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AutoWitness : Locating and Tracking Stolen Property While Tolerating GPS and Radio Outages. Santanu Guha , Kurt Plarre , Daniel Lissner , Somnath Mitra , Bhagavathy Krishna, Prabal Dutta , Santosh Kumar ACM SenSys 2010 - Sowhat 2010.11.23. Outlines. Motivation
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AutoWitness: Locating and Tracking Stolen Property While Tolerating GPS and Radio Outages SantanuGuha, Kurt Plarre, Daniel Lissner, SomnathMitra, Bhagavathy Krishna, PrabalDutta, Santosh Kumar ACM SenSys 2010 - Sowhat2010.11.23
Outlines • Motivation • Objectives & Challenges • Related Works • System Overview • Hardware • Design • Theft detection • Estimating distance & Turns • Evaluation • Conclusion
Outlines • Motivation • Objectives & Challenges • Related Works • System Overview • Hardware • Design • Theft detection • Estimating distance & Turns • Evaluation • Conclusion
Motivation • According to the FBI Uniform Crime Report, 2008 an estimated losses resulted from…
Outlines • Motivation • Objectives & Challenges • Related Works • System Overview • Hardware • Design • Theft detection • Estimating distance & Turns • Evaluation • Conclusion
Objectives & Challenges • Objectives • Detection of theft • Tracking of the stolen tag • Pinpointing of the location • Challenges - Cost & Energy • Hardware selection • Theft classifier • Tracking method
Outlines • Motivation • Objectives & Challenges • Related Works • System Overview • Hardware • Design • Theft detection • Estimating distance & Turns • Evaluation • Conclusion
Related Works • Traditional home security systems • Deter or detect burglary only • Unable to track or recover • Traditional asset tracking and vehicle recovery systems • detected • Not tolerate in-transit cloaking • High power • LoJack, the most common stolen vehicle recovery systems • A device to receive the activation signal needed • High-power transmissions once actived • Cost, $695
Outlines • Motivation • Objectives & Challenges • Related Works • System Overview • Hardware • Design • Theft detection • Estimating distance & Turns • Evaluation • Conclusion
System Overview Motion detection (vibration dosimeter) Classification (Accelerometer) Sufficient time & RF power available
Outlines • Motivation • Objectives & Challenges • Related Works • System Overview • Hardware • Design • Theft detection • Estimating distance & Turns • Evaluation • Conclusion
Hardware • Vibration dosimeter – Motion detect • 3-axis accelerometer – Theft classification & Distance estimation • 3-asix gyroscope – Turns estimation • GSM/GPRS modem – Transfer • Epic Core platform
Outlines • Motivation • Objectives & Challenges • Related Works • System Overview • Hardware • Design • Theft detection • Estimating distance & Turns • Evaluation • Conclusion
Design – Theft DetectionFlow Diagram Deep sleep Accelerometer sampling 1.05sec, @200Hz Compute variance of medians of every 15 samples Variance > threshold N Y Accelerometer sampling 4.2 sec, @200Hz Partition 5.25 sec worth of data in 5 intervals Decision tree classifier applied Majorityrule vehicular movement N Y Tracking
Design – Theft DetectionClassifier • Collecting data in different scenarios • Walking person • car • trolleys • Rolling chair • Activity classification work Using mobile phones to determine transportation modes[23] • Feature – energy & standard deviation
Design - Estimating distance & TurnsAngle estimate • Gyro rotation speed single integration change in the attitude • Absolute value of 1st difference • Thresholds, Dh & Dl • Activation time
Design - Estimating distance & TurnsDistance estimate • 2nd order Butterworth Filter to remove noise • Median of 20 samples mean of 10 such medians • Accelerometer Double integration Distance • Curved roads – angular rotation info. From gyro
Outlines • Motivation • Objectives & Challenges • Related Works • System Overview • Hardware • Design • Theft detection • Estimating distance & Turns • Evaluation • Conclusion
Evaluation – Theft Detection • 15000 samples (210 acc. readings/sample) • vehicle vs. person
Evaluation – Turn Estimation • 120 turns for 6 values of angles • Ground truth – GPS on Android G1 phone
Evaluation – Distance Estimation • 300 different road segments (0.2 ~ 1.5miles) • Ground truth – GPS on Android G1 phone
Outlines • Motivation • Objectives & Challenges • Related Works • System Overview • Hardware • Design • Theft detection • Estimating distance & Turns • Evaluation • Conclusion
Conclusion • Design & evaluation of the AutoWitness system • Deter, detect, and track personal property theft • Low-cost • Ultra-low energy