• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.878-884
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• 2013

This paper presents a transmission power control MAC protocol that allows terminals to vary transmit power level on data frame basis in ad hoc network. Unlike the IEEE 802.11 approach, we do not use the RTS/CTS packets to silence the neighboring nodes. Instead, channel gain and distance information between transmitter and receiver terminal are inserted in the RTS/CTS packets. These informations are used to dynamically bound the transmission power. Simulation results indicate that, compared to the GMAC, the proposed MAC protocol achieves a increase in the average frame delivery ratio and a decrease in the average frame delay.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.4
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• pp.759-766
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• 2015

This paper proposes a location-based key management scheme in wireless sensor networks, and among the existing location-based key management techniques, we focused on the LDK (Location Dependent Key management). In order to improve the problems occurred by communication interference, we introduced the key revision process and the method of key establishment using grid information. According to the simulation of this scheme, it increased connectivity while decreased compromise ratio than those of the previous LDK, futhermore, we confirmed that a hexagon distribution of AN reduces the network cost.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.8
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• pp.1386-1392
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• 2006

This study is a numerical representative modelling analysis for applying the process that unravels networks between cells in genetics to WWW of informatics. Using the probabilistic graphical model, the insight from the data describing biological networks is used for making a probabilistic function. Rather than a complex network of cells, we reconstruct a simple lower-stage model and show a genetic representation level from the genetic based network logic. We made probabilistic graphical models from genetic data and extends them to genetic representation data in the method of network modelling in informatics.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.692-700
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• 2012

The WiMedia Alliance has specified a Distributed Medium Access Control (D-MAC) protocol based on UWB for high speed wireless home networks and Wireless USB. In this paper, firstly, the fair SoQ-based Distributed Reservation Protocol (DRP) for D-MAC is analyzed. And a novel SoQ-based relay transmission protocol is proposed to overcome DRP conflicts fast. In the proposed protocol, each device executes the Satisfaction of QoS (SoQ) time slot allocation algorithm independently. And, in order to give the loser device due to DRP conflicts another chance to maintain QoS resources, the proposed relay transmission protocol helps the device reserve another indirect link maintaining the required QoS resources via a relay node.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.9
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• pp.1889-1894
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• 2011

Channel allocation is one of the important issues in the multichannel transmission. In the cognitive radio networks, channel allocation scheme should be designed to improve spectrum efficiency without interfering with the transmission of licensed users. In this paper, we propose a spectrum hole prediction based channel allocation scheme. The proposed channel allocation scheme, predicts spectrum hole by using the channel success rate, and limit the transmission of secondary user's data, and it reduces the interference to the primary user. The performance of proposed channel allocation scheme is evaluated by the computer simulation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.7
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• pp.1715-1722
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• 2010

In this paper we consider methods for selecting the next tracing node that take advantage of the history of traced positions during the packet-tracing. In the meantime, the proposed routing strategy that counters the tracing is to design the routing path is such a way that nodes on it are not close to the nodes whose location privacy is needed and zigzag or back-and-forth movements hardly take place. In simulations, the ratios of successful tracing were largely improved. It was shown that our routing scheme allows more data packets to be delivered to the destination while, enticing the tracer to move more long distances in the presence of multiple assets.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.4
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• pp.684-690
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• 2003

In this paper, a contention-based reservation access control algorithm and a slot allocation algorithm are proposed for non-real-time bursty traffic services in the wireless ATM networks. In order to reduce the collisions of the reservation request packets, the base station scheduler calculates the transmission probability using the number of RAS minislots and the estimated load of the reservation request packets. And it broadcasts the calculated transmission probability over the downlink control channel. Mobile terminals, which have traffic burst, select randomly a RAS minislot and transmit the reservation request packet by the received transmission probability. The reservation request packet contains the number of packets in the buffer. The slot allocation is based on the buffer status of the received reservation request packets. The base station scheduler allocates slots in proportion to the total number of slots that are requested by each terminal.

• Journal of information and communication convergence engineering
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• v.9 no.5
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• pp.610-614
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• 2011

Nowadays Mobile Ad Hoc Networks (MANETs) are a very popular and emerging technology in the world. MANETs helps mobile nodes to communicate with each other anywhere without using infrastructure. For this purpose we need good routing protocols to establish the network between nodes because mobile nodes can change their topology very fast. Mobile node movements are very important features of the routing protocol. They can have a direct effect on the network performance. In this paper, we are going to discuss random walk and random waypoint mobility models and their effects on routing parameters. Previously, mobility models were used to evaluate network performance under the different routing protocols. Therefore, the network performance will be strongly modeled by the nature of the mobility pattern. The routing protocols must rearrange the changes of accurate routes within the order. Thus, the overheads of traffic routing updates are significantly high. For specific network protocols or applications, these mobility patterns have different impacts.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10C
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• pp.749-757
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• 2008

In this paper, we propose an authentication scheme for EVPT (Emergency Vehicle Priority Transit) service in Vehiclar Ad-hoc Networks (VANET) enable a variety of vehicle comfort services, traffic management applications, and infotainment services. These are the basis for a new generation of preventive and active safety functions. By intelligently controlling signalling at intersections, providing additional information to the driver and warning the driver in critical situations. we therefore focus on vehicle-to-infrastructure communication for the authentication between emergency vehicles and traffic lights system. This authentication process should identify the vehicle, and provide privacy protection.

• Journal of KIISE:Information Networking
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• v.34 no.1
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• pp.27-32
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• 2007

Next-generation wireless networks are expected to support a wide range of services, including high-rate data applications, Various service types request differentiated QoSs(Qualities of Service) such as minimum data rate, accuracy, fairness and so on. Although resources of radio systems are limited, for many applications, it is important that certain QoS targets are required to be met. In this paper, we propose a QoS based scheduling algorithm for next generation systems, based on analyzing previous researches, and we develop the proposed QoS algorithm only for MIMO(multi-Input Multi-Output) systems. Moreover, we subsequently prove that the proposed algorithm optimize throughput relative to prespecified target values and converge to certain throughput.