Wireless Sensor Networks

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Wireless Sensor Networks

• By Eric Anderson

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Introduction

• Wireless Sensor Network (WSN) An autonomous, ad
  hoc system consisting of a collective of
  networked sensor nodes designed to
  intercommunicate via wireless radio.

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Introduction

• Wireless Communication via radio waves
• Autonomous Independent self-directed
• Ad hoc network A network without a fixed,
  well-defined infrastructure
• Sensor node Device that produces a measurable
  response to a change in physical condition

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Node Classification

• Individually addressable
• Each node is uniquely identified, facilitates
  object-based organization
• Ex Parking lot spaces
• Network data is aggregated
• Messages broadcast, reduction in network
  bandwidth
• Ex Temperature in room corner

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Node Examples
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WSN Goals

• Tracking Detect and track objects
• Classification Classify objects
• Estimation Estimate parameters and events of
  interest pertaining to objects
• Determination Determine the value of some
  parameter at a given location

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WSN Requirements

• Stationary or Mobile use
• Low energy consumption
• Self-organization and autonomy (locality)
• Robust and scalable
• Collaborative signal processing (emergent
  behavior through data fusion)
• Querying ability (possible message routing via
  cluster head promotion)

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Types of WSNs

• Environmental
• Medical
• Military
• Urban
• Civic
• Industrial
• Residential

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Environmental Usages

• Search and rescue
• Disaster relief
• Climate monitoring (weather prediction)
• Seismic detection (earthquakes, volcanos)
• Pollution tracking (patterns, density)
• Habitat monitoring (endangered species,
  www.greatduckisland.net)
• Geophysical monitoring (forest fires, river
  currents, contaminants, global warming, farms,
  marine microorganisms)

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Environmental Requirements

• Energy efficiency (long battery life)
• Intermittent connectivity
• Schedule sleep mode for redundant sensors
• Inexpensive nodes (large quantity needed)
• Reduced size of nodes (small, microscopic)
• Auto-configuration of sensors
• Scalable network
• Robust nodes to handle harsh environments (heat,
  water, snow, humidity, wind)

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Medical Usages

• Health care (insurance cards)
• Patient monitors (pulse, heart rate, glucose
  levels, child tracking, eye implants,
  defibrillators)
• Cybernetic enhancements
• Information tags (allergies, severe reactions)
• Medication notification system

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Medical Requirements

• Energy efficiency (long battery life,
  heat/kinetic/bio battery)
• Hidden device (not visually detectable)
• Biologically safe
• Fault-tolerant, reliable
• Encrypted bio information
• Interference-safe (RF noise, 900 MHz)

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Military Usages

• Tactical surveillance (land, sea)
• Tracking troop movement (both sides)
• Ubiquitous, undetected smart mines
• Battlefield communication
• Detection of hazardous agents (explosive,
  nuclear, biological, poisonous, radioactive)
• Environmental awareness (terrain mapping)

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Military Requirements

• Energy efficiency (long battery life)
• Schedule sleep mode for redundant sensors
• Ubiquitous and Undetectable
• Auto-deployment and self-organization
• Fault-tolerant, reliable
• Strong Encryption (low overhead)
• Auto-configuration of sensors
• Scalable network
• Robust nodes to handle harsh environments (heat,
  water, snow, humidity, wind)

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Urban Usages

• Civic
• Transportation systems (traffic)
• Auto-identification (drivers license)
• Parking lot availability sensors
• Security monitors (shopping malls, parking
  garages, city streets)
• Child abduction prevention
• Automated parking meter update

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Urban Usages

• Industrial
• Hotel room smart service
• Ubiquitous gambling cameras
• Product distribution (UPS)
• Inventory tracking/control
• Worker efficiency and daily routine (company
  badges)
• Quality assurance, process control

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Urban Usages

• Residential
• Home security
• Digital canvas
• Smart appliances (lights, thermostat, television,
  stereo, etc.)
• Life alert system (elderly, children near pool)
• Pet tracking (angel alert proximity detector)
• Dirt sensors (alert home owner when specific
  quadrants exceed dust/dirt quota)

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Urban Requirements

• Inexpensive nodes (large quantity needed)
• Reduced size of nodes (small, medium)
• Robust nodes to handle harsh environments
  (climate, people)
• Diverse range of sensor types (audible, visual,
  location, etc.)
• Interoperability (interface with home, commercial
  and government systems)
• Highly customizable (diverse user base)
• Scalable network (wide area of coverage)

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References

• http//www.cs.uno.edu/golden/MobileBook/
• M. Kochhal, L. Schwiebert, Sandeep Gupta.
  Role-based Hierarchical Self Organization for
  Wireless Ad hoc Sensor Networks
• J. Elson, K. Romer. Wireless Sensor Networks A
  New Regime for Time Synchronization. ACM SIGCOMM
  Computer Communications Review, volume 33,
  January 2003.
• Smart Sensor Networks. Advanced Network
  Technologies Division, Nation Institute of
  Standards and Technology. May 2001.
• D. Estrin, R. Govindan, J. Heidemann. Embedding
  the Internet. Communications of the ACM, volume
  43, May 2000.
• A. Mainwaring, J. Polastre, R. Szewczyk, D.
  Culler, J. Anderson. Wireless Sensor Networks for
  Habitat Monitoring. WSNA 02, September 2002.
• K. Romer, O. Kasten, F. Mattern. Middleware
  Challenges for Wireless Sensor Networks. Mobile
  Computing and Communications Review, volume 6,
  July 2002.