The appli cation includes an event detection algorithm to selectively transmit

The appli cation includes an event detection

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sor networks on active volcanoes in Ecuador. The appli- cation includes an event detection algorithm to selectively transmit data back to a base station during eruptions. 25 26 All of these deployments provided detailed observa- tions to domain scientists that were not otherwise possible. A few of the applications (Great Duck Island) did not filter any of the data on the nodes and transmitted all of the data back to the base station. The Volcano and Countersniper applications required filtering on the sensor node because the radio bandwidth was not high enough to transmit all of the sensor data (even without considering the energy costs). 2.2. Prevalence of Middleware So far we have provided a simplified presentation of WSN deployments as mere filters and wireless relays of sen- sor data. In fact, deployments of WSN include rich layers 2 J. Low Power Electronics 4, 1–10, 2008
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Hempstead et al. Survey of Hardware Systems for Wireless Sensor Networks Table II. Example WSN application domains. Computation requirements Application domain Desired lifetimes (Sample rates) Example Scientific applications Habitat/weather monitoring Months/decades very low Great Duck Island 21 Volcanic eruption detection Months/decades mid Volcano WSN 26 Military and security applications Building/border intrusion detection Years/decades low Structural and earthquake monitoring Years/decade low/mid Active battlefield sensing Months mid/high Sniper detection/localization 6 Medical applications Long-term health monitoring (pulse) Days low Untethered medical instruments (ECG) Days med EKG mote 7 Business applications Supply chain management Months low Expired/damaged goods tracking Months low Factory/fab monitoring Months/years med/high Industrial WSN 13 of network services that are necessary to form a reliable network. Systems researchers have developed open-source middleware algorithms that are used by many deploy- ments. Providing acceleration for typical middleware com- putations has the potential to reduce the overall energy consumption of the system. We now examine the Volcano monitoring application 25 26 to illustrate the use of middleware. The authors deployed a WSN on an active volcano on three occasions. Measurements of infrasound (audio signals less than 40 Hz) and seismic vibrations were recorded. A cus- tom event detection algorithm consisting of a weighted moving average filter is the most frequent computation run on the nodes. It is used to detect a possible vol- canic eruption and trigger a network-wide download of interesting data. A bulk data transfer algorithm developed by the authors (Fetch) is used to copy data back to the researchers several kilometers away. In this work the authors use FTSP, an open-source middleware package, to maintain time synchronization between nodes. 14 Because the network was spread over a large geographical area, nodes were required to relay messages for other nodes in the network. An open-source routing package called MintRoute was run on the nodes that enabled multi-hop routing of messages. 27 Many WSN deployments for sci- entific monitoring have similar needs in terms of sensing, bulk data transfer, networking, and time synchronization.
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  • Fall '18
  • Mr. Bhullar
  • Sensor node, Wireless sensor network

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