development techniques in the above sectors are now being used to improve software security in other fields. Secure coding, in particular, is a concept encompassing defensive programming and is capable of improving software security. In this paper, we propose a software security vulnerability detection method using an improved coding standard searching technique. Public static analysis tools were used to assess software security and to classify the commands that induce vulnerability. Software security can be enhanced by detecting Application Programming Interfaces (APIs) and patterns that can induce vulnerability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5C
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• pp.454-463
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• 2010

After the efficiency of H.264 video compression has been announced, it replaced MPEG-2 standard in several applications. So transcoding methods of MPEG-2 to H.264 have been studying because there are variety devices and contents followed by MPEG-2. Although H.264 supported various service such as IPTV, DMB, digital broadcasting etc, but users using MPEG-2 devices cannot accessible to them. This paper propose H.264 to MPEG-2 transcoding for users of MPEG-2 devices without displacement H.264. The proposed method predicted a motion vector for MPEG-2 encoder after it extracted from motion vectors of variable blocks in H.264 to improve processing time. Also it predicted a optimal motion vector using modified boundary matching algorithm after grasped a special character for boundary and background of object. The experimental results from proposed method show a considerable reduction in processing time, as much as 68% averagely, with a small objective quality reduction in PSNR.

• Electronics and Telecommunications Trends
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• v.16 no.3 s.69
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• pp.9-22
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• 2001

본 고는 차세대 초고속 가입자 접속기술인 VDSL의 개발현황과 표준화 진행을 분석하여 우리나라의 VDSL의 연구방향을 제시하고자 하는 것이다. 이를 위하여 제 외국의 표준화 단체를 중심으로 진행되고 있는 가입자 접속표준 및 기술규격 등을 검토 분석하고 그 변조 및 코딩체계의 개념으로 나타나는 수치자료에 대한 근거를 조사하여 궁극적으로 국내 기술 개발 방안을 마련하려는 것이다. 따라서 본 고의 초점은 현재 제안되고 있는 VDSL 시스템의 전체적인 윤곽과 구조에 관련된 기술, 표준화와 관련된 Unbundling 기술을 설명하고, ITU-T Group-15, ANSI T1E1.4, ETSI TM-6 등 표준화 단체에서 제안한 VDSL 변조 및 코딩기술을 제시하고자 한다.