• Journal of Navigation and Port Research
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• v.28 no.1
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• pp.31-36
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• 2004

In this paper, the characteristics of an inverted-F antenna for the 2.4GHz(ISM) Bluetooth system have been analysed in terms of the variation of design parameters. The antenna can be integrated on printed circuit board, and the characteristics in terms of the variation of the gap between feed line and shorting stub, gap between antenna's leg and ground plane, antenna leg's width, substrate's height and dielectric constant are analysed By using these characterization plot of design parameter, the tuning techniques are proposed to design optimum antenna. The designed antenna has 6.3%(150MHz) frequency bandwidth for VSWR under 1.5, and 3dBi gain.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.386-389
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• 2006

At ubiquitous environment of the future, the platform that is mobile and suitable in such environment transmit and receive many data freely. In medical treatment field, medical device with advancement of the sensor and multimedia technique will develop as the household and hand-held device. So It will be developed as the health care device easily exchanging data to other devices and transmitting information of medical device to server. In this paper, currently the mobile platform based on the PXA255 such as a powerful microprocessor which connected the WLAN for guaranteeing a mobility and a speed transmits medical information to hospital server. It put an importance in providing the system for an efficient service.

• The Journal of the Korea Contents Association
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• v.16 no.8
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• pp.90-96
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• 2016

The 3390 million people, around 83% of the adult population in Korea use smartphone. Although the safety problem of the certificate has been occurred continuously, most of these users use the certificate. These safety issues as a solution to 'The owner of a mobile phone using SMS authentication technology', 'Biometric authentication', etc are being proposed. but, a secure and reliable authentication scheme has not been proposed for replace the certificate yet. and there are many attacks to steal the certificate and private key. For these reasons, security experts recommend to store the certificate and private key on usb flash drive, security tokens, smartphone. but smartphones are easily infected malware, an attacker can steal certificate and private key by malicious code. If an attacker snatchs the certificate, the private key file, and the password for the private key password, he can always act as valid user. In this paper, we proposed a safe way to keep the private key on smartphone using smartphone's unique information and user password. If an attacker knows the user password, the certificate and the private key, he can not know the smart phone's unique information, so it is impossible to use the encrypted private key. Therefore smartphone user use IT service safely.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.1
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• pp.25-33
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• 1998

In this paper, we describe a single-gate MESFET mixer at PCS(Personal Communication Service) frequency band. The PCS frequency band is 1965~2025 MHz in FR and 140 MHz in IF irrespectly. The design of the mixer was executed by microwave simulator, EEsof Libra. The matching network is consisted of rectangular inductor, MIM capacitor and open stub. The ma- nufacture work was accomplished by the micro-pen and wedge-bonder. The mixer showed $6.69\pm0.65$ dB of conversion gain, $-14.9\pm3.5$dB of RF reflection coefficient and 57.83 dB of LO/IF isolation at 10 dBm of LO power when LO frequency is 1855 MHz. When this mixer is used at PCS terminal, IF-amplifier which compensates the conversion loss of diode mixer may be omitted.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.1
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• pp.82-86
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• 2016

This paper proposes a method for the immobilization of motorbike brakes in conjunction with near-field communication (NFC) technology in order to meet the increasing demand for security and convenience of motorbike drivers. We thought about the concept of wireless key, NFC security devices and automatic solenoid valve for setting the lock and unlock module. This paper propose the design and development of an innovative anti-theft alarm system for motorcycles using NFC smart devices based on RFID system, the basis of IoT and AES(advanced encryption standard) encryption Algorithm. The design concept is based on NFC communication strategy between the vehicle and owner. To do this concept, we designed motorcycle smart key system with general-purpose NFC system and the automatic solenoid valve for setting the lock and unlock module. First, we designed control unit and NFC card reader for motorcycle smart key system. Then we propose an AES encryption algorithm and prove that the motorcycle key system is controllable by showing the result of implementing and testing, after installing.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.4
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• pp.345-352
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• 2005

In up-to-date information anger time it is caused by with business of traffic accident control and analysis and two time it accomplishes a business. National Police Office which controls a traffic accident does not execute an up-to-date technique. And, it is working yet by the hand, There is to traffic accident analysis and the research regarding the analysis against the research which it follows in geography element and composition element and an accident cause is weak. Consequently, effectively establishment and it enforces a traffic safety policy and from the hazard which it evaluates traffic accident data the system and scientific analysis against a traffic accident occurrence cause and a feature in basic must become accomplished. The research which it sees constructs a traffic accident data in GIS base. It is like that, it uses the PDA where is not the collection of data of text form in existing and at real-time it converts store and an accident data rightly in standard traffic accident data form and it will be able to manage. It was related with a space data peculiarity and the research regarding the system development with the geography analysis data about an accident cause under manifesting it accomplished.