• 한국멀티미디어학회논문지
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• 제8권12호
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• pp.1572-1580
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• 2005

The common requirements for watermarking are usually invisibility, robustness, and capacity. We proposed the watermarking for 3D mesh model based on projection onto convex sets for invisibility and robustness among requirements. As such, a 3D mesh model is projected alternatively onto two convex sets until it converge a point. The robustness convex set is designed to be able to embed watermark into the distance distribution of vertices. The invisibility convex set is designed for the watermark to be invisible based on the limit range of vertex movement. The watermark can be extracted using the decision values and index that the watermark was embedded with. Experimental results verify that the watermarked mesh model has both robustness against mesh simplification, cropping, affine transformations, and vertex randomization and invisibility.

• 한국정보통신학회논문지
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• 제11권7호
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• pp.1254-1259
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• 2007

웨이브릿 변환 영상에서 저주파수 대역에 워터마크를 삽입하는 방법은 공격에 견고하지만 비가시성이 저하된다. 그리고 고주파수 대역에 워터마크를 삽입하는 방법은 비가시성이 좋지만 공격에 취약하다. 본 논문에서는 부대역의 특성과 인지가중치를 이용하여 삽입강도를 적응적으로 조절함으로써 워터마크의 비가시성과 견고성을 향상 시키는 방법을 제안한다. 실험 결과, 제안한 방법은 비가시성에서 $1.7dB{\sim}2.6dB$ 향상되고, 유사도 측정에서 $0.2{\sim}12.9$ 향상됨으로써, 기존의 방법에 비해 비기시성 및 견고성이 우수함을 알 수 있다.

• 방송공학회논문지
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• 제20권6호
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• pp.888-900
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• 2015

본 논문에서는 디지털 영상 콘텐츠의 저작권 보호를 위해 2차원 DWT를 이용하여 강인성(robustness), 비가시성(invisibility), 보안성(security)을 만족하는 blind 워터마킹 방법을 제안한다. 이 방법은 영상의 국부정보에 따라 워터마킹 위치를 결정하지 않고 영상의 크기와 워터마크 정보의 양에 따라 n-레벨 DWT를 수행하고, 그 결과 최고 부대역 전체에 워터마크 정보를 삽입하는 방법을 사용한다. 워터마크를 삽입할 때는 부대역의 종류와 그 부대역의 에너지 레벨에 따라 가중치를 주어 워터마크의 비가시성과 강인성을 조절한다. 이 방법은 다양한 해상도와 종횡비의 영상에 대해 다양한 화소값 변경공격과 기하학적 공격을 실험하고 기존연구와 비교하여 비가시성과 강인성은 물론 범용성까지 갖춘 방법임을 보인다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
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• pp.103-105
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• 2009

This paper presents a pseudorandom tag arrangement for improved RFID based mobile robot localization. First, four repetitive tag arrangements, including square, parallelogram, tilted square, and equilateral triangle, are examined. For each tag arrangement, the difficulty in tag installation and the problem of tag invisibility are discussed. Then, taking into account both tag invisibility and tag installation, a pseudorandom tag arrangement is proposed, which is inspired from a Sudoku puzzle. It is shown that the proposed tag arrangement exhibits spatial randomness quite successively without increased difficulty in installation.

• 한국정보통신학회논문지
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• 제10권7호
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• pp.1222-1228
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• 2006

본 논문에서는 적응적 임계값과 반화소 움직임 벡터를 이용한 비디오 워터마킹 방법을 제안한다. 기존의 방법은 모든 매크로블록에 대해 워터마크삽입 조건을 검색하고, 임의의 움직임 벡터에 워터마크가 삽입되므로 움직임 벡터 변경이 많고, 비가시성이 떨어진다. 제안한 방법은 PMV를 이용하여 임계값을 생성하고, 임계값보다 큰 움직임 벡터에 워터마크를삽입하므로 움직임 벡터 변경 횟수가 적고, 비가시성이 향상된다. 실험결과 제안한 방법은 바디오 비트스트림에 따라 평균 5.4 dB ~ 9.3 dB 의 비가시성 특성이 향상됨을 알 수 있었다.

• 복식
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• 제56권7호
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• pp.101-114
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• 2006

The purpose of this study was to delve into the features of paradigm in conjunction with changing convergence culture in the 21st century's knowledge-based society, the influence of convergence paradigm on fashion, and changes in convergence culture. After identifying the features of the paradigm of knowledge-based society in association with changing convergence culture, the characteristics of fashion paradigm were examined in con=junction with the characteristics of the paradigm, and the convergence phenomena of modern fashion were investigated to figure out fashion trends. The findings of the study were as follows: According to the features of ubiquitous technology based on the theories of Mark Weiser and other futurologists, the characteristics of changing convergence culture in knowledge-based society could be classified into invisibility, relationship and materialized virtuality. When relevant theories were reviewed, invisibility, relationship and materialized virtuality are identified as the unique features of the paradigm of changing convergence culture in knowledge-based society. But those characteristics aren't separate concepts. Instead, they are being connected and fused together, thanks to universalized digital technology and ubiquitous technology. Changing convergence culture has brought a change to fashion paradigm as well. There is a type of design that lets all the characteristics stand out, and another design fuses just some of them together conceptually or formally. That is, fashion paradigm is marked by a combination of invisibility, relationship and an embodiment of virtual reality to be in line with changes in convergence culture.

• 한국정보시스템학회지:정보시스템연구
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• 제16권4호
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• pp.51-73
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• 2007

Ubiquitous computing is enhancing computer use by making many computers available throughout the physical environment, but making them effectively invisible to the user. To facilitate the successful adoption and diffusion of ubiquitous computing, it is necessary to figure out the factors affecting the use of U-service. Though the research related to ubiquitous computing has been vigorously conducted from the aspect of system and service provider, there have been very few studies that focus on the user's perspective. Therefore, this study attempts to figure out major factors which are dedicated to the development of ubiquitous computing and u-service, and that ultimately influence the u-business outcome. This study derived the factors that characterize u-service, such as ubiquity, contextual offer, reliability, invisibility, and confidentiality, which are then combined in the TAM model and carry out the path analysis. The research findings indicate that ubiquity affects both the perceived usefulness and perceived ease of use. The reliability and confidentiality were found to affect the perceived usefulness, whereas the contextual offer and invisibility turned out to influence the perceived ease of use. Finally, the relationship among the perceived usefulness, perceived ease of use, and the attitude toward using are identical with the previous research findings related to the technology acceptance model(TAM).

• 정보처리학회논문지B
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• 제9B권5호
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• pp.609-614
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• 2002

워터마킹은 소유권을 주장하기 위하여 워터마크라는 디지털 신호를 영상에 첨가하는 것이다. 본 논문에서는 기존의 DCT를 이용한 디지털 워터마킹 방법을 개선하여 비가시성과 견고성을 동시에 향상시키는 새로운 DCT 기반의 디지털 워터마킹 방법을 제안한다. 제안한 방법에서는 원 DCT 계수의 상대적 중요성이 워터마킹된 DCT 계수에서도 보존되며, 원 DCT 계수의 왜곡을 최소화시키는 워터마크 재정렬 방법을 이용함으로서 비가시성과 견고성을 향상시킨다. 실험을 통하여 제안한 방법은 기존의 워터마킹 방법보다 비가시성을 약 9～12[dB] 향상시키며, 다양한 공격에 대해 견고성이 월등히 우수함을 확인하였다.

• Journal of Contemporary Eastern Asia
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• 제21권1호
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• pp.77-85
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• 2022

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.800-803
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• 2004

This paper presents a wavelet-based digital watermarking technique for still images. The digital watermarking considering human visual system (HVS) to increase the robustness and perceptual invisibility of digital watermark. The watermarking embedding is modified discrete wavelet transform (DWT) coefficients of the subbands of the images. The human visual system is number of factors that effect the noise sensitivity of human eyes that is considered to increase the robustness and perceptual invisibility of digital watermark. The watermark detection is blind watermark ( original image is not required ). Experimental results successful against attacks by image processing such as add noise, cropping, filtering, JPEG and JPEG2000 compression.