• Journal of the Institute of Convergence Signal Processing
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• v.9 no.4
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• pp.313-320
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• 2008

The dynamic clustering technique has some problems regarding energy consumption. In the cluster configuration aspect the cluster structure must be modified every time the head nodes are re-selected resulting in high energy consumption. Also, there is excessive energy consumption when a cluster head node receives identical data from adjacent cluster sources nodes. This paper proposes a solution to the problems described above from the energy efficiency perspective. The round-robin cluster header(RRCH) technique, which fixes the initially structured cluster and sequentially selects duster head nodes, is suggested for solving the energy consumption problem regarding repetitive cluster construction. Furthermore, the issue of redundant data occurring at the cluster head node is dealt with by broadcasting metadata of the initially received data to prevent reception by a sensor node with identical data. A simulation experiment was performed to verify the validity of the proposed approach. The results of the simulation experiments were compared with the performances of two of the must widely used conventional techniques, the LEACH(Low Energy Adaptive Clustering Hierarchy) and HEED(Hybrid, Energy Efficient Distributed Clustering) algorithms, based on energy consumption, remaining energy for each node and uniform distribution. The evaluation confirmed that in terms of energy consumption, the technique proposed in this paper was 29.3% and 21.2% more efficient than LEACH and HEED, respectively.

• The KIPS Transactions:PartC
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• v.14C no.5
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• pp.403-410
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• 2007

For reliable sensor network communication, secure data transmission mechanisms are necessary. In our work, for secure communication, we cluster the network field in hexagonal shape and deploy nodes according to Gaussian distribution. After node deployment, clusterheads and gateway nodes in each cluster play the role of aggregating and delivering the sensed data with suity information all the way to the base station. Our mechanism decreases the overhead and provides food performance. It also has resilience against various routing attacks.

• The Journal of the Acoustical Society of Korea
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• v.33 no.5
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• pp.341-350
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• 2014

In this paper, an energy efficient clustering scheme using self organization method is proposed. The proposed scheme selects a cluster head considering not only the number of neighbor nodes but also the residual battery amount. In addition, the network life time is extended by re-selecting the cluster heads only in case the current cluster head's residual energy falls down below a certain threshold level. Accordingly, the energy consumption is evenly distributed over the entire network nodes. The cluster head delivers the collected data from member nodes to a Sink node in a way of multi-hop relaying. In order to evaluate the proposed scheme, we run computer simulation in terms of the total residual amount of battery, the number of alive nodes after a certain amount of time, the accumulated energy cost for network configuration, and the deviation of energy consumption of all nodes, comparing with LEACH which is one of the most popular network clustering schemes. Numerical results show that the proposed scheme has twice network life-time of LEACH scheme and has much more evenly distributed energy consumption over the entire network.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.555-557
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• 2000

본 논문에서는 에드 혹 망의 멀티캐스트 라우팅 프로토콜인 ODMRP(On-Demand Multicast Routing Protocol)를 확장한 PatchODMRP를 제안한다. ODMRP는 멀티캐스트그룹의 송신원으로부터 수신원에 이르는 경로 상에 있는 노드들을 FG(Forwarding Group) 노드로 선출하여, 멀티캐스트 그룹 데이터 전송을 담당하는 메쉬를 구성하는 방법이다. 그런데 ODMRP는 주기적으로 이 메쉬를 구성하는 FG 노드들을 재선정하기 때문에 이 주기가 길어지면 메쉬 구성이 네트워크 노드들의 이동성을 따라가지 못해 메쉬 분리가 발생하고 데이터가 손실될 수 있다. 반면에 이 주기가 짧게 하면 오버헤드가 지나치게 커질 수 있다. 특히, 송신원의 수가 적은 경우 ODMRP의 메쉬는 매우 성기게 형성되는데, 이 때 호스트들의 이동성이 크면 메쉬 연결을 유지하기 위하여 이 주기를 짧게 잡아주거나, 높은 데이터 손실율을 감수해야 한다. 본 논문에서는 이 문제점을 해결하고자 각 FG 노드들이 BEACON 신호를 이용해 자신에 인접한 메쉬에 손실이 발생한 것을 인지하고 이를 국부적인 플러딩을 통하여 빠르게 복구하고 메커니즘을 ODMRP에 추가한 PatchODMRP 방식을 제안한다. 시뮬레이션을 통하여 기존의 ODMRP와 제안하는 ParchODMRP의 성능을 비교한 결과, ParchODMRP가 호스트의 이동성에 훨씬 강하며, ODMRP에 비하여 낮은 오버헤드로 높은 데이터 전달율을 제공할 수 있음을 보여주었다.

• The Journal of the Korea Contents Association
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• v.10 no.2
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• pp.14-24
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• 2010

Because WSNs operate with limited resources of sensor nodes, its life is extended by cluster-based routing methods. In this study, we use data on direction, distance, density and residual energy in order to maximize the energy efficiency of cluster-based routing methods. Through this study, we expect to minimize the frequency of isolated nodes when selecting a new cluster head autonomously using information on the direction of the upper cluster head, and to reduce energy consumption by switching sensor nodes, which are included in both of the new cluster and the previous cluster and thus do not need to update information, into the sleep mode and updating information only for newly included sensor nodes at the setup phase using distance data. Furthermore, we enhance overall network efficiency by implementing secure and energy-efficient communication through key management robust against internal and external attacks in cluster-based routing techniques. This study suggests the modified cluster head selection scheme which uses the conserved energy in the steady-state phase by reducing unnecessary communications of unchanged nodes between selected cluster head and previous cluster head in the setup phase, and thus prolongs the network lifetime and provides secure and equal opportunity for being cluster head.

• Journal of KIISE:Information Networking
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• v.32 no.6
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• pp.659-667
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• 2005

A Mobile Ad Hoc Network(MANET) is a multi hop wireless network with no prepared base stations or centralized administrations, where flocks of peer systems gather and compose a network. Each node operates as a normal end system in public networks. In addition to it, a MANET node is required to work as a router to forward traffic from a source or intermediate node to others. Each node operates as a normal end system in public networks, and further a MANET node work as a router to forward traffic from a source or intermediate node to the next node via routing path. Applications of MANET are extensively wide, such as battle field or any unwired place; however, these are exposed to critical problems related to network management, node's capability, and security because of frequent and dynamic changes in network topology, absence of centralized controls, restricted usage on network resources, and vulnerability oi mobile nodes which results from the special MANET's character, shared wireless media. These problems induce MANET to be weak from security attacks from eavesdropping to DoS. To guarantee secure authentication is the main part of security service In MANET because networks without secure authentication are exposed to exterior attacks. In this paper, a multistage authentication strategy based on CGSR is proposed to guarantee that only genuine and veritable nodes participate in communications. The proposed authentication model is composed of key manager, cluster head and common nodes. The cluster head is elected from secure nodes, and key manager is elected from cluster heads. The cluster head will verify other common nodes within its cluster range in MANET. Especially, ID of each node is used on communication, which allows digital signature and blocks non repudiation. For performance evaluation, attacks against node authentication are analyzed. Based on security parameters, strategies to resolve these attacks are drawn up.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.894-897
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• 2010

애드 혹 네트워크는 Access Point 나 기지국과 같은 기반 구조 없이 이동 노드들로만 구성되는 자율적이고 독립적인 네트워크이다. 각각의 노드들은 이동성을 가지기 때문에 이들로 이루어진 네트워크는 다양한 형태를 이루게 되며, 이들은 무선 자원과 에너지 상의 제약을 가지기 때문에 클러스터 형성과 유지 및 관리를 통해 네트워크의 안정성을 향상시키는 알고리즘이 필요하다. 애드 혹 네트워크 환경의 클러스터링 기법에서 클러스터 헤드는 호스트의 기능을 수행함과 동시에 라우팅 기능을 담당하는 라우터의 역할까지 수행한다. 따라서 클러스터 헤드의 에너지 고갈이나 부재는 클러스터를 붕괴시키고, 전체 네트워크의 통신을 어렵게 하며, 나아가서는 네트워크의 수명을 단축시킨다. 결국 클러스터 헤드의 효율적인 관리는 전반적인 네트워크의 성능을 결정짓는 핵심이라고 볼 수 있다. 때문에 본 논문에서는 무선 애드 혹 네트워크 환경에서 2-Level 트리 기반의 클러스터 라우팅 프로토콜을 제시한다. 본 논문에서는 클러스터 헤드와 이웃 노드들의 유지 및 관리를 통해 전체적인 네트워크의 throughput 을 향상 시키는 클러스터 알고리즘을 제안하였다. 또한 시뮬레이션을 통해 본 논문에서 제안한 알고리즘이 목적에 맞게 동작하는지 확인할 수 있었다.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.8
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• pp.889-897
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• 2014

With the development of wireless communication and sensor technology, sensor network applications in various fields have been applied. To minimize the power consumption of sensors in sensor network is one of the important factors in oder to extend the system life. The power consumption of each sensor within sensor network can be different depending on the communication method between head(sink) node and its node. In this paper, we propose a new hierarchical communication method to minimize the power consumption of each sensor. The proposed method divides the area of sensor network into four areas using divide-and-conquer method and selects the nearest node to head node in each area as a child node of the node. Next the hierarchical tree in the same way is constructed recursively until each area is no longer divided. Each sensor can communicate to head node using this hierarchical tree. The proposed results were compared with the previous methods through simulation, and showed excellent results in the energy efficiency of sensor network.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.244-248
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• 2007

센서 네트워크에서 에너지 소비는 전송거리와 보내고자 하는 데이터에 비례한다. LEACH-C와 같은 클러스터 기반 라우팅 기법들은 센서 노드들의 클러스터링을 통하여 데이터 전달 거리를 최소화시킴으로서 에너지의 효율성을 얻는다. 하지만 LEACH-C에서는 클러스터링을 구성할 때 클러스터 구성 노드들의 거리의 총합만을 고려한다. 본 논문에서는 에너지 사용에 큰 영향을 미치는 기지국과 클러스터 헤드간의 거리를 고려한 클러스터 헤드 선택 알고리즘을 제안한다. 제안 방법은 LEACH-C에 비해 기지국의 위치가 일정 거리 이상 떨어져 있을 경우 성능 향상 결과를 제공하였다. 이 결과는 클러스터 기반 라우팅 알고리즘에서 클러스터 헤드와 기지국간의 거리를 고려하는 것이 에너지 효율적인 측면에 영향을 미칠 수 있음을 보여 주었다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.1
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• pp.198-204
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• 2012

Generally, the clustering of sensor nodes in WSN is a useful mechanism that helps to cope with scalability problem and, if combined with network data aggregation, may increase the energy efficiency of the network. The Hierarchical clustering routing algorithm is a typical algorithm for enhancing overall energy efficiency of network, which selects cluster-head in order to send the aggregated data arriving from the node in cluster to a base station. In this paper, we propose the improved-LEACH that uses comparably simple and light-weighted policy to select cluster-head nodes, which results in reduction of the clustering overhead and overall power consumption of network. By using fine-grained power model, the simulation results show that i-LEACH can reduce clustering overhead compared with the well-known previous works such as LEACH. As result, i-LEACH algorithm and LEACH algorithm was compared, network power-consumption of i-LEACH algorithm was improved than LEACH algorithm with 25%, and network-traffic was improved 16%.