• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.43 no.5 s.311
• /
• pp.57-67
• /
• 2006

Intellectual property rights are gathering strength theses days. Because digital contents are easily reproduced and distributed by advanced computers and networks. Digital watermarking is one of the best solutions for this problem. Generally, frequency-domain watermarking algorithms are preferred since they are more robust than spatial-domain algorithms. However, coefficients in the frequency domain are floating-point numbers. Thus, it is not easy to manipulate those floating-point coefficients and frequency-domain watermarking algorithms have some limitations in their applications. In order to overcome this difficulty, we employ an integer transform in this paper. In addition, our proposed algerian can extract the watermark from both the spatial and frequency domains. We embed the watermark into a specific bit-plane of mid-frequency coefficients. This is equivalent to the differential energy watermarking (DEW) in the spatial domain. Our simulation results show that the proposed algorithm is imperceptible, good for the watermark payload, and robustness against various attacks. Moreover, it is more efficient than any other algorithm working in only one domain.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.38 no.1
• /
• pp.37-43
• /
• 2001

In this paper, we propose a new optical security technique using two phase masks based on interferometer. A binary random phase image is used as a reference image and the encrypted image is generated according to the phase difference between the reference image and the original image. If there is no phase difference of a same pixel position in two phase masks, interference intensity of the pixel has minimum value and if phase difference of a same pixel position in two phase masks is $\pi$, its interference intensity has maximum value. We can decrypt the original image by putting two phase masks on each of the two optical paths of the Mach-Zehnder interferometer. Computer simulation and the optical experiments show a good performance of the proposed optical security system.

• The Journal of Korean Academy of Prosthodontics
• /
• v.54 no.1
• /
• pp.28-34
• /
• 2016

Implant has been an effective treatment option for the patients with oligodontia. However, it still remains unclear when the implant should be placed. Skeletal growth that can appear even after the growth period can lead to infraocclusion of the implant which can cause functional or esthetic complications. In order to minimize these problems, definitive restorations should be placed after the functional and esthetic rehabilitation is achieved through the use of provisional restorations. Definitive restorations made with monolithic zirconia were created by replicating provisional restorations by using the latest CAD/CAM technology. These definitive restorations were delivered to the patient and clinical observation after the treatment showed satisfactory result.

• Korean Journal of Optics and Photonics
• /
• v.14 no.3
• /
• pp.255-259
• /
• 2003

In this paper, we propose an improved image encryption and decryption method using a virtual image and a joint transform correlator (JTC). The encrypted image is obtained by the Fourier transform of the product of a virtual-phase image and a random-phase image, and a Fourier transform of the decrypting key generated by the proposed phase assignment rule is used as the Fourier decrypting key. Based on the solution, the original image is reconstructed using JTC in the frequency-domain. The proposed method using a virtual image, which does not contain any information from the original image, prevents the possibility of counterfeiting by unauthorized people. And also the auto-correlation terms, which are the drawback of a JTC system, contribute to reconstructing the original image rather than to disturbing its identification. But because phase-only encryptions are sensitive to noise and scratches, phase errors can be generated in fabricating the encrypted image or the Fourier decrypting key so the errors that are responsible for degradation of the quality of the reconstructed image are analyzed and the solution is demonstrated. Computer simulations show the solution, and the proposed method is very useful for JTC architecture.

• Korean Journal of Optics and Photonics
• /
• v.14 no.6
• /
• pp.636-642
• /
• 2003

We proposed the optical system using two divided halftone images to hide the original image and a joint transform correlator. The encryption procedure is performed by the Fourier transform of the product of each divided image by visual cryptography and the same random image which is generated by computer processing. As a result, we can obtain two Fourier divided images which are used as the encrypted image and the decrypting key, respectively. In the decryption procedure, both the encrypted image and the decrypting key are located on the joint input plane. Then the original image is reconstructed on a CCD camera which is located in the output plane. An autocorrelation term of joint transform correlator contributes to decrypt the original image. To demonstrate the efficiency of the proposed system, computer simulations and noise analysis are performed. The result show that the proposed system is a very useful optical certification system.

• Journal of Software Assessment and Valuation
• /
• v.16 no.1
• /
• pp.13-19
• /
• 2020

It can be seen that the infringement of copyright cases is increasing as the society becomes more complex and advanced. During the software copyright dispute, there may be a dispute over whether the software is duplicated and made into upgraded software. In this paper, we intend to propose an analysis method for determining whether to upgrade software. For the software upgrade analysis, a software similarity analysis technique was used. The analysis program covers servers, management programs, and Raspberry PC programs. The first analysis confirms the correspondence between program creation information and content. In addition, it analyzes the similarity of functions and screen composition between the submitted program and the program installed in the field. The second comparative analysis compares and analyzes similarities by operating two programs in the same environment. As a result of comparative analysis, it was confirmed that the operation and configuration screens of the two programs were identical. Thus, minor differences were found in a few files, but it was confirmed that the two programs were mostly made using the same or almost similar source code. Therefore, this program can be judged as an upgrade program.

• Journal of Industrial Convergence
• /
• v.20 no.9
• /
• pp.47-58
• /
• 2022

Digital content is difficult to distinguish between the original and the replica due to its nature. For this reason, NFT technology using blockchain technology is attracting attention because it can guarantee the proof and scarcity of the original digital content. However, the NFT buyer does not own the copyright to the digital content, but the ownership. In particular, since the minting process of issuing NFTs is possible for anyone, there is a copyright threat to the copyright holder. In this study, we propose a verification protocol based on DID for the process of issuing and transacting NFTs for copyright protection of copyright holders' digital contents. As a research method, the problems of research cases related to digital contents were analyzed and the safety was comparatively analyzed. NFT issuance can only be issued by copyright holders whose identity has been verified through DID, and only users who have completed authentication can participate in the transaction to prevent indiscriminate theft and use of digital content and form a safe and transparent transaction market.

• The Journal of the Convergence on Culture Technology
• /
• v.8 no.5
• /
• pp.749-754
• /
• 2022

High adhesion and water resistance of the skin surface are required for wearable and skin-attachable electronic patches in various medical applications. In this study, we report a stretchable electronic patch that mimics the drainable structure pattern of the hexagonal channels of frog's pads and the sucker of an octopus based on carbon-based conductive polymer composite materials. The hexagonal channel structure that mimics the pads of frogs drains water and improves adhesion through crack arresting effect, and the suction structure that mimics an octopus sucker shows high adhesion on wet surfaces. In addition, the high-adhesive electronic patch has excellent adhesion to various surfaces such as silicone wafer (max. 4.06 N/cm²) and skin replica surface (max. 1.84 N/cm²) in dry and wet conditions. The high skin-adhesive electronic patch made of a polymer composite material based on a polymer matrix and carbon particles can reliably detect electrocardiogram (ECG) in dry and humid environments. The proposed electronic patch presents potential applications for wearable and skin-attachable electronic devices for detecting various biosignals.

• Journal of Software Assessment and Valuation
• /
• v.15 no.2
• /
• pp.51-57
• /
• 2019

On increasing illegal software copyright, the need for similarity analysis is now rising. The reliability of object material are becoming important when it's moving from developer to evaluation experts. Object material as a comparison data, is the important data to the evaluation expert which is delivered from agencies such as courts and police stations. The object material is submitted at first to the Copyright Commission and then delivered to the evaluation expert with safe. However, if the similarity result is not satisfied to the both side, they will claim to the reliability of the object material such as source code modification or revision etc. Software objects is produced in a file format and are recognized as being able to be modified. Therefore, the reliability to the object material is studied in various ways, and a forensic is proposed as one method. This study showed the suggestion to keep reliability of the object material through the actual evaluation cases.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.26 no.2
• /
• pp.435-447
• /
• 2016

As data can be permanently stored and freely distributed, in modern society, the Internet became a world that remembers everything forever. Because of that, there has been increasing the number of accident with never-forgetting data and, as a result, a movement has been emerged to apply a notion of 'oblivion' to internet world. The movement is called 'The right to be forgotten.' However, 'The right to be forgotten' in a higher level which internet users want to be guaranteed is very limited in the juridical approach because of the confliction with the other basic rights and problems. On the other hand, the requests of individuals to guarantee 'The right to be forgotten' has been urged digital extinction technology, such as volatile SNS, Digital Aging System, to be developed. With introduction of oblivion, digital extinction technology with setting expire date on digital information can present a new solution on assuring 'The right to be forgotten.' This research establishes the detail scope of, analyzes the level of assurance of, and, through digital extinction technology with the established scope, suggest the potential assurance of the 'The right to be forgotten'.