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

University of Stuttgart Center of Excellence 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

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

University of Stuttgart Center of Excellence 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

University of Stuttgart Center of Excellence 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

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

University of Stuttgart Center of Excellence 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

University of Stuttgart Center of Excellence 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

University of Stuttgart Center of Excellence 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

University of Stuttgart Center of Excellence 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

University of Stuttgart Center of Excellence 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,...

University of Stuttgart Center of Excellence