Browsing the physical world in real-time
By: Vincent Tao
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• Conceived: 1997, NASA/Jet Propulsion
Laboratory
CMSC 828S / Saket Navlakha / 2

• Conceived: 1997, NASA/Jet Propulsion
Laboratory
• Idea:
– sensor chips to monitor and control environment
– sensations transmitted via internet in real-time
CMSC 828S / Saket Navlakha / 3

• Conceived: 1997, NASA/Jet Propulsion
Laboratory
• Idea:
– sensor chips to monitor and control environment
– sensations transmitted via internet in real-time
• Why is this different?
CMSC 828S / Saket Navlakha / 4

• Conceived: 1997, NASA/Jet Propulsion
Laboratory
• Idea:
– sensor chips to monitor and control environment
– sensations transmitted via internet in real-time
• Why is this different?
– Cheaper sensors  more possibility
– Networked (not individual) sensors
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• Interoperable
– In-site (on-site) sensors
• Measuring physical properties of an area
– Remote sensing
• Via radiation reflected or emitted from object
• GPS
– Web
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• Interoperable
– In-site (on-site) sensors
• Measuring physical properties of an area
– Remote sensing
• Via radiation reflected or emitted from object
• GPS
– Web
• Implies data formatting standards (Open GIS)
– Web Map Service, Geographic Markup Language,
SensorML, etc
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• Intelligent
– Sense environment and respond
– Communicate amongst each other
– Data integration
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• Flexible
– Different types of sensors
• Deterministic
• Triggered
• On-demand
– Broken sensors
– Fault tolerant to noise, redundant
– Weather conditions
– Easy deployment
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• Scalability
– Large number of interacting sensors
– Large number of simultaneous requests
– Efficiently locate sensors
– Adapt to sensor join/leaves
• Size: does one size fit all?
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• Scalability
• Size: does one size fit all?
– smaller panels (less energy harvesting)
– smaller antennae (less radio range)
– smaller batteries (less power)
– larger sensors (harder to manage, intrusive)
 What about tiered architecture?
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• Microsoft Research project
• Goals:
– Ease of data publication
– Application-to-application compatibility
– Primitives to query live sensors
 Create SensorNet
• Display: MSN Virtual Earth
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• Data Publishing Toolkit (DPT)
– Publishes sensor metadata (location/type) to GeoDB
– Publishes sensor data in response to queries
• Uses sensor ontology standards
• GeoDB
– Indexes metadata; uses hierarchical triangular mesh
(HTM)
– Queries submitted by keyword, location, etc.
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• Data Publishing Toolkit
• GeoDB
• Aggregator
– Data integration: mashes sensor data with client side
GUI (e.g. MSN Virtual Earth overlay)
– User query  GeoDB relevant sensors  DPT realtime data  aggregate/summarize
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• Advantages
– Data owner only talks to DPT
– End users only browse web page and query data
 GeoDB and Aggregator transparency
• Disadvantages?
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• Ubiquity & Invisibility
• Overview of problems
• Four layers
– Sensor: sensor design, materials, etc
– Communication: protocols, standards, etc
– Location: routing, addressing, etc
– Information: data integration, distribution, etc
• Which can be different? Which need standardization?
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• Next: algorithms & techniques to solve problems (e.g. HTM, P2P communication, statistical data modeling, more applications)
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