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Proactive monitoring in natural environments. Ian Marshall , Computing Laboratory, University of Kent i.w.marshall@kent.ac.uk Technical Director of the Envisense Research centre http://envisense.org. Current research methods. Single expensive package In situ process studies
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Proactive monitoring in natural environments Ian Marshall, Computing Laboratory, University of Kent i.w.marshall@kent.ac.uk Technical Director of the Envisense Research centre http://envisense.org
Current research methods • Single expensive package • In situ process studies • Low spatial resolution • Short lifetime • Small areas
Wireless Sensor networks • Ad-hoc wireless communication • Physical measurement • No access to mains • Large area (sq kms) • Long life (months) • Many measurement points
WSN management • Low probability of manual intervention • Highly dynamic, unpredictable environment • Very unreliable nodes and comms • Need to automate response to events • ‘model free’ adaptive control
SECOAS Scroby sands wind farm and its impact on sedimentation processes
CEFAS Survey April 2002
Mechanical General Arrangement Buoy (yellow) Radio equipment Warp Data cable Chain Chain Plough anchor Warp
Initial Deployment Areas 6 Sensors 150m apart Shore station 1 NM
Seabed Package • Measure Oceanographic variables (15 minute cycle) • Temperature (1 sample/min) • Pressure (1 sample/s for 5 mins) • Turbidity (10 samples/min) • Tilt (aka current) - (1 sample/s for 5 mins) • Conductivity (1 sample/min) • Adapt sampling rates • Adaptively log data • Transmit selected data to radio buoy
Adaptive sampling • Measure, delete, combine, forward, sleep • Use local variability, neighbour variability and internal state • Self configure using distributed evolutionary “algorithm” (bacteria) • Can adjust priorities and frequency of actions • Can form groups (quorum sensing) • Reward set by user using a diffusion (gossip) protocol – changes drive auto-reconfiguration of genome
Summary • Autonomous adaptive control is needed in environmental sensor networks • Network protocols must support and respond to application semantics (be app aware) • In simulation adaptation was almost as good as optimal sliding window • In practice it dealt well with change from calm to stormy • More research will be needed • www.secoas.org • www.envisense.org