@INPROCEEDINGS {qun_mobihoc07, author = {Bo Sheng and Qun Li and Weizhen Mao and Wen Jin}, booktitle = {{ACM} International Symposium on Mobile Ad Hoc Networking and Computing ({Mobihoc})}, PAGES = {219--228}, TITLE = {Outlier Detection in Sensor Networks}, Address ={Montreal, Canada}, Month={Sept.}, YEAR = {2007} } Abstract Outlier detection has many important applications in sen- sor networks, e.g., abnormal event detection, animal behav- ior change, etc. It is a difficult problem since global infor- mation about data distributions must be known to identify outliers. In this paper, we use a histogram-based method for outlier detection to reduce communication cost. Rather than collecting all the data in one location for centralized processing, we propose collecting hints (in the form of a his- togram) about the data distribution, and using the hints to filter out unnecessary data and identify potential outliers. We show that this method can be used for detecting outliers in terms of two different definitions. Our simulation results show that the histogram method can dramatically reduce the communication cost.