• Journal of Broadcast Engineering
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• v.19 no.3
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• pp.342-354
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• 2014

This paper deals with digital watermarking methods to protect ownership of image with targeting the ultra-high multi-view or free-view image service in which an arbitrary viewpoint image should be rendered at the user side. The main purpose of it is not to propose a superior method to the previous methods but to show how difficult to construct a watermarking scheme to overcome the viewpoint translation attack. Therefore we target the images with various attacks including viewpoint translation. This paper first shows how high the error rate of the extracted watermark data from viewpoint-translated image by basic schemes of the method using 2DDCT(2D discrete cosine transform) and the one using 2DDWT(2D discrete wavelet transform), which are for 2D image. Because the difficulty in watermarking for the viewpoint-translated image comes from the fact that we don't know the translated viewpoint, we propose a scheme to find the translated viewpoint, which uses the image and the corresponding depth information at the original viewpoint. This method is used to construct the two non-blind watermarking methods to be proposed. They are used to show that recovery of the viewpoint affect a great deal of the error rate of the extracted watermark. Also by comparing the performances of the proposed methods and the previous ones, we show that the proposed ones are better in invisibility and robustness, even if they are non-blind.

• The Journal of Society for e-Business Studies
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• v.23 no.2
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• pp.21-31
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• 2018

Korean banknotes are similar in size, and their braille tend to worn out as they get old. These characteristics of Korean banknotes make the blind people, who mainly rely on the braille, even harder to distinguish the banknotes. Not only that, this can even lead to economic loss. There are already existing systems for recognizing the banknotes, but they don't support Korean banknotes. Furthermore, because they are developed as a mobile application, it is not easy for the blind people to use the system. Therefore, in this paper, we develop a Raspberry Pi-based banknote recognition system that not only recognizes the Korean banknotes but also are easily accessible by the blind people. Our system starts recognition with a very simple action of the user, and the blind people can hear the recognition results by sound. In order to choose the best feature extraction algorithm that directly affects the performance of the system, we compare the performance of SIFT, SURF, and ORB, which are representative feature extraction algorithms at present, in real environments. Through experiments in various real environments, we adopted SIFT to implement our system, which showed the highest accuracy of 95%.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.5
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• pp.98-109
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• 2007

The era of Web 2.0, which is the web environment that offers end user oriented web platform, has arrived. Moreover, as the interest in UCC (User Created Contents) environment increases, it is a fact that the involvement of the users in multimedia contents is increasing rapidly. When the aim of Web 2.0, i.e. active involvement of the user, is considered, the necessity and the understanding about accessibility problem of the people who have difficulties about accessing web information, such as elderly and visually handicapped people, is increasing as well. This research analyzes the problems of virtually handicapped users to access web-based UCC services, and proposes an efficient implementation plan for a web-based UCC service that enables smooth access for them. Especially, the validity of the proposed method was verified by comparing the reaction time of the visually handicapped users with that when using the existing UCC services, through the implementation of the test page according to the plan proposed in this research.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.4
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• pp.305-313
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• 2013

As an FMT (Filtered Multi-Tone) transmission method of Wideband VHF communication system specified by the ETS (European Telecommunications Standards) EN 300 392-2, this paper introduces three existing realization methods, i.e., the direct filtering method using different band SRRC (Square-Root Raised Cosine) filters for each subcarrier, the PPN-DFT method using the IDFT-PPN (Poly-Phase Network) and PPN-DFT at the transmitter and receiver, respectively, and the Extended DFT method. Then, it proposes the extended IDFT-SDFT (Sliding Discrete Fourier Transform) that computes the DFT values only for interested subcarriers every sample time, and shows that it has an advantage of blind symbol timing (using no training symbol) individually for each user signal (independently of other users' signals) in the multi-user environment where the subcarriers are assigned in contiguous or interleaved blocks to each user and each user signal possibly experiences different channels.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.3_1spc
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• pp.600-606
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• 2013

This paper describes the development of a novel walking assistance robot for the elderly and infirm. In the case of simple walking assistance devices, the walking safety and effectiveness are somewhat low; hence, caregivers are frequently required. The walking assistance robot developed in this research is capable of securely and conveniently assisting a walking user by using electric motors and various devices without a caregiver. The main features include the following. First, the walking safety is improved by using a pelvis supporter, and the robot is able to follow the user effectively by means of ergonomic motion sensors and electric powered wheels. Second, it is possible to adjust the load applied to the lower body by adjusting the height of the pelvis supporter. Finally, it is possible to inform the approximate distance and direction of any obstacle around the robot using the sounds and vibrations for the blind and the hearing impaired. The performance of the developed walking assistance robot was successfully verified using a walking assistance test in a narrow-corridor environment.

• Journal of information and communication convergence engineering
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• v.2 no.4
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• pp.251-255
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• 2004

In this paper, we present a watermarking scheme based on the DWT (Discrete Wavelet Transform) and the ANN (Artificial Neural Network) to ensure the copyright protection of the digital images. The problem to embed watermark is not clear to select important coefficient in the watermarking. We used the RBF (Radial-Basis Function) to solve the problem. We didn't apply the whole wavelet coefficients, but applied to only the wavelet coefficients in the selected node. Using the ANN, although even the watermark casting process and watermark verification process are in public, nobody knows the location of embedding watermark except of authorized user. As the result, the watermark is good at the strength test-filtering, geometric transform and etc.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.59-62
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• 1999

CDMA receiving algorithms, such as single/multi user detector and smart antenna system which have been proposed to suppress ISI and MAI. still suffer from the residual interferences among the output signals. A blind adaptive CMA post-processing technique, which is able to suppress the residual ISI and MAI symbol-by-symbol was proposed. It can be easily applied to any conventional detector at the expense of a small amount of additional computations. In this paper, a solution for the convergence problem of proposed method is proposed and analyzed. Through computer simulations it was shown that the proposed method has stable convergence property and good performance in BER.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2001.11a
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• pp.318-321
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• 2001

We have designed an Internet voting system applicable for worldwide voting which is based on Ohkubo et. al,'s scheme[9] combined with Public Key Infrastructure (PKI). To the best of our knowledge, this is the first trial to serve secure Internet voting system to the world. In our system, voter's privacy is guaranteed by using blind signature and mix-net, and robustness is provided through the threshold encryption scheme. By employing Java technology, we propose a way of typical implementation for internet voting system. Furthermore, PKI permits worldwide key distribution and achieve “one certificate/one vote” policy. Therefore, anyone can participate in the voting if he gets a certificate from Certificate Authority (CA). By the joint work between Korean and Japanese teams, the implementation aims to select MVPs in 2002 FIFA World Cup Korea-Japan$\^$TM/ in easy and friendly manner for any Internet user to participate and enjoy Internet voting.

• Journal of Information Processing Systems
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• v.9 no.2
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• pp.247-258
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• 2013

A new secure network communication technique that has been designed for mobile wireless services, is presented in this paper. Its network services are mobile, distributed, seamless, and secure. We focus on the security of the scheme and achieve anonymity and reliability by using cryptographic techniques like blind signature and the electronic coin. The question we address in this paper is, "What is the best way to protect the privacy and anonymity of users of mobile wireless networks, especially in practical applications like e-commerce?" The new scheme is a flexible solution that answers this question. It efficiently protects user's privacy and anonymity in mobile wireless networks and supports various applications. It is employed to implement a secure e-auction as an example, in order to show its advantages in practical network applications.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.365-368
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• 2008

This paper introduce the model of remote monitoring system that combine information technology in electrical safety checks that has been done by professional staff. And for general use, electrical safety Value-Added Service using remote check data were presented. In the near future, If demand and interests of Value-Added Service will be increased, this will be a electrical safety Value-Added Service as an important role in the blind spot of country electricity disaster.