line of sight is not a requirement), an energy source such as a battery coupled with a solar cell, a package to protect components against sometimes harsh environment, Each pod also typically requires a support such as a pole or tripod. The number of pods may vary, with examples of sensor webs with 12 to 30 pods. The shape of a sensor web may impact its usefulness, for instance a particular deployment made sure each pod was in range to communicate with at least two other pods. Sensor web measurement cycles have typically been between 30 seconds and 15 minutes for deployed systems thus far. Sensor webs consisting of pods have been deployed that have spanned miles and run continuously for years. Sensor webs have been fielded in harsh environments (including deserts, mountain snowpacks, and Antarctica) for the purposes of environmental science and have also proved valuable in urban search and rescue and infrastructure protection. The technology is not only monitoring the environment but sometimes also controlling the environment by actuating devices. See also Internet of Things Web of Things Observations and Measurements Open Geospatial Consortium Semantic Sensor Web Sensor Grid: Sensor Web Meets Grid Computing SensorML References Further reading Sensor Webs, K.A. Delin, S.P. Jackson, and R.R. Some NASA Tech Briefs 1999, 23, 90 open access publication. The Sensor Web: Distributed Sensing for Collective Action, Kevin A. Delin Sensors Online July 2006, 18 open access publication. The Sensor Web: A Distributed, Wireless Monitoring System, Kevin A. Delin Sensors Online April 2004, 21 open access publication. New Generation Sensor Web Enablement, Arne Bröring, Johannes Echterhoff, Simon Jirka, Ingo Simonis, Thomas Everding, Christoph Stasch, Steve Liang, Rob Lemmens Sensors 2011, Volume 11, Number 3, 2652-2699 open access publication. Environmental Studies with the Sensor Web: Principles and Practice, Kevin A. Delin, Shannon P. Jackson, David W. Johnson, Scott C. Burleigh, Richard R.Woodrow, J. Michael McAuley, James M. Dohm, Felipe Ip, Ty P.A. Ferré, Dale F. Rucker, Victor R. Baker Sensors 2005, 5, 103-117 open access publication. OGC Sensor Web Enablement: Overview and High Level Architecture, Botts, Percivall, Reed, and Davidson OGC White Paper, July 2006 open access publication. Open Sensor Web Architecture: Core Services,Xingchen Chu, Tom Kobialka, Bohdan Durnota, and Rajkumar Buyya, Proceedings of the 4th International Conference on Intelligent Sensing and Information Processing (ICISIP 2006,IEEE Press, Piscataway, New Jersey, USA, , 98-103pp), Dec. 15-18, 2006, Bangalore, India. open access publication. A