Semantic Mediation On The Sensor Web

1. Semantic Mediation
On The Sensor Web
Arne Bröring, Patrick Maué, Christian Malewski,
Krzysztof Janowicz
IGARSS, 25.7.2012, München

2. Variety of environmental sensors…

3. Sensor Web
 Interoperable sensor infrastructure required
 Sensor Web
an infrastructure which enables the interoperable usage of sensor
resources by providing services for:
(1) discovery, (2) access, (3) tasking, & (4) eventing & alerting.
 Sensor Web Enablement (SWE) by
– Web Service interfaces & data encodings

4. Geosensor Infrastructure Stack
Application Layer
Sensor Web Layer
Sensor Layer

5. Challenge: On-the-fly Integration
Service 1
Service 2

6. Problem: Match Assurance
Observed Property:
air_flow_direction
Output:
wind_direction
Characteristics have to match syntactically & semantically!

7. Goal:
Automated Integration of
Sensors and Services

8. Sensor Bus
Application Layer
Sensor Web Layer
Sensor Layer
Sensor Bus

9. Semantic Mediation
Sensor Bus
Required
Characteristics
Advertised
Characteristics
Mediator
*

10. Semantic Mediation
1. Semantic Annotation
2. Concept Creation
3. Matchmaking
4. Conversion

11. Semantic Annotation - Service
 Via SubscribeService message:
SubscribeService * serviceA
* observedProperty
* http://sweet#Temperature
* uom
* K
* http://ssn#SurvivalRange
* <QuantityRange>
<uom code=‘m’/>
<value>-50 0</value>
</QuantityRange>

12. W3C SSN Ontology

13. Concept Creation - Service

14. Semantic Annotation - Sensor
...
<sml:output name = ‘water_temperature'>
<swe:Quantity
definition = 'http://sweet#WaterTemperature'>
<swe:uom code = ‘Cel' />
</sml:output>
...
<sml:capabilities>
<swe:QuantityRange
definition = ‘http://ssn#SurvivalRange’>
<swe:uom code = ‘m’ />
<swe:value>-100 0</swe:value>
</swe:QuantityRange>
 Via referenced SensorML file:

15. Concept Creation - Sensor

16. Matchmaking

17. Conversion With SWRL Rules
 Example to attach conversion rule
AdvertisedObservationValue(?aSO),
isParameterizedBy(?aSO, Celsius)
->
applyConversionRule(?aSO,
DegreeCelsiusToKelvin)

18. Communicating Mediation
 Example of a Mediate message
Mediate * sensor1 * serviceA
* sweet#WaterTemperature
* sweet#Temperature
* <math>
<mrow>
<mi>VAL</mi>
<mo>+</mo>
<mi>273,15</mi>
</mrow>
</math>

19. Discussion & Future Work
 Aligned ontologies are required
 incorporation of automated ontology alignment
 Maintenance of SWRL rules
 automatic generation from unit dictionaries
 Support for spatial & temporal matchmaking
 Improve support for quantitative matchmaking
 usage of SWRL rules

20. Acknowledgements
This work is financially supported by the project
Flexible and Efficient Integration of Sensors and
Sensor Web Services funded by the European
Regional Development Fund (ERDF) for NRW
(contract number N 114/2008).

21. Questions?
Thank you!
Arne Bröring, Ph.D.
Email: arneb@uni-muenster.de
Project website: http://52north.org/sensorBus