• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.2
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• pp.514-537
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• 2020

Wireless sensor network (WSN) is a distributed network composed of many sensory nodes. It is precisely due to the clustering unevenness and cluster head election randomness that the energy consumption of WSN is excessive. Therefore, a many-objective optimization WSN energy balance model is proposed for the first time in the clustering stage of LEACH protocol. The four objective is considered that the cluster distance, the sink node distance, the overall energy consumption of the network and the network energy consumption balance to select the cluster head, which to better balance the energy consumption of the WSN network and extend the network lifetime. A many-objective optimization algorithm to optimize the model (LEACH-ABF) is designed, which combines adaptive balanced function strategy with penalty-based boundary selection intersection strategy to optimize the clustering method of LEACH. The experimental results show that LEACH-ABF can balance network energy consumption effectively and extend the network lifetime when compared with other algorithms.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3950-3957
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• 2010

Wireless sensor network is composed of sensor node with limited sources, and to maintain and repair is vexatious once made up. Accordingly it is important matter to maximize the network lifetime by minimizing the energy consumption in wireless sensor network, and utilizing the limited sources efficiently. In this paper, I propose a technique arranging the cluster number with efficiency in clustering method to optimize the energy consumption. The energy usage needed for wireless transmission varies in distance(threshold). This technique reduces the energy consumption considering the threshold when arranging the cluster number. I verify that the clustering method organized through the valid processes outperform the LEACH(Low-Energy Adaptive Clustering Hierarchy) in total energy consumption.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06d
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• pp.520-525
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• 2007

센서 네트워크에서 에너지의 제한은 이전의 다른 많은 네트워크 시스템과 구별되는 특징을 가지게 한다. 따라서 센서 네트워크에서의 가장 중요한 연구 주제는 에너지를 절약하도록 하는 것에 초점이 맞춰진다. 기존의 센서 네트워크에서는 주로 Network, Mac, Phy 계층에서 연구가 진행되었으며, 또한 사용자가 센서 네트워크의 Lifetime을 미리 정할 수 없었다. 하지만, 어떤 센서 네트워크에서는 어떤 특정한 시간까지 생존할 필요가 있을 것이다. 이 논문에서는 미리 정해진 Lifetime을 보장하는 노드의 응용 수준에서의 에너지 소모 모델을 제공한다. 이와 같은 일을 하기위해서, 첫 번째로, 센서 네트워크에서의 응용을 6가지로 구분하고, 응용에서 필요로 되는 5가지 연산을 정의했다. 두 번째로 이러한 5가지의 연산을 포함하는 에너지 소모 모델을 만들었으며, 이것을 가지고 각각의 연산에서 소모되는 에너지를 통계적인 기법을 통해서 계산한다. 마지막으로 노드가 미리 정해진 시간까지 생존하도록 각각의 노드에서 응용의 에너지 소모 계획을 다시 작성한다. 예를들면, 응답주기와 센싱주기의 변경을 통하여 에너지의 소모를 줄일 수 있다. 결과적으로 이러한 일들은 노드가 정해진 시간까지 생존하도록 보장해 준다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.2B
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• pp.269-278
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• 2010

In the clustering protocol, lifetime of the cluster members radically decrease because frequency interference between clusters make every cluster member consume a lot of energy to maintain or increase its transmission rate. In this paper, we analyze the frequency interference among the clusters with the game theory which deals with resource bargaining problems between players, and present a rational power allocation strategy. Both the cases that each cluster tries to selfishly occupy and cooperatively share the resource are analyzed in terms of non-cooperative and cooperative games. In simulation, we compare the cooperative game with non-cooperative game in terms of the node lifetime.

• Journal of the Korea Society of Computer and Information
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• v.21 no.10
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• pp.29-35
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• 2016

In this paper, we propose a scheme to prolong the lifetime of the sensor network by reducing the power consumption of the sensor node. The proposed algorithm reduces the number of transmissions and sensing at the application layer. We combine the VIS scheme with the MSZ algorithm and call it as the SZM/VIS algorithm. The actual temperature data was collected using the sensor nodes to assess the performance of the proposed algorithm. The proposed algorithm was implemented through the programming and was evaluated under various setting values. Experimental results show that the SZM/VIS has a slightly improved transmission ratio than that of the MSZ while has the periodic transmission capability like as the MSZ. Also the SZM/VIS can significantly reduces the sensing ratio like that of the VIS. Our algorithm has the advantages of instantaneous, simplicity, small overhead and robustness. Our algorithm has just negligible side effects by controlling the parameter properly depending on the application types. The SZM/VIS algorithm will be able to be used effectively for the applications that need to be managed within a certain range of specific properties, such like crop management.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.12
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• pp.1186-1194
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• 2012

In order to resolve the energy efficiency in wireless sensor networks, a multihop transmission technique is utilized. However, multihop transmission in wireless sensor networks (WSN) has pros and cons. It reduces total energy consumption, while it may cause a severe decrease in network lifetime. To solve this problem, we suggest the so called strike and bargaining algorithm (SBA). The routing path is determined by wages of nodes. Each node negotiates its wage with their neighbor nodes and determine a reasonable value to reach a optimally balanced point. By analysis and simulations, we show SBA can achieve a near optimal solution.

• Journal of Communications and Networks
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• v.16 no.5
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• pp.493-501
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• 2014

Coverage completeness is an important indicator for quality of service in wireless sensor networks (WSN). Due to limited energy and diverse working conditions, the sensor nodes have different lifetimes which often cause network holes. Most of the existing methods expose large limitation and one-sidedness because they generally consider only one aspect, either coverage rate or energy issue. This paper presents a novel method for coverage hole detection with residual energy in randomly deployed wireless sensor networks. By calculating the life expectancy of working nodes through residual energy, we make a trade-off between network repair cost and energy waste. The working nodes with short lifetime are screened out according to a proper ratio. After that, the locations of coverage holes can be determined by calculating the joint coverage probability and the evaluation criteria. Simulation result shows that compared to those traditional algorithms without consideration of energy problem, our method can effectively maintain the coverage quality of repaired WSN while enhancing the life span of WSN at the same time.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.9
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• pp.4301-4319
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• 2017

Adopting mobile chargers (MC) in rechargeable wireless sensors network (R-WSN) to recharge sensors can increase network efficiency (e.g., reduce MC travel distance per tour, reduce MC effort, and prolong WSN lifetime). In this study, we propose a mechanism to split the sensing field into partitions that may be equally spaced but differ in distance to the base station. Moreover, we focus on minimizing the MC effort by providing a new charging mechanism called the sector-based charging schedule (SBCS), which works to dispatch the MC in charging trips to the sector that sends many charging requests and suggesting an efficient sensor-charging algorithm. Specifically, we first utilize the high ability of the BS to divide the R-WSN field into sectors then it select the cluster head for each sector to reduce the intra-node communication. Second, we formulate the charging productivity as NP-hard problem and then conduct experimental simulations to evaluate the performance of the proposed mechanism. An extensive comparison is performed with other mechanisms. Experimental results demonstrate that the SBCS mechanism can prolong the lifetime of R-WSNs by increasing the charging productivity about 20% and reducing the MC effort by about 30%.

• Smart Structures and Systems
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• v.6 no.3
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• pp.263-275
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• 2010

In the last decade, wireless sensor networks have emerged as a promising technology that could accelerate progress in the field of structural monitoring. The main advantages of wireless sensor networks compared to conventional monitoring technologies are fast deployment, small interference with the surroundings, self-organization, flexibility and scalability. These features could enable mass application of monitoring systems, even on smaller structures. However, since wireless sensor network nodes are battery powered and data communication is the most energy consuming task, transferring all the acquired raw data through the network would dramatically limit system lifetime. Hence, data reduction has to be achieved at the node level in order to meet the system lifetime requirements of real life applications. The objective of this paper is to discuss some general aspects of data processing and management in monitoring systems based on wireless sensor networks, to present a prototype monitoring system for civil engineering structures, and to illustrate long-term field test results.

• Journal of information and communication convergence engineering
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• v.11 no.4
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• pp.288-292
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• 2013

In this paper, a carbon implant is investigated in detail from the perspectives of performance advantages and side effects for the thick n-type metal-oxide-semiconductor field-effect transistor (n-MOSFET). Threshold voltage ($V_{th}$) adjustment using a carbon implant significantly improves the $V_{th}$ mismatch performance in a thick (3.3-V) n-MOS transistor. It has been reported that a bad mismatch occurs particularly in the case of 0.11-${\mu}m$ $V_{th}$ node technology. This paper investigates a carbon implant process as a promising candidate for the optimal $V_{th}$ roll-off curve. The carbon implant makes the $V_{th}$ roll-off curve perfectly flat, which is explained in detail. Further, the mechanism of hot carrier injection lifetime degradation by the carbon implant is investigated, and new process integration involving the addition of a nitrogen implant in the lightly doped drain process is offered as its solution. This paper presents the critical side effects, such as Isub increases and device performance shifts caused by the carbon implant and suggests an efficient method to avoid these issues.