• Convergence Security Journal
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• v.20 no.3
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• pp.13-20
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• 2020

Recently, the need of researches and developments about WSN(Wireless Sensor Network) technologies, which can be applied to services that require continuous monitoring or services to specific areas where accesses are limited, has gradually increased due to their expansion of application areas and the improvement of the efficiency. Especially, in the defense field, researches on the latest IT technologies including sensor network areas are actively conducted as an alternative to avoid the risk factors that can be occurred when personnel are put in, such as boundary and surveillance reconnaissance and to utilize personnel efficiently. In this paper, we analyze the conditions for increasing the life span of sensing nodes that make up sensor network by applying clustering and location-based techniques and derived the factors for extending the life span of them. The derived factors include CH(Cluster Head) election scheme and optimal path selection from CH to BS(Base Station). We proposed final scheme using derived factors and verified it through simulation experiments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.10
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• pp.801-807
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• 2013

WSN consists of hundreds to thousands of sensor nodes. In order to solve the problem of energy consumption imbalance cluster head is reelected in every round, while node authentication scheme is utilized for secure communication. However, re-clustering increases the overhead of sensor nodes and during the node authentication phase the frequent AREQ/AREP message exchange also increases the overhead. Therefore, a secure and energy efficient protocol, by which overhead of sensor nodes is reduced and long time communication is achieved, is required for wireless sensor network. In this paper, an energy efficient and reliable IDE-LEACH protocol for WSN is proposed. The proposed protocol is prolongs networks lifetime about average 20% compared to the LEACH-based protocols and all attending nodes in communication form BS authentication consisted of trusted nodes.

• Journal of KIISE:Information Networking
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• v.37 no.1
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• pp.35-41
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• 2010

Since the ad-hoc network allow nodes to communicate each other without infrastructure system and predefined configuration, it comes into the spotlight that is suitable to ubiquitous society. In ad-hoc network, route recovery mechanism is considered important. Normally route recovery is needed to solve the link failure problem because there is no route maintaining system like a router in ad-hoc networks. In this paper we propose BS-AODV(Bidirectional Searching-AODV) route recovery method. The proposed method is a local repair method that can be applied in all of the network area. Unlike a limited local repair method in AODV. the proposed method adopts the bidirectional searching method where the upstream/downstream nodes can send the route maintenance messages. Restricting the flooding of route request messages, the proposed scheme attempts to minimize the costs of local repair, the performance of the proposed scheme is evaluated through the simulations. In two scenarios which variate the node numbers and node speed, the comparison among the proposed scheme, AODV and AOMDV is shown in terms of the control traffic and data delivery ratio.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.10A
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• pp.823-829
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• 2011

Recently, wireless body area network (WBAN) has received much attention as an application for the ubiquitous healthcare system. In WBAN, each sensor nodes and a personal base station such as PDA have an energy constraint and computation overhead should be minimized due to node's limited computing power and memory constraint. The reliable data transmission also must be guaranteed because it handles vital signals. In this paper, we propose a systematic network coding scheme for WBAN to reduce the network coding overhead as well as total energy consumption for completion the transmission. We model the proposed scheme using Markov chain. To minimize the total energy consumption for completing the data transmission, we made the problem as a minimization problem and find an optimal solution. Our simulation result shows that large amount of energy reduction is achieved by proposed systematic network coding. Also, the proposed scheme reduces the computational overhead of network coding imposed on each node by simplify the decoding process.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.925-928
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• 2010

Wireless sensor networks are composed of a large number of sensor nodes with limited energy resources. One critical issue in wireless sensor networks is how to gather sensed information in an energy efficient way since the energy is limited. The clustering algorithm is a technique used to reduce energy consumption. It can improve the scalability and lifetime of wireless sensor network. In this paper, we introduce a clustering protocol with mode selection (CPMS) for wireless sensor networks. Our scheme improves the performance of BCDCP (Base Station Controlled Dynamic Clustering Protocol) and BIDRP (Base Station Initiated Dynamic Routing Protocol) routing protocol. In CPMS, the base station constructs clusters and makes the head node with highest residual energy send data to base station. Furthermore, we can save the energy of head nodes using modes selection method. The simulation results show that CPMS achieves longer lifetime and more data messages transmissions than current important clustering protocol in wireless sensor networks.

• Electronics and Telecommunications Trends
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• v.27 no.1
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• pp.122-135
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• 2012

최근 스마트폰의 급격한 보급과 음성 위주의 이동통신 서비스가 무선 멀티미디어 콘텐츠를 중심으로 하는 데이터 위주의 서비스로 전환됨에 따라 모바일 데이터가 급증하고 있다. 그러나, LTE에서의 Macro-BS(eNB) 기반의 point-to-point 링크의 스펙트럼 효율은 이미 이론적 한계치에 근접하여 저전력의 소규모 기지국 노드를 채용하는 이종망 환경을 도입하는 노력이 3GPP를 중심으로 전개되고 있다. 본고에서는 급증하는 모바일 트래픽 수요를 수용하기 위해 개발되고 있는 소규모 저전력 셀 기반의 HetNet 기술개발 동향과 대용량의 모바일 콘텐츠를 이동통신 단말기의 근접성을 기반으로 기지국 트래픽 부하 없이 제공하기 위해 개발되고 있는 단말기 간 직접 통신 기술 개발현황을 소개한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.3
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• pp.459-470
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• 2013

${\mu}TESLA$ is well known as the most representative energy-efficient broadcast authentication method. Until now, there are many researches that figure out the problems or limitation of ${\mu}TESLA$ and mitigate or solve them, but most researches have been verified in the environment far from the real world. We consider the necessity of verifying what the real efficiency of ${\mu}TESLA$ is. In this paper, we assume that sensors that continuously repeat hibernation and activity perform communication under the UWSN(Unattended WSN), which BS does not stay in the network. In this environment, we newly inspect the performance of ${\mu}TESLA$ by performing various simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.6A
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• pp.405-419
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• 2012

In this paper, we propose a joint base station(BS) and relay precoders design in multi-relay aided multi-user all-multiple-input multiple-output(MIMO) system. The design criterion is to minimize user sum mean square error(SMSE) with relay sum power constraint(RSPC) where only local channel state information(CSI)s are available at relays. Local CSI at a relay is defined as the CSI of the channel which the relay itself accesses, out of among all the 1st hop and the 2nd hop channel in the system. With BS precoder structure which is concatenated with block diagonalization(BD) precoder, each relay can determine its own precoder using only local CSI. Proposed scheme is based on sequential iteration of two stages; stage 1 determines BS precoder and relay precoders jointly with SMSE duality, and stage 2 determines user receivers. Proposed scheme can be demonstrated theoretically to be always converge. We verify that proposed scheme outperforms simple amplify-and-forward(SAF), MMSE relay, and proposed schemes in [1] in terms of both SMSE and sum-rate performances.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.616-619
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• 2008

In this paper, we design and implement the authentication system for home network service and applied it to actual sensor nodes. We achieved authentication key, encryption and decryption applied RC5 encryption algorithm of SNEP. In addition, we used pair-wise key pre-distribution for prevention of authentication sniffing in wireless sensor network. The experiment environment consists of a base station receiving data and sensor nodes sending data. Each sensor nodes sends both the data and encrypted authentication key to the base station. As a simulation environment, we assumed some what-if scenarios of security menaces in home network service. And we slightly altered the TOS_Msg construction of TinyOS. The experiences had shown that the malfunction doesn't happen in communication among other groups. And we confirmed in tests that the system is secure when a sensor having malicious propose is added.

• Convergence Security Journal
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• v.9 no.2
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• pp.71-78
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• 2009

It is very difficult to apply previous security protocols to WSNs(Wireless Sensor Networks) directly because WNSs have resource constrained characteristics such as a low computing ability, power, and a low communication band width. In order to overcome the problem, we proposes a secure group communication scheme applicable to WSNs. The proposed scheme is a combined form of the TEEN(Threshold sensitive Energy Efficient sensor Network protocol) clustering based hierarchical routing protocol and security mechanism, and we assume that WSNs are composed of sensor nodes, cluster headers, and base stations. We use both private key and public key cryptographic algorithms to achieve an enhanced security and an efficient key management. In addition, communications among sensor nodes, cluster headers, and base stations are accomplished by a hierarchical tree architecture to reduce power consumption. Therefore, the proposed scheme in this paper is well suited for WSNs since our design can provide not only a more enhanced security but also a lower power consumption in communications.