Browsing by Author "Chang, Jyh-Huei"

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An Efficient Relay Sensor Placing Algorithm for Connectivity in Wireless Sensor Networks
(2011-01-01)
Chang, Jyh-Huei
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資訊工程學系
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Department of Computer Science
Randomly deployed sensor networks often make initial communication gaps inside the deployed area, even in an extremely high-density network. How to add relay sensors such that the underlying graph is connected and the number of relay sensors added is minimized is an important problem in wireless sensor networks. This paper presents an Efficient Relay Sensor Placing Algorithm (ERSPA) for solving such a problem. Compared with the minimum spanning tree algorithm and the greedy algorithm, ERSPA achieves better performance in terms of the number of relay sensors added. Simulation results show that the average number of relay sensors added by the minimal spanning tree algorithm is approximately two times that of the ERSPA algorithm.
An efficient relay sensors placing algorithm for connectivity in wireless sensor networks
(2006)
Chang, Jyh-Huei
;
Jan, Rong-Hong
;
資訊工程學系
;
Department of Computer Science
Randomly deployed sensor networks often make initial communication gaps inside the deployed area even in an extremely high-density network. How to add relay sensors such that the underlying graph is connected and the number of relay sensors added is minimized is an important problem in wireless sensor networks. This paper presents an Efficient Relay Sensors Placing Algorithm (ERSPA) for solving such a problem. Compared with minimum spanning tree algorithm and greedy algorithm, ERSPA achieves a better performance in terms of number of relay sensors added. Simulation results show that the average number of relay sensors added by minimal spanning tree algorithm is approximately up to two times than ERSPA algorithm.
An Energy-Aware, Cluster-Based Routing Algorithm for Wireless Sensor Networks
(2010-11-01)
Chang, Jyh-Huei
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資訊工程學系
;
Department of Computer Science
Cluster-based routing protocols have special advantages that help enhance both scatability and efficiency of the routing protocol. Likewise, finding the best way to arrange clustering so as to maximize the network's lifetime is now an important research topic in the field of wireless sensor networks. In this paper, we present an Energy-Aware, Cluster-Based Routing Algorithm (ECRA) for wireless sensor networks to maximize the network's lifetime. The ECRA selects some nodes as cluster-heads to construct Voronoi diagrams and rotates the cluster-head to balance the load in each cluster. A two-tier architecture (ECRA-2T) is also proposed to enhance the performance of the ECRA. The simulations show that both the ECRA-2T and ECRA algorithms outperform other routing schemes such as direct communication, static clustering, and LEACH. This strong performance stems from the fact that the ECRA and ECRA-2T rotate intra-cluster-heads to balance the foal to all nodes in the sensor networks. The ECRA-2T also leverages the benefits of short transmission distances for most cluster-heads in the lower tier.
Message Ferry Routing Algorithm for Data Collection in Partitioned and Buffer-Limited Wireless Sensor Networks
(2012-07-01)
Chang, Jyh-Huei
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Jan, Rong-Hong
;
資訊工程學系
;
Department of Computer Science
"In some particular environments such as battlefield, disaster recovery and wide area surveillance, most existing routing algorithms will fail to deliver messages to their destinations. Thus, it is an important research issue of how to deliver data in disconnected wireless sensor networks. This paper presents two efficient message ferry routing algorithms, denoted as MFRA1 and MFRA2, for data collection in disconnected wireless sensor networks. Both algorithms are designed to find feasible routes for the message ferry such that the buffers of sensors will not overflow after a complete sequence. A complete sequence is the visit sequence of message ferry which visits every sensor node at least once. We find the shortest sequence for message ferry which visits every sensor exactly once and then we check the feasibility of the visit sequence. If there is a sensor overflow, MFRA1 and MFRA2 fix the overflow by partitioning the initial visit sequence into some sub-sequences such that the ferry visits the overflow node twice in the resulting sequence. The above process will continue until a feasible solution is found. Simulation results show that both MFRA1 and MFRA2 are better than other schemes in terms of the amount of data lost, because the other schemes neglect the case of sensor overflow."