Browsing by Author "Lai, Ten H."

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Exploiting spatial correlation at the link layer for event-driven sensor networks
(2012)
Lin, Chih-Yu
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Tseng, Yu-Chee
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Lai, Ten H.
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資訊工程學系
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Department of Computer Science
Wireless Sensor Networks (WSNs) can generally be classified into two categories: time-driven and event-driven. In an event-driven WSN, sensors report their readings only when they detect events. In such behaviour, sensors in the event area may suffer from higher contention. In this paper, we solve this problem by jointly considering two sub-issues. One is exploiting the spatial correlation of sensor data and the other is designing a specific MAC protocol. We propose a novel hybrid TDMA/CSMA protocol with the following interesting features that differentiate itself from traditional TDMA-based protocols: (1) the TDMA part is based on very loose time synchronisation and is triggered by the appearance of events; (2) the slot assignment strategy associated with the TDMA part takes the spatial correlation of sensor data into consideration and thus allows less strict slot allocation than conventional TDMA schemes. Simulation results show the efficiency of the proposed protocol.
Message-efficient in-network location management in a multi-sink wireless sensor network
(2006)
Lin, Chih-Yu
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Tseng, Yu-Chee
;
Lai, Ten H.
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資訊工程學系
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Department of Computer Science
A wireless sensor network consists of many tiny sensor nodes. The distributed memory spaces of sensors can be considered as a large distributed database, in which one can conduct in-network data processing. This paper considers a sensor network used for object tracking where distributed location updates and queries are performed inside the network. Although this issue has been intensively studied for cellular networks, the same problem in sensor networks has very different characteristics. In this paper, we propose an efficient location management scheme for object tracking in a multi-sink sensor network where users can inquire the locations of objects via any sink in the network. A message-efficient algorithm that describes how to perform location updates and queries is proposed. Furthermore, two distributed virtual tree construction algorithms are also presented. The goal is to reduce the overall update and query cost. The efficiency of the proposed algorithms is evaluated and verified by simulations.
SPECIAL ISSUE: PERVASIVE COMPUTING THROUGH NETWORKED SENSING DEVICES
(2007)
Lai, Ten H.
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Jan, Rong-Hong
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Jiang, Jehn-Ruey
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交大名義發表
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National Chiao Tung University