• Journal of Advanced Navigation Technology
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• v.14 no.6
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• pp.859-864
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• 2010

In the next generation system, a study on realization of Multi-Core system is in progress for applying it in multi service network. Therefore some mobile systems are expected to be appeared. These systems can support WiBro, WCDMA, CDMA, etc with single terminal. These systems have to support various FA using broadband frequency and hand over to other service network. Especially, in the telecommunication system composed of cell, the transmit power can be interference at adjacent system, has effect on system channel capacity and cell size. In this paper, we improve the unstable transmit power caused by unsettled system operation, propose the RF(Radio Frequency) Calibration method which can use the transmit power stably even during hand over between heterogeneous networks causing unstable power change. Also we used proposed method and analysed used electricity of system during hand over between heterogeneous networks.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.632-637
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• 2019

Recent researches on autonomous driving of vehicles are becoming very active, and it is a trend to assist safe driving and improve driver's convenience. Autonomous vehicles are required to combine artificial intelligence, image recognition capability, and Internet communication between objects. Because mobile telecommunication networks have limitations in their processing, they can be easily implemented and scale using an easily expandable Wi-Fi network. We propose a wireless design method to construct such a vehicle control network. We propose the arrangement of AP and the software configuration method to minimize loss of data transmission / reception of mobile terminal. Through the design of the proposed network system, the communication performance of the moving vehicle can be dramatically increased. We also verify the packet structure of GPS, video, voice, and data communication that can be used for the vehicle through experiments on the movement of various terminal devices. This wireless design technology can be extended to various general purpose wireless networks such as 2.4GHz, 5GHz and 10GHz Wi-Fi. It is also possible to link wireless intelligent road network with autonomous driving.

• The Journal of Bigdata
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• v.7 no.2
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• pp.75-90
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• 2022

Recently, complex and sophisticated analysis of transportation is required due to changes in the socioeconomic environment and the development of bigdata technology. Especially, the revision of 3 laws including PERSONAL INFORMATION PROTECTION ACT makes it possible to combine various types of mobility data. But strengthen personal information protection makes inefficiency in utilizing mobility bigdata. In this paper, we proposed the "Virtual fusion methdology via mobility bigdata" which is a methodology for indirect data fusion for various mobility bigdata such as mobile data and transportation card data, in order to resolve legal restrictions and enable various transportation analysis. And we also analyzed regional bus passenger in Seoul capital area and Cheongju city with aforementioned methodology for verification. This methdology could analyze behavioral pattern of passenger with the MCGM(Mobility Comprehensive Genetic Map), graph with position and time, making with mobile data. Consquently, using MCGM, which is a result for indirect data fusion, makes it possible to analyze various transportation problems.

• Journal of Ubiquitous Convergence Technology
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• v.2 no.2
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• pp.67-77
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• 2008

Representation of various types of information in an interactive virtual reality environment on mobile devices had been an attractive and valuable research in this new era. Our main focus is presenting spatial indoor location sensing information in 3D perception in mind to replace the traditional 2D floor map using handheld PDA. Designation of 3D virtual reality by Virtual Reality Modeling Language (VRML) demonstrates its powerful ability in providing lots of useful positioning information for PDA user in real-time situation. Furthermore, by interpolating portal culling algorithm would reduce the 3D graphics rendering time on low power processing PDA significantly. By fully utilizing the CC2420 chipbased sensor nodes, wireless sensor network was established to locate user position based on Received Signal Strength Indication (RSSI) signals. Implementation of RSSI-based indoor tracking method is low-cost solution. However, due to signal diffraction, shadowing and multipath fading, high accuracy of sensing information is unable to obtain even though with sophisticated indoor estimation methods. Therefore, low complexity and flexible accuracy refinement algorithm was proposed to obtain high precision indoor sensing information. User indoor position is updated synchronously in virtual reality to real physical world. Moreover, assignment of magnetic compass could provide dynamic orientation information of user current viewpoint in real-time.

• Journal of Satellite, Information and Communications
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• v.8 no.4
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• pp.95-99
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• 2013

GPS service is generally being used in the navigation application such as the car navigation and the smart phone. Recently, GPS service continues to increase in the timing application such as the mobile telecommunication network, the smart grid, and the financial network. As GPS signals are sensitive to GPS jamming, it should be monitored and protected. In oder to prevent and minimize the damage caused by GPS jamming, many countries are developing and operating GPS jamming monitoring system. This paper presents the implementation and the test results of the GPS jamming equipment which provides the detection, the direction finding and the location of GPS jamming.

• Journal of Information Technology Services
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• v.12 no.3
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• pp.111-126
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• 2013

As the gaps become narrower in interconnection fee and volume rate, the MNOs began to introduce flat pricing for unlimited voice traffic competitively in Korea wireless telecommunication market : 'unlimited talks within intra-network' by the 1st operator, followed by the 3rd operator's 'unlimited talks over all networks'. As a result, subscribers tip in toward the third ranked operator and could bring a substantial change to steadfast market structure over the last decade in Korea. This paper aims to develop a simple economic model to analyze competition with flat pricing for unlimited voice traffic, and to check whether the pricing can be appropriate for the MNOs. The results show that MNOs already step in the necessary conditions to launch flat pricing for voice traffic. It also predicts that the MNOs compete with unlimited talk over all networks and set a single fee in an equilibrium. At present, the MNOs run virtually identical pricing for unlimited talk over all networks, considering their differentiation with respect to service quality, coverage and brand preference.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.3037-3039
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• 2005

The AIS(Automatic Identification System) transmits the position of ships and other information to prevent accidents which could occur in the sea. It has to be developed SOTDMA(Self-Organized Time Division Multiple Access) Algorithm which is important on wireless communication method for the AIS because It is based on ITU(International Telecommunication Union) M.1371-1 of the international standard therefore, we need to develop a performance evaluation simulator efficiently to develop and analyze SOTDMA Algorithm. this paper shows the method of designing it. Real ships access The VHF maritime mobile band but in this performance evaluation simulator several ship objects access the shared memory. Real ships are designed as the object and the wireless communication channel is designed as the shared memory. The ships apply for real virtual data which got from assistance hardware and The SOTDMA Algorithm driving state verifies the performance evaluation simulator by IEC(International Electrotechnical commission) 61993-2. After verifying results the performance evaluation simulator is correctly satisfied with IEC 61993-2. So we expect that it helps not only the AIS technology developed but also verify new SOTDMA Algorithm

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.478-480
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• 2005

The AIS(Automatic Identification System) transmits the position of ships and other information to prevent accidents which could occur in the sea. It has to be developed SOTDMA(Self-Organized Time Division Multiple Access) Algorithm which is important on wireless communication method for the AIS because It is based on ITU(International Telecommunication Union) M.1371-1 of the international standard therefore, we need to develop a performance evaluation simulator efficiently to develop and analyze SOTDMA Algorithm. This paper shows the method of designing it. Real ships access The VHF maritime mobile band but in this performance evaluation simulator several ship objects access the shared memory. Real ships are designed as the object and the wireless communication channel is designed as the shared memory. The ships apply for real virtual data which got from assistance hardware and The SOTDMA Algorithm driving state verifies the performance evaluation simulator by IEC(International Electrotechnical commission) 61993-2. After verifying results the performance evaluation simulator is correctly satisfied with IEC 61993-2. So we expect that it helps not only the AIS technology developed but also verify new SOTDMA Algorithm.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.2
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• pp.23-32
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• 2010

WiBro(Wireless Broadband), the service based on IEEE 802.16e(mobile WiMAX) standard, is a wireless broadband Internet technology being developed by the domestic telecommunication industry. In this paper, we analyze security vulnerabilities of WiBro focusing on initial authentication phase and propose a specification-based intrusion detection system that can detect those vulnerabilities. We first derive a specification from the normally operational process of the initial authentication based on PKMv2 EAP-AKA and formalize the derived specification as a state transition diagram. Proposed system executes the intrusion detection based on those specification and state transition diagram. In this paper, to verify the detection capability of proposed system, we construct a test bed network and execute scenario-based test.

• The KIPS Transactions:PartD
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• v.11D no.6
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• pp.1247-1258
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• 2004

The LBS(Location-Based Service), which is based on individual's mobility, is required increasingly as mobile telecommunication and various infrastructures have developed rapidly. The technologies for LBS are location determination technology, service platform technology, contents provider technology and moving object database technology generally. Among these, service platform must be interoperable with location gate-way server and provide common function of billing, authentification, protect location information, privacy control, location trigger and intelligent acquisition and so on. The TTA(Telecommunications Technology Association) published specification that defines a standard protocol for safe and simple interface between LBS client and LBS platform and the OpenLS(Open Location Service) in OGC (Open GIS Consortium) released implementation specifications for providing Location based core services. In this paper, we implemented service platform for LBS which is able to interoperable with location gateway server and contents provider and is caracterized as follows. First, it could require and response location information from different types of location gateway server with same interface. Second, it complies with the standard interfaces with OpenLS 4 contents providers for core LBS. Third, it could provide location of wired phone as well as wireless mobile terminal compling with the standard protocol. Last, it could provide trajectorH information based past location as well as current location, because it is able to interoperable with moving object DBMS. This paper contributes to the construction and practical use of LBS by providing the method of implementation of service platform for LBS.