• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.646_647
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• 2009

소형 다상 외전형 BLDC 전동기의 코깅토크를 최소화하기 위해 코깅토크의 발생원인 중 하나인 영구자석의 형상에 샘플링 포인트 기법인 LHS를 이용한 최적화 알고리즘을 적용하여 코깅토크를 최소화하는 최적 설계를 수행 하였다. 총 3번의 반복계산을 하여 코깅토크가 최소화 되는 최적점을 계산한 결과,최대 코깅토크가 0.20 [N.m]에서 0.15 [N.m]로, 초기 형상의 약 75%로 감소되었다

• Journal of the Korea Computer Industry Society
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• v.3 no.7
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• pp.871-880
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• 2002

In this paper, I proposed the adaptive watermarking based on the discrete wavelet transform for the very robust watermarking against intentional distortion which attacks on image. A watermark is an binary image such as document(sign), and such watermark image is embedded in the LH and HL band of wavelet transformed domain for copyright protection of image data. To evaluate robustness of the proposed method, we applied some basic algorithm of image processing such as brightening, darkening, sharpening, blurring, cropping, histogram equalizing and lossy compression(JPEG, gif). As a result of experiment, the proposed method has the good image quality and the high perceptibility of watermark. It was demonstrated by experiments that the proposed algorithm can provide an excellent protection under various attacks.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.11
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• pp.2027-2032
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• 2007

In this paper, digital watermarking method using quad-tree algorithm and the lowest frequency band is proposed. The proposed algorithm searches the coefficient of the watermark by using quad-tree algorithm and inserts the watermark by the Cox's algorithm. The simulation of the proposed algorithm is implemented about the effect of various weight factors in Cox's algorithm, that of embedding watermark in each subband coefficient (HH, LH, HL), and that of embedding in the lowest frequency band (LL). As a simulation result, the bigger weight factors in Cox's algorithm show strong to noise. The watermarking performance of simultaneously embedding in HH, LH, and HL band is better than that of different cases. In addition, insertion the watermark to the LL band about $30{\sim}60%$ of all watermarks improves the watermarking performance in comparison with the case of not using the LL band.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.64-66
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• 2009

소형 다상 의전형 BLDC 전동기의 코깅토크를 최소화하기 위해 코깅토크의 발생원인 중 하나인 고정자 슬롯의 형상에 샘플링 포인트 기법인 LHS를 이용한 최적화 알고리즘을 적용하여 코깅토크를 최소화하는 최적 설계를 수행 하였다. 총 3번의 반복계산을 하여 코깅토크가 최소화 되는 최적점을 계산한 결과, 최대 코깅 토크가 1.07 [N.m]에서 0.75 [N.m]로, 초기 형상의 약 70%로 감소되었다.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.8
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• pp.579-588
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• 2013

This paper proposes an effective watermarking approach for copyright protection of fire video images. The proposed watermarking approach efficiently utilizes the inherent characteristics of fire data with respect to color and texture by using a gray level co-occurrence matrix (GLCM) and fuzzy c-means (FCM) clustering. GLCM is used to generate a texture feature dataset by computing energy and homogeneity properties for each candidate fire image block. FCM is used to segment color of the fire image and to select fire texture blocks for embedding watermarks. Each selected block is then decomposed into a one-level wavelet structure with four subbands [LL, LH, HL, HH] using a discrete wavelet transform (DWT), and LH subband coefficients with a gain factor are selected for embedding watermark, where the visibility of the image does not affect. Experimental results show that the proposed watermarking approach achieves about 48 dB of high peak-signal-to-noise ratio (PSNR) and 1.6 to 2.0 of low M-singular value decomposition (M-SVD) values. In addition, the proposed approach outperforms conventional image watermarking approach in terms of normalized correlation (NC) values against several image processing attacks including noise addition, filtering, cropping, and JPEG compression.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.3
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• pp.249-255
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• 2013

In this paper, we propose an algorithm to detect scale invariant object from IR image obtained in the sea environment. We create horizontal edge (HL), vertical edge (LH), diagonal edge (HH) of images through 2-D discrete Haar wavelet transform (DHWT) technique after noise reduction using morphology operations. Considering the sea environment, Gaussian blurring to the horizontal and vertical edge images at each level of wavelet is performed and then saliency map is generated by multiplying the blurred horizontal and vertical edges and combining into one image. Then we extract object candidate region by performing a binarization to saliency map. A small area in the object candidate region are removed to produce final result. Experiment results show the feasibility of the proposed algorithm.

• The KIPS Transactions:PartD
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• v.15D no.2
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• pp.171-178
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• 2008

Since the XML standard was introduced by the W3C in 1998, documents that have been written in XML have been gradually increasing. Accordingly, several systems have been developed in order to efficiently manage and retrieve massive XML documents. BitCube-a bitmap indexing system-is a representative system for this field of research. Based on the bitmap indexing technique, the path bitmap indexing system(LH06), which performs the clustering of similar paths, improved the problem that the existing BitCube system could not solve, namely, determining similar paths. The path bitmap indexing system has the advantage of a higher retrieval speed in not only exactly matched path searching but also similar path searching. However, the similarity calculation algorithm of this system has a few particular problems. Consequently, it sometimes cannot calculate the similarity even though some of two paths have extremely similar relationships; further, it results in an increment in the number of meaningless clusters. In this paper, we have proposed a novel method that clustering, the similarity between the paths in order to solve these problems. The proposed system yields a stable result for clustering, and it obtains a high score in clustering precision during a performance evaluation against LH06.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.2
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• pp.113-122
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• 2005

In this paper, we propose a multi-watermarking algorithm to satisfy two purposes: fragility against malicious attacks and robustness against non-malicious attacks. The algorithm can be used for image authentication using coefficients of Discrete Wavelet Transform(DWT). In the proposed method, watermarks are generated by combining binary image with some features extracted from the subband LL3, and then they are embedded into both the spatial and frequency domain. That is, on the spatial domain they are embedded into the Least Significant Bit(LSB) of all pixels of image blocks, and on the frequency domain the coefficients of the subband LH2 and HL2 are adjusted according to the watermarks. Thus the algorithm not only resists malicious attack but also permits non-malicious attacks such as blurring, sharpening, and JPEG compression.

• Broadcasting and Media Magazine
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• v.8 no.2
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• pp.149-159
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• 2003

현재 사회 전반에 걸쳐 급격히 증가하고 있는 멀티미디어 정보를 효율적으로 관리, 활용할 수 있는 방법이 다양하게 연구되고 있다. 본 연구에서는 내용기반 영상검색을 위한 다중 영상특징 추출방법과 특징결합 방법을 제시한다. 우선 전처리 및 캐니 에지 검출법으로 질의영상내 물체영역의 에지를 검출한다. 그 다음에 제안한 볼록 다각형 알고리즘을 통해 분할된 물체영상을 획득한다. 분할된 물체영상은 HSV 공간으로 변환되고 히스토그램 인터섹션 방법으로 유사도가 측정된다. 또한 분할된 물체영상은 웨블릿 변환 영상으로도 변환된다. 이러한 변환후 웨블릿 부밴드의 LL 영역에 제안하는 거리 밴드 평균 오토코릴로그램 알고리즘을 적용하여 오토코릴로그램 유사도를 측정한다. 그리고 GLCM을 이용한 엔트로피와 콘트라스트 유사도는 LH, HL 영역에서 측정된다. 전 과정을 통해 얻은 4개의 다중 영상특징은 수정된 보다 카운트 방법으로 결합되고 최종 유사도가 결정된다. 실험결과 제안한 다중 영상특징을 사용한 검색 방법이 단일 영상특징을 사용하는 검색 방법보다 소환성과 정확성의 성능에 있어 우수함을 보였다. 그리고 NMRR 측정에서도 개선된 성능을 보였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.300-303
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• 2005

본 논문에서는 디지털 멀티미디어 데이터의 저작권 보호를 위하여 웨이블릿 기반 인간 시각 시스템과 주파수 계수의 공간적 특성을 이용한 워터마킹 알고리즘을 제안하였다. 원영상을 1-Level 분해하여 HL1영역과 LH1영역을 4${\times}$4 영역으로 블록화하고 각 블록의 엔트로피와 텍스쳐 값이 가장 좋은 영역을 찾는다. 워터마크가 삽입될 영역은 상위 레벨 계수들의 상관도 특성에 따라서 3-Level 영역에 워터마크를 삽입하였다. 성능평가로 JPEG 압축, 필터링 등 워터마크된 영상에 외부공격을 가하여 워터마크 추출여부를 확인하였고, 실험결과 제안한 알고리즘은 JPEG 압축 50% 이상에서 90%이상의 상관도를 보였고, 샤프닝, 필터링 및 부분삭제 영상변형에 강인함을 보였다.