Information Technology Reference
In-Depth Information
5
Bounding Data Aggregation for
Ubiquitous Applications within
Wireless Se
nsor Networks
Sami J. Habib
CoNTENTS
5.1 Introduction ................................................................................................ 137
5.2 Structure of a Sensor and Its Related Work ........................................... 138
5.3 Modeling Data Aggregation within WSN ............................................. 141
5.4 An Overview of Scheduling Algorithms ............................................... 142
5.5 Computational Results.............................................................................. 14 4
5.6 Conclusion and Future Work ................................................................... 145
References............................................................................................................. 149
We have formulated the data collection process within wireless sensor
networks as a scheduling problem to alleviate workload on the data collec-
tion centers. A sensor device has three tasks: sensing data, processing data,
and transmitting the collected data. We modeled the sensor's three tasks as a
task-flow graph (TFG), and then we combined all TFGs for all sensors within
the Wireless Sensor Network (WSN) as a super task-flow graph (STFG). We
utilized two scheduling algorithms, as soon as possible (ASAP) and as late
as possible (ALAP), to order all tasks within the STFG subject to the data
collection centers' limitations. The experimental results provide excellent
boundaries on how early and how late to schedule all sensors' tasks with the
variation of the number of data collection centers.
5.1 Introduction
Many ubiquitous applications for a wireless sensor network (WSN) have
emerged, such as battlefield surveillance, disaster relief, border control,
and environmental and habitat monitoring. These ubiquitous applica-
tions are executed by a large set of sensors, which are distributed over a
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