• IEMEK Journal of Embedded Systems and Applications
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• v.8 no.6
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• pp.339-345
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• 2013

This paper addresses the system lifetime maximization algorithm in multi-hop sensor network system. A multi-hop sensor network consists of many battery-driven sensor nodes that collaborate with each other to gather, process, and communicate information using wireless communications. As sensor-driven applications become increasingly integrated into our lives, we propose a energy-aware scheme where each sensor node transmits informative data with adaptive data rate to minimize system energy consumption. We show the optimal data rate to maximize the system lifetime in terms of remaining system energy. Furthermore, the proposed algorithm experimentally shows longer system lifetime in comparison with greedy algorithm.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.279-282
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• 2003

This paper proposes a medium-access control(MAC) protocol designed for wireless multi-hop sensor networks which is used for connecting physical world and cyber computing space. Wireless multi-hop sensor networks use battery-operated computing and sensing device. We expect sensor networks to be deployed in an ad hoc fashion, with nodes remaining inactive for long time, but becoming suddenly active when specific event is detected. These characteristics of multi-hop sensor networks and applications motivate a MAC that is different from traditional wireless MACs about power conservation scheme, such as IEEE 802.11. Proposed MAC uses a few techniques to reduce energy consumption. Result show that proposed MAC obtains more energy sayings.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.209-211
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• 2005

This paper proposes a adaptive medium-access control(MAC) protocol designed for low-power wireless multi-hop sensor networks which is used for connecting physical world and cyber computing space. Wireless multi-hop sensor networks use battery-operated computing and sensing device. We expect sensor networks to be deployed in an ad hoc fashion, with nodes remaining inactive for long time, but becoming suddenly active when specific event is detected. These characteristics of multi-hop sensor networks and applications motivate a MAC that is different from traditional wireless MACs about power conservation scheme, such as IEEE 802.11. Proposed MAC uses a few techniques to reduce energy consumption. Result show that proposed MAC obtains more energy savings.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.206-208
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• 2005

Wireless sensor network's value has increased greatly in recent years in the fields of Ubiquitous Computing that function as solution to reduce both the limitation and collision about RFID Technology. The research for wireless sensor network technology is proceeding with the research for various sensor nodes, powerful routing algorithms, securities for data transmission, and valid applications. This paper suggests that we make the new multi-hop routing algorithm using RSS in order to implement enhanced multi-hop routing algorithm. This paper should demonstrate that the routing algorithm using suggested RSS is superior to routing algorithm based on established BSDV(Destination Sequenced Distance Vector).

• The KIPS Transactions:PartC
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• v.14C no.6
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• pp.519-524
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• 2007

One of the most important issues on the sensor network with resource limited sensor nodes is prolonging the network lifetime by effectively utilizing the limited node energy. The most representative mechanism to achieve a long lived sensor network is the clustering mechanism which can be further classified into the single hop mode and the multi hop mode. The single hop mode requires that all sensor nodes in a cluster communicate directly with the cluster head(CH) via single hop md, in the multi hop mode, sensor nodes communicate with the CH with the help of other Intermediate nodes. One of the most critical factors that impact on the performance of the existing multi hop clustering mechanism is the cluster size and, without the assumption on the uniform node distribution, finding out the best cluster size is intractable. Since sensor nodes in a real sensor network are distributed non uniformly, the fixed size mechanism may not work best for real sensor networks. Therefore, in this paper, we propose a new dynamic size multi hop clustering mechanism in which the cluster size is determined according to the distance from the sink to relieve the traffic passing through the CHs near the sink. We show that our proposed scheme outperforms the existing fixed size clustering mechanisms by carrying out numerical analysis and simulations.

• Journal of Communications and Networks
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• v.14 no.4
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• pp.443-450
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• 2012

As for cluster-based wireless sensor networks (WSNs), cluster lifetime is one of the most important subjects in recent researches. Besides reducing the energy consumptions of the clusters, it is necessary to make the clusters achieve equal lifetimes so that the whole network can survive longer. In this paper, we focus on the cluster lifetimes in multi-hop WSNs with cooperative multi-input single-output scheme. With a simplified model of multi-hop WSNs, we change the transmission schemes, the sizes and transmission distances of clusters to investigate their effects on the cluster lifetimes. Furthermore, linear and uniform data aggregations are considered in our model. As a result, we analyze the cluster lifetimes in different situations and discuss the requirements on the sizes and transmission distances of clusters for equal lifetimes.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.2
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• pp.114-119
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• 2010

Network technology has been developed rapidly for digital service in these days. ZigBee, one of the IEEE 802.15.4 protocols, supporting local communication has become the core technology in the wireless network area. In this paper we designed an integrated fire monitoring system using a mobile robot and the ZigBee sensor nodes which are deployed to monitor fires. When a fire breaks out, the image information of the scene of a fire is transmitted by an autonomous mobile robot and we also monitor the current position of the robot. Furthermore, the data around the place where the fire breaks out and the positions of the sensor nodes can be transmitted to a server via the multi-hop communication in the real time.

• The KIPS Transactions:PartC
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• v.12C no.6 s.102
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• pp.875-880
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• 2005

One of the most important issues in the sensor network with resource-constrained sensor nodes is prolonging the network lifetime by efficiently utilizing the given energy of nodes. The most representative mechanism to achieve a long-lived network is the clustering mechanism. In this paper, we propose a new dynamic-size multi-hop clustering mechanism in which the burden of a node acting as a cluster head(CH) is balanced regardless of the density of nodes in a sensor network by adjusting the size of a cluster based on the information about the communication load and the residual energy of the node and its neighboring nodes. We show that our proposed scheme outperforms other single-hop or fixed-size multi-hop clustering mechanisms by carrying out simulations.

• The Journal of the Korea Contents Association
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• v.8 no.1
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• pp.177-185
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• 2008

Research on media access control (MAC) scheme for Wireless Sensor Network (WSN) has been mainly focused on energy efficiency improvement, while interest on latency is relatively weak. However, end-to-end latency could be a critical limitation specifically in the multi-hop network such as wireless multimedia sensor networks. In this paper we propose a media access control scheme with distributed transmission power control to Improve end-to-end transmission latency as well as reduce power consumption in multi-hop wireless sensor networks. According to the simulation results, the proposed scheme is turned out to be an energy efficient scheme with improved end-to-end transmission latency.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.177-179
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• 2006

This paper presents an analysis architecture of embedded operating systems for wireless sensor network. Wireless multi-hop sensor networks use battery-operated computing and sensing device. We expect sensor networks to be deployed in an ad hoc fashion, with very high energy constraints. These characteristics of multi-hop wireless sensor networks and applications motivate an operating system that is different from traditional embedded operating system. These days new wireless sensor network embedded operating system come out with some advances compared with previous ones. The analysis is focusing on understanding differences of dominant wireless sensor network OS, such as TinyOS 2.0 with TinyOS 1.x.