• International Journal of Internet, Broadcasting and Communication
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• v.7 no.1
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• pp.49-56
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• 2015

As WSN is energy constraint so energy efficiency of nodes is important. Because avoiding long distance communication, clustering operating in rounds is an efficient algorithm for prolonging the lifetime of WSN and its performance depends on duration of a round. A short round time leads to frequent re-clustering while a long round time increases energy consume of cluster heads more. So existing clustering schemes determine proper round time, based on the parameters of initial WSN. But it is not appropriate to apply the round time according to initial value throughout the whole network time because WSN is very dynamic networks nodes can be added or vanished. In this paper we propose a new algorithm which calculates the round time relying on the alive node number to adapt the dynamic WSN. Simulation results validate the proposed algorithm has better performance in terms of energy consumption of nodes and loss rate of data.

• The Transactions of the Korea Information Processing Society
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• v.6 no.10
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• pp.2649-2658
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• 1999

This paper proposes a new solution to support Internet Multicast for mobile hosts. The proposed algorithm is based on the remote subscription approach of IETF Mobile IP that mobile node re-subscribes to its desired multicast groups while at a foreign network. In addition, we adopt the bi-directional tunneling to minimize the disruption of multicast service due to movement of a host from network to another. This paper also analyzes the handoff latencies and data packet loss amount of our algorithm and compares to other approaches. Our analysis shows that the proposed algorithm has good robustness, scalability and routing efficiency.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.871-874
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• 2009

수천 개의 센서 노드들이 센서 필드에 전개되어 있는 경우에 센서 노드의 상태를 효율적으로 관리하는 것은 매우 중요한 기술이다. 본 논문에서는 기본적으로 PEGASIS 라우팅 알고리즘을 이용하여 노드들 간의 상대 거리 정보를 수집하여 센서 노드의 위치 정보를 탐지하고 이를 이용하여 임의의 노드가 고장이 났을 경우, 데이터 전송을 원활히 하기 위한 최적의 재라우팅을 설정하는 방법을 제시하고자 한다.

• Journal of Korea Water Resources Association
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• v.45 no.3
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• pp.243-252
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• 2012

The objective of this study is to analyze lateral inflow hydrologically. The IUH of lateral inflow is sum of the impulse responses of total cells in basin. This IUH bases on the Muskingum channel routing method, which hydrologically re-analysed to represent it as a linear combination of the linear channel model considering only the translation and the linear reservoir model considering only the storage effect. Rectangular and triangular basins were used as imaginary basins and IUH of each basin were derived. The derived IUH have different characteristics with respect to basin's shape. The storage coefficient of lateral inflow was also derived mathematically using general definitions of concentration time and storage coefficient. As a result, the storage coefficient of lateral inflow could be calculated easily using basin's width, length and hydrological characteristics of channel.

• The KIPS Transactions:PartC
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• v.14C no.3 s.113
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• pp.267-276
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• 2007

In OSPF, the larger and more unstable the area, the greater the likelihood for performance problems associated with routing protocol recalculation. Generally, an area should have no more than 50 routers. Areas with unstable links should be smaller. Military tactical data network is used for military operations during war-time. It consists of wireless network for mobility of node. Thus, it has low-bandwidth and unstable property. In addition, it is expected that many kinds of router-failure, Link-failure and recovery at emergency period. However, Military tactical data network is designed with about one and half times the number of recommendation. This paper proves that the traffic is limited by the increase of re-calculation of area.

• Journal of the Korea Society of Computer and Information
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• v.7 no.4
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• pp.188-198
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• 2002

In this paper, we propose an active network to support reliable data transmission in the mobile ad-hoc network. The active network uses DSR(Dynamic Source Routing) protocol as its basic routing protocol, and uses source and destination nodes as key active nodes. For reliable improvement the source node is changed to source active node to add function that its buffer to store the last data with the flow control for data transmission per destination node. The destination node is changed to destination active node to add function that it requests the re-transmission for data that was not previously received by the destination active node with the flow control for data reception per source active node As the result of evaluation. we found the proposed active network guaranteed reliable data transmission with almost 100% data reception rate for slowly moving mobile ad-hoc network and with more 95% data reception rate, which is improvement of 3.5737% reception rate compared with none active network, for continuously fast moving mobile ad-hoc network.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.1
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• pp.38-43
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• 2011

Cluster-based routing is high energy consumption of cluster head nodes. A recent approach to resolving the problem is the dynamic cluster technique that periodically re-selects cluster head nodes to distribute energy consumption of the sensor nodes. However, the dynamic clustering technique has a problem that repetitive construction of clustering consumes the more energies. 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 cluster head nodes, is suggested for solving the energy consumption problem regarding repetitive cluster construction. A simulation result were compared with the performances of two of the most 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 26.5% and 20% more efficient than LEACH and HEED, respectively.

• The KIPS Transactions:PartC
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• v.14C no.3 s.113
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• pp.277-284
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• 2007

The routing algorithm many used in the wireless sensor network features the clustering method to reduce the amount of data transmission from the energy efficiency perspective. However, the clustering method results in high energy consumption at the cluster head node. Dynamic clustering is a method used to resolve such a problem by distributing energy consumption through the re-selection of the cluster head node. Still, dynamic clustering modifies the cluster structure every time the cluster head node is re-selected, which causes energy consumption. In other words, the dynamic clustering approaches examined in previous studies involve the repetitive processes of cluster head node selection. This consumes a high amount of energy during the set-up process of cluster generation. In order to resolve the energy consumption problem associated with the repetitive set-up, this paper proposes the Round-Robin Cluster Header (RRCH) method that fixes the cluster and selects the head node in a round-robin method The RRCH approach is an energy-efficient method that realizes consistent and balanced energy consumption in each node of a generated cluster to prevent repetitious set-up processes as in the LEACH method. The propriety of the proposed method is substantiated with a simulation experiment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.27-30
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• 2012

In the Cluster-Based Routing Protocol (CBRP) a cluster header in each cluster should be elected. The cluster headers consume energy much more than other nodes because they manage and operate all of mobile nodes in their cluster. The traditional CBRP elects a cluster header without considering the remaining electric energy of each node. So, there exists problems that the cluster header has short average lifetime, and another cluster header should be elected again frequently. In this paper, we propose the improved protocol which prolongs the lifetime of the cluster header, decreases of header re-elected problem, decreases of header re-elected problem and enhances the stability of the path. In order to achieve this, when a cluster header is elected in a cluster, the remaining electric energies of all the nodes are compared with one another, and the node with the highest energy is elected as the cluster header. Also, the node with the second highest energy is elected as the second header. If the elected cluster header is unable to perform the role of the cluster header because the remaining energy level goes low, it sends a beacon message to neighbor member nodes and the second header will serve as the cluster header.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.3
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• pp.243-249
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• 2020

With the development of the 4th Industry Revolution and the progress of related technologies, people have been using various services in a more convenient way in their daily lives. Among these technologies, the smart mobility is a service that effectively transports people or packets from the origin to the final destination using a variety of methods/vehicles. With respect to the smart mobility technology, the shuttle service is operational at the final destination. The conventional shuttle operation only takes into account the shuttle operability and does not consider the shuttle-passenger efficiency at all by the one-way routing. Therefore, in this paper, we propose the smart shuttle algorithm that can change the routes to efficiently support boarding passengers. Our proposed scheme consists of 3 algorithms: the shuttle operating algorithm, the re-routable shuttle traveling algorithm, and the passenger-riding algorithm. All those 3 algorithms are effectively co-operated and collaborated for better performance. In-depth experiments were conducted to analyze and to show the superior performance, resulting in an average 23.6% reduction of destination-arrival time per passenger, average 10.37% reduction of shuttle-waiting time per passenger, and average 15.38% decrease of shuttle traveling time per hour. This proves that our smart shuttle traveling scheme reveals the whole remarkable performance, effectively using the re-routable characteristics.