Browsing by Author "Liu, Yung-Chih"

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Address assignment and routing schemes for ZigBee-based long-thin wireless sensor networks
(2008)
Pan, Meng-Shiuan
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Fang, Hua-Wei
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Liu, Yung-Chih
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Tseng, Yu-Chee
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資訊工程學系
Wireless sensor networks (WSNs) have been extensively, researched recently. This paper makes two contributions to this field. First, we promote a new concept of long-thin (LT) topology for WSNs, where a network may have a member of linear paths of nodes as backbones connecting to each other. These backbones are to extend the network to the intended coverage areas. At the first glance, a LT WSN only seems to be a special case of numerous WSN topologies. However, we observe, from real deployment experiments, that such a topology is quite general in many applications and deployments. The second contribution is that we show that the address assignment and thus the tree routing scheme defined in the original ZigBee specification may work poorly, if not fail, in a LT topology. We thus propose simple, yet efficient, address assignment and routing schemes for a LT WSN. Simulation results and prototyping experiences are also reported.
Imprecision-Tolerant Location Management for Object-Tracking Wireless Sensor Network
(2010-03-01)
Lin, Chih-Yu
;
Tseng, Yu-Chee
;
Liu, Yung-Chih
;
資訊工程學系
;
Department of Computer Science
An important issue of wireless sensor networks is object tracking, where the key steps include event detection, target classification, location estimation and location management. The main theme of this paper is location management. Because imprecision is an inherent property in object-tracking sensor networks, this paper focuses on the scenarios where users can tolerate a certain degree of imprecision in their query results. We intend to develop a location management scheme that can achieve two goals. First, multiple precision levels are provided. Second, the query cost is proportional to the precision level. To achieve these two goals, we propose a tree-based imprecision-tolerant location management scheme that includes three major components: (1) update and query mechanisms that can support imprecision-tolerant queries, (2) the approach to taking the statistics of imprecision-tolerant queries and (3) a tree construction algorithm that can reduce the query cost and minimize the increment of update cost. Performance evaluations are conducted through simulations to verify the proposed scheme.