• Smart Structures and Systems
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• v.10 no.3
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• pp.271-298
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• 2012

Researchers have made significant progress in recent years towards realizing effective structural health monitoring (SHM) utilizing wireless smart sensor networks (WSSNs). These efforts have focused on improving the performance and robustness of such networks to achieve high quality data acquisition and distributed, in-network processing. One of the primary challenges still facing the use of smart sensors for long-term monitoring deployments is their limited power resources. Periodically accessing the sensor nodes to change batteries is not feasible or economical in many deployment cases. While energy harvesting techniques show promise for prolonging unattended network life, low power design and operation are still critically important. This research presents the WiSeMote: a new, fully integrated ultra-low power wireless smart sensor node and a flexible base station, both designed for long-term SHM deployments. The power consumption of the sensor nodes and base station has been minimized through careful hardware selection and the implementation of power-aware network software, without sacrificing flexibility and functionality.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.433-435
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• 2007

Geographic wireless sensor networks use position information for Greedy routing. Greedy routing works well in dense network where as in sparse network it may fail and require the use of recovery algorithms. Recovery algorithms help the packet to get out of the communication void. However, these algorithms are generally costlier for resource constrained position based wireless sensor type networks. In the present work, we propose a Void Avoidance Algorithm (VAA); a novel idea based on virtual distance upgrading that allows wireless sensor nodes to remove all stuck nodes by transforming the routing graph and forward packet using greedy routing only without recovery algorithm. In VAA, the stuck node upgrades distance unless it finds next hop node which is closer to the destination than itself. VAA guarantees the packet delivery if there is a topologically valid path exists. NS-2 is used to evaluate the performance and correctness of VAA and compared the performance with GPSR. Simulation results show that our proposed algorithm achieves higher delivery ratio, lower energy consumption and efficient path.

• Journal of the Korea Computer Industry Society
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• v.10 no.3
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• pp.79-86
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• 2009

This paper proposes a mechanism for prompt and efficient construction of sensor network connecting sensor nodes and base stations using limited length edges minimum spanning tree. This mechanism can rapidly build a connecting tree which may be used in routing of sensor network. In an experiment for 2000 input terminal nodes, this mechanism can curtail 94.7% construction time comparing with the method by naive minimum spanning tree without tree length overheads. This shows the proposed mechanism can apply well to the application of swift construction of a sensor network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.183-186
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• 2012

To process continuous queries on a sensor network, it is required to transfer query predicates and build a query index on each sensor node. However, if we transfer query predicates to all sensor nodes, it makes the number of messages for query predicates increase. In this paper, we propose the scheme to construct the tree based relationship structure using data region of the sensor node and select the target nodes to transfer query predicates. we also implement the tree based relationship structure and measure the number of messages for sending predicates.

• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.1
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• pp.93-98
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• 2020

Research on underwater sensor networks is increasing due to such reasons as marine resource management, maritime disaster prediction and military protection. Many underwater sensor networks performs wireless communication using an acoustic sound wave band signal having a relatively low frequency. So the digital part of their modem can take charge of carrier band signal processing. To enable this, the sampling rate of the baseband band signal should be increased to a sampling rate at which carrier band signal processing is possible. In this paper, we designed a sampling rate increasing circuit based on a CIC interpolator for underwater sensor nodes. The CIC interpolator has a simple circuit structure. However, since the CIC interpolator has a large attenuation of the pass band and a wide transition band, an inverse sinc LPF is added to compensate for frequency response of the CIC interpolator. The proposed interpolator was verified in time domain and frequency domain using ModelSim and Matlab.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.10 no.3
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• pp.86-91
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• 2011

Wireless sensor network (WSN) is a distributed self-organizing network which contains a large number of tiny multi-functional sensor nodes. The network life time is an important issue in WSN because every sensor node has a constraint on electric supply. In this paper, an energy consumption model is described and a GA-based algorithm will be used to optimize the energy consumption by analyzing the working model of sensor nodes. The model will provide an effective reference of working pattern for WSN. This algorithm is evaluated through analysis and simulations.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.1
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• pp.9-21
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• 2010

In this paper, optimum design of distributed detection is considered for a parallel sensor network system consisting of a fusion center and multiple passive sonar nodes. Nonrandom fusion rules are employed as the fusion rules of the sensor network. For the nonrandom fusion rules, it is shown that a threshold rule of each sensor node has uniformly most powerful properties. Optimum threshold for each sensor is investigated that maximizes the probability of detection under a constraint on energy consumption due to false alarms. It is also investigated through numerical experiments how signal strength, false alarm probability, and the distance between three sensor nodes affect the system detection performances.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.330-333
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• 2009

WSNs is evolving different kinds of networks depending on different circumstances, among those we have HWSNs (Hybrid Wireless Sensor Networks) which invokes sensor nodes mobility. In hybrid wireless sensor networks (HWSNs), reducing energy consumption of resource constrained and adaptability to the sensors nodes motion are the crucial problems; to overcome this we need a scalable MAC protocol. Many MAC protocols have been proposed by different researchers, but in this paper we propose LMAC because it outperforms S-MAC, T-MAC and D-MAC protocols comparing to its improvement of energy efficiency and mobile adaptability.

• Annual Conference of KIPS
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• 2004.05a
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• pp.1259-1262
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• 2004

Detecting environmental hazards and monitoring remote terrain are among many sensor network applications. In case of fire detection, it is significantly valuable to monitor fire-spot's shape and trend in time. Mobile ad hoc sensor nodes right round are responsible for sensoring, processing and networking packets, or even launching extinguisher. In this paper, we proposed a ring-oriented Multicast architecture based on "Fisheye State Routing" (MFSR) to organize a group of mobile ad hoc sensor nodes in a multicast way. It is familiar with traditional mesh-based multicast protocol [1] in mobile ad hoc network, trying to concentrates on efficiency and robustness simultaneously. Certain applications-based solution for hazards is proposed, quantitative results including architecture and recovery algorithms of MFSR are also investigated in this paper.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.5
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• pp.666-669
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• 2020

Energy harvesting sensor networks have the ability to collect energy from the environment to overcome the power limitations of traditional sensor networks. The sensor network, which has a limited transmission range, delivers data to the destination node through a multi-hop method. The routing protocol should consider the power situation of nodes, which is determined by the residual power and energy harvesting rate. At this time, if only considering the magnitude of the power, power imbalance can occur among nodes and it can induce instantaneous power shortages and reduction of network lifetime. In this paper, we designed a routing protocol that considers the balance of power as well as the residual power and energy harvesting rate.