• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.553-555
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• 2003

Mobile Ad hoc network에서 이동 노드들의 안정적이고 신뢰성이 높은 데이터 전송을 하기 위해서 multipath routing을 통하여 소스 목적지 노드간에 다중 경로를 구하고 기존의 라우팅 방법과 비교해 본다. 또한 다중 경로를 활용하는 방법과 경로구간의 링크 다운 시에 보다 빠른 복원을 할 수 있는 방법을 제시하고자 한다. 모바일 노드들의 이동성과 낮은 대역폭으로 인한 데이터 손실을 줄이는 방법으로 데이터 트래픽을 다중경로에 분산시키는 Traffic Load Balancing 방법과 데이터 전송 중에 발생하는 링크 다운 시에 새로운 경로를 찾는 메커니즘이 아닌 중간 경로에서 기존에 유효한 경로를 이용하는 Local recovery 방법을 소개하고자 한다.

• Journal of the Korea Society of Computer and Information
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• v.19 no.1
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• pp.31-41
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• 2014

This paper proposes a virtual mobile ad-hoc network (VMANET) model that automatically divides heterogeneous mobile devices of a MANET into a number of network groups depending on the communication capacity(data rate) of different network operational models such as IEEE 802.11g, IEEE 802.11b, and Frequency Hopping. In addition, it supports a distinct routing protocol for each network group of VMANETs, resulting in running multiple routing protocols concurrently on different groups of VMANETs. To reduce the network congestion and improve the network load balance, a default MANET gateway is configured in each VMANET and these gateways are responsible for integrating the MANET and IP networks. Experiment results show that the proposed model outperforms the conventional IMANET by significantly increasing throughput and reducing network congestion and network delay.

• Journal of Communications and Networks
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• v.11 no.2
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• pp.187-195
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• 2009

The application of mathematical analysis to the study of wireless ad hoc networks has met with limited success due to the complexity of mobility, traffic models and the dynamic topology. A scenario based universal mobile telecommunications system (UMTS) time division duplex (TDD) opportunistic cellular system with an ad hoc behaviour that operates over UMTS frequency division duplex (FDD) licensed cellular network is considered. In this paper, we present a new routing metric which overall improves system performance in terms of interference and routing which operate in an ad hoc network in an opportunistic manner. Therefore we develop a simulation tool that addresses the goal of analysis and assessment of UMTS TDD opportunistic radio system with ad hoc behavior in coexistence with a UMTS FDD primary cellular networks.

• Journal of the Korea Society for Simulation
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• v.19 no.3
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• pp.1-6
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• 2010

Simulation analysis may be the essential means to either evaluate performance of systems or optimize system parameters for new design. Including many variations for design and implementation, MANET (Mobile Ad-hoc NETwork) is one target area of such an analysis. Since every node, however, included in the network has mobility, one MANET could be overlapped or merged with another one which use a different transport protocol. In order to communicate among nodes in this case, the new merged network should configure paths and addresses in advance. Configuring paths and addresses generates much overheads which ultimately cause delay in communicating data. Performance analysis is required to improve the data transport performance by minimizing overheads. This paper proposes a sound address auto-configuration method which is based on an on-demand manner and then presents modeling and performance analysis of the method. NS-2 simulation results verify that the proposed method can not only alleviate overheads, which are inevitably generated for address auto-configuration processes, and but also decentralize them in time.

• Journal of Korea Society of Industrial Information Systems
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• v.10 no.3
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• pp.30-37
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• 2005

Ad hoc network is a collection of mobile nodes without using any infrastructure, it , is using in the various fields. Because ad hoc network is vulnerable to attacks such as routing disruption and resource consumption, it is in need of routing protocol security. In this paper, we propose two secure route-discovery protocols. One is a protocol using hash function. This protocol is weak in active attack but has some merits such as small data of transmission packet and small computation at each hop. The other is a protocol using hash function and public key cryptography. This protocol is strong in active attack.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.5
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• pp.47-57
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• 2006

Mobile Ad-hoc networks have various implementation constraints such as infrastructure-free, no trusted authority, node mobility, and the limited power and small memory of mobile device. And just like wired networks, various security issues such as authentication, confidentiality, integrity, non-repudiation, access control, availability and so on have been arisen in mobile Ad-hoc networks. But we focus on authentication of these security issues because it is quitely affected by the characteristics of networks. In this paper, we propose the authentication protocol that can limit the size of certificate repository as $log_2N$ and assures to make a trusted certificate path from one node to another, adopting the concept of Hamming distance. Particularly, our protocol can construct a trusted certificate path in spite of decreasing or increasing the number of nodes in mobile Ad-hoc network.

• Journal of KIISE:Information Networking
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• v.33 no.5
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• pp.369-379
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• 2006

In recent years, there have been many researches about Ad-hoc Networks which is available to communicate freely between mobile devices by using multi-hop without any support of relay base or access point. TCP that used the most widely transport protocol in the Internet repeats packet loss and retransmission because it increases congestion window size by using reactive congestion control until packet loss occurs. As a result of this, energy of mobile device is wasted unnecessarily. In this paper, we propose TCP-New Veno in order to improve the energy efficiency of mobile device. According to the state of network, the scheme adjusts appropriate size of congestion window. Therefore, the energy efficiency of mobile device and utilization of bandwidth are improved by the scheme. From the simulation by using ns-2, we could see more improved energy efficiency with TCP-New Veno than those with TCP in Ad-hoc Networks.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.238-240
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• 2001

문선 네트워크 분야에서 기존의 Mobile IP 외에 별도의 기반 시선 없이 각 노드만으로 네트워크를 구성하여 통신하는 Mobile Ad hoc Network (MANET)에 관한 연구가 활발히 진행되고 있다. 본 논문에서는 MANET에서의 노드 에너지 소비량을 공정하게 조절하는 라우팅 알고리즘을 제안한다. 기존에 제시된 라우팅 알고리즘들은 데이터 경로 결정의 요소로 각 노드의 에너지 정보를 사용하고 있다. 이에 반해 본 논문에서 제시하는 알고리즘은 각 노드의 에너지 뿐만 아니라, 네트워치 통신에 대한 기여도를 사용한다. MANET에서 노드는 일반 호스트이면서 동시에 다른 노드의 데이터에 대한 라우터의 역할도 수행한다. 노드가 호스트가 아닌 라우터로써 많은 에너지를 소비하게 되면, 이 노드는 네트워크 통신에 대한 기여도가 높다고 한 수 있다. 시뮬레이션을 통한 견과는 우리가 제시하는 라우팅 알고리즘이 네트커핀 전반에 걸쳐 에너지를 공정하고 균등하게 분포 시킬 수 있다는 것을 보여준다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1177-1186
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• 2003

The multimedia ad hoc wireless network is quite an attractive issue since it offers a flexible solution to enable delivery of multimedia services to mobile end users without fixed backbone networks. However, with the unique design challenges of ad hoc wireless networks, it is a non-trivial issue to provide bounded delay guarantee, with fair share of resources. In this paper, we implemented the delay guaranteed fair queueing (DGFQ) scheme distributively. Through the results of performance evaluation, we can conclude that DGFQ also performs well to control bounded delay in multimedia ad hoc wireless networks.

• The Journal of the Korea Contents Association
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• v.11 no.1
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• pp.65-71
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• 2011

In this paper, the RFID / USN-based ad-hoc network structure is presented for efficient operation of a container terminal yard. Communication between fixed or mobile devices in the container terminal yard is accomplished through the ad-hoc node, to collect the status information of a container in real time. Any outside shipper of the container as well as central server allows to share the status information of a container through ad-hoc communication. In addition, to predict the maximum wireless transmission range of nodes by RFID tag position in the yard, LAODV (Location based AODV) routing protocol is proposed. The validity is proved by performance evaluation via computer simulation.