Title
Separating the wheat from the chaff: practical anomaly detection schemes in ecological applications of distributed sensor networks
Abstract
We develop a practical, distributed algorithm to detect events, identify measurement errors, and infer missing readings in ecological applications of wireless sensor networks. To address issues of non-stationarity in environmental data streams, each sensor-processor learns statistical distributions of differences between its readings and those of its neighbors, as well as between its current and previous measurements. Scalar physical quantities such as air temperature, soil moisture, and light flux naturally display a large degree of spatiotemporal coherence, which gives a spectrum of fluctuations between adjacent or consecutive measurements with small variances. This feature permits stable estimation over a small state space. The resulting probability distributions of differences, estimated online in real time, are then used in statistical significance tests to identify rare events. Utilizing the spatio-temporal distributed nature of the measurements across the network, these events are classified as single mode failures - usually corresponding to measurement errors at a single sensor - or common mode events. The event structure also allows the network to automatically attribute potential measurement errors to specific sensors and to correct them in real time via a combination of current measurements at neighboring nodes and the statistics of differences between them. Compared to methods that use Bayesian classification of raw data streams at each sensor, this algorithm is more storage-efficient, learns faster, and is more robust in the face of non-stationary phenomena. Field results from a wireless sensor network (Sensor Web) deployed at Sevilleta National Wildlife Refuge are presented.
Year
Venue
Keywords
2007
DCOSS
ecological application,consecutive measurement,specific sensor,single sensor,measurement error,wireless sensor network,practical anomaly detection scheme,common mode event,potential measurement error,current measurement,real time,previous measurement,anomaly detection,statistical distribution,sensor web,statistical significance,state space,distributed algorithm,air temperature,probability distribution,common mode,spectrum,single mode
Field
DocType
Volume
Data mining,Ecology,Anomaly detection,Computer science,Brooks–Iyengar algorithm,Real-time computing,Probability distribution,Distributed algorithm,Wireless sensor network,Sensor web,Observational error,Rare events
Conference
4549
ISSN
Citations 
PageRank 
0302-9743
24
1.17
References 
Authors
18
3
Name
Order
Citations
PageRank
Luís M. A. Bettencourt1949.47
Aric A. Hagberg2635.77
Levi B. Larkey3744.60