• The KIPS Transactions:PartB
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• v.19B no.2
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• pp.83-92
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• 2012

Multimedia contents can be copied and manipulated without quality degradation. Therefore, they are vulnerable to digital forgery and illegal distribution. In these days, with increasing the importance of multimedia security, various multimedia security techniques are studied. In this paper, we propose a content authentication algorithm based on reversible watermarking which supports JPEG compression commonly used for multimedia contents. After splitting image blocks, a specific authentication code for each block is extracted and embedded into the quantized coefficients on JPEG compression which are preserved against lossy processing. At a decoding process, the watermarked JPEG image is authenticated by extracting the embedded code and restored to have the original image quality. To evaluate the performance of the proposed algorithm, we analyzed image quality and compression ratio on various test images. The average PSNR value and compression ratio of the watermarked JPEG image were 33.13dB and 90.65%, respectively, whose difference with the standard JPEG compression were 2.44dB and 1.63%.

• Journal of the Korea Convergence Society
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• v.9 no.2
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• pp.151-156
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• 2018

In this paper, an efficient reversible watermarking algorithm is proposed. By using the proposed algorithm, it is possible to increase the amount of copyright-related information to be embedded in cover image. Depending on the spatial locality and surface characteristics, it is possible to precisely predict the pixel value using neighboring pixels. If the predicted pixel value almost the same as the pixel value of the cover image, the differential value between the predicted pixel value and the pixel value of cover image is very small. So, the frequency is increased greatly at the peak point of histogram of difference sequence. Thus, it is possible to increase greatly the amount of secret data to be embedded in cover image. The experimental results show that the proposed watermarking algorithm is superior to the previous algorithms.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.3
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• pp.316-324
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• 2001

A table compression method for reversible variable length code is proposed in this paper. TNWT(Transition Number and Weight of Tree) method, which uses the transition number of bits within a symbol and the level of a code tree, is proposed. Compression of table values is performed after arrangment of values that is not distinghishable by transition number and weights. In decoding, the transition number and weight of code are used. In this method, the table for RVLC decoding can be implemented with a smaller memory.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.3
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• pp.7-13
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• 2015

Generally, watermarking can be used copyright for contents such as audios, videos, images, and texts. With the development of Internet, many malicious attackers illegally copy relational databases synchronized applications Therefore, it is needed for the protection of databases copyright, because databases involve various sensitive information such as personal information, information industry, and secret national intelligence. Thus, the protection of relational databases is a major research field in the databases research topics. In this paper, we will review previous researches related the protection of relational databases and propose new method for relational data. Especially, we propose watermarking scheme for databases using reversible method in this paper. As an experimental result, the proposed scheme is very strong to malicious attacks. In addition, we proved our proposed scheme is to apply real application.

• Journal of Digital Contents Society
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• v.19 no.2
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• pp.371-376
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• 2018

In the system security technology, the information hiding field is developed as technologies for embedding information, which are generally used as contents media. The proposed technique is a technical steganography technique which uses a technique of concealing certain information through physical / statistical change of signal values of contents. Recently, there have been various studies based on histogram shifting in reversible data concealment. In multi - peak histogram shifting, the capacity of data concealment gradually increased by applying multiple peak histogram method. In this paper, we analyze the effect of concealment in terms of adopting the histogram shift method including skipping. In addition, we propose multi - branch data concealment as a general method to improve concealment capacity. The above proposal has proved to be an example using mathematical expressions, and further improvement measures could be derived.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.452-452
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• 2006

• Bulletin of the Korean Chemical Society
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• v.19 no.11
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• pp.1156-1160
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• 1998

Alternating multilayer films of a cationic bipolar amphiphile and an anionic polyelectrolyte were prepared by a self-assembly method based on electrostatic attraction between opposite charges. The bipolar amphiphile contains an azobenzene unit in order to allow for a trans-cis photoisomerization to take place. Optical birefringence or dichroism was induced in the self-assembled film upon linearly polarized light irradiation. This dichroism could be reversibly written and erased by irradiation with light of an appropriate wavelength.

• The Journal of the Korean dental association
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• v.57 no.4
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• pp.241-247
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• 2019

Etiology of temporomandibular disorders is multifactorial origin and complex. therefore, reversible and conservative treatment is recommended in the initial approach of TMD. oral appliances are widely used to manage TMDs, while their mechanisms of action and its effects remain controversial and unclear. The purpose of this paper was to review information regarding the types, designs, and materials of occlusal appliances and the rationale for the continued use of OS for the management of TMDs.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.6 no.3
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• pp.25-34
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• 2007

Steganography is hiding messages in cover materials like image, audio, etc. The previous studies are limited in the shifting problem of the histogram and capacity. This paper proposes a new technology which overcomes these two problems. Our new technology uses two colors as a pair and chooses either changing to its partner or remaining as they are according as each hiding bit. As a result, we show that the result of this technology shows that the hiding capacity is higher than other methods.

• Journal of Information Processing Systems
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• v.6 no.4
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• pp.435-452
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• 2010

This paper proposes a novel reversible data hiding scheme based on a Vector Quantization (VQ) codebook. The proposed scheme uses the principle component analysis (PCA) algorithm to sort the codebook and to find two similar codewords of an image block. According to the secret to be embedded and the difference between those two similar codewords, the original image block is transformed into a difference number table. Finally, this table is compressed by entropy coding and sent to the receiver. The experimental results demonstrate that the proposed scheme can achieve greater hiding capacity, about five bits per index, with an acceptable bit rate. At the receiver end, after the compressed code has been decoded, the image can be recovered to a VQ compressed image.