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Achieving Long-Term Surveillance in VigilNet. Tian He, Pascal Vicaire, Ting Yan, Qing Cao, Gang Zhou, Lin Gu, Liqian Luo, Radu Stoleru, John A. Stankovic, Tarek F. Abdelzaher Department of Computer Science University of Virginia Charlottesville, USA.
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Achieving Long-Term Surveillance in VigilNet Tian He, Pascal Vicaire, Ting Yan, Qing Cao, Gang Zhou, Lin Gu, Liqian Luo, Radu Stoleru, John A. Stankovic, Tarek F. Abdelzaher Department of Computer Science University of Virginia Charlottesville, USA
Other Applications Wildlife Monitoring Flock Protection Alarm System Border Surveillance
Our Solution: VigilNet Application Velocity / Trajectory Inference Programming Abstractions Target Classification Middleware Power Mng 2 Time Sync Localization Group Mngt Power Mngt 3 Routing Routing Power Mngt 1 Signal Filtering Data-Link MAC Sensor Drivers Physical MICA2 / MICAz / XSM Motes
Focus of This Presentation: Power Consumption • No power management => 4 days lifetime! • 99% of energy consumed waiting for potential targets! Energy Distribution
Focus of This Presentation: Power Consumption • Power management => 10 months lifetime! Lifetime x 75 • 98% of energy consumed in sleep mode! 98% Energy Distribution
Topics: Hardware Energy Scavenging Topology Control Sensing Coverage Predefined Scheduling Data Aggregation Etc… Practicality? Performance in Real Deployments? Applicability to Surveillance System? Combination of Schemes? State of the Art
Power Management in VigilNet • Turning nodes off as often and as long as possible. • Questions: • When to turn nodes off (to save power)? • When to wake nodes up (to optimize system performance)? • What are the tradeoffs? • Combination of four schemes: • Node level power management. • Group level power management. • Network level power management. • On-demand wakeup.
Group Level: Sentry Selection • Redundant Coverage!
Group Level: Sentry Selection • Redundant Coverage! => Sentry Selection
Group Level: Sentry Selection • Load Balancing?
Group Level: Sentry Selection • Load Balancing? => Sentry Rotation
Group Level: Sentry Selection • Tradeoff: Detection Latency versus Density 50 125 500 Probability of Target Detected Within First 1,000m Radius=20m Radius=8m Radius=2m 1,000m 1,000 10 100 100m Number of Nodes in Area 100m x 1,000m Area
Sentry Level: Duty Cycle Scheduling • Target Takes Time To Go Through the Network.
Sentry Level: Duty Cycle Scheduling • Target Takes Time To Go Through the Network.=> Duty Cycle Scheduling
Sentry Level: Duty Cycle Scheduling • Putting It All Together
Sentry Level: Duty Cycle Scheduling • Tradeoff: Detection Latency Versus Duty Cycle 100% Probability of Target Detected Within First 1,000m 1000 Nodes, V=10m/s 1000 Nodes, V=30m/s 40% 0% 20% Duty Cycle 1,000m 100m Area
Network Level: Tripwire Scheduling • Exploiting Knowledge About the Target
Network Level: Tripwire Scheduling • Exploiting Knowledge About the Target
Network Level: Tripwire Scheduling • Tripwire partition based on distance to a base
On-Demand Wakeup Wakeup Detection Wakeup Path To Base Station Wakeup Nodes For Future Detection
Details of Wakeup Operation • Sleeping Node: Wakeup x% of the Time • Wakeup Operation: Send Message with Long Preamble
Evaluation by Third Party: Test Field 300m X 200m, 200 motes Mote Field
1.Initial Detection 2.Classification 3.Periodic updates Evaluation by Third Party:Detection, Classification, and Tracking Average Localization Error: 6.24m Average Velocity Error: 6%
Key Results: Lifetime • Lifetime • No Power Management => 4 Days • + Sentry Selection and Rotation => 28 Days • + Duty Cycle Scheduling => 5 Months(12.5% Duty Cycle) • + Tripwire Service => 10 Months(16 Tripwires, ¼ Awake) • Tracking Performance Penalty • ~ 3 to 5 Seconds
Key Results: Detection Performance Penalty • ~ 3 to 5 Seconds
Summary • Successfully integrate 4 power management strategies into real system. • Analytical model and extensive simulation to predict system performance under various configurations. • Practical feasibility of tracking system using XSM2s with 10 months lifetime.
My Webpage: www.cs.virginia.edu/~pv9f • Tian’s Webpage:www.cs.umn.edu/~tianhe • Research Group Webpage:www.cs.virginia.edu/~control Questions?