Wireless Sensor Networks

1. Wireless Sensor Networks • Sensory • Wireless • Ad hoc

2. Trend of Computers • Large machines • PCs • Laptops • PDAs • What is next?

3. Ubiquitous Computing • Mark Weiser: The most profound technologies are those that disappear. They weave themselves into the fabric of everyday life until they are indistinguishable from it.

4. Sensory Computing • Sensor network (sensornet) • Establishing a connection between virtual world and physical world • 千里眼，顺风耳

5. Enabling Technology • Wireless • Micro-fabrication and integration • Embedded systems

6. What a Sensornet Can Do • Monitoring • People • Vehicles • Animals • Environment • Fabs • Supply chains • …

7. What a Sensor Node Looks Like • Sensor • Processor • RF

8. Sensornet Architecture • Sensornet, gateway, Internet, users • Query • Sensory data • Information

9. Advantages of Sensornet • Energy advantage • Short-range communication • Trade-off: # of hops

10. Advantages of Sensornet • Detection advantage • More sensors, shorter distance to the target • Better signal-to-noise ratio (SNR)

11. Advantages of Sensornet • Structure advantage • Robustness due to redundancy • In-network processing

12. Disadvantage • Small sensors • Limited on: • Power • Communication range & bandwidth • Computation power • Memory

13. Power • Short-range communication • On-demand sensory • Short duty cycle • More computing, less communication • Field charging

14. Communication • Scalability • In-network processing or aggregation

15. Computation and Memory • Efficient algorithms • Less computing cycles • Less storage requirement

16. Satellite and Sensornet • Satellite • Global view • Sensornet • Detailed view

17. Applications • Military battlefield awareness • Rapid deployment • Monitoring battlefield or bases

18. Applications • Disaster situations • Fire • Chemical leakage • Nuclear plant • …

19. Applications • Environmental monitoring • Pollution • Water level • …

20. Applications • Asset and warehouse management • Tracking assets • With RFID

21. Applications • Industrial process control • Monitoring manufacturing processes • Monitoring equipments, such as motors, pipes • Monitoring servers • Monitoring any irregular situations and failures

22. Applications • Building monitoring and control • Low wiring cost • Cut down energy cost • Air control • Biological agents or chemical pollutants

23. Applications • Security and surveillance • Airports • Subways • Nuclear power plants

24. Applications • Health care • Monitoring vital signs of patients • In-home elder care: monitoring subtler behaviors of an elders

25. Applications • Automotive • Vehicle-centric sensornet • Robot with sensors • Non-traditional • Mobile • Possible long distance

26. Example • Great Duck Island • 190 sensors monitor the nesting petrels • Avoid to disturb the bird

27. Example • BP, an oil and gas giant • Losing track of 900 railcars last year • Solution: to fit each railcar with a network of sensors --- that not only track where the railcars is at all times, but can monitor weight, internal temperature, etc.

28. Example • BP • Monitoring customers’ liquefied petroleum gas fuel tanks • 25% improvement in efficiency • The tanks have gauges but customer would forget to look at them until it was too late

29. Example • BP • Tracking lone workers • To avoid hazardous areas where they may be at risk

30. Example • Intel • Now, all equipments are manually inspected once a quarter, found 80% of problems • With sensornet, 95% of the problems can be found

31. Example • In Pickberry Vineyard, a sensornet monitors: • soil moisture • rainfall • wind velocity and direction

32. Outline of the Book • Localization and tracking • Networking sensors • Infrastructure establishment • Sensor tasking and control • Sensor network database • Sensor network platform and tools