CoOL: A Context Ontology Language to enable Contextual Interoperability

Transcription

1 CoOL: A Context Ontology Language to enable Contextual Interoperability Thomas Strang thomas.strang@dlr.de Korbinian Frank frank@informatik.uni-muenchen.de Claudia Linnhoff-Popien linnhoff@informatik.uni-muenchen.de 1

2 Context-Aware Services 1. click! uploading pics 2.? 3. pickup photos 2

3 CoOL: A Context Ontology Language to enable Contextual Interoperability Outline Motivation & Requirements New model to specify contextual knowledge Using the model in context-aware service frameworks Determination of contextual interoperability 3

4 Next step... The Requirements 4

5 Ubiquitous Computing Distributed Computing Mobile Computing Ubiquitous Computing Mobile Networks Mobile Information Access Adaptive Applications Context-Awareness Ad-hoc Networks Smart Sensors & Devices GNSS Mobile Radio Network Inertial Navigation Sys Short Range Network Interoperability Specification Gap!! Everything which has to be evaluated by the computer must be specified! 5

6 Service Interoperability Levels: service interoperability signature signatureprotocol protocol protocol semantic semantic semantic context sublevel sublevel sublevel sublevel sublevel sublevel sublevel sublevel Perspectives: dynamic component A static component compatibility (symmetric) substitutability (asymmetric) on any (sub-)level dynamic component B compatibility and substitutability defined individually specification of shared knowledge enables interoperability 6

7 Requirements Requirements on specification methodology: high level of formality distributed composition partial validation incompleteness quality of information equal use of scalar and non-scalar types applicability to existing service frameworks An ontology is a hierarchically structured set of terms for describing a domain that can be used as a skeletal foundation for a knowledge base. by Swartout, Patil, Knight and Russ, 1996 Fact Instance Concept Class 7

8 Next step... The Model 8

9 New Model to specify Contextual Knowledge Temperature 5 C 35 C 3 F 10 C -7 C 60 F 95 F 0 C 80 F 13 C Aspect Scale ContextInformation Entity characterized by 9

10 Frame oriented view to the ASC Model (I) Aspect Scale ContextInformation hasdefaultscale: hasscale: Scale Scale 10

11 Frame oriented view to the ASC Model (II) Aspect Scale ContextInformation hasaspect: hasmember: hasunit: membercheck: hasintraoperation: hasinteroperation: Aspect ContextInformation Unit Operation IntraOperation InterOperation 11

12 Frame oriented view to the ASC Model (III) Aspect Scale ContextInformation =1 1 0 =1 0 characterizes: hasscale: meanerror: timestamp: hasquality: Entity Scale ContextInformation ContextInformation ContextInformation 12

13 Scales and Metrics First Economy D: E: Business ComfortScale Skales are unsorted sets! B: A: C: GaussKrügerScale better (comfort) First Business Economy better (budget) Application specific order by use of MetricOperation ci 1 ci 2 = better(ci 1, ci 2, p j ) c i Scale better (Viag/O2) E B C A D better (user) ComfortScale comfortscale= new Vector( First, Business, Economy); comfortscale.contains( ci ); Construction and Access GKScale gkscale = new GKScale("Tour Eiffel", 10km); gkscale.checkmember( ci ); Enables comparison and order of non-scalar types! 13

14 Next step... The Architecture 14

15 Context-Aware Service Framework integrating the Model Interaction Direct Service Discovery Customer Customer Domain Domain Context Provider Domain Service Service Directory Directory (e.g. (e.g. SLP-DA) SLP-DA) Delegated Svc. Discovery incl. Context Binding Lookup Announcements Invocation Relevance Criteria Context Middleware/ Mgt. Middleware/ Intermediate Access Intermediate Point Invocation Context Informationen Service Service Provider Provider Domain Domain Context Mgt. Implementation Query Knowledge Reasoner (Inference Engine) Monitor & Event Generator Rules Ontologies Facts ASC CoOL based Knowledge 15

16 Next step... Determination of Interoperability 16

17 Context Bindings Signature of an operation: Signature Level String orderpizza( int pizzanumber, String deliveryaddress,...); What is it??? Semantic Level Which values??? Context Level Context Binding = Binding of Parameter to Scale+Aspect Example: Parameter deliveryaddress specific scale ( all with ) Adler, T Berti, A Costa, K Zupe, L Aspect Postal Address 17

18 Contextual Compatibility Three types of parameter: input parameter output parameter implicit parameter Which values expects the operation? Which values delivers the operation? For which values is the service itself available? Example: Query FORALL S <- #iskompatible(#kilometer_scale,s). Determination of Contextual Compatiblity Kilometer_Scale Meter_Scale Result: #Kilometer_Scale, #Meter_Scale, #NM_Scale from Binding NM_Scale feet_scale 18

19 Contextual Substitutability Three types of parameter: input parameter output parameter implicit parameter Which values expects the operation? Which values delivers the operation? For which values is the service itself available? Scope business hours for service food delivery 3 implicit parameter current time Scale is the Scope

20 Contextual Substitutability User Scope business hours Scope business hours NCS Handover motivates implicit parameter current time Any change in context can motivate/cause a handover! 20

21 Context Ontology Language (CoOL) SOAP WSDL UDDI co.xsd + co.owl wsdl-cb.xsd soap-cb.xsd CoOL Integration CoOL Core Artifacts.flo Artifacts.flo Artifacts.flo Context Observation ASC in F-Logic ASC in OWL ASC in DAML+OIL Reasoner Reasoner (Inference (Inference Engine) Engine) Ontobroker individual use for Inferencing + Validation Tools (e.g. from Semantic Web) 21

22 Summary and Conclusion Specification of contextual knowledge based on the ASC model using ontologies Architecture with ontology reasoner in the context provider domain Interoperability determination via context bindings Conclusion: Context Ontology Language (CoOL) as a projection of the model into a specification language can be used to specify and determine interoperability from different perspectives. Thank you! For further information: Thomas Strang <thomas.strang@dlr.de> 22