Semantic Mediation On The Sensor Web

Semantic Mediation

On The Sensor Web

Arne Bröring, Patrick Maué, Christian Malewski,

Krzysztof Janowicz

IGARSS, 25.7.2012, München

Variety of environmental sensors…

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

Geosensor Infrastructure Stack

Application Layer

Sensor Web Layer

Sensor Layer

Challenge: On-the-fly Integration

Service 1

Service 2

Problem: Match Assurance

Observed Property:

air_flow_direction

Output:

wind_direction

Characteristics have to match syntactically & semantically!

Goal:

Automated Integration of

Sensors and Services

Sensor Bus

Application Layer

Sensor Web Layer

Sensor Layer

Sensor Bus

Semantic Mediation

Sensor Bus

Required

Characteristics

Advertised

Characteristics

Mediator *

Semantic Mediation

1. Semantic Annotation

2. Concept Creation

3. Matchmaking

4. Conversion

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>

W3C SSN Ontology

Concept Creation - Service

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:

Concept Creation - Sensor

Matchmaking

Conversion With SWRL Rules

Example to attach conversion rule

AdvertisedObservationValue(?aSO),

isParameterizedBy(?aSO, Celsius)

->

applyConversionRule(?aSO,

DegreeCelsiusToKelvin)

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>

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

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).

Questions?

Thank you!

Arne Bröring, Ph.D.

Email: arneb@uni-muenster.de

Project website: http://52north.org/sensorBus