• Journal of the Korea Computer Graphics Society
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• v.9 no.2
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• pp.1-9
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• 2003

Information assurance(IA) refers to methodologies to protect engineering information by ensuring its availability, confidentiality, integrity, non-repudiation, authentication, access control, etc. In collaborative design, IA techniques are needed to protect intellectual property, establish security privileges and create "need to know" protections on critical features. Aside from 3D watermarking, research on how to provide IA to distributed collaborative engineering teams is largely non-existent. This paper provides a framework for information assurance within collaborative design, based on a technique we call role-based viewing. Such role-based viewing is achieved through integration of multi-resolution geometry and security models. 3D models are geometrically partitioned, and the partitioning is used to create multi-resolution mesh hierarchies. Extracting an appropriately simplified model suitable for access rights for individual designers within a collaborative design environment is driven by an elaborate access control mechanism.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.751-754
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• 2001

일반적으로 디지털 컬러 영상의 워터마킹 구현방법은 기존의 워터마킹 방법을 RGB 컬러 성분에 대해 각각 적용하였기 때문에 컬러 영상의 특성을 충분히 고려하지 못했다. 그러나 인간의 시각 체계(HVS : Human Visual System)의 특성을 이용하면 컬러 영상에 더욱 효과적으로 워터마크를 삽입할 수 있다. 본 논문에서는 다해상도 이산 웨이브렛 변환 영역에서의 인간의 시각 체계의 특성을 이용한 컬러 영상 워터마킹 방법을 제안하였다.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.11a
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• pp.9-12
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• 2003

웨이블릿 변환(Wavelet Transform)의 압축 방식 중 최근 압축률에서 뛰어난 성능을 보이는 MTWC 알고리즘의 특성을 이용하여 추출된 중요 계수에만 워터마크를 삽입하는 방법으로 디지털 영상에 시각적으로 보이지 않게 워터마크를 삽입하고, 워터마크된 영상과 PN(Pseudo Noise)code와의 계수차를 이용하여, 위터마크를 추출하는 통계학적 접근 방법을 제시하며, 워터마크가 삽입된 영상에 대한 다양한 공격(Attack)등에 대해서 기존의 방법들과 비교하여 효과적으로 워터마크를 추출할 수 있는 강인함을 실험을 통해 증명해 보였다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.461-463
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• 2003

인터넷의 활성화로 멀티미디어 콘텐츠의 저작권 보호에 대한 필요성이 점차 증대되고 있다. 본 연구에서는 디지털 워터마킹 기술을 이용하여 사용자 레벨에 따라 차별화된 콘텐츠 서비스를 제공하여 저작권을 보호할 수 있는 새로운 기술을 연구하였다. 여기서는 유료 사용자와 무료 사용자의 두 계층으로 분리하여 서비스를 할 수 있도록 하였으며, 유료 사용자는 고품질의 서비스를 무료 사용자는 저품질의 콘텐츠나 가시적인 로고가 들어가 있는 콘텐츠를 서비스 받도록 차별화할 수 있다. 디지털 워터마킹 기술은 콘텐츠의 품질을 높일 수 있는 정보를 은닉하는 데 활용된다.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.863-867
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• 2021

In this paper, in order to hide the watermark in the LSB of the color image, a color image watermarking technique with high security is proposed by using the adjacent pixels of the image and the spatial encryption technique. According to the technique proposed in this paper, the quality of the stego-image generated by hiding the watermark in the LSB of the color image is so excellent that the difference from the original image cannot be recognized, and the original watermark can be extracted from the stego-image without loss. If the watermark is hidden in the image using the proposed technique, the security of the watermark is maintained very high because the watermark hidden in the stego-image is multi-encrypted. The proposed watermarking technique can be used in applications such as military and intellectual property protection that require high security.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2005.11a
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• pp.105-108
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• 2005

본 논문에서는 지상파 디지털 방송시스템의 단일 주파수망 (SFN; Single Frequency Network) 구성을 위해 DTV (Digital Television) TxID (Transmitter Identification)용 저간섭 ZCD (Zero Correlation Duration) 확산코드를 제시하였다. ZCD 확산코드는 코드발생기의 구현이 용이함과 동시에 ZCD특성을 가짐으로 인해서, TxID에서 발생되는 인접코드 간섭 (ICI; Inter Code Interference) 및 다중경로 간섭 (MPI; Multi-Path Interference) 문제를 확산코딩기법을 이용하여 근원적으로 해결해주는 역할을 하고 있으며, 주기를 가변적으로 조절할 수 있어 TxID를 위한 워터마킹 (Watermarking)시에 발생하는 Truncated error를 제거할 수 있다. 본 논문에서는 AWGN (Additive White Gaussian Noise) 잡음 및 ICI, MPI와 같은 다양한 간섭환경을 모의실험에 반영하여 도출된 DER (Detection Error Rate)특성을 분석함으로써, TxID용 저간섭 ZCD 확산코드의 유용성을 입증하였다.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.6
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• pp.83-92
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• 2005

This paper presents a watermarking approach that the 1-level Discrete Wavelet Transform(DWT) coefficients of a $64{\ast}64$ binary logo image as watermarks are inserted in LL band and other specific frequency bands of the host image using Multi-Resolution Analysis(MRA) Wavelet transform for copyright protection of image data. The DWT coefficients of the binary logo image are inserted in blocks of LL band and specific bands of the host image that the 3-level DWT has been performed in the same orientation. We investigate Significant Coefficients(SCs) in each block of the frequency areas in order to prevent the quality deterioration of the host image and the watermark is inserted by SCs. When the host image is distorted by difference of the distortion degree in each frequency, we set the thresholds of SCs on each frequency and completely insert the watermark in each frequency of the host image. In order to be invisibility of the watermark, the Human Visual System(HVS) is applied to the watermark. We prove the proper embedding method by experiment. Thereby, we rapidly detect the watermark using this watermarking method and because the small size watermarks are inserted by HVS and SCs, the results confirm the superiority of the proposed method on invisibility and robustness.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.1946-1953
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• 2006

Because the embedded watermark of luminance component guarantees the extraction of ownership information when the color image is converted to gray scale image, the information of ownership right as to the luminance component is embedded in the luminance-chrominance color space such as YCbCr. Therefore, this paper proposes watermark embedding, extraction and authentication algorithm of color image. which considers the device and performance of multimedia contents service by focusing on the robustness and invisibility of watermark. The color image is converted from RGB color space to YCbCr color space, and then the properties of each component of Y(Luminance), Cb(Color Differences) and Cr(Color Differences) are considered in order to embed, extract and certify multi-level watermark in the frequency domain based on the wavelet. As a result, it can guaranteed the robustness for the JPEG compression and invisibility of watermark for multi-level.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.5
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• pp.2698-2717
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• 2019

This paper proposes a multi-stage encryption technique to enhance the level of secrecy of image to facilitate its secured transmission through the public network. A great number of researches have been done on image secrecy. The existing image encryption techniques like visual cryptography (VC), steganography, watermarking etc. while are applied individually, usually they cannot provide unbreakable secrecy. In this paper, through combining several separate techniques, a hybrid multi-stage encryption technique is proposed which provides nearly unbreakable image secrecy, while the encryption/decryption time remains almost the same of the exiting techniques. The technique consecutively exploits VC, steganography and one time pad (OTP). At first it encrypts the input image using VC, i.e., splits the pixels of the input image into multiple shares to make it unpredictable. Then after the pixel to binary conversion within each share, the exploitation of steganography detects the least significant bits (LSBs) from each chunk within each share. At last, OTP encryption technique is applied on LSBs along with randomly generated OTP secret key to generate the ultimate cipher image. Besides, prior to sending the OTP key to the receiver, first it is converted from binary to integer and then an asymmetric cryptosystem is applied to encrypt it and thereby the key is delivered securely. Finally, the outcome, the time requirement of encryption and decryption, the security and statistical analyses of the proposed technique are evaluated and compared with existing techniques.

• Journal of Korea Multimedia Society
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• v.8 no.6
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• pp.783-789
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• 2005

This paper is proposed a watermarking technique for copyright protection of multimedia contents. We proposed adaptive watermark detection algorithm using stochastic perceptual model and statistical decision method in DMWT(discrete multi wavelet transform) domain. The stochastic perceptual model calculates NVF(noise visibility function) based on statistical characteristic in the DMWT. Watermark detection algorithm used the likelihood ratio depend on Bayes' decision theory by reliable detection measure and Neyman-Pearson criterion. To reduce visual artifact of image, in this paper, adaptively decide the embedding number of watermark based on DMWT, and then the watermark embedding strength differently at edge and texture region and flat region embedded when watermark embedding minimize distortion of image. In experiment results, the proposed statistical decision method based on multiwavelet domain could decide watermark detection.