Bounding data fusion for ubiquitous-applications within wireless sensor networks

We have formulated the data collection process within wireless sensor networks as a scheduling problem to alleviate workload on the data collection centers. A sensor device has three tasks, which are mainly sensing data, processing and transmitting the collected data. We modeled the sensorpsilas three tasks as a task-flow graph (TFG), and then we combined all TFGs for all sensors within WSN as a super task-flow graph (STFG). We have utilized two scheduling algorithms, as soon as possible (ASAP) and as late as possible (ALAP), to order all tasks within STFG subject to the data collection centerspsila limitations. Our experimental results provide excellent bounds on how early and how late to schedule all sensorspsila tasks with the variation of the number of data collection centers.