• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.169-175
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• 2011

This paper addresses mobile IP router which communicate between nodes in Ad Hoc network as well as supply attachment to outer Internet. Ad Hoc network is one which exchanges information through cooperations among nodes without wire infrastructure, mobile IP router considers the network as one mobile unit, and supports Internet connection in mobile as well as fixed spaces. Therefore, this router can accommodate the routing of Ad Hoc network, and provide nodes in Ad Hoc network with Internet connection. So mobile IP router can provide Ad-Hoc terminals with the diverse wireless services, such as Internet connection service, routing, mobility, and so on.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.53-63
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• 2009

This paper is to develop WiMAX CPE(wireless AP) that can provides Wi-Fi terminal with wireless Internet service by connecting to Wibro wireless network. This AP aims to support WiBro in upstream interface basically, and Wi-Fi and 100M Ethernet interface in downstream. So, we has developed the equipment for business that wireless ISP can provide many Internet customers with wireless Internet service by using Wi-Fi terminal in subway, car, ship, and so on, and the equipment for users that a user can purchase and then install in person. For the latter, multiple Wi-Fi terminals that be registered in WiBro service can be connected to Internet simultaneously.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.3
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• pp.325-333
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• 1998

In this paper, conventional STM(Synchronous Transfer Mode) supports another traffics by using idle channels. Proposed mobile terminals are distributed independently at the BSA(Basic Service Area). So, MAC(Medium Access Control) specified on the wireless ATM networks, which is managing statistics multiplewing functions, idle channel's ultilization is maximized and multimedia service characteristic for conventional wired networks based fixed assignment scheme(connection-oriented) and random assignment scheme(connection-oriented) improving on dynamic reservation based MAC protocol.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.05a
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• pp.132-137
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• 1998

In this paper, conventional STM(Synchronous Transfer Mode) supports another traffics by using idle channels Proposed mobile terminals are distributed independently at the BSA(Basic Service Area). So, MAC(Medium Access Control) specified on the wireless ATM networks, which is managing statistics multiplexing functions, idle channel's utilization is maximized and multimedia service characteristic for conventional wired networks based fixed assignment scheme(connection-oriented) and random assignment scheme(connectionless) improving on dynamic reservation based MAC protocol.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.395-403
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• 2011

Various studies were performed for providing the latest spatio-temporal information in mobile GIS Environments. The two-way synchronization scheme collects updated spatio-temporal data in the field and synchronizes with a server by using the wireless network. However, the other mobile terminals have to perform periodically synchronizes with a server. In this paper, we propose the update propagation scheme about spatio-temporal data collected from the mobile terminal. The update propagation scheme does considering various factors where an influence is in the update propagation. Therefore, it provides various update propagation policies according to each factors.

• The Journal of the Korea Contents Association
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• v.1 no.1
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• pp.109-117
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• 2001

The WAP gateway. for wireless internet applications services, is a software that is placed between the user terminals(PDA, mobile phones) and the WAP/Web server. H is a middleware system that converts the protocol of a packet network to the protocol on the WAP network, and supports the encoding of WML documents. In this paper, we designed and implemented the WAP gateway based on the WAP specification version 1.2 announced by the WAP forum. It provides cross-platform compatibility by being implemented by the Java language. Compared with a Kannel system using a Nokia tool kit version 1.2, it provides a more excellent performance and a stability.

• The KIPS Transactions:PartC
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• v.14C no.1 s.111
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• pp.7-16
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• 2007

3G telecommunication and wireless LAN provide various wireless communication services with their own native advantages and disadvantages. Currently WiBro service was developed to make up for the disadvantages of those services, and 3G-WLAN-WiBro underworking system which enables a user who uses triple-mode terminals to use those three networks was proposed. Even though each network adopts mutual authentication process between users and networks to provide security and accounting, they use different authentication protocols. In this paper, integrated authentication and key management protocol is proposed which makes use of previously used authentication information and supports safe roaming when a user moves from one network to another one under a same service provider on the 3G-WLAN-WiBro interworking network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9A
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• pp.1075-1082
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• 2004

Wireless LAN is a rather mature communication technology connecting mobile terminals. IEEE 802.11 is a representative protocol among Wireless LAN technologies. The basic medium access control (MAC) mechanism of IEEE 802.11 is called distnbuted coordination function (DCF). DCF shows poor throughput and high drop rate as the number of stations and offered traffic load increase. In this paper we propose an effective mechanism using dynamic mimmum contention window(CWmin) in wireless LAN~ and show that performance improves via simulations. Proposed dynamic CWmin scheme exhibits superior performance as the number of stations and offered load grow. As, our proposed scheme is expected to be more effective in highly densed wireless LAN environment.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2007.02a
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• pp.87-96
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• 2007

Ubiquitous is a Latin-derived word meaning "to exist at any time and place" like water or air. In computing, the word "ubiquitous" indicates an environment in which users have access to networks without any limitation regarding computer networks or places. Important issues in building Ubiquitous Korea (U-Korea) are the social problems appearing with a rapid increase in the old age population. Nowadays, with the rise of the nuclear family, the increase in the number of elderly people living alone, and the change in the status of women, both wives and husbands are employed outside the home, and the relatives who would be responsible for supporting the elderly sometimes are on long or short business trips, and it happens that old people can't be looked after. Therefore the government developed a wireless paging system for the sick, disabled, old and weak so that when an emergency happens, by just simply dialing 119, an emergency aid center could take prompt action. However, the present wireless paging systems composing the under-layer of the emergency aid information system have some problems, such as, a lack of reliability, problems among terminals, mobile transmitters and receiving terminals, the users' refusal to admit the need for the system and poor operational skills, administrators' perfunctory management and checks, etc. On account of these problems, the system efficiency has degraded and therefore a system upgrade is necessary. In this paper, we attempt to evaluate the newly implemented SAFE119 system, a new wireless paging system seeking to correct the problems of the current system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.51-56
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• 2017

With the rapid increase in the number of mobile terminals, demand for wireless technologies has sharply increased these days. While wireless communication provides advantages such as ease of deployment, mobility of terminals, continuity of session, and almost comparable transmission bandwidth to the wired communication, it has vulnerability to malicious radio attacks such as eavesdropping, denial of service, session hijacking, and jamming. Among a variety of methods of preventing wireless attacks, the MTD(Moving Target Defense) is the technique for improving the security capability of the defense system by constantly changing the ability of the system to be attacked. In this paper, in order to develop a resilient software defined radio communication testbed system, we present a novel MTD approach to change dynamically and randomly the radio parameters such as modulation scheme, operating frequency, packet size. The probability of successful attack on the developed MTD-based SDR communication system has been analysed in a mathematical way and verified through simulation.