CONCURRENCY AND COMPUTATION: PRACTICE AND EXPERIENCE Concurrency Computat.: Pract. Exper. 2010; 22:1240–1251 Published onlinein Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/cpe.1583 Distributed diagnosis over wireless sensors networks Nathalie Dessart 1 , Hac` ene Fouchal 2, ∗, † and Philippe Hunel 2 1 GRIMAAG, Universit´ e des Antilles et de la Guyane, Martinique, France 2 CReSTIC, Universit´ e de Reims Champagne-Ardenne, Reims, France SUMMARY This paper studies how to detect anomalies in a distributed manner by using wireless sensor networks (WSNs). We focus on a medical context, where the existing works generally provide large environments to monitor patients using sensors as simple transducers. Those devices forward sensed health parameters to a main base station. This station collects received data and may perform some computations. In this paper, we perform some distributed tasks on the sensors. We propose a distributed algorithm, which allows to raise alarms under some initial rules to alert efficiently medical staff in case of critical situations without needless warnings. Each mote monitors a parameter. When this parameter reaches an abnormal value, the mote communicates with other motes in order to check if it is a ‘local’ anomaly or if the patient is in an abnormal situation. In such cases an alarm is raised. We implemented our algorithm over a network of micaZ sensors running under TinyOS. The obtained results show promising perspectives. Copyright © 2010 John Wiley & Sons, Ltd. Received 16 January 2010; Accepted 6 February 2010 KEY WORDS: wireless sensor networks; monitoring; distributed decision; TinyOS 1. INTRODUCTION Nowadays, we notice a growth of devices’ capabilities with computers becoming more and more powerful. Nevertheless, wireless sensors bring us face to face with tiny wireless devices with very small capabilities: small memory size, reduced energy and small computation power. Moreover, these tiny devices organized in networks communicate using wireless communications, which are prone to packets loss, weak links or interferences. Therefore, research on wireless sensor ∗ Correspondence to: Hac` ene Fouchal, CReSTIC, Universit´ e de Reims Champagne-Ardenne, Moulin de La Housse, Reims, France. † E-mail: Hacene.Fouchal@univ-reims.fr Contract/grant sponsor: Publishing Arts Research Council; contract/grant number: 98-1846389 Copyright 2010 John Wiley & Sons, Ltd.