• 한국컴퓨터정보학회논문지
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• 제25권2호
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• pp.105-111
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• 2020

태양 에너지 수집형 무선 센서 네트워크(SP-WSN)는 지속적으로 에너지를 수집할 수 있어 배터리 기반 센서 네트워크의 에너지 제약 문제를 완화할 수 있다. 하지만 고정된 싱크를 사용한다면, 싱크 주변에 위치한 노드들의 에너지 소비가 상대적으로 증가하는 문제, 즉 에너지 사용 불균형 문제는 해결하지 못한다. 따라서 최근의 연구에서는 SP-WSN에 모바일 싱크를 사용하여 에너지 불균형 문제에 접근하고 있다. 한편, 무선 전력 전송 기술 발전에 따라 WSN에서 모바일 싱크가 데이터 수집뿐 아니라 무선 전력 전송을 통한 에너지 충전의 역할도 할 수 있다. 본 논문에서는 무선 전력 전송이 가능한 모바일 싱크와 효율적인 클러스터링 기법(클러스터 헤드 선출 포함)을 이용하여 SP-WSN의 에너지 불균형 문제를 최소화하는 기법을 제안한다. 제안 기법은 클러스터 헤드를 무선 전력 전송을 사용하여 충전시키고, 효과적인 헤드 선출을 통해 헤드 주변 노드의 에너지 핫스팟을 완화시켜, 결과적으로 모바일 싱크로 수집되는 데이터양을 증가시킨다.

• 융합보안논문지
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• 제7권4호
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• pp.43-50
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• 2007

센서 노드들의 전기에너지 양은 극히 제한적이고, 밧데리 교체는 무선 센서 망에서는 매우 어렵다. 본 논문은 다른 라우터에서 에너지 손질에 대한 수학적 모델을 제안하며, 직접 Diffusion 기반에 에너지 소비를 근거로 하여 해석한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제3권6호
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• pp.597-611
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• 2009

With the advent of ubiquitous computing society, many advanced technologies have enabled wireless sensor networks which consist of small sensor nodes. However, the sensor nodes have limited computing resources such as small size memory, low battery life, short transmission range, and low computational capabilities. Thus, decreasing energy consumption is one of the most significant issues in wireless sensor networks. In addition, numerous applications for wireless sensor networks are recently spreading to various fields (health-care, surveillance, location tracking, unmanned monitoring, nuclear reactor control, crop harvesting control, u-city, building automation etc.). For many of them, supporting security functionalities is an indispensable feature. Especially in case wireless sensor networks should provide a sufficient variety of security functions, sensor nodes are required to have more powerful performance and more energy demanding features. In other words, simultaneously providing security features and saving energy faces a trade-off problem. This paper presents a novel energy-efficient security architecture in an IEEE 802.15.4-based wireless sensor network called the Hybrid Adaptive Security (HAS) framework in order to resolve the trade off issue between security and energy. Moreover, we present a performance analysis based on the experimental results and a real implementation model in order to verify the proposed approach.

• Journal of information and communication convergence engineering
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• 제10권4호
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• pp.359-364
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• 2012

Harvesting energy from the environment is essential for many applications to slow down the deterioration of energy of the devices in sensor networks and in general, the network itself. Energy from the environment is an inexhaustible supply which, if properly managed and harvested from the sources, can allow the system to last for a longer period - more than the expected lifetime at the time of deployment, or even last indefinitely. The goal of this study is to develop a simple algorithm for ns-2 to simulate energy harvesting in wireless sensor network simulations. The algorithm is implemented in the energy module of the simulator. Energy harvesting algorithms have not yet been developed for ns-2. This study will greatly contribute to the existing knowledge of simulating wireless sensor networks with energy harvesting capabilities in ns-2. This paper will also serve as a basis for future research papers that make use of energy harvesting.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권2호
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• pp.504-521
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• 2016

Recently, energy harvesting technology has been integrated into wireless sensor networks to ameliorate the nodes' energy limitation problem. In theory, the wireless sensor node equipped with an energy harvesting module can work permanently until hardware failures happen. However, due to the change of power supply, the traditional hierarchical network routing protocol can not be effectively adopted in energy harvesting wireless sensor networks. In this paper, we improve the Low-Energy Adaptive Clustering Hierarchy (LEACH) protocol to make it suitable for the energy harvesting wireless sensor networks. Specifically, the cluster heads are selected according to the estimation of nodes' harvested energy and consumed energy. Preference is given to the nodes with high harvested energy while taking the energy consumption rate into account. The utilization of harvested energy is mathematically formulated as a max-min optimization problem which maximizes the minimum energy conservation of each node. We have proved that maximizing the minimum energy conservation is an NP-hard problem theoretically. Thus, a polynomial time algorithm has been proposed to derive the near-optimal performance. Extensive simulation results show that our proposed routing scheme outperforms previous works in terms of energy conservation and balanced distribution.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권6호
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• pp.1357-1378
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• 2013

Energy constraint of wireless sensor networks makes energy saving and prolonging the network lifetime become the most important goals of routing protocols. In this paper, we propose an Energy Efficient Chain-based Routing Protocol (EECRP) for wireless sensor networks to minimize energy consumption and transmission delay. EECRP organizes sensor nodes into a set of horizontal chains and a vertical chain. Chain heads are elected based on the residual energy of nodes and distance from the header of upper level. In each horizontal chain, sensor nodes transmit their data to their own chain head based on chain routing mechanism. EECRP also adopts a chain-based data transmission mechanism for sending data packets from the chain heads to the base station. The simulation results show that EECRP outperforms LEACH, PEGASIS and ECCP in terms of network lifetime, energy consumption, number of data messages received at the base station, transmission delay and especially energy${\times}$delay metric.

• International journal of advanced smart convergence
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• 제7권3호
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• pp.101-109
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• 2018

In this paper, we propose an adaptive filtering scheme of connection requests for the defense of malicious energy consumption attacks against wireless computing devices with limited energy budget. The energy consumption attack tries to consume the battery energy of a wireless device with repeated connection requests and shut down the wireless device by exhausting its energy budget. The proposed scheme blocks a connection request of the energy consumption attack in the middle, if the same connection request is repeated and its request result is failed continuously. In order to avoid the blocking of innocuous mistakes of normal users, the scheme gives another chance to allow connection request after a fixed blocking time. The scheme changes the blocking time adaptively by comparing the message arriving ate during non-blocking period and that during blocking period. Evaluation shows that the proposed defense scheme saves up to 94% energy consumption compared to the non-defense case.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2006년도 춘계종합학술대회
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• pp.111-114
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• 2006

본 논문은 Ad hoc 망에서 Wireless network interface의 broadcast와 point-to-point의 다양한 크기의 데이터 패킷을 송신, 수신, 폐기 시 나타나는 에너지 소비를 측정을 분석한다. IEEE 802.11 wireless network interface를 사용하여 각 상황에 따라 측정하였고, 그것을 선형 식으로 나타내므로 프로토콜 디자이너나 개발자들에게 즘 더 유용한 정보를 제공한다. 그리고 Energy-aware 디자인과 네트워크 프로토콜들의 평가를 위한 실질적인 무선 환경에서의 에너지 소비 동작의 정보를 분석하고자 한다.

• 한국컴퓨터정보학회논문지
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• 제24권5호
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• pp.1-9
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• 2019

In this paper, we propose the algorithms which determine 1) the efficient anchor-node visiting route of mobile sink in terms of energy supply and 2) the efficient energy amount to be charged to each anchor node, by using the information of each anchor node and the mobile sink. Wireless sensor networks (WSNs) using mobile sinks can be deployed in more challenging environments such as those that are isolated or dangerous, and can also achieve a balanced energy consumption among sensors which leads to prolong the network lifetime. Most mobile sinks visit only some anchor nodes which store the data collected by the nearby sensor nodes because of their limited energy. The problem of these schemes is that the lifetime of the anchor nodes can be shorten due to the increased energy consumption, which rapidly reduces the overall lifetime of WSN. This study utilizes a mobile sink capable of wireless power transmission to solve this problem, so a mobile sink can gather data from anchor nodes while charging energy to them. Through the performance verification, it is confirmed that the number of blackout nodes and the amount of collected data are greatly improved regardless of the size of the network.

• Journal of Power Electronics
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• 제19권3호
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• pp.827-834
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• 2019

Wireless power transfer via coupled magnetic resonances has been a hot research topic in recent years. In addition, the number of related devices has also been increasing. However, reverse signals transfer is often required in addition to wireless power transfer. The structure of the circuit for a wireless power transfer system via coupled magnetic resonances is analyzed. The advantages and disadvantages of both parallel compensation and series compensation are listed. Then the compensation characteristics of the inductor, capacitor and resistor were studied and an appropriate compensation method was selected. The reverse signals can be transferred by controlling the compensation of the resistor. In addition, it can be demodulated by extracting the change of the primary current. A 3.3 MHz resonant frequency with a 100 kHz reverse signals transfer system platform was established in the laboratory. Experimental results demonstrate that wireless power and reverse signals can be transferred synchronously.