1. 1 Where do spatial context-models end and where do ontologies start? A proposal of a combined approach Christian Becker Distributed Systems Daniela Nicklas Applications of Parallel and Distributed Systems Universität Stuttgart, Germany Center of Excellence 627: Spatial World Models for Mobile Context-Aware Applications

2. University of Stuttgart Center of Excellence 627 2 Context Management Starting Point Context-Aware Applications: adapt their behavior depending context need context management 2 approaches of context management: context models: database-style: applications can select/query context information for adaptation contextual ontologies: knowledge representation and deduction: applications can define complex situations

3. University of Stuttgart Center of Excellence 627 3 Physical World Context Model Context Models Applications query (filter) Update(id, value) Sensors (Fusion) Update(id, value) Application State

4. University of Stuttgart Center of Excellence 627 4 Location, identity, and time properties of each spatial object location and ID: primary access path for context used for selection: What is there? (location) What is John doing? (ID) time: often implicit ("now") explicit for history and prognosis combined with location or ID: who was here yesterday? (location + time) where was I yesterday? (ID + time) lost key

5. University of Stuttgart Center of Excellence 627 5 Classification of Context Models dynamics: low to high update rate stationary vs. mobile objects/sensor values spatial scope local to global complexity of abstraction level of detail, #objects

6. University of Stuttgart Center of Excellence 627 6 Shared Context Models GIS data integration, schema matching S S S S sensor fusion Federation query Application

7. University of Stuttgart Center of Excellence 627 7 Five tiers of spatial ontologies [Frank 2003] Ontology Tier 0: Physical Reality Ontology Tier 1: Observable Reality Ontology Tier 2: Object World Ontology Tier 3: Social Reality Ontology Tier 4: Cognitive Agents Interpretation

8. University of Stuttgart Center of Excellence 627 8 Context Models and Contextual Ontologies Ontology Tier 0: Physical Reality Ontology Tier 1: Observable Reality Ontology Tier 2: Object World Ontology Tier 3: Social Reality Ontology Tier 4: Cognitive Agents Context Models Contextual Ontologies

9. University of Stuttgart Center of Excellence 627 9 Shared Context Models GIS data integration, schema matching S S S S sensor fusion context model layer observation layer tier 1 tier 2 tier 3 Federation query federation layer query Application tier 4

10. University of Stuttgart Center of Excellence 627 10 A Combined Approach Federation Inference Machine, Reasoning Rules query interpretation Application query Application GIS data integration, schema matching S S S S sensor fusion context model layer reasoning layer observation layer tier 1 tier 2 tier 3 tier 4 federation layer

11. University of Stuttgart Center of Excellence 627 11 Conclusion context models: efficient management of large-scale context contextual ontologies: support for reasoning combined approach: select context based on context models add semantic information and reason about selection open questions how to represent semantic information? (Rules,...) consistency, coherence, data quality, trust,...

12. University of Stuttgart Center of Excellence 627 12 www.nexus.uni-stuttgart.de