• ETRI Journal
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• 제22권1호
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• pp.20-29
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• 2000

In this paper, we present a design of video and audio single chip encoder/decoder for portable multimedia application. The single-chip called as video audio signal processor (VASP) consists of a video signal processing block and an audio single processing block. This chip has mixed hardware/software architecture to combine performance and flexibility. We designed the chip by partitioning between video and audio block. The video signal processing block was designed to implement hardware solution of pixel input/output, full pixel motion estimation, half pixel motion estimation, discrete cosine transform, quantization, run length coding, host interface, and 16 bits RISC type internal controller. The audio signal processing block is implemented with software solution using a 16 bits fixed point DSP. This chip contains 142,300 gates, 22 Kbits FIFO, 107 kbits SRAM, and 556 kbits ROM, and the chip size is $9.02mm{\times}9.06mm$ which is fabricated using 0.5 micron 3-layer metal CMOS technology.

• 한국정보처리학회논문지
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• 제6권11호
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• pp.3140-3149
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• 1999

Skew correction for document images can be using a rotational transformation of pixel coordinates. In this paper we propose a method which corrects the document skew, by an amount of $\theta$ degrees, using block information, where the block is defined as a rectangular area containing adjacent black pixels. Processing speed of the proposed method is faster than that of the method using pixel transformation, since the number of floating-point operations can be reduced significantly. In the proposed method, we rotate only the four corner points of each block, and then identify the pixels inside the block. Two methods for inside pixel identification are proposed; the first method finds two points intersecting the boundary of the rotated block in each row, and determines the pixels between the two intersection points as the inside pixel. The second method finds boundary points based on Bresenham's line drawing algorithm, using fixed-point operation, and fills the region surrounded by these boundaries as black pixels. We have measured the performance of the proposed method by experimenting it with 2,016 images of various English and Korean documents. We have also proven the superiority of our algorithm through performance comparison with respect to existing methods based on pixel transformation.

• 한국컴퓨터정보학회논문지
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• 제10권5호
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• pp.109-114
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• 2005

Twofish 암호알고리즘은 AES인 Rijndael 암호알고리즘에 비하여 알고리즘 자체가 간결하며, 구현의 용이성이 좋지만 처리속도가 느린 단점을 가진다. 그러므로 본 논문은 Twofish 암호알고리즘의 속도를 향상시키기 위하여 개선된 MDS 블록을 설계하였다. 기존 MDS 블록은 Twofish 암호시스템의 critical path를 점유하게 되는 블록으로서 처리속도의 병목현상으로 인한 속도저하의 문제점이 존재하였다. MDS 블록에서 연산자로 사용되는 곱셈연산을 감소시키기 위하여 본 논문은 LUT 연산과 modul-2o연산을 사용하여 MDS자체에 대한 속도저하 및 병목현상을 제거하였다 이러한 결과로 새롭게 설계된 MDS블록을 포함하는 Twofish 암호시스템은 기존 Twofish 암호시스템에 비하여 10$\%$정도 처리속도의 향상을 가져옴을 확인하였다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.612-617
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• 2009

In a DCT coding, degradations called block artifact and mosquito noise are appeared in reconstructed pictures. They should be reduced in post processing after decoding without superabundant processing. However, an estimation of mosquito noise is rare because of its difficulty. To realize an estimation of mosquito noise level, we extract a block that mosquito noise will be easy to occur. Mosquito noise level is calculated at a selected side of the block. In this processing, only the sides of high probability block are used. Then, a block value is taken by averaging. Finally, the picture value is calculated by averaging of this. Estimation method is evaluated by using the MPEG-4 decoded pictures. Quantization scale of coding and the estimated mosquito noise level are compared. As the results, we recognize the proposed method gives almost reasonable mosquito block and absolute level. Father, adaptive filter is controlled by the estimated mosquito noise level. It is recognized that the high quality of decoded picture is kept and the mosquito noise is reduced effectively at the picture with degradation.

• Journal of Information Processing Systems
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• 제11권2호
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• pp.266-279
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• 2015

In this paper, we propose a novel block cipher mode of operation, which is known as the counter chain (CC) mode. The proposed CC mode integrates the cipher block chaining (CBC) block cipher mode of operation with the counter (CTR) mode in a consistent fashion. In the CC mode, the confidentiality and authenticity of data are assured by the CBC mode, while speed is achieved through the CTR mode. The proposed mode of operation overcomes the parallelization deficiency of the CBC mode and the chaining dependency of the counter mode. Experimental results indicate that the proposed CC mode achieves the encryption speed of the CTR mode, which is exceptionally faster than the encryption speed of the CBC mode. Moreover, our proposed CC mode provides better security over the CBC mode. In summary, the proposed CC block cipher mode of operation takes the advantages of both the Counter mode and the CBC mode, while avoiding their shortcomings.

• Journal of Information Processing Systems
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• 제15권2호
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• pp.410-421
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• 2019

Distributed compressed sensing (DCS) states that we can recover the sparse signals from very few linear measurements. Various studies about DCS have been carried out recently. In many practical applications, there is no prior information except for standard sparsity on signals. The typical example is the sparse signals have block-sparse structures whose non-zero coefficients occurring in clusters, while the cluster pattern is usually unavailable as the prior information. To discuss this issue, a new algorithm, called backtracking-based adaptive orthogonal matching pursuit for block distributed compressed sensing (DCSBBAOMP), is proposed. In contrast to existing block methods which consider the single-channel signal reconstruction, the DCSBBAOMP resorts to the multi-channel signals reconstruction. Moreover, this algorithm is an iterative approach, which consists of forward selection and backward removal stages in each iteration. An advantage of this method is that perfect reconstruction performance can be achieved without prior information on the block-sparsity structure. Numerical experiments are provided to illustrate the desirable performance of the proposed method.

• 한국멀티미디어학회논문지
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• 제6권7호
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• pp.1189-1199
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• 2003

본 논문에서는 계층화 모션 추정법과 병렬 처리를 이용한 차량의 움직임 측정 알고리즘을 제안한다. 본 시스템에서는 CMOS 센서를 통하여 도로 영상을 캡쳐한다. 그 다음에 영상을 작은 블록들로 나누고 블록매칭을 이용하여 각 블록의 움직임을 계산한다. 그리고 움직임이 비슷한 블록들을 클러스터링하여 차량의 움직임을 측정한다. 본 논문에서는 실시간 동작을 위하여 계층화 모션 추정법과 병렬 처리에 의거한 블록매칭 알고리즘을 제안한다. 병렬처리를 위해서는 파이프라인과 데이터 플로우 기법을 도입하였다. 본 논문에서 제안된 시스템은 기존의 내장형 시스템을 이용하여 구현되었다. 제안된 블록매칭 알고리즘은 PLD(Programmable Logic Device)를 이용하여 구현하였고 클러스터링 알고리즘은 ARM 프로세서를 이용하여 구현하였다. 실험 결과에 의하면 본 논문에서 구현된 시스템은 차량의 움직임을 실시간으로 추출할 수 있었다.

• 한국멀티미디어학회논문지
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• 제5권6호
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• pp.665-673
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• 2002

본 논문에서는 LFSR(Linear Feedback Shift Register)의 대안으로 소개되고 있는 셀룰라 오토마타(CA: Cellular Automata)를 소개하고 이를 이용한 새로운 블록 암호 알고리즘을 제안한다. 제안된 블록 암호 알고리즘의 성능과 안전성 평가를 위해 쇄도효과와 수행속도에 대해 표준 블록 암호 알고리즘과 비교를 수행하고 또한 차분 분석법(Differential Cryptanalysis)에 대하여 제안 알고리즘에 대한 축소된 버전으로 평가를 수행한다. 부가적으로 제안 암호 알고리즘의 출력 비트열에 대하여 FIPS PUB 140-2(Federal Information Processing Standards publication 140-2)의 랜덤 수열에 대한 통계적 검정을 수행함으로써 출력 수열이 랜덤함을 보인다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권11호
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• pp.3970-3990
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• 2021

In view of the problems of insufficient data collection and processing capability of multi-source heterogeneous equipment, and low visibility of equipment status at the ship block construction site. A data collection method for ship block construction equipment based on wireless sensor network (WSN) technology and a data processing method based on edge computing were proposed. Based on the Browser/Server (B/S) architecture and the OneNET platform, an online monitoring system for ship block construction equipment was designed and developed, which realized the visual online monitoring and management of the ship block construction equipment status. Not only that, the feasibility and reliability of the monitoring system were verified by using the intelligent tire frame system as the application object. The research of this project can lay the foundation for the ship block construction equipment management and the ship block intelligent construction, and ultimately improve the quality and efficiency of ship block construction.

• 융합신호처리학회논문지
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• 제23권3호
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• pp.179-184
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• 2022

본 논문은 탐색 알고리즘 없이 자동으로 모델의 합성곱 필터의 개수를 최적으로 결정할 방법에 대해 연구하고자 한다. 본 논문은 SENet에서 제안한 SE Block을 합성곱 신경망에 연결하고 하단의 학습하지 않는 합성곱 신경망을 연결한 HSE Block을 제안한다. HSE Block 모델에 두 개의 데이터셋을 이용하여 필터의 개수를 3 epoch 당 1개씩 증가시키는 실험과 필터 내의값에 따라 필터의 개수를 증가시키는 실험을 수행하였다. 이 실험을 바탕으로 한 층의 HSE Block이 아닌 다층의 HSE Block으로 모델을 구성하고, 기존의 실험할 때 사용한 데이터셋에 비해 더욱 학습하기 어려운 데이터셋을 사용하여 실험을 진행하였다. 기존보다 학습하기 어려운 데이터셋에 대해 HSE Block의 개수를 2개, 3개, 4개, 5개로 두고 실험을 수행함으로써 HSE Block의 효과를 검증하였다.