• Title/Summary/Keyword: Invisibility

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Video Watermarking Scheme for Scalable Video Coding using ROI

  • Yoon, Ji-Sun;Kwon, Seong-Geun;Lee, Suk-Hwan;Song, Yoon-Chul;Kim, Min-Hwan;Kwon, Ki-Ryong
    • Journal of Korea Multimedia Society
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    • v.11 no.6
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    • pp.796-806
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    • 2008
  • This paper presents a blind video watermarking algorithm that has the robustness against spatial, temporal, and SNR scalability and transcoding for the copyright protection of video contents in heterogeneous multimedia service. The proposed process of watermark embedding and detecting is accomplished on base layer for considering spatial scalability. The watermark consists of the string and the ordering number of string for considering temporal scalability. Thus, each of frames has the bitstream of one character and a ordering number of its character. To robust against FGS, the proposed algorithm quantizes low and middle frequency coefficients in ROI region of each of frames and embeds its watermark bitstream into the specific bits of the quantized coefficients. Experimental results verified that the proposed algorithm satisfies the invisibility of watermark and also has the robustness against spatial scalability, temporal scalability and FGS.

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Structural Design of Cheongna City Tower

  • Chung, Kwangryang;Kim, Jung-Hyun;Song, Younghoon;Kim, Sihyeong;Kang, Jihun
    • International Journal of High-Rise Buildings
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    • v.10 no.3
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    • pp.193-201
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    • 2021
  • Cheongna City Tower is a 448-meter-high rise observatory tower with 8.7:1 aspect ratio located at central lake park in Incheon Cheongna international city. The tower is a crystal shaped image and it turns invisible when the façade is activated. The tower was planned to be hexagonal 30-story building with two basements which are composed of mega frame structure using mega column and mega brace. In order to minimize the wind effect, the blow-through area was installed so that the wind can pass through. This observatory tower is an unprecedented project since the whole building is covered by façade for invisibility effect.

Ways of Seeing: An Anatomy of Whiteness in Claudia Rankine's The White Card

  • Choi, Yoon-Young
    • American Studies
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    • v.44 no.2
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    • pp.97-129
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    • 2021
  • In The White Card (2019), Claudia Rankine dramatically interrogates whiteness's persistent, reflexive habit of trying to preserve a state of innocence, expressing her vision of how this tendency blinds white liberal subjectivity to the structural reality of institutionalized racism in America. Rankine's exposure of the invisibility to which people of color are usually consigned by American whiteness is inseparable from her critical interrogation of how the hypervisibility of victims of racial violence provides white liberal subjectivity opportunities to intervene and feel good about itself. What Rankine enacts in the play is a process of repetition and revision, signifyin(g) on racial violence and its history; acts of racial violence continue to accrete, and her act of signifyin(g) on the countless acts of racial violence in America conveys the understanding that this text cannot be rewritten if white America continues to attend solely to individual, ostensibly isolated, acts of racial injustice.

A Structural Model on Usage Behavior of Ubiquitous Campus Service (유비쿼터스 특성이 U-서비스 이용에 미치는 영향: U-캠퍼스 환경을 중심으로)

  • Park, Cheol;You, Jae-Hyun
    • Information Systems Review
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    • v.8 no.1
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    • pp.81-99
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    • 2006
  • Recently, the area of ubiquitous has gained a great attention both in academics and in business organizations as we are entering an ubiquitous society where people can interact at "anytime" and "anywhere". To preoccupy the leading status for the next generation of IT technology, many countries such as Korea, Japan, and US are concerned the ubiquitous. In this tendency, companies want to identify what factors make people use ubiquitous in order to develop the effective ubiquitous service and to supply the higher quality service. However, prior researches on ubiquitous are focused on technical area such as higher data delivery, efficient compression of images, so they do not have given companies beneficial materials for making fascinating ubiquitous services. To offer the service materials for development, from the viewpoint of the customer, important factors to use ubiquitous services are investigated in this study. Moreover, the study was progressed up to the new area of investigation how much these factors influenced ubiquitous service actual usage. To achieve these goals, Ubiquitous service adopting reflected in ubiquitous service characteristics was suggested in this study. The results of this study are as follows. First, contextual offer, ubiquity, invisibility are positively related to perceived value. Second, perceived value is positively related to usage intention but perceived risk is negatively related to usage intention. Third, usage intention is positively related to usage frequency. Based on these results, managerial implications for ubiquitous service vitalization are discussed. Lastly, the limitation of this research and further research issues are suggested.

Image Fusion Watermarks Using Multiresolution Wavelet Transform (다해상도 웨이블릿 변환을 이용한 영상 융합 워터마킹 기법)

  • Kim Dong-Hyun;Ahn Chi-Hyun;Jun Kye-Suk;Lee Dae-Young
    • 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.

Watermarking Using Multiresolution Wavelet Transform and Image Fusion (다중 해상도 웨이블릿 변환과 영상 융합을 이용한 워터마킹)

  • Kim Dong-Hyun;Jun Kye-Suk;Lee Dae-Young
    • The KIPS Transactions:PartB
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    • v.12B no.7 s.103
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    • pp.729-736
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    • 2005
  • In this paper. the proposed method for the digital watermarking is based on the multiresolution wavelet transform. The 1-level Discrete Wavelet Transform(DWT) coefficients of a $2N_{wx}{\times}2N_{wy}$ binary logo image used as a watermarks. The LL band and middle frequency band of the host image that the 3-level DWT has been performed are divided into $N_{wx}{\times}N_{wy}$ size and we use large coefficients at the divided blocks to make threshold. we set the thresholds that completely insert the watermark in each frequency of the host image. The thresholds in each frequency of the host image differ each other. The watermarks where is the same positions are added to the larger coefficients than threshold in the blocks at LL band and middle frequency band in order to prevent the quality deterioration of the host image. The watermarks are inserted in LL band and middle frequency band 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. We rapidly detect the watermark using this watermarking method. And because the small size watermarks are inserted by HVS, the results confirm the superiority of the proposed method on invisibility and robustness.

A Study on Invisibility Improvement of Watermarking Image (워터마킹 영상의 비가시성 개선에 관한 연구)

  • Kim, Hyeong-Gyun;Lee, Yang-Weon
    • Journal of Advanced Navigation Technology
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    • v.11 no.3
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    • pp.329-336
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    • 2007
  • The use of digital imaging technique and digital contents based on internet has grown rapidly for last several years, and the needs of digital image protection become more important. For the purpose of copyright protection on digital image, the verification of authentication techniques like content authentication, ownership authentication, illegal copy and etc are needed. Digital watermarking, the invisible encryption technique to insert digital watermark into image, the sophisticated perceptual information should be used for providing transparency and robustness of images on watermarking process. In this paper, we implement the digital watermarking algorithm for preventing forged attack, ownership protection and authentication by transforming the wavelet algorithms in frequency domain in terms of human visual system.

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Secure Convertible Undeniable Signature Scheme Using Extended Euclidean Algorithm without Random Oracles

  • Horng, Shi-Jinn;Tzeng, Shiang-Feng;Fan, Pingzhi;Wang, Xian;Li, Tianrui;Khan, Muhammad Khurram
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.7 no.6
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    • pp.1512-1532
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    • 2013
  • A convertible undeniable signature requires a verifier to interact with the signer to verify a signature and furthermore allows the signer to convert a valid one to publicly verifiable signature. In 2007, Yuen et al. proposed a convertible undeniable signature without random oracles in pairings. However, it is recently shown that Yuen et al.'s scheme is not invisible for the standard definition of invisibility. In this paper, we propose a new improvement by using extended Euclidean algorithm that can overcome the visibility attack. The proposed scheme has been evaluated based on computation and communication complexities and the performance comparisons of Yuen et al.'s scheme and various convertible undeniable signature schemes are provided. Moreover, it has been observed that the proposed algorithm reduces the computation and communication times significantly.

하이퍼볼릭 메타물질: 깊은 서브파장 나노포토닉스를 위한 신개념 플랫폼

  • No, Jun-Seok
    • Proceedings of the Korean Vacuum Society Conference
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    • 2015.08a
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    • pp.78-78
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    • 2015
  • Metamaterials, artificially structured nanomaterials, have enabled unprecedented phenomena such as invisibility cloaking and negative refraction. Especially, hyperbolic metamaterials also known as indefinite metamaterials have unique dispersion relation where the principal components of its permittivity tensors are not all with the same signs and magnitudes. Such extraordinary dispersion relation results in hyperbolic dispersion relations which lead to a number of interesting phenomena, such as super-resolution effect which transfers evanescent waves to propagating waves at its interface with normal materials and, the propagation of electromagnetic waves with very large wavevectors comparing they are evanescent waves and thus decay quickly in natural materials. In this abstract, I will focus discussing our efforts in achieving the unique optical property overcoming diffraction limit to achieve several extraordinary metamaterials and metadevices demonstration. First, I will present super-resolution imaging device called "hyperlens", which is the first experimental demonstration of near- to far-field imaging at visible light with resolution beyond the diffraction limit in two lateral dimensions. Second, I will show another unique application of metamaterials for miniaturizing optical cavity, a key component to make lasers, into the nanoscale for the first time. It shows the cavity array which successfully captured light in 20nm dimension and show very high figure of merit experimentally. Last, I will discuss the future direction of the hyperbolic metamaterial and outlook for the practical applications. I believe our efforts in sub-wavelength metamaterials having such extraordinary optical properties will lead to further advanced nanophotonics and nanooptics research.

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A Watermarking Technique using Block-based Wavelet Transform (블록 기반 웨이블릿 변환을 이용한 워터마킹 기법)

  • 이정수;김회율
    • Journal of Broadcast Engineering
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    • v.5 no.2
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    • pp.290-299
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    • 2000
  • In this paper, we introduce a watermarking technique using a block-based wavelet transform. Our objective is to achieve the invisibility of the watermark embedded into an image. That is, the difference between the original image and the watermarked image is perceptually invisible. Also, we propose a scheme that is robust to common Image processing by embedding the watermark into ail frequencies. Especially, we certified that the proposed watermarking algorithm was robust to JPEG compression and noise. In addition, our detection scheme can detect the manipulated area for the purpose of authentication. From the experimental results, we conclude that the proposed watermarking system satisfied the objectives proposed in this paper.

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