Delivery Context

UWA WG is developing a Delivery Context Ontology (Rhys Lewis and José M. Cantera, Working Draft 15 Apr 2008).

Why do we need a DC Ontology? (our vision)

• Interoperability, i.e., exchange descriptions of entities (devices, users, channels...)

• Representation, i.e., enable in-memory manipulation and storage of those descriptions

• Queriability, i.e., provide a query mechanism to extract data

• Knowledge management, i.e., consistency-checking, inference (classification), rules...

Problem:: translate the following to RDF: "Bluetooth has a range of 10 meters"

How to represent measurable qualities (quantities) in RDF?

• Using properties:

  • (1) Forbid heterogeneity, unanimous agreement on a single (implicit) unit: <#BT> ex:range "10".

  • (2) Property-per-unit, e.g., <#BT> ex:rangeInMeters "10".

• Using datatypes:

  • (3) Datatype-per-unit, e.g., <#BT> ex:range "10"^^ex:meters

  • (4) Parseable datatype, e.g., <#BT> ex:range "10 m"^^ex:quantityAndSymbol

• Quantity as a resource:

  • (5) Unit as classes, e.g., <#BT> ex:range [ rdf:type ex:Meter, ex:value "10" ]

  • (6) Unit as instances, e.g., <#BT> ex:range [ ex:measuredIn ex:meter, ex:value "10" ]

What others are doing

• CIA Factbook: (pattern 1)
  <#Spain> fb:area_total "504782" . (what??)

• US Census: (pattern 4)
  <#ny> census:landArea "122283145776 m^2" .

• DBPedia: (pattern 2)
  <#Kobe_Bryant> p:heightFt "6", p:heightIn "6".

• Current DC Ontology: (pattern 5)
  <#Centimeters> rdf:type owl:Class .
  <#Feet> rdf:type owl:Class .
  <#oneCentimeter> rdf:type <#Centimeters> , dc:value "1.0" .

Our proposal

• MUO Ontology

  • Classes: muo:UnitOfMeasurement, muo:Prefix, muo:PhysicalQuality...

  • Properties: muo:measuredIn, muo:prefSymbol...

• MUO Basic Instances

  • Units: meter, second...

  • Prefixes: kilo-, mili-, ...

  • Physical qualities: length, time...

• MUO Services

  • Conversion service

  • Reasoning service

MUO in practice

MUO alignment

Warning: may be obsolete!

Class diagram

Warning: may be obsolete!

MUO Services

• Conversion service:

  • Retrieve unit definitions from the web

  • Use unit definition to know how to do conversions

• Reasoning service:

  • Consistency checking (e.g.: measure a length in seconds -- Wrong!)

  • Conversion to preferred units (e.g.: everything to International System)

  • Leverage "old" RDF triples

• HTTP and SOAP bindings (a-la SPARQL protocol).

• Reference implementation (will be) available as open source

• MUO Services as an alternative to modeling conversions in OWL

Conclusions

• You cannot force people to always use International System

• You cannot force people to change their ontologies and triples

• Integrate with SW stack, e.g., call the reasoner "FROM" a SPARQL endpoint (HTTP binding) --> enable SW pipes and mash-ups

Future work

• Immediate: discuss with the community! Some topics:

  • Blank nodes?

  • DL-compatibility? (e.g., annotation properties)

  • Efficient implementation of services, esp. querying?

  • rdf:value?

• Mid-term:

  • Member Submission to W3C (in progress)

  • Stable mailing list for discussion?

  • Other applications: currency?

Acknowledgements

• MyMobileWeb project: Jose Manuel Cantera (Telefónica I+D) and Miguel Jiménez (Universidad Politécnica de Madrid)
• The Unified Code for Units of Measurement (UCUM): Gunter Schadow and Clement J. McDonald
• Work on MUO is partially supported by Spanish Ministerio de Industria under grant MyMobileWeb