Browsing by Author "Lo, LC"

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Decentralized energy-conserving and coverage-preserving protocols for wireless sensor networks
(2005)
Huang, CF
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Lo, LC
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Tseng, YC
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Chen, WT
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資訊工程學系
The wireless sensor network is an emerging technology that may greatly facilitate human life by providing ubiquitous sensing, computing, and communication capability. However, to maintain sufficient coverage and to achieve long system lifetime are two contradicting factors in designing the topology of a sensor network. In this paper, we propose several decentralized protocols that schedule sensors' active and sleeping periods to prolong the network lifetime while maintain the sensing field sufficiently covered. The proposed protocols are based on a model similar to that of [8], but improve the results of [8] In several senses. First, our approach can significantly reduce the computational complexity incurred, and at the same time achieve better accuracy in determining the coverage of the sensing area. Second, we further enhance the results of [8] by proposing an optimization mechanism to further balance or reduce sensors' energy expenditure.
Design and synthesis of activity probes for glycosidases
(2002-10-17)
Tsai, CS
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Li, YK
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Lo, LC
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應用化學系
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Department of Applied Chemistry
[GRAPHICS] A new synthetic route was developed for the preparation of activity probe 1 for beta-glucosidase in this study. The key glycosidation step begins with benzyl p-hydroxyphenylacetate. Benzylic functionalization for the construction of the trapping device was achieved at later stages. Probe 1 was shown to be able to label the target enzyme. This cassette-like design offers great flexibility for future alterations. It would allow the synthetic scheme to expand to other glycosidase probes with different linker/reporter combinations.
Facile synthesis toward the construction of an activity probe library for glycosidases
(2006-03-20)
Shie, TH
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Chiang, YL
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Lin, JJ
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Li, YK
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Lo, LC
Chemical probes that selectively label the glycoside hydrolase (GH) subfamilies have proven to be a powerful tool in GH-related research. We have previously demonstrated the design and synthesis of an activity probe for beta-glucosidase adopting a cassette-like design in a model study. Herein we report an improved synthetic route using (4-hydroxyphenyl)acetic acid 2-cyanoethyl ester as the precursor for the latent trapping device. Parallel syntheses were performed for the preparation of a library based oil the structure of a key intermediate. The recognition head of this library covers a series of six sugars, including alpha- and beta-D-Glc, alpha- and beta-D-Gal, alpha-D-Man and alpha-L-Fuc. Each member in this versatile intermediate library could serve as the building block in constructing an activity probe for GHs. As demonstrated in this study, three probes that have the 1,2-cis configuration were thus prepared for the first time to target alpha-D-glucosidase, alpha-D-galactosidase, and alpha-L-fucosidase, respectively. (c) 2006 Elsevier Ltd. All rights reserved.
Synthesis of activity probes for beta-xylosidase
(2006-04-01)
Lo, LC
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Chu, CY
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Lin, FA
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Pan, YR
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Li, YK
Due to their industrial interest and significance, developing a rapid method for screening beta-xylosidase activities would certainly facilitate the research and improve production in xylan-related industries especially in the pulp and paper industries. Here we report the synthesis of two activity probes, LCL-6X and -12X, for beta-xylosidase. They both carry a beta-xylopyranosyl recognition head, which is linked to a latent trapping device consisting of a 2-fluoromethylphenoxyl group and a biotin reporter group. They differ only in the length of their hydrophobic linker. A model study using a beta-xylosidase from T koningii demonstrates that both probes could successfully label the target hydrolase and give rise to biotinylated proteins. They could thus potentially become a powerful tool in screening beta-xylosidase from microbial sources.
The coverage problem in three-dimensional wireless sensor networks
(2004)
Huang, CF
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Tseng, YC
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Lo, LC
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資訊工程學系
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Department of Computer Science
One of the fundamental issues in sensor networks is the coverage problem, which reflects how well a sensor network is monitored or tracked by sensors. In this paper, we formulate this problem as a decision problem, whose goal is to determine whether every point in the service area of the sensor network is covered by at least a sensors, where a is a given parameter and the sensing regions of sensors are modeled by balls (not necessarily of the same radius). This problem in a 2D space is solved in [1] with an efficient polynomial-time algorithm (in terms of the number of sensors). In this paper, we show that tackling this problem in a 3D space is still feasible within polynomial time. The proposed solution can be easily translated into an efficient polynomial-time distributed protocol.