S S S e e e n n n s s s o o o r r r s s s & & & T T T r r r a a a n n n s s s d d d u u u c c c e e e r r r s s s ISSN 1726-5479 © 2012 by IFSA http://www.sensorsportal.com Distributed Information Extraction from Large-scale WSNs: Approaches and Open Research Issues Elena GAURA, James BRUSEY, John HALLORAN, Tessa DANIEL Cogent Computing Applied Research Centre, Coventry University, UK CV1 5FB E-mail: e.gaura@coventry.ac.uk, www.cogentcomputing.org Received: /Accepted: /Published: Abstract: Regardless of the application domain and deployment scope, the ability to retrieve information is critical to the successful functioning of any wireless sensor network (WSN) system. In general, information extraction procedures can be categorized into three main approaches: agent- based, query-based and macroprogramming. While query-based systems are the most popular, macroprogramming techniques provide a more general-purpose approach to distributed computation. Finally, the agent-based approaches tailor the information extraction mechanism to the type of information needed and the configuration of the network it needs to be extracted from. This chapter offers an extensive survey of the literature in the area of WSN information extraction, covering in Sections 1 and 2 the three main approaches above. Section 3 highlights the open research questions and issues faced by deployable WSN system designers and discusses the potential benefits of both in- network processing and complex querying for large scale wireless informational systems. Copyright © 2012 IFSA. Keywords: Information extraction, wireless sensor networks, macroprogramming, mobile agents, query-based systems