• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.3 s.309
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• pp.1-8
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• 2006

In this paper, we propose a new post-processing method, based on the theory of the projection onto convex sets (POCS) to reduce the blocking artifacts in decoded images. We propose a few smoothness constraint set (SCS) and its projection operator in the wavelet transform (WT) domain to remove unnecessary high-frequency components caused by blocking artifacts. We also propose a new method to find and preserve the original high frequency components of the image edge. Experimental results show that the proposed method can not only achieve a significantly enhanced subjective quality, but also have the PSNR improvement in the output image.

• Journal of Korea Multimedia Society
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• v.6 no.5
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• pp.805-815
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• 2003

In this paper, we present the development of document compression codec using segmentation, wavelet lifting and bitplane coding. We use the segmentation to preserve the text appearance. We performed integer-to-integer wavelet lifting and also performed bitplane subblock coding for document compression. We acquired a high compression ratio and an efficient compression by encoding only the significant subblocks in the bitplane subblock coding. We also implemented scalar quantization by subband-oriented bit shifting. The system performs color conversion and downsampling before wavelet lifting and also performs graycode conversion and quantization before subblock coding. In the experiment, we show the performances of the system by presenting the high compression ratios and high PSNR values.

• Journal of Broadcast Engineering
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• v.5 no.1
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• pp.31-40
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• 2000

In this paper, we propose an edge histogram to efficiently represent the edge distribution in the image for MPEG-7. To this end, we adopt global, semi-global, and local edge histogram bins. Also, we extract the edge information from the image in terms of image blocks rather than pixels, which reduces the extraction complexity and is also applicable to the block-based compression standards such as MPEG-1, and 2. Experimental results show that the proposed method yields better retrieval accuracy and feature extraction speed comparing to other non-homogeneous texture descriptors of MPEG-7 including the wavelet-based descriptor and local edge-based descriptor.

• Journal of Korean Society of Archives and Records Management
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• v.19 no.3
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• pp.223-245
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• 2019

As the foundation for the Fourth Industrial Revolution, blockchain is becoming an essential core infrastructure and technology that creates new growth engines in various industries and is rapidly spreading to the environment of businesses and institutions worldwide. In this study, the characteristics and trends of blockchain technology were investigated and arranged, its application to the records management section of public institutions was required, and the procedures and methods of construction in the records management field of public institutions were studied in literature. Finally, blockchain technology was applied to the records management to propose an archive chain model and describe possible expectations. When the transactions that record the records management process of electronic documents are loaded into the blockchain, all the step information can be checked at once in the activity of processing the records management standard tasks that were fragmentarily nonlinked. If a blockchain function is installed in the electronic records management system, the person who produces the document by acquiring and registering the document enters the metadata and information, as well as stores and classifies all contents. This would simplify the process of reporting the production status and provide real-time information through the original text information disclosure service. Archivechain is a model that applies a cloud infrastructure as a backend as a service (BaaS) by applying a hyperledger platform based on the assumption that an electronic document production system and a records management system are integrated. Creating a smart, electronic system of the records management is the solution to bringing scattered information together by placing all life cycles of public records management in a blockchain.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.8
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• pp.1531-1536
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• 2016

In this paper, we propose a fast motion estimation algorithm which is important in performance of video encoding. Even though so many fast algorithms for motion estimation have been published due to its tremendous computational amount of for full search algorithm, efforts for reducing computations in motion estimation still remain. In the paper, we propose an algorithm that reduces unnecessary computations only, while keeping prediction quality the same as that of the full search. The proposed algorithm does not calculate block matching error for each candidate at once to find motion vectors but divides the calculation procedure into several steps and calculates partial sum of block errors. By doing that, we can estimate the minimum error point early and get the enhancement of calculation speed by reducing unnecessary computations. The proposed algorithm uses smaller computations than conventional fast search algorithms with the same prediction quality as full search.

• The Journal of the Korea Contents Association
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• v.10 no.4
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• pp.28-35
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• 2010

The variable block size motion estimation (ME) and compensation (MC) using multiple reference frames is adopted in H.264/AVC to improve coding efficiency. However, the computational complexity for ME/MC increases proportional to the number of reference frames and variable blocks. In this paper, we propose a new efficient reference frame selection algorithm to reduce the complexity while keeping the visual quality. First, a motion vector reference map is constructed by SAD of $4{\times}4$ block unit for multi reference frames. Next, the variable block size motion estimation and motion compensation is performed according to the motion vector reference map. The computer simulation results show that the average loss of BDPSNR is -0.01dB, the increment of BDBR is 0.27%, and the encoding time is reduced by 38% compared with the original method for H.264/AVC.

• Journal of Creative Information Culture
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• v.5 no.2
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• pp.173-182
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• 2019

Recently, creative teaching methods have received a lot of attention in the university community. Creative teaching methods can maximize the effectiveness of the creative education through the voluntary participation of students. One of the most important skills in creative teaching methods is communication because many students are passive in their real classes. An economic reward system helps to improve students' communication skills because it motivates students to study harder. Therefore, a blockchain media based on an economic reward system can be useful teaching tools. This paper proposes a creative teaching method using blockchain media to improve communication skills. The proposed method consists of eight steps, and it was applied to classes for the last three years. The results show that the proposed method helps students improve their communication skills.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1357-1358
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• 2015

본 논문에서는 축사에서 비젼 기반으로 이동 객체를 분류하는 방법을 제안한다. 제안하는 방법은 축사 내 설치된 CCTV로부터 영상을 입력받아 Adaptive GMM알고리즘을 이용하여 이동 객체를 추출한다. 다음, 이동 객체 가 사람인지 소인지 또는 차량인지 분류하기 위해 이동 객체의 특징을 추출한다. 이동 객체 특징 추출 방법으로는 기존의 Monolithic-based방법인 HoG알고리즘을 개선하여 축사의 복잡한 환경에서 다양한 자세를 가지는 사람과 소 그리고 차량의 구조적 특징을 추출한다. 추출한 특징은 벡터화 하여 SVM분류기 입력값에 적합하도록 한다. SVM 분류를 통해 이동 객체의 구조적 특징을 블록화 하여 이동 객체의 신체 모델을 생성한다. 마지막으로 생성된 신체 모델을 이용하여 이동 객체가 사람인지 소인지 또는 차량인지 분류한다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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• pp.565-567
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• 2000

필기 한글 인식에서 원래 패턴의 모양을 유지하는 골격선 추출은 중요하다. 세선화에 의존하는 기존 방법은 작은 잡음에 민감하다는 단점을 안고 있다. 본 논문은 필기 한글 패턴에 적합한 새로운 골격선 추출 방법을 제안한다. 먼저 한글 패턴은 T-접점과 B-접점이라는 두가지 모양 특징을 중심으로 분할할 수 있다는 관찰에 근거하여 유사블록으로 이루어진 부품 집합으로 분할한다. 또한 세 개 이상의 획이 복잡한 형태로 만나는 지점을 결합 부품으로 분할한다. 그런 다음, 각 부품에서 접점의 형태에 따라 결합 부품을 추가 탐지한다. 결합 부품과 인접한 부품들의 연관 관계에 따라 골격선을 구하고, 골격선의 연결성을 보장하기 위해서 선분 연장을 수행한다. 본 논문에서 기존의 방법과의 비교를 위해 다섯 가지 비교 기준을 설정하고, 이를 기반으로 비교 분석하였다. 본 논문에서 제안한 방법이 여러 기준에서 세선화-기반 방법보다 우수함을 보였다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.55-57
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• 2004

DCT(Discrete Cosine Transform)는 현존하는 블록기반 영상 압축 코딩기법의 핵심이 되는 부분이다. 많은 고속 방법이 제안되었으며, 최근 들어 SIMD 병렬구조를 이용한 고속방법들이 제안되고 있다. 본 논문에서는 SIMD명령어를 가지는 프로세서에서 4$\times$4 정수변환의 속도를 최적화하기 위한 알고리즘을 제안한다. 본 논문에서 제안하는 알고리즘은 128비트 SIMD영령어로 확장이 가능하며 비슷한 구조를 가지는 Hadamard 변환에서 적용할 수 있다. 제안하는 방법을 펜티엄4 2.4G에서 구현할 경우 H.264 참조 부호화기의 4$\times$4 정수변환 방법보다 64비트 SIMD 명령어를 사용할 경우 4.34배 128-bit SIMD 명령어를 사용할 경우 6.77배의 성능을 얻을 수 있다.