• Proceedings of the KSR Conference
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• 2011.05a
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• pp.652-659
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• 2011

Due to overuse of commercial network systems such as bluetooth and WI-FI, the problems of frequency interruption and line-crossing may arise. For this reason, wireless communication frequency ISM 2.4GHz, a recently adapted concept in Korea which is employeed by RF-CBTC system, is predicted not to have guarantee for outstanding and continuous performance. Therefore in this study, considering these problems, 5GHz capacity wireless Lans with international standard 802.11a/b/g applied were installed in the underground urban transit areas and it was proved that these lans exceeded the performance level of 2.4GHz with international standard 802.11b which is being introduced in the nation. In addition, it was verified through carrying out an application test that the communication condition was stable in a running train with high speed in the tunnel.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.281-284
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• 2005

WPA is a security service that greatly increases data protection and access control on WLANs. WPA uses TKIP that is secure algorithm of 802.11i and 802.1X/EAP authentication. It provides enhanced secure ability with the dynamic security key to correct WEP's weaknesses. In this paper, we obtain measured data transmission time that by how to create secure key of WPA in the wired and wireless network. The result shows that the delay of data transmission time was not long even if used WPA.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.186-189
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• 2015

최근 GPS가 탑재된 스마트폰의 보급이 늘어나면서 위치 기반 서비스가 빠르게 성장해 왔다. 위치조회의 방법은 크게 GPS를 이용한 위치 조회 서비스, 네트워크 위치 조회 서비스, 하이브리드 위치조회 서비스가 있다. 사용자 또는 제 3자가 위치 조회를 요청하였을 경우 사용자의 스마트폰에 장착된 소형 GPS 모듈을 조회하여 제공하여 준다. 하지만 GPS 모듈의 경우 실내에서는 취약하므로 만약 조회한 스마트폰의 위치가 실내에 있다면 Wi-Fi, 모바일 네트워크를 이용하여 위치를 조회하여 제공한다. 본 논문에서는 GPS 기반 위치 조회, 네트워크 기반 위치 조회, 하이브리드 위치 조회를 소개 및 비교 분석한다.

• Journal of the Semiconductor & Display Technology
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• v.19 no.2
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• pp.51-54
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• 2020

To develop gas-distinguishing sensor system, it is highly required to integrate multiple sensors for effective detection of a single targeted gas or mixture of gases. In addition, it is important to collect the reliable data from individual sensors into one integrated measuring device. Collecting the data of toxic gases on the spot should be done without inhalation. We suggest simple wirelessly running system for data collection that guarantees both reliability of data sources and safety. Here, we made a multi-gas measuring instrument(device) combined with Bluetooth module which provides a safe and precise big data accumulation system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.906-907
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• 2014

금형이나 부품절삭가공 등에 사용하고 있는 공작기계(밀링, 선반)는 Gcode라는 좌표값에 따라 공작기계를 동작시킨다. 공작기계가 많을 경우에는 휴대용 데이터 캐리어(data carrier) 이용하여 각각의 공작기계에 Gcode 데이터를 다운로딩 하고 있다. 현재에는 이러한 불편함을 해소하기 위하여 고가의 최신기술을 도입한 UTP, Wi-Fi, USB, CF 등을 기반으로 Gcode 데이터를 전송하는 시스템을 개발하고 있지만, 과거에 구입한 구형장비의 경우에는 RS-232를 사용하고 있어 데이터 전송이 불편함이 있다. 본 논문에서는 ATmega128을 활용하여 WGTE(Wireless Gcode Transfer Equipment)를 개발하여 시중에 상용화 되고 있는 고가의 장비를 대신할 수 있는 블루투스(bluetooth) 기반의 WGTE를 개발하고자 한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.10-14
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• 2019

The number of security incidents is increasing as the Internet of Things(IoT) is distributed widely. The security incidents of IoT can cause financial damages. Moreover, It can become direct threats to humans. In order to prevent these problems, the security installation for IoT devices is important. This paper describes the definition of IoT devices, security incident case, architecture, and the security threats that can occur when a device is connected to network without security installation.

• Journal of Navigation and Port Research
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• v.43 no.5
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• pp.289-295
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• 2019

In this paper, we implemented a safety navigation mobile application that converged AtoN information and location-based services. When application user uses the smartphone's GPS sensor to transmit the user's vessel location data to the data server, the user receives information of which its providing range is considered, such as stored AtoN data, neighboring vessels information, danger area, and weather information in the server. Providing information is sorted based on the smartphone's direction and inclination and it will be also delivered via wireless network (5G, LTE, 3G, WiFi). Additionally the application is available to implement other functions such as information provision through voice and text alarming service when the user's vessel is either approaching or entering the danger area, and an expanded information provision service that is available in shadow area linking with data-storing methods; other linkable data such as weather and other neighboring vessels will be applied based on the lasted-saved data perceived from the non-shadow area.

• International Journal of Computer Science & Network Security
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• v.21 no.12
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• pp.75-80
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• 2021

In this paper, a dual-band Koch Snowflake antenna is proposed for wireless communication systems. Fractal geometry, CPW-feed and stepped ground planes are used to improve the impedance bandwidth. By properly introducing a hexagonal split-ring slot to radiating element, a lower frequency band is generated. The proposed structure is fabricated and tested. Experiment results exhibit dual-band of 0.73-0.98 GHZ and 1.6-3.1 GHz which makes this antenna suitable candidate for GSM900, GSM1800, UTMS2100, Wi-Fi 2400 and LTE2600 bands. In addition, a good radiation pattern, a satisfactory peak gain and a radiation efficiency, which reaches 95%, are achieved.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.10
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• pp.1157-1165
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• 2012

In this paper, we measure and analyze propagation characteristic of heating, ventilation, and air conditioning(HVAC) ducts within buildings for wireless networks. We analyze the duct structures, implement the feeders exciting propagating modes, and simulate the excitation characteristic. We measure the propagation characteristic of HAVC ducts at 2.45 GHz WiFi band and compare it with that of LOS and partitioned office environments. We propose the design method of wireless network using HVAC ducts based on our results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.455-458
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• 2005

Current medical information management systems use man's hands or wired network for information transmission. It is difficult to check the situation information of the patient in real time. Moreover, it is also cumbersome to transfer the information. In this paper, we obtain the bio-signal in real time through wireless LAN, and store the carrer information of the patient at the management server in the hospital. We studied about development of system which provide the management server in the hospital. We studied about development of system which provide a career information service through PDA to the doctor as well as patients.