• Journal of KIISE:Information Networking
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• v.32 no.3
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• pp.310-317
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• 2005

In opposition to conventional networks, mobile ad hoc networks usually do not offer trust about nodes or online access through certificate authorities or centralized servers. But, nodes in those systems need process that can search path as well as trust each other to exchange data in safety For these reasons, traditional security measures that require online trusted authorities or certificate storages are not well-suited for securing ad hoc networks. In this paper, I propose a secure and effective method to search the optimized path using profitable flooding techniques on certificate chains in MANETS(Mobile Ad hoc NETworks). This system includes not only using routing protocols that are generally broadcasting packets but also finding nodes securely and verifing the process through tiust relationships between nodes that are searched.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.119-124
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• 2010

The MAC layer in ad-hoc network which makes network of nodes without infrastructure for a time has became an issue to reduce delay, allocate fairly bandwidth, control TX/RX power and improve throughput. Specially, the problem to reduce power consumption in ad-hoc network is very important part as ad-hoc devices use the limited battery. For solution of the problem, many power control algorithms, such as distribute power control, PCM (Power Control MAC) and F-PCF (Fragmentation based PCM), are proposed to limit power consumption until now. Although the algorithms are designed to minimize power consumption, the latency communication zone is generated by power control of RX/TX nodes. However the algorithms don't suitably reuse the space. In this paper proposes the algorithm to improve data throughput through Spatial Reuse based on a power control method.

• The KIPS Transactions:PartC
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• v.16C no.1
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• pp.65-72
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• 2009

Due to the popularity of mobile devices and advances in wireless communication technologies, a mobile ad hoc network has received a lot of attention. In the existing data replication management research, the use of a replica has been shown to be an efficient technique for improving data accessibility. However, to use a replica in ad hoc networks, the data consistency between the original data and the replica should be guaranteed. In the traditional research, a mobile node should check an original data whether the data is updated or not. However, It may be costly or sometimes impossible to check the original data. In the case of the time constraint applications, the checking cost can cause more serious problem. In this paper, we propose the time-guarantee based cache invalidation schemes for time constraint applications and the threshold based compensation method to enhance the time-guarantee based scheme. The proposed schemes can remove the "rollback" problem. Simulation results show that our schemes outperform the previous ones in terms of access time with little loss of data currency.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.76-89
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• 2014

In this paper, we propose a MAC(Media Access Control) protocol based on flexible RWT(RTS Waiting Time) for underwater mobile ad-hoc networks with a three-way handshaking mechanism. This protocol can solve a problem of collision between RTS(Request-To-Send) and CTS(Clear-To-Send) packets in existing MACA(Multiple Access with Collision Avoidance) protocol. This proposed MAC protocol is also an effective protocol which can apply to underwater mobile ad-hoc networks in a real field by using implementable technologies. We set flexible RTS Waiting Time called RWT, considering various characteristics of underwater environment. It is possible to support variable network size according to node mobility. Finally, we conduct a performance evaluation between proposed MAC protocol and existing MACA based MAC protocol through practical implementation and experiment. As a result, we verify the superiority of our proposed MAC protocol in terms of throughput, packet drop rate, average transmission time, energy consumption and channel utilization.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.7B
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• pp.659-667
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• 2009

Mobile Ad-hoc Network consists of mobile nodes without immobile base station. In mobile ad-hoc network, network cutting has occurred frequently in node because of energy restriction and frequent transfer of node. Therefore, it requires research for certain techniques that react softly in topology alteration in order to improve reliability of transmission path. This paper proposes path selection techniques to consider mobility of node that respond when search path using AOMDV routing protocol. As applying proposed techniques, We can improve reliability and reduce re-searching number of times caused by path cutting.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.4
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• pp.39-45
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• 2009

With the rapid growth of recent wireless mobile computing application technology and handheld mobile terminal device development technology, one of the big issue in these fields is to design online games in wireless mobile ad hoc network environment. Online games in mobile computing environment have lots of constraints for developing online games because mobile terminals have many limitations such as low performance of processor, limited memory space, small bandwidth of wireless communication, and confined life of battery power. Therefore, most of mobile games are restrictive in the function of online and multi-play up to date. In this paper, the online MMORPG game, capable of multi-play with many other mobile users using mobile terminals in wireless mobile computing environment, is designed and implemented. Proposed mobile online game uses bluetooth to construct temporary wireless mobile ad hoc network with other mobile clients, and designed to carry out online MMORPG game with these clients. It also supports multi-play among them.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06d
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• pp.259-261
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• 2006

모바일 애드 혹 네트워크에서 에너지 효율을 위한 많은 라우팅 프로토콜들이 제안되었다. 이미 제안된 프로토콜들에 대한 내용을 살펴보면 에너지 효율을 높이기 위한 경로를 찾는 방법, 경로를 설정하는데 소비하는 패킷의 수를 줄이는 방법, 설정 시간을 줄이기 위한 방법과 이미 설정된 라우팅 정보를 보다 효율적으로 유지하기 위한 방법을 제시하였다. 이와 같은 문제들을 해결하기 위해 본 논문에서는 채널을 라우팅 정보와 데이터를 전송을 하는 채널로 각각 나누고, 이로 인해 얻을 수 있는 장점에 대해 설명한다. 그리고 라우팅 정보를 얻는 과정에서 채널을 나눔으로써 변경되는 라우팅 프로토콜에 대해 제안한다.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.254-257
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• 2010

최근 모바일 컴퓨팅 기술이 급격이 발전하면서, 이동 애드-혹 네트워크(Mobile Ad-Hoc Network, MANET)에 대한 연구가 활발히 진행되고 있다. 그러나 대다수의 MANET에 관한 연구는 하나의 MANET 내에서 이루어지는 라우팅 방법이나 에너지 관리에 대한 것으로 MANET 내에서 검색에 실패 했을 경우에 대한 해결 방법은 없는 상태이다. 본 논문에서는 하나의 MANET에서 검색에 실패한 경우에 기반망인 무선 AP를 이용하여 또 다른 MANET으로 연결하고 정보를 검색 할 수 있도록 탐색범위 확장을 위한 방법을 제안한다. 본 논문에서 제안한 방법은 보다 넓은 범위에서 필요로 하는 정보를 가진 단말을 탐색할 수 있게 함으로써 MANET에서의 검색 성공률을 높일 수 있다.

• Convergence Security Journal
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• v.11 no.5
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• pp.13-19
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• 2011

Mobile nodes in MANETs have the nature of unrestricted mobility so that they will join and leave the network frequently. Therefore, it important consideration to determine the optimal distance progress between relaying nodes along the route in order to maintain the established route for an arbitrary length of time (i.e., route duration). In this paper, we derived the link maintenance probability by considering the initial distance between two relaying nodes and node mobility. Based on the link maintenance probability, we further analyzed the route stability by considering the impact of distance progress between relaying nodes along the route.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.4
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• pp.87-93
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• 2016

In this paper, we propose a RF energy harvesting based routing protocol in mobile ad-hoc wireless sensor networks. The main features and contributions of the proposed routing protocol are as follows. First, establishment of routing route based on both remaining energy of mobile sensor nodes and RF energy harvesting. Second, establishment of routing route by considering availability and stability of route based on energy of mobile sensor nodes to increase lifetime of networks and route. The performance evaluation of the proposed routing protocol using OPNET shows that the routing method considering both route availability and route stability based on RF energy harvesting can increase efficiently route lifetime.