Linked Open (Dynamic) Data for Smart sensing and Measuring environments. The paper was presented at The 3rd International Conference on Ambient Systems, Networks and Technologies August 27-29, 2012, Niagara Falls, Ontario, Canada

1. Politecnico di Torino
Dip. Automatica e Informatica
Torino, Italy
The 3rd International Conference on
Ambient Systems, Networks and Technologies
August 27-29, 2012, Niagara
Falls, Ontario, Canada
http://elite.polito.it
Publishing LO(D)D:
Linked Open (Dynamic) Data for Smart
sensing and Measuring environments
Fulvio Corno, Faisal Razzak

2. Goals
 Enable sensor networks to publish their data in a
standard way
 Enable distributed applications to consume sensor
data from different sources
 Enable data publication, consumption, computation,
re-publication, etc with minimal effort
 Extend the Linked Open Data cloud with time-
varying (sensor) data streams
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3. Outline
 Context and Motivation
 Proposed Architecture
 Proposed solutions
 Experimental results
 Conclusions
3 ANT’2012, Niagara Falls, Canada LO(D)D

4. Context
Smart Sensing and Measuring Environments
Smart Homes Sensor and
Smart Factories
Smart Grid Actuator Networks
Environment monitoring
Social mobile applications
Smart Appliances
Affordable and efficient sensors
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5. Context
Smart Sensing and Measuring Environments
Smart Appliances
acceleration
acceleration compass
compass GPS
air pressure proximity
temperature microphone
energy light camera
(active, reactive, rev
BT Scan
erse, kVAr, ...)
Affordable and efficient sensors
5 ANT’2012, Niagara Falls, Canada LO(D)D

6. Context
Smart Sensing and Measuring Environments
Smart Appliances
Affordable and efficient sensors
Motion
RFID
Smoke Pressure
Gyroscope
Proximity 2D codes
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7. Motivation
 Applications need to
Application Application
access information from
multiple environments
 Standard way to
Environ Environ Environ
publish and consume
ment ment ment information
 About accessible
Applian Applian Applian
environments
ces ces ces  About available
applicances, sensors and
their characteristics
sensors sensors sensors
 About the actual data
measured by sensors
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8. Approach
 Applications need to
Adopt Semantic Web access information from
«Linked Open Data
(LOD)» approach multiple environments
 Standard way to
publish and consume
Static information:
Can be encoded in RDF information
according to a public  About accessible
Ontology environments
 About available
Dynamic information: applicances, sensors and
New approach to their characteristics
represent streams of RDF
events  About the actual data
measured by sensors
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9. General LO(D)D Architecture
Smart Static
Environment information
Producer publishes
Application about
E sensor
streams
G monitors
F
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10. General LO(D)D Architecture
Smart Static
Environment information
Producer publishes
E Application about
E F sensor
G streams
E
G monitors describes
F
E Sensor
G E
data
F channel
G Sensor
updates F
data
channel
G
Sensor
data
channel
10 ANT’2012, Niagara Falls, Canada LO(D)D

11. General LO(D)D Architecture
Smart Static subscribes
Environment information
Producer publishes
E Application about Consumer
E F sensor E Application
G streams
E
G monitors describes
F Consumer
E
E
E Sensor Application
G E E
data
F channel
G Sensor G
Consumer
updates F Application
data F
channel receives
G G
Sensor
data
channel
11 ANT’2012, Niagara Falls, Canada LO(D)D

12. Proposed solutions
Producer  Open source libraries and API to
Application
Consumer
Application
enable application to interact with
LO(D)D data
Static
information  RDF document with meta-data (PID)
about  Publisher information
sensor
streams  List of channels, their source data, their
datatypes, and subscription URI/key
E
F
G
 RDF «fragments» representing each
E event
 Contains: event#, sensor id, timestamp,
Sensor
data value, unit of measure
channel  Uses publish-subscribe pattern as
12 transportNiagara Falls, Canada for distributing
ANT’2012, mechanism LO(D)D

13. Publisher Information Document (PID)
 According to lightweight «Publisher» ontology
 Contains declarations of all channels handled by this
publisher – all needed static information
 Gives information to subscribe to channels
 Created by <RDF:Description RDF:about="&Publisher;energymtr">
publisher API <publisher:Location RDF:datatype="&xsd;string">
Torino, Italia</publisher:Location>
 Published over
<publisher:subscribekey>sub-xxxxxx-42904d46dEEEEE
http </publisher:subscribekey>
<publisher:channelName>Energy Meters
</publisher:channelName>
<RDF:type RDF:resource="&Publisher;Channel"/>
</RDF:Description>
13 ANT’2012, Niagara Falls, Canada LO(D)D

14. Event data fragments
 Indivudual data points encoded in RDF
 Self-consistent information (e.g. Unit of measure)
 Standard syntax and semantics
 Application-independent representation
 Compact <rdf:Description RDF:about = "&publisher;emergymtrChan1">
<publisher:MeterNumber RDF:datatype="&xsd;int">
encodings 231 </publisher:MeterNumber>
available <publisher:Unit RDF:datatype="&xsd;string" >
http://purl.oclc.org/NET/muo/ucum/unit/power-level/
bel-kilowatt</publisher:Unit>
<publisher:hasTimeStamp RDF:datatype="&xsd;dateTime">
2012-02-02T13:06:41.056Z </publisher:hasTimeStamp>
<publisher:hasCurrentValue RDF:datatype ="&xsd;double">
0.3 </publisher:hasCurrentValue>
14 </RDF:Description> Falls, Canada
ANT’2012, Niagara LO(D)D

15. Cloud based Transport mechanism
 Provides the updates to subscribers whenever
publishers update data
 New RDF fragments are sent to the cloud service
 Maintains list of subscribers
 Handles logic to provide transport from Publisher to
many Subscriber in real time
 It makes the Publisher a “light-weight component”
 Publisher is independent from the number of connected
subscribers
...and others
pubsubhubbub
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16. Publisher and Consumer APIs
 Publisher Library
 Creates PID file an offers it on http
 Creates channels onto cloud service
 Sends updates to channel, encoding it in RDF
 Consumer Library
 Parses PID file and provides channel information
 Subscribes to one or more channels
 Notifies application whenr new data is available, decoding
it from RDF
 Same application may be producer and consumer at
the same time
 Applications need not manage RDF explicitly
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17. Preliminary Experiment
Building Infrastructure
Politecnico di Torino
poliEnergy
PID
Publishes
P
• 126 Electrical
Meters.
• Take reading
every 15
minutes
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18. Preliminary Experiment
Building Infrastructure
Politecnico di Torino
poliEnergy
PID
Publishes C
P
P
• 126 Electrical
Meters. poliEnergy
• Take reading Aggregator
PID
every 15
minutes
• Aggregates
reading into 3
ranges.
• Publishes using 3
channels
18 ANT’2012, Niagara Falls, Canada LO(D)D

19. Preliminary Experiment
Building Infrastructure
Politecnico di Torino
poliEnergy
PID
Publishes C
P
P
• 126 Electrical
Meters. poliEnergy
• Take reading Aggregator
PID
every 15
minutes
• Aggregates
reading into 3
ranges.
• Publishes using 3
C channels
19 ANT’2012, Niagara Falls, Canada LO(D)D

20. Conclusions
 Open applications with
open data
 Exploiting existing
standards (RDF and
pub/sub)
 Extensible to different
type of sensor data
 Highly scalable
http://elite.polito.it
fulvio.corno@polito.it
faisal.razzak@polito.it
20 ANT’2012, Niagara Falls, Canada LO(D)D

21. 21 ANT’2012, Niagara Falls, Canada LO(D)D