• 한국통신학회논문지
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• 제21권11호
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• pp.2789-2800
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• 1996

Real time fractal coding for successive QCIF 144*176 luminance images has been implemented on a 50MHz IBM 486 personal computer. To satisfy the frame encoding speed and data compression ratio, following algorithms are adopted. In order to minimize encoding time, extension SAS being not searching of domain blocks is used. for reducing the bits per pixel, conventioal 4*4 range block is extended to 8*8 range block. and range block extension decrease quality of decoded image. For improvement quality of decoded image, the paper apply quad-tree partition mothod. In order to divide **8 range block, self-simiarity is compared 8*8 range block with spatial contractive transformed 8*8 domain block. According to self-simiarity, the block is partitioned and owing to block partition, increased encoding time is minimized. According to self-simiarity of 8*8 range block and spatial contractive transformed 8*8 domain block, number of fractal factor is varied. Simultaneously with minimizing the decrement of decoded image's quality, transmittion rate and encoding time is shorted. The results enable us to process the real-time fractal coding. For the claire test image, the average PSNR was 32.4dB, 0.12 bit rates and 33ms coding time per frame.

• 한국통신학회논문지
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• 제27권6A호
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• pp.584-591
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• 2002

본 논문에서는 블록간의 유사성과 선형조합을 이용하여 블록화 현상 (blocking artifact)을 효율적으로 제거하는 알고리듬을 제안하였다. 제안한 방법에서는 모든 블록을 DCT 계수에 따라서 저주파 블록과 고주파 블록으로 나눈다. 그리고 블록화 현상이 나타나는 블록 경계면을 중심으로 하는 블록을 치역 블록 (range block)이라 정의하고, 이 치역 블록과 유사한 블록을 탐색영역 범위 안에서 찾은 다음 이를 정의역 블록 (domain block)이라라 정의한다. 그리고 탐색과정에서는 좀 더 정확한 정의역 블록을 참기 위해 치역 블록의 블록 경계면을 중심으로 양쪽으로 나누어진 부 블록 특성과 블록간 유사성을 이용하였다. 마지막으로 탐색과정에서찾은 정의역 블록과 블록화 현상이 발생한 치역 블록과의 선형 조합(linear combination)을 이용하여 치역 블록의 화소 값을 바꿈으로써 블록화 현상을 제거하였다. 모의 실험 결과로부터 제안한 방법이 기조의 방법에 비하여 PSNR 측면에서 0.04∼04 dB 정도의 향상을 얻었을 뿐만 아니라 주관적 화질 면에서도 우수한 성능을 나타냄을 확인하였다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1999년도 KOBA 방송기술 워크샵 KOBA Broadcasting Technology Workshop
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• pp.57.2-62
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• 1999

Fractal coding is image compression techniques using one of image characteristics self-transformability. In fractal image coding, the encoding process is to select the domain block similar to a range block. The reconstructed image quality of fractal image coding depends on similitude between a range block and the selected domain block. Domain block similar to a range blocks. In fact, the error of the reconstructed image adds up the generated error in encoding process and the generated error in decoding process. But current domain block estimating function considered only the encoding error. We propose a domain block estimating function to consider not only the encoding error but also the decoding error. By computer simulation, it was verified to obtain the high quality reconstructed image.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1996년도 Proceedings International Workshop on New Video Media Technology
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• pp.72-76
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• 1996

We propose a novel algorithm for fractal video sequence coding, based on the circular prediction mapping (CPM), in which each range block is approximated by a domain block in the circularly previous frame. In our approach, the size of the domain block is set to be same as that of the range block for exploiting the high temporal correlation between the adjacent frames, while most other fractal coders use the domain block larger than the range block. Therefore the domain-range mapping in the CPM is similar to the block matching algorithm in the motion compensation techniques, and the advantages of this similarity are discussed. Also we show that the CPM can be combined with non-contractive inter-frame mapping (NCIM), improving the performance of the fractal sequence coder further. The computer simulation results on real image sequences demonstrate that the proposed algorithm provides very promising performance at low bit-rate, ranging from 40 Kbps to 250 Kbps.

• 한국정보통신학회논문지
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• 제8권6호
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• pp.1121-1125
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• 2004

본 논문은 H.264/AVC를 위한 고속 블록 모드 결정 알고리즘에 대해 연구한다. H.264/AVC는 단일 크기의 블록을 이용하여 움직임 추정을 수행하는 기존 동영상 부호화 방식과는 다르게 16$\times$16, 16$\times$8, 8$\times$16, 8$\times$8, 8$\times$4, 4$\times$8, 4$\times$4의 7가지 서브 블록을 이용하는 가변 블록 움직임 추정을 채택한다. 이 방식은 효율적인 움직임 추정을 가능하게 하지만 동영상 부호화의 연산량을 크게 증가시키는 원인으로 작용한다. 고속 블록 모드 결정 알고리즘은 먼저 매크로블록에 존재하는 4개의 8$\times$8 블록을 기준으로 8$\times$8 보다 큰 블록 모드와 8$\times$8 보다 작은 블록 모드로 블록 영역을 예측한다. 여기서 8$\times$8 보다 큰 블록 모드로 예측되면 각 8$\times$8 블록간의 움직임 벡터 거리를 임계값과 비교하여 8$\times$8 이상의 블록 모드로 합병한다. 이는 8$\times$8보다 큰 블록 모드의 움직임 추정을 위해 RDO를 16$\times$16, 16$\times$8, 8$\times$16 8$\times$8에 대해 모두 수행하는 것이 아니라 각각의 8$\times$8 블록에 대해서만 수행하므로 블록 모드 결정을 위한 연산량을 효율적으로 감소시킬 수 있다.

• 한국정보통신학회논문지
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• 제8권7호
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• pp.1405-1409
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• 2004

본 논문은 H.264/AVC의 전체 부호화 과정의 큰 부분을 차지하는 블록 모드 결정의 연산량을 효율적으로 줄이면서도 영상의 화질을 감소시키지 않는 블록 모드 결정 알고리즘을 연구한다. 움직임 추정의 연산량 감소를 위해 매크로블록을 8$\times$8 보다 큰 블록 모드와 8$\times$8 보다 작은 블록 모드로 영역을 예측하여 모든 블록 모드 결정의 연산량을 줄인다. 여기서 8$\times$8 보다 작은 블록은 중요한 움직임 정보나 급격한 외각선의 경계를 포함 가능성이 높으므로 정확한 움직임 추정이 필요하다. 이를 위하여 8$\times$8 블록내 모든 블록 크기에 대해서 $RDC_{M\timesN}$를 구하고 가장 작은 $RDC_{M\timesN}$를 갖는 블록을 선택한다. 이때 $RDC_{M\timesN}$의 결정을 위하여 SATD와 이웃하는 탐색 블록의 화소값 평균의 차이를 이용한 움직임 강도를 사용하는 방식을 제안한다. 제안된 알고리즘은 매크로블록 내에서 블록 모드의 결정을 고속으로 수행하면서도 정확한 움직임 추정 및 보상을 가능하게 한다.

• 한국농공학회논문집
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• 제52권4호
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• pp.63-71
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• 2010

This study was performed to evaluate the planting properties and root potential of planting block with mixing seeding of herbaceous plants and cool-season grasses in CSG blocks manufactured by cemented sand and materials (CSG) in order to develop environmentally friendly CSG block applied revegetation. Five types of CSG mix designs with cement contents were determined, and the mechanical properties of CSG materials were studied experimentally. To analyze growth properties of plants within CSG block, germination ratio, visual cover, plant height and root potential were measured in four weeks and eight weeks after seeding. The germination regardless mixture seeding of plants and CSG mixproportions started within 4 ~ 7 days after seeding and the germination ratio were in the range of 60 ~ 65 %. The visual cover of kinds of plants evaluated by visual rating system were in the range of 6 ~ 8 in case of seeding the species of cool-season grasses and were in the range of 4 ~ 6 in case of seeding the species of herbaceous plants in four weeks after seeding. The root potential of CSG block with the species of cool-season grasses and herbaceous plants were in the range of $5.7{\times}10^{-3}{\sim}7.7{\times}10^{-3}$ MPa and $2.3{\times}10^{-3}{\sim}6.7{\times}10^{-3}$ MPa in eight weeks after seeding, respectively.

• 한국컴퓨터정보학회논문지
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• 제24권6호
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• pp.73-80
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• 2019

In this paper, we propose an effective dynamic range compression (DRC) method of infrared images. A histogram of infrared images has narrow dynamic range compared to visible images. Hence, it is important to apply the effective DRC algorithm for high performance of an infrared image analysis. The proposed algorithm for high dynamic range divides an infrared image into the overlapped blocks and calculates Shannon's entropy of overlapped blocks. After that, we classify each block according to the value of entropy and apply adaptive histogram modification method each overlapped block. We make an intensity mapping function through result of the adaptive histogram modification method which is using standard-deviation and maximum value of histogram of classified blocks. Lastly, in order to reduce block artifact, we apply hanning window to the overlapped blocks. In experimental result, the proposed method showed better performance of dynamic range compression compared to previous algorithms.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.63-64
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• 2007

Polystyrene-block-polymethyl methacrylate (PS-b-PMMA) can pattern nanoscale structures over large areas. However these patterns have a short-range order. These short-range order limits their utility in some applications. Consequently, we have to overcome this limitation of block-copolymer. In this study we added a electrical field to the standard block-copolymer patterning method for long-range ordered arrays of nanostructures. This method is conformed by annealing a block copolymer with applied voltages. It is very simple method that do not have any additional hour. In this reason it can be applied easily for other nanostructure fabrications. This method opens up a new route to the controlled phase separation of block copolymers with precise place of the nanostructures.

• 한국산업융합학회 논문집
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• 제3권4호
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• pp.369-378
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• 2000

Conventional fractal image compression methods have many problems in searching time for matching domain block. Proposed method is an improved method of Fisher's Quadtree Decomposition in terms of time, compression ratio, and PSNR. This method determines range block in advance using QR algorithm. First, input image is partitioned to $4{\times}4$ range block and then recomposition is performed from bottom level to specified level. As a result, this proposed method achieves high encoding and decoding speed, high compression ratio, and high PSNR than Fisher's Quadtree Decomposition method.