Statistics-based outlier detection for wireless sensor networks

Abstract

Wireless sensor network (WSN) applications require efficient, accurate and timely data analysis in order to facilitate (near) real-time critical decision-making and situation awareness. Accurate analysis and decision-making relies on the quality of WSN data as well as on the additional information and context. Raw observations collected from sensor nodes, however, may have low data quality and reliability due to limited WSN resources and harsh deployment environments. This article addresses the quality of WSN data focusing on outlier detection. These are defined as observations that do not conform to the expected behaviour of the data. The developed methodology is based on time-series analysis and geostatistics. Experiments with a real data set from the Swiss Alps showed that the developed methodology accurately detected outliers in WSN data taking advantage of their spatial and temporal correlations. It is concluded that the incorporation of tools for outlier detection in WSNs can be based on current statistical methodology. This provides a usable and important tool in a novel scientific field.

Keywords:

• outlier detection
• wireless sensor networks
• spatial correlation
• temporal correlation
• time-series analysis
• geostatistics

Acknowledgements

This work was supported by the EU's Seventh Framework Programme in the context of the SENSEI project. This spatial and temporal analysis was developed when Y. Zhang was a PhD-intern in the Department of Earth Observation Science at the International Institute for Geo-Information Science and Earth Observation (ITC).

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