- Link:
- http://hdl.handle.net/1783.1/7493
- Collection:
-
- Subjects
- Wireless sensor networks Data transmission systems Querying (Computer science) Synchronization
- Creator:
- Wang, Lixing
- Description
- Thesis (M.Phil.)--Hong Kong University of Science
and Technology, 2012
- Description
- vi, 37 p. : ill. ; 30 cm
- Description
- HKUST Call Number: Thesis CSED 2012
Wang
- Description
- In a wireless sensor network (WSN), each sensor
monitors environmental parameters, and reports its readings to a
base station, possibly through other nodes. A sensor works in
cycles, in each of which it stays active for a fixed duration, and
then sleeps until the next cycle. The frequency of such cycles
determines the portion of time that a sensor is active, and is the
dominant factor on its battery life. The majority of existing work
assumes globally synchronized WSN where all sensors have the same
frequency. This leads to waste of battery power for applications
that entail different accuracy of measurements, or environments
where sensor readings have large variability. To overcome this
problem, we propose LS, a query processing framework for locally
synchronized WSN. We consider that each sensor ni has a distinct
sampling frequency fi, which is determined by the application or
environment requirements. The complication of LS is that ni has to
wake up with a network frequency Fi≥fi, in order to forward
messages of other sensors. Our goal is to minimize the sum of Fi
without delaying package transmissions. Specifically, given a
routing tree, we first present a dynamic programming algorithm that
computes the optimal network frequency of each sensor; then, we
develop a heuristic for finding the best tree topology, if this is
not fixed in advance.
- Format
- 341 bytes
- Format
- text/html
- Language
- en_US
- Type
- Thesis
- Access:
- Instructions in case access is denied
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