Overview of Sensor Networks

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Overview of Sensor Networks

• Kyung-Lang Park
• Supercomputing Lab., Yonsei University
• (2004. 9. 10)

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Contents

• Prologue
• Overview of Sensor Networks
• Introduction
• WSN Applications
• Challenges

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PROLOGUE
Ubiquitous.. Where are we going?
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Ubiquitous Computing Environment
Intelligence and global
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Our Research Direction
Provide Users convenience
Provide intelligence in a system
Establish Interoperability between systems
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What differentiate ubiquitous from other
computing environments?
Virtual world (Codes)
Real world (Physical object)
Input device
Passive Static
Delivery of Digital Contents
Display
Digital env.
Ubiquitous env.
sensor
Active Intelligent
Embedded Virtuality
controller
Machinery control real world based on sensed data
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OVERVIEW OF SENSOR NETWORKS
David Culler and Deborah Estrin, (U.C.
Berkeley) Mani Srivastava (U.C. Los Angeles)
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Introduction

• The advances in science and technology are deeply
  intertwined
• Microscope vs. Bacteria
• Telescope vs. Stars
• Satellites vs. Earth surface.
• Semiconductor and computer technology make sensor
  networks and It can bring advances in science and
  technology

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Definition of sensor networks

• Inexpensive, low-power communication devices
• providing dense sensing close to physical
  phenomena,
• processing and communicating this information,
  and
• coordinating actions with other nodes

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Sensor network applications

• Monitoring space
• Environmental monitoring, precision agriculture,
  indoor climate control, intelligent alarm
• Monitoring things
• Structural monitoring, ecophysiology,
  condition-based equipment maintenance, medical
  diagnostics
• Monitoring the interactions of things with each
  other and the encompassing space
• Disaster management, emergency response, asset
  tracking, manufacturing process flow

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Monitoring space

• Redwood tree
• Attach 16 wireless sensors to the tree
• The top of tree warms rapidly as the sun rises
• Initial study just extract environmental data,
  but later, the network will perform the
  front-tracking algorithm with in the tree itself

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Technical Challenges

• Hardware and networks
• Microprocessors, power, and storage
• Node consists of a microprocessor, data storage,
  sensors, ADC, a data transceiver, controller, an
  energy source
• Size, Cost, and Power
• Microsensors
• Sophisticated structures to detect phenomena
• Low-power
• Microelectromechanical systems (MEMS)
• Microradios
• Low-power, long-distance, noiseless

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Technical Challenges

• System and Software
• TinyOS
• Operating systems for sensors
• Small size, low power
• Event-driven approach, but never consume
  processor cycles while waiting for future events
• A typical top-level application might receive and
  process a stream of filtered sensor readings,
  deliver important notifications to the network
• Network sensor platforms
• Berkely motes, Intel iMOTE, Smart Dust
• Self-organized networks
• No router
• Connectivity
• Thin packet stack
• Dissemination and data collection
• Conserving power and bandwidth
• Privacy

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In this seminar

• Overview and Application
• Sensors
• WiseNET
• The Flock Wireless Mote Networks
• Context-awareness
• Anatomy of Context-aware application
• Georgia Tech. Context Toolkit