• Journal of Korea Multimedia Society
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• v.13 no.4
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• pp.582-593
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• 2010

Recently the commercial value of GIS(geographic information system) has been increased with growing application demands of spatial information in life space. Also, GIS has been expanded to the integrated information system that provides the ease access to map information by public users and also the combined service of GIS map data and various multimedia contents. But several security problems of GIS map data have brought up at GIS industries, such as the illegal copy and distribution of GIS map data. Furthermore, the copyright protection of GIS map data has not been researched yet compared with image and video contents. This paper presents a polyline based watermarking scheme for the copyright protection of GIS vector map. The proposed scheme analyzes the structure of vector map and embeds adaptively the watermark by using the distance distribution of polyline components. From experimental results, we verified that the proposed scheme satisfies the invisibility and the robustness of geometrical attacks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.1
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• pp.102-107
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• 2005

With the advancement which development and information communication of the computer is quick about lower with multimedia technical diffusion of network base the necessity the use of the digital image technique which is various regarding the protection of sharp increasing multimedia contents raised its head in the social whole. the copyright protection against a multimedia data hazard the authentication techniques it will be able to confirm the content authentication, ownership authentication, illegal copy of the image which stands is demanded. confronts to the water marking technique of existing and the researches the fact that against a picture is most. In this paper, It does not damage the video data which is a multimedia contents not to be, it inserts copyright information and it protects the right of ownership. It is with a copyright protection which leads the wavelet transform which is a watermark of frequency base from visual system viewpoint in the human being center with it proposes the watermarking technique against a forgery prevention.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2005.05a
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• pp.125-129
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• 2005

디지털 영상물에 대한 저작권을 보호하기 위해 저작권자의 고유한 영상을 기존 디지털 영상에 삽입하는 것을 워터 마킹이라고 부른다. 삽입된 워터 마크가 효과적으로 사용되기 위해서는 영상의 다양한 왜곡이나 변형에도 강건할 수 있게 그 강도가 강해야 하며, 동시에 워터 마크가 삽입된 영상의 왜곡을 식별할 수 없게 그 강도를 약하게 하여야 한다. 비가시성을 유지한 채 가능한 한 강한 워터마크를 삽입하는 것은 워터마크를 적용 하는 데 매우 중요한 문제이다. 대부분의 워터 마크 알고리듬에서 삽입될 워터 마크의 강도는 원영상과 워터마크 영상간의 물리적인 차이에 근거하여 계산된 특정 값으로 고정한 채, 이 값을 모든 영상에 동일하게 적용하고 있다. 인간의 경우 자극의 탐지는 주변 영상의 밝기나 대비 등 여러 요소에 의해 변화되므로 디지털 영상에 삽입된 워터 마크의 탐지도 영상의 특징에 따라서 변화될 수 있다. 본 연구에서는 원영상으로부터 세 수준의 밝기와 세 수준의 대비를 갖는 기본 영상들을 만든 후, 기본 영상에서 탐지될 수 있는 워터 마크의 강도가 변화되는 지를 살펴보았다. 연구 결과 영상의 밝기가 밝아질수록, 대비가 커질수록 지각될 수 있는 워터 마크의 강도는 더 커지는 것으로 나타났다. 또한 회귀분석을 통해 영상의 밝기와 대비에 근거하여 삽입될 워터 마크의 강도를 결정할 수 있는 회귀 식을 만들어 내었다. 이러한 회귀 식은 주어진 영상의 통계 치에 근거하여 워터 마크 강도를 적응적으로 변화시킬 수 있는 알고리듬을 개발하는 데 유용하게 사용될 수 있을 것이다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.4
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• pp.571-583
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• 2013

Internet banking service has a advantage that is unrestricted by time. If automated programs are able to attack Internet banking services, a number of accounts can be attacked at the same time and as a result, damage will be considerably increased. To cope with such attacks, two methods, VPS and MS watermark, were introduced by Arcot and MS respectively. The methods use text-based CAPTCHAs in the process of transfer approval to distinguish automated programs from legal human users. In this paper, we point out the security threats of the methods when those are applied to Internet banking services. Especially, we consider the attack that are performed by extract specific string from text-based CAPTCHAs and it's countermeasure. Also we suggest a method of enhancing security of internet banking services. Our method is based on contents-based CAPTCHAs that are consist of known transfer information between user and server.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.59-263
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• 2003

정보통신의 비약적인 발전에 힘입어 멀티미디어 데이터는 언제 어디서든 전송 받거나 공유할 수 있게 되었다. 아날로그 형태에서 디지털의 아날로그를 형태로 빠르게 대체되고 있으며, 디지털로 신호를 표현하는 방법은 기존 사용하여 표현하는 방법에 비해 많은 장점을 가지고 있다. 하지만 디지털로 된 데이터는 언제 어디서든 대단위 복제가 가능하다. 즉, 저작권 침해, 불법 복제 및 배포, 손쉽게 위조할 수 있다는 점이 그것이다. 디지털 컨텐츠의 불법 복제와 유통은 저작자의 창작 의욕과 수입원을 차단하는 매우 중요한 문제이며, 이를 방지하기 위해서 멀티미디어 데이터의 저작권을 가진 소유자가 원하는 정보를 삽입함으로써 데이터의 저작권 보호와 복사 방지 및 불법적인 유통을 막고자 하는 기술이 개발되고 있다. 디지털 영상 정보의 보호를 위해 디지털 영상의 불법적인 내용 조작을 막고, 영상의 소유권을 보장할 수 있는 방법으로 디지털 워터마크(Digital Watermark)가 있다. 디지털 워터마크는 공개키 알고리즘이나 방화벽 등으로 해독된 영상에 대하여 부가적인 보호를 제공한다. 디지털 영상에 대한 저작권 정보, 배포자 정보 그리고 사용자 정보를 영상에 삽입함으로써 훗날 법적인 문제가 발생하였을 때 해결책을 제시할 수 있다. 본 논문에서는 디지털 영상 데이터의 정보 보호를 위해 주파수 영역에서의 웨이브릿 변환(Wavelet Transform)을 이용한 이미지 적응 디지털 워터마킹(Image-Adaptive Digital Watermarking) 방법을 제안한다. 이미지 적응 웨이브릿(Image-Adaptive Wavelet)은 영상을 주파수적으로 분해하면서 각 대역들의 공간 영역에서의 정보를 함께 지니고 JND(Just noticeable difference)을 포함한다. 이미지 적응 웨이브릿의 이러한 특성을 이용하여 다해상도 분해하고, 손실 압축(toss Compression) 이나 필터링(Filtering), 잡음(Noise) 등에 크게 영향받는 저주파 성분과 인간의 시각적으로 큰 의미를 갖는 고주파 성분의 특성을 이용하여 워터마크를 삽입한다.

• Journal of Broadcast Engineering
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• v.6 no.1
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• pp.50-57
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• 2001

A digital watermarking is a newly developed scheme to embed invisible or inaudible information Into the host data in order to insist the copyright of the owner or the creator. This paper describes a robust data embedding scheme that employs inner product and adaptive quantization. Compared to the previous works for digital watermarking, our proposed scheme can embed relatively large amount of Information, since a secrete key Is not directly relaxed to the watermark data. A secret key is used for the design of random direction vectors. which are taken Inner product with the DCT transformed feature set data. In odder to achieve robustness against malicious attacks. we exploit the Properties of human visual system In designing the random direction vectors which behave as embedded noises. Experimental results show that we can recover the embedded information without utilizing the original host data. We also demonstrate that the ownership assertion is possible even though The watermarked data may undergo common signal processing operations, such as JPEG compression. clopping. and filtering.

• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.552-559
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• 2011

In this paper, a new image watermarking algorithm is proposed which can hide specific information of an ID card's owner in photo image for preventing ID's photo forgery. Proposed algorithm uses the image segmentation and the correlation peak position modulation of spread spectrum. The watermark embedded in photo ensures not only robustness against printing and scanning but also sufficient information capacity hiding unique number such as social security numbers in small-sized photo. Another advantage of proposed method is extracting accurate information with error tolerance within some rotation range by using $2^h{\times}2^w$ unit sample space not instead $1{\times}1$ pixels for insertion and extraction of information. 40 bits information can be embedded and extracted at $256{\times}256$ sized ID photo with BER value of 0 % when the test condition is 300dpi scanner and photo printer with 22 photos. In conclusion, proposed algorithm shows the robustness for noise and rotational errors occured during printing and scanning.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.55-63
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• 2010

In this paper, a new video watermarking algorithm using 3D wavelet transform and position encoding of spread spectrum correlation is proposed as a method for ensuring enough payload in order to protect copyright for video contents. This algorithm provides better robustness than other watermarking methods in bit error and rotation because it uses the position encoding and $4{\times}4$ sample space instead of $1{\times}1$ pixel to express a digit. The evaluation result over 6 video clips shows that the PSNR is over 31dB at strength 11 when histogram is narrow and it satisfies the transparency. Also, it shows the robustness of the proposed watermark algorithm that the BER is 0% to three codecs.

• Journal of KIISE:Information Networking
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• v.37 no.2
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• pp.150-156
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• 2010

Audio watermarking is the process of embedding inaudible information in an audio signal and has been widely used for copyright protection. In this research, we use the audio watermarking not for copyright protection but for the transmission of side information for user convenience, presenting an algorithm suitable for this purpose. Our new algorithm includes watermark embedding/extraction methods during acoustic transmission through the air that employ energy modulation of the audio signal and an efficient two-step synchronization method. The proposed algorithm is evaluated in experiments of conveying information from audio speakers to a mobile phone. The results show that reliable transmission is possible within a 5m range, which is an improvement achieved by our algorithm as compared to the existing one.

• Journal of Advanced Navigation Technology
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• v.13 no.3
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• pp.459-465
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• 2009

Digital watermarking is a technique to insert a visually imperceptible information into an image so that the information can be extracted for the purposes of ownership verification or authentication. And watermarking techniques can be classified as either fragile or robust. Robust watermarks are useful for copyright and ownership assertion purposes. They cannot be easily removed and should resist common image manipulation procedures such as rotation, scaling, cropping, etc. On the other hand, fragile watermarks are easily corrupted by any image processing procedure, it can detect any change to an image as well as localizing the areas that have been changed. In this paper, we propose a fragile watermarking algorithm using a special hierarchical structure for integrity verification of image and detection of manipulated location. In the proposed method, the image to be watermarked is divided into blocks in a multi-level hierarchy and calculating block digital signatures in this hierarchy. The proposed method thwarts the cut-and-paste attack and the experimental results to demonstrate the effectiveness of the proposed method.