• Journal of Korea Spatial Information System Society
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• v.6 no.2 s.12
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• pp.77-84
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• 2004

The purpose of this study is to suggest an effective guideline for reducing communication costs and improving qualities of Intelligent Transport Systems (ITS) by totally or partially integrating wireless communication networks between equipments of ITS Centers and Roadside in the National ITS Physical Architecture. We analyzed wire and wireless communication networks such as wireless LAN and satellite communications in the National Highway Traffic Management System (NHTMS) for receiving and transmitting transportation data. Also, we analyzed operation and communication costs to find out right communication networks for ITS. The results of this study will be used to build and operate many other ITS systems including Korea Highway Corporation.

• 한국ITS학회:학술대회논문집
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• 2003.11a
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• pp.159-164
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• 2003

• 한국ITS학회:학술대회논문집
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• 2004.11a
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• pp.149-153
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• 2004

• 한국ITS학회:학술대회논문집
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• 2008.11a
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• pp.132-136
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• 2008

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.2 no.2 s.3
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• pp.55-64
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• 2003

This research is about executing the suitability evaluation of the data through wireless communication system in comparison with the data through the wire system used in National Highway Traffic Management System. The communication system for the evaluation was established on Peoyngteak-Anjung section(about 19 Km) at Route 38 in southern National Highway of the National Capital region where image detectors with the communication by wire were set up. In the situation, the comparison of the data transmission rates between the wire system and the proposed system was accomplished. Before we evaluate the possibility of application about the proposed system, the elements of wireless systems performed the spot investigations. Traffic data transmission test among the equipments was accomplished on the section of the Route 38 where wireless communication equipments were set up. And then, the test of traffic data transmission between the field equipment and the data collective center of wireless communication system was carried out. It evaluated the reliability of wireless communication data for the suitability evaluation of cable/wireless data collected while 73 days.

• 한국ITS학회:학술대회논문집
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• 2005.11a
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• pp.125-129
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• 2005

• The KIPS Transactions:PartA
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• v.11A no.6
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• pp.451-458
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• 2004

The previous studies focussed on the security problem and the fast re-authentication mechanism during handoffs in a single wireless LAN system. When the multiple wireless LAN systems share their network infrastructure one another, we propose an authentication mechanism allowing the subscriber to Perform the authentication procedure with the authentication server of its own wireless LAN system even in areas of other wireless LAN systems as well as in areas of its own wireless LAN system. In the proposed mechanism, the access point or the authentication server of other wireless LAN systems plays a role of the authentication agent between the subscriber and the authentication server of the subscriber's wireless LAN system. The proposed authentication mechanism is designed on the basis of the 802.1X and EAP-MD5 protocols.

• Journal of Korea Spatial Information System Society
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• v.3 no.1 s.5
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• pp.63-73
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• 2001

The purpose of this study is to develop a method of integrating diverse communication networks for effectively providing ITS(Intelligent Transport System) services. In this paper, in oder to integrate communication networks, we have defined ITS services, its requirements and functions of communications. Also, we have analyzed the six important ITS services in the National ITS Architecture along with the characteristics of wireless communications. Based on the ITS service scenarios, we have derived the communication methods for ITS services.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.1
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• pp.92-100
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• 2008

The existing transportation systems is emerged as a major obstacle to solve the problems such as a traffic jam and the increasing cost for a distribution and a traffic safety. In hun, ITS targeting intellectual vehicles and transportation infrastructure like road and signals is getting more important and the standards of ITS wireless communication is also getting attention. New traffic control strategies are being developed to utilize real-time traffic information collected by detection method using ITS wireless technology. Especially, DSRC system is being expanded wit ETCS and the use of OBU is spreading. These infrastructures will have much influence on ITS industry and a profound study on the method of utilizing a present infrastructure is going on in various fields. The optimum traffic signal control system using quality real-time information through these infrastructure is under development and so is WISDOM. Accordingly, this paper proposes communication protocol utilizing DSRC to collect real-time traffic information in WISDOM.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.3
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• pp.51-58
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• 2010

According to dramatic increase of wireless communication demand, more spectrum resources are needed to support considerable and various wireless services, so cognitive radio(CR) was proposed to reuse unused frequency efficiently. Also, FCC revises its policies regarding the usage of the TV white spaces by unlicensed users. CR is an intelligent wireless communication system that is aware of the radio environment and is capable of adapting its operation to the statistical variations. Spectrum sensing is the key task of the CR systems. However, since spectrum sensing performance changes according to the received signal that is received various geography environment, regional characteristics are considered to estimate the path-loss. Therefore, for more accurate analysis and simulation, we demonstrate the spectrum sensing performance of CR system by various method applying Okumura-hata propagation model.