• Journal of Communications and Networks
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• 제12권2호
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• pp.103-113
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• 2010

In this paper, a tradeoff between the total energy consumption-per-bit and the end-to-end rate under spatial reuse in wireless multi-hop network is developed and analyzed. The end-to-end rate of the network is the number of information bits transmitted (end-to-end) per channel use by any node in the network that is forwarding the data. In order to increase the bandwidth efficiency, spatial reuse is considered whereby simultaneous relay transmissions are allowed provided there is a minimum separation between such transmitters. The total energy consumption-per-bit includes the energy transmitted and the energy consumed by the receiver to process (demodulate and decoder) the received signal. The total energy consumption-per-bit is normalized by the distance between a source-destination pair in order to be consistent with a direct (single-hop) communication network. Lower bounds on this energy-bandwidth tradeoff are analyzed using convex optimization methods. For a given location of relays, it is shown that the total energy consumption-per-bit is minimized by optimally selecting the end-to-end rate. It is also demonstrated that spatial reuse can improve the bandwidth efficiency for a given total energy consumption-per-bit. However, at the rate that minimizes the total energy consumption-per-bit, spatial reuse does not provide lower energy consumption-per-bit compared to the case without spatial reuse. This is because spatial reuse requires more receiver energy consumption at a given end-to-end rate. Such degraded energy efficiency can be compensated by varying the minimum separation of hops between simultaneous transmitters. In the case of equi-spaced relays, analytical results for the energy-bandwidth tradeoff are provided and it is shown that the minimum energy consumption-per-bit decreases linearly with the end-to-end distance.

• International journal of advanced smart convergence
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• 제9권2호
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• pp.185-194
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• 2020

Designing of a hierarchical clustering algorithm is one of the numerous approaches to minimize the energy consumption of the Wireless Sensor Networks (WSNs). In this paper, a homogeneous and randomly deployed sensor nodes is considered. These sensors are energy constrained elements. The nominal selection of the Cluster Head (CH) which falls under the clustering part of the network protocol is studied and compared to Low Energy Adaptive Clustering Hierarchy (LEACH) protocol. CHs in this proposed process is the function of total remaining energy of each node as well as total average energy of the whole arrangement. The algorithm considers initial energy, optimum value of cluster heads to elect the next group of cluster heads for the network as well as residual energy. Total remaining energy of each node is compared to total average energy of the system and if the result is positive, these nodes are eligible to become CH in the very next round. Analysis and numerical simulations quantify the efficiency and Average Energy Ratio (AER) of the proposed system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권3호
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• pp.819-837
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• 2014

Data centers, which implement cloud service, have been faced up with quick growth of energy consumption and low efficiency of energy. 60GHz wireless communication technology, as a new option to data centers, can provide feasible approach to alleviate the problems. Aiming at energy optimization in 60GHz wireless data centers (WDCs), we investigate virtualization technology to assign virtual resources to minimum number of servers, and turn off other servers or adjust them to the state of low power. By comprehensive analysis of wireless data centers, we model virtual network and physical network in WDCs firstly, and propose Virtual Resource Mapping Packing Algorithm (VRMPA) to solve energy management problems. According to VRMPA, we adopt packing algorithm and sort physical resource only once, which improves efficiency of virtual resource allocation. Simulation results show that, under the condition of guaranteeing network load, VPMPA algorithm can achieve better virtual request acceptance rate and higher utilization rate of energy consumption.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 추계학술발표대회 논문집
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• pp.327-331
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• 2008

In this paper, we argue that new&renewable energy resources are difficult to be managed with GIS technology due to their spatiotemporal features, and suggest that spatiotemporal database and sensor network can be applied to the new&renewable energy management system as advanced technology. To give the motivated issues, we introduce and analyze the concept of the spatiotemporal database and sensor network, and the case studies in each applications.

• Journal of Power Electronics
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• 제10권3호
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• pp.320-327
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• 2010

In this paper, multiple offshore wave energy converters with different output characteristics are connected to one power distribution substation. The connection between the power take-off of the different wave energy converters and the electrical power transmission system is presented in order to investigate whether multiple wave energy converters can augment energy yield and improve network integration capabilities. Moreover, the model of an array of wave energy converters is developed with the goal of analyzing the effects of the offshore wave farm on the electrical network to which it is connected. It is also developed to ensure that the electricity generated by the array is sufficiently controllable, and of a quality that can be integrate into the electricity supply network without unduly increasing the cost of connection, production or delivery.

• 전자공학회논문지
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• 제49권9호
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• pp.27-34
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• 2012

오늘날 ICT 네트워크에서 에너지 소모는 전체 에너지 소모의 10% 내외로 가까운 미래에 에너지가 현저하게 증가 할 것이다. 그러한 이유로 ICT 네트워크에서 에너지를 절약하려는 연구가 상당히 활발하게 이루어지고 있다. 본 논문에서 네트워크 레벨에서 네트워크 품질을 보장하면서 에너지 절약이 가능한 방법을 검토한다. 네트워크를 구성하는 노드와 링크는 에너지 프로파일에 따라 에너지가 소모된다고 가정하였다. 특히 IP 네트워크에서, 다양한 에너지 프로파일 모델을 기본으로 하여 네트워크가 소모하는 에너지 모델을 정식화하고, IP 네트워크 품질을 만족하면서 에너지 절약이 가능한 energy-aware QoS 라우팅 방안을 제시하고 검토한다. 본 논문에서 시뮬레이션을 이용하여, 에너지 프로파일에 따라 IP 네트워크가 소모하는 에너지의 차이가 크며, 적절한 에너지 프로파일 모델을 개발한다면 에너지 절약이 가능함을 보여 준다. 또 IP 네트워크의 품질을 유지하면서 에너지 절약이 가능한 energy-aware QoS 라우팅 중 min_used_path(MP) heuristic을 이용한 방법이 네트워크의 노드 및 링크의 감소율이 다른 방법에 비해 우수하고, 에너지 절약 효과가 다른 방법에 비해 우수함을 분명히 한다. 따라서 결론적으로 본 논문에서는 energy-aware QoS 라우팅의 한 방법인 min_used_path(MP) heuristic을 적용하여 네트워크 품질 유지하면서 에너지를 절약 할 수 있음을 확인 하였다.

• 한국콘텐츠학회논문지
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• 제9권9호
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• pp.31-40
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• 2009

센서 네트워크에서는 신뢰성 있는 데이터 전송, 각 노드의 에너지 효율성 그리고 노드의 부하 분산을 통한 네트워크 수명의 최대화가 중요하다. 본 논문에서는 무선 센서 네트워크에서 동적 단일 경로를 이용하여 이러한 내용을 고려한 동적 단일경로 설정기법(DSPR : Dynamic Single Path Routing)을 제안한다. 각 노드는 싱크까지의 홉 카운트와 평균 잔존 에너지로 계산된 최소 비용을 가지는 동적 단일 경로로 데이터를 전송한다. 이 때, 각 노드들은 자신의 전송 과정을 감시하고 경로 손상을 탐지한 노드는 코스트 테이블을 참조하여 손상된 경로를 동적으로 변경함으로써 네트워크의 신뢰성을 높이고 노드들의 에너지 소모를 균등하게 분산시킨다. 또한 네트워크 토폴로지 변화 발생시 전체 네트워크를 재구성하는 대신에 변화에 관련된 부분만을 동적으로 재구성하여 각 노드에서의 불필요한 에너지 소모를 최대한 억제함으로써 네트워크 수명을 증가시킨다. 실험결과 본 논문에서 제안하는 DSPR이 각 노드의 에너지 소모를 최소화하여 네트워크 수명을 증가시키고 신뢰성과 에너지 효율성에서 우수함을 보였다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 춘계 학술대회 학술발표 논문집
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• pp.129-133
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• 2003

The work described in this paper deals with the proposed application of an Artificial Neural Network Model for the Advanced Pressurized Water Reactor APR-1400 transient identification. The approach adopted for testing the network take note of the expectation which should be fulfilled by a network for real-time application, like testing with data in on-line mode and use of actual or real-life patterns for training. The recall test performed demonstrates that use of neural network for transient identification is indeed an attractive preposition.

• Journal of Communications and Networks
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• 제10권4호
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• pp.396-402
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• 2008

The use of network coding in wireless networks has been proposed in the literature for energy efficient broadcast. However, the decoding complexity of existing algorithms is too high for low-complexity devices. In this work we formalize the all-to-all information exchange problem and shows how to optimize the transmission scheme in terms of energy efficiency. Furthermore, we prove by construction that there exists O(1) -complexity network coding algorithms for grid networks which can achieve such optimality. We also present low-complexity heuristics for random. topology networks. Simulation results show that network coding algorithms outperforms forwarding algorithms in most cases.

• ETRI Journal
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• 제44권1호
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• pp.155-167
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• 2022

The Internet of Things (IoT) is a new paradigm that connects physical and virtual objects from various domains such as home automation, industrial processes, human health, and monitoring. IoT sensors receive information from their environment and forward it to their neighboring nodes. However, the large amounts of exchanged data are vulnerable to attacks that reduce the network performance. Most of the previous security methods for IoT have neglected the energy consumption of IoT, thereby affecting the performance and reducing the network lifetime. This paper presents a new multistep routing protocol based on cellular learning automata. The network lifetime is improved by a performance-based adaptive reward and fine parameters. Nodes can vote on the reliability of their neighbors, achieving network reliability and a reasonable level of security. Overall, the proposed method balances the security and reliability with the energy consumption of the network.