A Formal Model of Events Based on the Foundational Ontology DOLCE+DnS Ultralight Ansgar Scherp, Thomas Franz, Carsten Saathoff, Steffen Staab Information Systems & Semantic Web University of Koblenz Germany ADAPT Oberseminar, Koblenz, June

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 2 Outlook  Motivation  Events in Emergency Response  Formal Model of Events  Existing Event Models  Future Work

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 3 Motivation  Events need to be modeled and are useful in a variety of application domains  Lifelogs, multimedia experience sharing  Emergency response  Cultural heritage  News  Sports  Surveillance  However  Event detection and annotation from different sources  Using different data models and proprietary solutions  Event descriptions need to be shared between systems

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 4 Emergency Control Center Forward Liaison Officer Creates event with photo Calls to report about an incident Creates incident event with audio Requests to report about a situation Reports about incident by taking photos etc. Emergency Response Coordination Emergency Hotline Fire Department Police Department Coordinate and keep up to date Report and update about the incident Coordinate and keep up to date Report and update about the incident Citizen Events in Emergency Response  EU Integrated Project WeKnowIt Several emergency response entities are involved Using different event-based systems Common understanding of events is needed to efficiently communicate between ER entities Events are enriched with multimedia data (documentary support)

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 5 Formal Representation of Events Humans like to think in terms of events & entities Event model is a human-centered approach to capture human experience and knowledge Development of the Event-Model-F Sophisticated modeling support for occurrences in which humans participate F = E +1, homage to event model E by Westermann & Jain Specification in Web Ontology Language (OWL) Formalized in Description Logics Useful for the interoperability of computer systems

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 6 What is an event? Events Perduring entities that unfold over time Occurrences in which humans participate (not technical, low-level events within computer systems!) Subject to discussions and interpretations by humans Objects Enduring entities that unfold over space Events and objects require each other

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 7 Requirements to a Common Event Model Participative aspect Participation of living and non-living objects in events Temporal aspect and spatial aspect Can be specified by absolute or relative reference points Structural aspect Mereology, i.e., event (de-)composition Causal, i.e., E 1  E 2 Correlative, i.e., E 2 and E 3 overlap with common cause Interpretation Structural relations matter to subjectivity and interpretation Experiential aspect (documentation) Annotation of events with sensor data such as media data

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 8 Non-functional Requirements Extensibility Include future aspects for describing events Axiomatization & formal precision Required for a common understanding of events Interoperability between systems Modularity Reduce complexity by selecting only what is required Reusability Share common events/objects for different interpretations Reuse of domain knowledge Separation of concerns Core model needs to be applicable in many different domains Separate structural knowledge from domain-specific knowledge

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 9 Design Approach 1.Chose of foundational ontology DOLCE+DnS Ultralight as modeling basis Aims at capturing the most essential aspects in the world Defines disjunctive upper classes Event, Object, Quality and Abstract Follows a pattern-oriented approach for ontology design 2.Use of ontology design patterns  Generic solution to recurring modeling problem  Reduces complexity of the designed model 3.Define Event-Model-F as core ontology Provides structural knowledge for a specific field that Spans across multiple domains, e.g., lifelogs, ER, etc. Build on top and aligned with DOLCE+DnS Ultralight

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 10 Ontology Stack Core Ontologies Domain Ontologies Foundational Ontologies  Foundational Ontologies  Span across multiple fields, each covering multiple domains  Core Ontologies  Situated in one field, but span across multiple domains  Examples: annotation, communication, events,...  Domain Ontology  For a specific domain, e.g., fishery, human body, emergency response, etc.

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 11 Modeling Basis of our Core Ontologies DnS as fundamental design principle for Event-Model-F Descriptions and Situations (DnS) pattern Formal representation of context through use of roles Decoupling concrete events and objects from their roles in a specific contextual situation Description Specification of roles required in a specific situation Can be understood as template Situation Observable real-world situation, i.e., a concrete combination of events and objects Satisfies a description, if it fits into the template

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 12 Example: Descriptions and Situations Pattern BirthdayPartyDescription defines roles BirthdayEvent (Event) BirthdayChild (Object) BirthdayGuests (Objects) BirthdayCake (Object) BirthdayMusic (Object) BirthdayPartySituation defines concrete events and objects July 5 th John Peter, Marie, Tom, Bob, … 3-layer-cream-cake Loud music Different interpretation of same the BirthdayPartySituation Neighbor is annoyed by the loud music

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 13 Ontology Patterns of Event-Model-F Event-Model-F defines six core ontology patterns based on Description and Situation pattern (1) Participation pattern (2) Mereology pattern (composition) (3) Causality pattern (4) Correlation pattern (5) Documentation pattern (6) Interpretation pattern

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 14 (1) Participation Pattern Participation of living and non-living objects in events Reuse of domain knowledge EventParticipationDescription defines exactly 1 DescribedEvent defines min 1 Participant defines some LocationParameter defines some TimeParameter defines only (DescribedEvent or Participant or LocationParameter or TimeParameter) isSatisfiedBy exactly 1 EventParticipationSituation

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 15 (2) Mereology Pattern Composite event consists of multiple component events Composition along time, space, and space-time EventCompositionDescription defines exactly 1 Composite defines min 1 Component defines only (Composite or Component or EventCompositionConstraint) isSatisfiedBy exactly 1 EventCompositionSituation

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 16 (3) Causality Pattern Event (cause) implies other event (effect) Causal relationship holds under some justification Causes and effects are events, and only events EventCausalityDescription defines exactly 1 Cause defines exactly 1 Effect defines exactly 1 Justification defines only (Cause or Effect or Justification) isSatisfiedBy exactly 1 EventCausalitySituation

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 17 (4) Correlation Pattern Correlate events have a common cause Happen at the same time or share some overlap Useful, as often only correlation is observable and the common cause remains unknown EventCorrelationDescription defines min 2 Correlate defines exactly 1 Justification defines only (Correlate or Justification) isSatisfiedBy exactly 1 EventCorrelationSituation

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 18 (5) Documentation Pattern Provide documentary evidence for an event Annotation of events with photos, video, audio, etc. EventDocumentationDescription defines exactly 1 DocumentedEvent defines some Documenter defines only (DocumentedEvent or Documenter) isSatisfiedBy exactly 1 EventDocumentation- Situation Documenter classifies, e.g., DigitalData defined in COMM (Core Ontology on Multimedia) providing a formal model of MPEG-7 Low-level Multimedia Descriptors

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 19 (6) Interpretation Pattern Explicit modeling of contextual views on events Combines the instantiations of patterns (1) to (5) EventInterpretationDescription defines exactly 1 Interpretant defines min 1 RelevantSituation defines only (Interpretant or RelevantSituation) isSatisfiedBy exactly 1 EventInterpretationSituation For example: interpretation of a power outage Citizen: power outage on our street causes severe problems Officer: power outage of three blocks is less important than a power outage of the hospitals

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 20 Short Example: Serious Weather Conditions During serious weather conditions a flood happens Power pole snappes and causes a power outage Citizen observes this event from his home

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 21 Related Work and Existing Event Models Existing research focuses on processing low-level signals and actions  Events that happen within computerized systems  For example, publish-subscribe systems, complex event processing, event signal processing, reactivity on the web Existing event models  For example, Event Model E, EventML, Event Calculus, CIDOC CRM, VERL, SsVM, Event Ontology, Eventory  Do not follow a systematic development approach  Semantically ambiguous  Conceptually narrow  Hinders interoperability of different event-based systems

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide Comparison to Existing Event Models SsVM = Semantic-syntactic video model VERL = Video event representation language CIDOC CRM = Conceptual reference model for cultural heritage

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 23 Non-functional Requirement Extensibility Pattern-oriented approach of DOLCE+DnS Ultralight Specializing/extending existing patterns, adding new patterns, … Axiomatization & formal precision Bases on foundational ontology DOLCE+DnS Ultralight Semantically precise Modularity Pattern-oriented design Reusability Integrating existing domain ontologies Separation of concerns Structural knowledge is defined in the ontology design patterns Domain-specific knowledge is linked through classifying roles

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide Event-Model-F API Programming interface to Event-Model-F Enable direct use of the Event-Model-F without requiring to know the internal details of the ontology Layered architecture of the API Your Application Event-Model-F Extended API Event-Model-F Core API RDF Storage (Sesame) Will be released under open source license Will be released under open source license (soon)

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 25 SemaPlorer 25 Place Object Type Event Use of Event-Model-F in the Emergency Response scenario with the distributed SemaPlorer application Explore & visualize semantic Web 2.0 data in real-time Large, mixed-quality, semantically heterogeneous data Winner of Billion Triples Challenge, ISWC, Karlsruhe, Germany, 2008

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide Future work on Event-Model-F Extraction of events and objects from Web content Reasoning on Event-Model-F with Linked Geo Data Behaviour model Object model to represent (3D) Objects Event-Model-F Website  Provides the ontology and examples in OWL  Technical report with Description Logic axiomatization   1st Int. Workshop on Events in Multimedia  With Ramesh Jain (UCI) and Mohan Kankanhalli (NUS)  Conjunct with ACM Multimedia conference 

ISWeb - Information Systems & Semantic Web Ansgar Scherp Event-Model-F Slide 27 Thank you for your attention! Questions? Ansgar Scherp Reference: A. Scherp, T. Franz, C. Saathoff and S. Staab, F---A Model of Events based on the Foundational Ontology DOLCE+DnS Ultralight, International Conference on Knowledge Capturing (K-CAP), Redondo Beach, CA, USA, September, 2009.