• 제목/요약/키워드: topology control

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A Hierarchical Autonomous System Based Topology Control Algorithm in Space Information Network

  • Zhang, Wei;Zhang, Gengxin;Gou, Liang;Kong, Bo;Bian, Dongming
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제9권9호
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    • pp.3572-3593
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    • 2015
  • This article investigates the topology control problem in the space information network (SIN) using a hierarchical autonomous system (AS) approach. We propose an AS network topology control (AS-TC) algorithm to minimize the time delay in the SIN. Compared with most existing approaches for SIN where either the purely centralized or the purely distributed control method is adopted, the proposed algorithm is a hybrid control method. In order to reduce the cost of control, the control message exchange is constrained among neighboring sub-AS networks. We prove that the proposed algorithm achieve logical k-connectivity on the condition that the original physical topology is k-connectivity. Simulation results validate the theoretic analysis and effectiveness of the AS-TC algorithm.

이동성 있는 무선 센서 네트워크에서 노드의 상태를 고려한 에너지 효율적인 토폴로지 제어 방법 (An Energy Efficient Topology Control Algorithm using Additional Transmission Range Considering the Node Status in a Mobile Wireless Sensor Network)

  • 윤명준;전한얼;김석규;이재용
    • 한국통신학회논문지
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    • 제37B권9호
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    • pp.767-777
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    • 2012
  • Topology control increases channel efficiency by controlling transmission power of a node, and as a result, network lifetime and throughput are increased. However, reducing transmission range causes a network connectivity problem, especially in mobile networks. When a network loses connectivity, the network topology should be re-configured. However, topology re-configuration consumes lots of energy because every node need to collect neighbor information. As a result, network lifetime may decrease, even though topology control is being used to prolong the network lifetime. Therefore, network connectivity time needs to be increased to expend network lifetime in mobile networks. In this paper, we propose an Adaptive-Redundant Transmission Range (A-RTR) algorithm to address this need. A-RTR uses a redundant transmission range considering a node status and flexibly changes a node's transmission range after a topology control is performed.

Tolerance Control for the Inner Open-Switch Faults of a T-Type Three-Level Rectifier

  • Lee, June-Seok;Lee, Kyo-Beum
    • Journal of Power Electronics
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    • 제14권6호
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    • pp.1157-1165
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    • 2014
  • The T-type topology is a three-level topology that has an advantage in terms of its number of switching device and its efficiency when compared to the neutral-point clamped (NPC)-type topology. With the recent increase in the usage of the T-type topology, the interest in its reliability has also increased. Therefore, a tolerance control for a T-type rectifier is necessary to improve the reliability of applications when an open-switch fault occurs. NPC-type rectifiers cannot eliminate input current distortion completely. However, the T-type rectifier is able to restore distorted current. In this paper, a tolerance control for the $S_{x2}$ and $S_{x3}$ open-switch faults of a T-type rectifier is proposed where it is advantageous in terms of efficiency when compared with other tolerance controls. The performance of the proposed tolerance control is verified through simulation and experimental results.

CEDM 구동용 Power Topology 설계 (Design of Power Topology for CEDM Driving)

  • 이종무;김춘경;천종민;박민국;권순만
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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    • pp.576-578
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    • 2005
  • This paper deals with the design of power topology for nuclear power plants. Although rod control system is still classified into non-safety class. much attention on its reliability issue has been given so far because of its importance for the stable operation of the reactor in the plant. In terms of technical aspects, proposed design is reviewed to satisfy system requirements. This paper deals with a design of power topology for driving Control Element Drive Mechanism (CEDM) that is used to withdraw or insert control rods in nuclear reactor.

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무선 센서 네트워크에서 서비스에 필요한 데이터 전송량을 확보하기 위한 토폴로지 관리 방법 (Topology Control Scheme Providing Throughput Requirement of a Service in Wireless Sensor Networks)

  • 윤명준;김석규;이재용
    • 한국통신학회논문지
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    • 제40권9호
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    • pp.1767-1775
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    • 2015
  • 무선 센서 네트워크는 다양한 응용 서비스에 이용이 가능한 네트워크이다. 다양한 응용 서비스에 따라서 서비스에서 요구하는 네트워크 전송량은 매우 다양하다. 특히 무선 센서 네트워크에서는 센서 노드의 에너지 소모를 줄이고 통신 효율성을 높이기 위해서 다양한 토폴로지 제어 방법들이 제시되어 왔다. 이러한 토폴로지 제어 방법들은 대부분 통신의 효율성 측면에서 연구가 되어왔기 때문에 실제 응용 서비스에서 요구되는 데이터 전송량을 만족시키지 못하는 문제점이 있다. 본 논문에서는 이러한 문제를 해결하기 위해서 응용 서비스에서 요구하는 데이터 전송량을 만족시킬 수 있도록 하는 토폴로지 제어 알고리즘을 제시하였다.

Energy-Connectivity Tradeoff through Topology Control in Wireless Ad Hoc Networks

  • Xu, Mengmeng;Yang, Qinghai;Kwak, Kyung Sup
    • ETRI Journal
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    • 제39권1호
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    • pp.30-40
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    • 2017
  • In this study, we investigate topology control as a means of obtaining the best possible compromise between the conflicting requirements of reducing energy consumption and improving network connectivity. A topology design algorithm capable of producing network topologies that minimize energy consumption under a minimum-connectivity constraint is presented. To this end, we define a new topology metric, called connectivity efficiency, which is a function of both algebraic connectivity and the transmit power level. Based on this metric, links that require a high transmit power but only contribute to a small fraction of the network connectivity are chosen to be removed. A connectivity-efficiency-based topology control (CETC) algorithm then assigns a transmit power level to each node. The network topology derived by the proposed CETC heuristic algorithm is shown to attain a better tradeoff between energy consumption and network connectivity than existing algorithms. Simulation results demonstrate the efficiency of the CECT algorithm.

An Energy Efficient Localized Topology Control Algorithm for Wireless Multihop Networks

  • Shang, Dezhong;Zhang, Baoxian;Yao, Zheng;Li, Cheng
    • Journal of Communications and Networks
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    • 제16권4호
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    • pp.371-377
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    • 2014
  • Localized topology control is attractive for obtaining reduced network graphs with desirable features such as sparser connectivity and reduced transmit powers. In this paper, we focus on studying how to prolong network lifetime in the context of localized topology control for wireless multi-hop networks. For this purpose, we propose an energy efficient localized topology control algorithm. In our algorithm, each node is required to maintain its one-hop neighborhood topology. In order to achieve long network lifetime, we introduce a new metric for characterizing the energy criticality status of each link in the network. Each node independently builds a local energy-efficient spanning tree for finding a reduced neighbor set while maximally avoiding using energy-critical links in its neighborhood for the local spanning tree construction. We present the detailed design description of our algorithm. The computational complexity of the proposed algorithm is deduced to be O(mlog n), where m and n represent the number of links and nodes in a node's one-hop neighborhood, respectively. Simulation results show that our algorithm significantly outperforms existing work in terms of network lifetime.

Topology Aggregation for Hierarchical Wireless Tactical Networks

  • Pak, Woo-Guil;Choi, Young-June
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제5권2호
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    • pp.344-358
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    • 2011
  • Wireless tactical network (WTN) is the most important present-day technology enabling modern network centric warfare. It inherits many features from WMNs, since the WTN is based on existing wireless mesh networks (WMNs). However, it also has distinctive characteristics, such as hierarchical structures and tight QoS (Quality-of-Service) requirements. Little research has been conducted on hierarchical protocols to support various QoS in WMN. We require new protocols specifically optimized for WTNs. Control packets are generally required to find paths and reserve resources for QoS requirements, so data throughput is not degraded due to overhead. The fundamental solution is to adopt topology aggregation, in which a low tier node aggregates and simplifies the topology information and delivers it to a high tier node. The overhead from control packet exchange can be reduced greatly due to decreased information size. Although topology aggregation is effective for low overhead, it also causes the inaccuracy of topology information; thus, incurring low QoS support capability. Therefore, we need a new topology aggregation algorithm to achieve high accuracy. In this paper, we propose a new aggregation algorithm based on star topology. Noting the hierarchical characteristics in military and hierarchical networks, star topology aggregation can be used effectively. Our algorithm uses a limited number of bypasses to increase the exactness of the star topology aggregation. It adjusts topology parameters whenever it adds a bypass. Consequently, the result is highly accurate and has low computational complexity.

무선 센서 네트워크에서 트래픽 정보를 이용한 토폴로지 제어 기법 (TRaffic-Aware Topology Control Algorithm in Wireless Sensor Networks)

  • 정연수;최훈;백윤주
    • 한국통신학회논문지
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    • 제33권7B호
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    • pp.510-517
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    • 2008
  • 센서 네트워크는 조밀하게 배치된 많은 수의 센서 노드로 구성되며, 극심한 에너지 제약을 가진다. 또한 네트워크의 충분한 통신 영역과 센싱 영역을 확보 할 수 있도록 스스로 토폴로지를 구성해야 한다. 본 논문에서는 이러한 토폴로지를 구성하기 위해 무선 센서 네트워크의 트래픽 정보를 이용하여 에너지 효율을 향상시키는 기법(TRaffic-Aware Topology control: TRAT)을 제시한다. 제안한 기법은 트래픽 정보를 근거로 활동 노드의 수와 각 노드의 전송 세기를 조절한다. 실험 결과, 제안한 기법은 기존의 토폴로지 제어 기법과 비교하여 30% 정도의 성능 향상을 보였다.

A Multi-Chain Based Hierarchical Topology Control Algorithm for Wireless Sensor Networks

  • Tang, Hong;Wang, Hui-Zhu
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제9권9호
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    • pp.3468-3495
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    • 2015
  • In this paper, we present a multi-chain based hierarchical topology control algorithm (MCHTC) for wireless sensor networks. In this algorithm, the topology control process using static clustering is divided into sensing layer that is composed by sensor nodes and multi-hop data forwarding layer that is composed by leader nodes. The communication cost and residual energy of nodes are considered to organize nodes into a chain in each cluster, and leader nodes form a tree topology. Leader nodes are elected based on the residual energy and distance between themselves and the base station. Analysis and simulation results show that MCHTC outperforms LEACH, PEGASIS and IEEPB in terms of network lifetime, energy consumption and network energy balance.