Browsing by Author "Wu, FJ"

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A probabilistic signal-strength-based evaluation methodology for sensor network deployment
(2005)
Kuo, SP
;
Tseng, YC
;
Wu, FJ
;
Lin, CY
;
資訊工程學系
The deployment of senor networks have attracted a lot of attention recently. In essence this issue is concerned with how well a sensing field is monitored by sensors to achieve a particular coverage. In this paper, we propose a signal-strength-based approach to evaluate how well a sensing field is covered/monitored. We first formulate object tracking by a single sensor as a Gaussian-error model. Then we establish an error model on location estimation given that the location of an object is known. This leads to a model to evaluate a sensor network with given locations of sensors. We then apply the result to several applications, such as adding more sensor nodes for error reduction and scheduling power modes (awake or sleep) of sensors, and demonstrate our simulation results.
Highly oriented (Zr0.7Sn0.3)TiO4 thin films grown by rf magnetron sputtering
(1998-02-01)
Wu, FJ
;
Tseng, TY
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Thin films of (Zr0.7Sn0.3)TiO4 on Si(100) were prepared by rf magnetron sputtering in the present study. Films of a highly preferred [020] orientation, as demonstrated by X-ray diffraction and transmission electron microscopic examinations, were grown successfully on a Si substrate with in situ postannealing at 700 degrees C. The chemical composition of the films, measured by secondary ion mass spectroscopy, exhibited a uniform concentration distribution for all species. A study by X-ray photoelectron spectroscopy further revealed some firm evidence of a molecular orbital that affected the chemical structure. The dielectric constants of 400-nm-thick (Zr0.7Sn0.3)TiO4 films in the present study were >18 for the films with a preferred orientation and similar to 11 for polycrystalline films.