Sensor Networks and Environmental Monitoring

1. Sensor Networks and Environmental Monitoring Jacques Panchard

2. What is a Sensor Network? • Ad hoc network (self-organized) • Environment-to-person communication • Nodes: • large number (100-1000s) • sensing capability • communication, processing, memory capabilities • energy constrained • mobile/immobile • Base station - BS • energy unconstrained (if connected to the power grid) • mobile/immobile

3. “The network is the sensor” * Requires robust distributed systems of • thousands of • physically-embedded, • unattended, • and often untethered, devices. *(Manges & Smith, Oakridge Natl Labs, 10/98)

4. What is a Sensor Network? { • sensor • aggregator • relay

5. Why a Sensor Network? • Possible users: • Authorities • disaster prevention • pollution monitoring • law enforcement...) • Scientific community • create or validate models • Economy • Agriculture • Industry • Services • Private (home automation) • Quality of life improvement • Energy saving Possible tasks: • data gathering: • seismic • acoustic • medical • intelligence • monitoring: • climate • equipment • movement

6. Sensor Networks : design issues • Power efficiency • Node life-time • Network life-time • Especially important for self-powered nodes • Localization • Range based (Time Of Flight, RSSI etc.) • Range free (based on anchors with known positions and hop count) • GPS is often impractical because it is energy hungry • Security • Secure Positioning • Data Validation • Packaging • Strong environmental constraints depending on the application • Data Processing

7. Alternatives to sensor networks • Remote sensing (satellite) • Cellular networks (GSM, GPRS...) • Individual sensing and manual data gathering

8. The case for environmental monitoring • •"The UK Government's chief scientist now says climate change is a far worse danger than international terrorism" (BBC News, 10 Jan 04) • •Environmental phenomena are a major scientific and societal concern: • –Pollution • –Water • –Climate • •Information technology, communications and sensing are enabling technologies • •Due to current technological changes, there will be a watershed phenomenon in • –Ability to monitor • –Price point • –Infrastructure • –Data processing Courtesy of Prof. Martin Vetterli

9. Monitoring situation • Several orders of magnitude difference in size and price! • Today • €100k / point • 5-10 years horizon • €10-100 / Courtesy of Prof. Martin Vetterli

10. Implications for science and society •On the science side • –Completely new datasets are obtainable • (sensor networks as new telescopes) • –New scientific questions can be addressed • –Scientific theories can be verified/validated • –Measurement and simulation can be tuned •On the societal side • –Regulators have access to more data • –Closing the loop: sensing and actuating • –Communities can become involved Courtesy of Prof. Martin Vetterli

11. Case studies • Air pollution monitoring (static and dynamic scenarios) • Water/climate monitoring • Ground dynamics (glaciers, moving grounds, avalanches etc.) Courtesy of Prof. Martin Vetterli

12. A platform for environmental monitoring: the Mica2 motes • Made by Crossbow Technology Inc • Designed for sensor networks • Atmel ATMega128 processor • Chipcon CC1000 radio • Runs TinyOS from its Flash Memory • 51-pin connector to interface itself • Add-on sensor boards provide sensing for Temperature, Humidity, etc. 5

13. The Operating System: tinyOS • TinyOS created at UC Berkeley, now at Sourceforge • Library includes network protocols & distributed services • Also includes sensor drivers and DAQ tools • Powerful OS, Large community support 6

14. TinyOS Programming Model • Event-driven, concurrent OS • nesC – supports the TinyOS concurrency model • Applications :: Built of components connectedby well defined • bi-directional interfaces • Components :: Form the executable by linking together. • Use & Provide Interfaces • Interfaces :: Declare commands & events Sample Dependency Graph of Components The Concurrency Model • Executes only one program • Two Threads :: Tasks & Hardware Event Handlers • Tasks :: Functions that run to completion • H.E.H :: Response to hardware interrupt • Only H.E.H’s may pre-empt tasks or other H.E.H’s • Data race conditions are highly probable 7

15. COMMON-Sense Net Agriculture and water management in rural India with the use of wireless sensor networks Jacques Panchard (IP10) with Profs. Jean-Pierre Hubaux and Yves Pigneur

16. Water scarcity today Water supply, distribution of unserved populations Sanitation, distribution of unserved populations • Consequence: Growing humanitarian crises and political instability Source: UNESCO – World Water Assessment Programme, 2003

17. Water and agriculture Developing countries: amount of water withdrawn for irrigation is more than twice the actual irrigation requirements Source: FAO – Land and Water development division, 2003 Agriculture is largely responsible for ground water’s depletion and salinization.

18. Research Challenges • Test the relevance of the ad-hoc sensor networks model in a concrete application • Assess the use of environment-to-person ICTs in developing countries • Challenge the ad-hoc networking com-munity’s assumptions on environmental monitoring (focus on agriculture) • Raise and address new technical challenges based on a concrete implementation Field Social Sciences EnvironmentalSciences ICTS

19. A concrete test case

20. A concrete test case (2) • Pavagada “taluk”: 50 villages over a radius of 25km. Around 100’000 inhabitants • Chennakeshava Pura : around 2000 inhabitants • Semi-arid climate • Marginal farmers (< 1 ha) and small farmers (< 2 ha) • No powered irrigation • Cultures:groundnut (for oil), cereals trees: areca nut, coconut...rice in some irrigated patches

21. Chennakeshava User survey • We conducted a survey in three villages of Karnataka in April-August 2004. • The population was segmented in several user groups: farmers (irrigated, non-irrigated), traders, shepherds, labourers. • It was conducted by local people, asking open questions about « What are your information needs?» Key findings [Rao 2004]: • Information needs are of two kinds: person-to-person andenvironment-to-person. • They differ but overlap between the different segments of the population [Rao 2004] PR Seshagiri Rao, Information needs for farming and livestock management in semiarid tracts of southern India, Technical report, 2004

22. Survey results Irrigated Farmers Non irrigated Farmers

23. Data requirements

24. An heterogeneous sensor network

25. System characteristics • Self-organizing network of heterogeneous wireless sensor-nodes (ease of deployment, non-intrusiveness) • Self-powered and autonomous • Nodes communicate in a multihop fashion • Low data-rate • Dynamic scalability • Node failure detection • Internet-connectivity

26. Consortium and resources

27. Consortium: a historical perspective EPFL/SDC Cooperation Fund Chennakeshavapura Trust (NGO) S. Rao SDC IISc EPFL HYDRAM Prof. Mermoud CAOS Prof. Gadgil MICS IP10 LCA Prof. Hubaux, J. Panchard CEDT Prof. Jamadagni UNIL HEC Prof. Pigneur

28. Project deliverables • Environmental monitoring sensor network • User requirements for environmental monitoring in rural developing area • Study on relevance of sensor networks for environmental monitoring (focused on developing countries) • Impact assessment • Business plan and deployment scenario (replicable and scalable) • Publication of papers on technical challenges • For updated information: http://commonsense.epfl.ch