• The KIPS Transactions:PartC
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• v.13C no.5 s.108
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• pp.621-626
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• 2006

A mobile ad hoc network (MANET) is an infrastructureless network that supports multi-hop communication. For the MANET nodes wishing to communicate with nodes in the wired Internet, the global Internet connectivity is required and this functionality can be achieved with the help of the Internet gateway. For the support of reliability and flexibility, multiple Internet gateways can be provisioned for a MANET. In this case, load-balancing becomes one of the important issues since the network performance such as the network throughput can be improved if the loads of the gateways are well-balanced. In this paper, we categorize the load-balancing mechanisms and propose a new metric for load-balancing. Simulation results show that our proposed mechanism using the hop distance and the number of routing table entries as a load-balancing metric enhances the overall network throughput.

• Journal of the Korea Computer Industry Society
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• v.2 no.7
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• pp.983-996
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• 2001

Mobile Ad Hoc Network (MANET) is a network architecture which has no backborn network and is deployed temporarily and rapidly in emergency or war without fixed mobile infrastructures. All communications between network entities are carried in ad-hoc networks over the wireless medium. Due to the radio communications being extremely vulnerable to propagation impairments, connectivity between network nodes is not guaranteed. Therefore, previously developed routing algorithms in wired networks cannot be used. And many new algorithms have been undergone. This study proposes the Secondary Header approach to the cluster based routing protocol (CBRP). In case, the main header becomes abnormal status so that the main header can not participate the communications between network entities, the secondary header immediately replaces the primary header without selecting process of the new primary header. The performances of proposed algorithm CBRP-SH(Cluster Based Routing Protocol using Secondary Header) are compared with CBRP and results are presented in order to show the effectiveness of the algorithm.

• The KIPS Transactions:PartC
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• v.12C no.4 s.100
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• pp.581-588
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• 2005

The performance of mobile devices and wireless networks is improved rapidly and Mobility management skills such as Mobile IP and ad-hoc technology were developed. So the requirement of processing the distributed computing is highly increased in any place and any time or in the state of movement. Therefore we studied the mobile grid system to process the distributed applications properly in wireless networks. In addition to typical computational resources, Mobile Grid brings new resources such as sensor, mobile devices or other wireless devices to distributed computing for the purpose of resource-sharing. In this paper, we design and implement the mobile grid system in wireless lan network environment for the providing the grid service. Also, we evaluate the performance of mobile grid system using the processing the distributed applications in implemented mobile grid environments.

• Journal of Communications and Networks
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• v.6 no.4
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• pp.343-351
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• 2004

Scalability is one of the toughest challenges in ad hoc networking. Recent work outlines theoretical bounds on how well routing protocols could scale in this environment. However, none of the popular routing solutions really scales to large networks, by coming close enough to these bounds. In this paper, we study the case of link state routing and OLSR, one of the strongest candidates for standardization. We analyze how these bounds are not reached in this case, and we study how much the scalability is enhanced with the use of Fish eye techniques in addition to the link state routing framework. We show that with this enhancement, the theoretical scalability bounds are reached.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.517-519
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• 2004

Chord(6)는 N개의 노드로 이루어진 P2P(Peer-to-Peer)네트워크에서 검색에 사용되는 메시지를 O(logN)으로 줄인 P2P 검색 알고리즘이다. 하지만 모바일 Ad-hoc 네트워크에 이를 적용할 경우 검색 성공률이 매우 떨어져 (1000개의 노드가 도보속도(2m/s)로 움직이는 경우： 검색 성공률 30%이하)P2P 검색이 거의 이루어지지 않는 문제점이 발생한다. 본 논문에서는 이 같은 문제점을 극복하기 위한 알고리즘인 Backtracking Chord을 제안한다. Backtracking Chord 방식은 O(logN)메시지를 사용하여 순차적으로 t번까지 검색을 요청함으로써(t： Timeout의 횟수(0 < t< logN)) t에 따라 최고 88%(t>4)까지 검색 성공률을 높일 수 있다.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.767-768
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• 2006

In this paper we propose a new routing protocol, which takes residue energy of nodes into account in order to prevent node failures resulting from energy shortage. Our routing protocol examines the smallest value of node residue energy ($E_m$) from each of all possible routing paths and selects the path which has the largest value of $E_m$. We prove, through simulation, that our routing protocol extends the lifetime of nodes which have limited amount of energy, reducing chances of path replacement. It is also shown that our proposed protocol helps alleviate network performance degradation.

• Annual Conference of KIPS
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• 2011.11a
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• pp.651-653
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• 2011

본 논문에서는 모바일 노드들의 움직임이 심한 MANET 환경에서의 데이터의 전송을 안정적이고 신뢰성있게 하기 위한 방법을 제시하고자 한다. 우회경로가 적은 경우보다 우회경로가 많이 확보되었을 때 상호간의 통신이 더욱 안정적이나, 기존 연구에서는 이러한 고려가 충분히 되어있지 않고, 경로 설정 당시 알고리즘에 의해 최적화된 경로라고 판단된 경로만 기억해 놓기때문에 경로 손실이 되었을 때에 우회경로가 존재 함에도 불구하고 패킷 전송을 실패하게 된다. 본 논문에서는 확률에 기반한 안정도를 측정하고 MANET 환경에서 패킷전달 가능성이 높은 다중경로 라우팅 프로토콜 아이디어를 제시한다.

• Annual Conference of KIPS
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• 2022.05a
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• pp.82-83
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• 2022

Ad-hoc On-demand Distance Vector (AODV), is one of well-designed routing protocols in mobile ad hoc networks. It supports the functionality of node mobility modules through multiple control messages to create and maintain paths for data transfer. Even though a number of studies have been conducted to achieve rapid discovery of paths across the network, but few have focused on impact of control messages. This paper proposes a method to adjust the transmission time of messages used in path recovery according to their individual characteristics. Simulation results show the improved performance of the proposed algorithm rather than traditional AODV routing protocol.

• Journal of KIISE:Information Networking
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• v.33 no.1
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• pp.38-48
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• 2006

For extending of hot-spot of WLAN, (2) proposes internetworking scheme between wireless LAN (WLAN) and mobile ad-hoc network (MANET), which employ the same layer-2 protocol with different mode. Compared to internetworking schemes between UMTS (Universal Mobile Telecommunications Systems) and WLAN (3-4), the scheme from (2) has relatively low overhead and latencies because WLAN and MANET are physically and logically similar to each other. However, the mode switching algorithm proposed in r2] for internetworking between WLAN and MANET only considers signal strength and determines handoff, and mobile nodes following a zigzag course in pollution area may perform handoff at short intervals. Furthermore, (2) employs mobile IPv6 (MIPv6) at base, which brings still high delay on handoff and overhead due to signal message exchange. In this paper, we present optimized internetworking scheme between WLAN and MANET, modified from (2). To settle ping-pong handoff from (2), we propose adaptive mode switching algorithm. HMIPv6 is employed for IP connectivity and mobility service in WLAN, which solves some shortcomings, such as high handoff overhead and vulnerable security. For routing in MANET, OLSR is employed, which is a proactive Protocol and has optimally reduced signal broadcasting overhead. OLSR operates with current P protocol compatibly with no change or modification. The proposed internetworking scheme based on adaptive mode switching algorithm shows better performance than scheme from (2).

• Proceedings of the Korea Society for Simulation Conference
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• 2005.05a
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• pp.139-143
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• 2005

The P2P is a network environment supporting data exchange which is directly connected peers without limit of existing server-client and intervening central server for resource or offered service with each peer. JXTA is a representative of P2P system. JXTA is a typical distributed computing model that proposed by Sun Microsystems. JXTA that doesn't require centralized services or resources is adaptable in extreme changes of network organization. MANET(Mobile Ad Hoc Network) is a representative wireless network that is composed of mobile nodes without infrastructure. So MANET establishes the path for the communication of each peers and maintains the newest routing information by exchanging routing information. In this paper, we propose a technique of JXTAMAUET which implements JXTA which is the P2P network system from the wireless network which is becoming the foundation of ubiquitous computing. For the performance evaluation of the JXTAMANET, we use simulation.