• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.480-483
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• 2018

In this paper, we study the interference canceling and image sensing processing technology of multiple light sources for high speed transmission in CMOS sensor based visible light communication system. To improve transmission capacity in optical camera communications via image sensors, different data must be transmitted simultaneously from each LED. However, multiple LED light source environments for high-speed transmission can cause interference between adjacent LEDs. In this case, since the visible light communication system generally uses intensity modulation, when a plurality of LEDs transmit data at the same time, it is difficult to accurately detect the respective LEDs due to the light scattering interference of the adjacent LEDs. In order to solve this problem, the ON / OFF state of many LEDs of the light source is accurately recognized by using a dual CMOS sensor, and the spectral estimation technique and the pixel image signal processing technique of each LED are proposed. This technique can accurately recognize multiple LED pixels and improve the total average bit error rate and throughput of a MISO-VLC system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.5
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• pp.348-355
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• 2019

UHF and microwave RFID systems are widely applied in various fields because they can read a plurality of tag information within a radius of several meters ahead of the RFID reader. However, they cannot detect the position of the tag in applications that recognize only a tag at a specific position. In this study, we propose a new RFID system that can interrogate the tag of a specific location selectively by using the position information of the tag. This can be done by only adjusting the reader's operating frequency. To verify the feasibility of the proposed system, we implemented a 2.4 GHz RFID reader whose frequency can be varied by using a phase-locked loop circuit and a backscattered tag. Experimental results confirm that the tag position can be sensed exactly.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.5
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• pp.9-17
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• 2018

Recently, the increasing interest of biometric systems has led to the creation of many researches of biometrics forgery. In order to solve this forgery problem, this paper proposes a method of determining whether a synthesized face made of artificaial intelligence is real face or fake face. The proposed algorithm consists of two steps. Firstly, we create the fake face images using various GAN (Generative Adversarial Networks) algorithms. After that, deep learning algorithm can classify the real face image and the generated face image. The experimental results shows that the proposed algorithm can detect the fake face image which looks like the real face. Also, we obtained the classification accuracy of 88.7%.

• Convergence Security Journal
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• v.10 no.4
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• pp.21-30
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• 2010

Wireless network is one of the 2010's most important security issues. As smartphone is popularize, the number of Wireless Internet users is really growing and wireless AP spring up everywhere. But most wireless AP haven't being managed properly in terms of security, Wireless Internet users also don't recognize important of security. This situation causes grave security threats. This paper design and analyze a new cyber attack whose it circulates malware via QR code and activates Mobile AP to induce service charge. The new vulnerability we suggest forces to activate Mobile AP of smartphone based on Android and responds to all Probe Request are generated around, and brings induction of service charge and communication problems in its train.

• Journal of KIISE
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• v.42 no.12
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• pp.1544-1550
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• 2015

Recently, the development of practical wearable robot interfaces has resulted in the emergence of wearable robots such as arm prosthetics or lower-limb exoskeletons. In this paper, we propose a novel method of wrist movement intention estimation based on a regression technique using electromyography of human bio-signals. In daily life, changes in user arm position changes cause decreases in performance by modulating EMG signals. Therefore, we propose an estimation method for robust wrist movement intention for arm position changes, combining several movement intention models based on the regression technique trained by different arm positions. In our experimental results, our method estimates wrist movement intention more accurately than previous methods.

• Journal of Satellite, Information and Communications
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• v.5 no.2
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• pp.69-74
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• 2010

In this paper, we present an indoor positioning system based on light emitting diode (LED). Because LED is a semiconductor light emitting device, we can easily switch and modulate electrical signals into lightwave signals at high speed using LEDs. We assigned unique 8-bit ID address to each LED lights. Photo diode receives data from 16-LED lights and takes correlation coefficient beteween received data and each LED-ID. Using correlation coefficient, proposed positioning system shows resolution of 50 cm in dimensions of $4\;m\;{\times}\;4\;m\;{\times}\;2\;m$.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.83-89
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• 2012

Recently, due to widespread use of smartphones, the number of applications of the QR code is increased rapidly. QR codes, a kind of 2-dimensional barcode, is used to encode information such as simple URLs or namecards, especially for corporates' advertisement. Users can get some information easily by taking picture of the target QR code, however, fake or altered QR codes can cause serious problems, e.g., URL hijacking or infringement of private information because no one can identify the buried information in the QR code by his naked eye. In this paper, I summarize threats to the QR code and present how to tackle these threats.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.6
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• pp.29-36
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• 2005

RFID(Radio Frequency Identification) will be used for recognizing things and offering distinctive information in Ubiquitous environment. But we are not ready to provide security service to RFID. Therefore we propose the approach of safe RFID system which provides the solution for eavesdrop, forgery, and modification based on Pre-Distribution protocol and RC5 security algorithm. First We distributes the secret key to the Tag with the Reader that is major subject on RFID system using Pre-Distribution protocol. Then we will provide to various security services and privacy protection using RC5 security algorithm. The proposed safe RFID system simulated on ATmega128 evaluate environment.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2505-2507
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• 2001

The RF signal is distorted since the cross-talk noise from adjacent tracks and ISI(Inter Symbol Interference) is also incresed as recording density is increased. These cross-talk noise and ISI are main reason of reading error for the embossed pits on the disc. In this study we suggest a new coding method, spaced modulation technique and a detection technique for the spaced modulation. We report the result shows detection performance is improved when we use the suggested spaced modulation code and the detection technique instead of conventional modulation code.

• Journal of Internet Computing and Services
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• v.10 no.2
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• pp.53-63
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• 2009

e-Passport system is new type of emigration and immigration control system and it is a research to introduce the e-Passport Authentication Protocol with Improved Efficiency is lively proceeded over the entire world. The e-Passport's chip has a biometric information and personal identification information, Radio Frequency Identification(RFID) technology is used for communication with the Inspection System(IS). However, the feature of the RFID system may bring about various security threats such as eavesdropping, data forgeries, data alternation, cloning, biometric data-leakage. Therefore, in this paper, we analyse the e-Passport system's authentication protocol to protect vulnerability and proposed e-Passport system's authentication protocol reduce computation. Also, we compared their efficiency.