1. Ontology-Based User Modeling for Pedestrian Navigation Systems Panayotis Kikiras, Vassileios Tsetsos, and Stathes Hadjiefthymiades P ervasive C omputing R esearch G roup C ommunication N etworks L aboratory Department of Informatics and Telecommunications University of Athens – Greece UbiqUM ’06 @ Riva del Garda

2. Outline Pedestrian Wayfinding and Navigation: The Theory Ontology-based User Modeling Existing User Models User Navigation Ontology OntoNav: A Semantic Navigation System Conclusion & Future Research

3. What Is Wayfinding A cognitive procedure for orientation and navigation of the user in huge and complex environments Involves four main steps: 1.Orientation 2.Route Selection 3.Routing Control 4.Recognition of destination

4. What Affects Wayfinding Individual’s characteristics –Sex, age, perceptual and mental abilities, motor abilities, prior knowledge of the environment, … Environment’s characteristics –Luminosity, signage, structure, obstacles, … Learning processes –Learning abilities & strategies, … Not everyone has the same navigational skills  Personalized navigation is necessary

5. User Profile Components Mental/Cognitive Characteristics Sensory AbilitiesMotor Abilities Navigational Preferences User Interface Preferences User Demographics User Profile Only audio info Only visual info Age Gender Avoid stairs Hearing abilities Visual quality Wheelchair Escort-aided mobility Orientation disability Mental impairment

6. Ontology-based User Modeling Ontology is –“a formal, explicit specification of a shared conceptualization” (Studer, 1998 - original: Gruber, 1993) –a core knowledge representation technique in Semantic Web (OWL language) User types ↔ ontology classes User characteristics ↔ class properties Such modeling enables Semantic Web reasoning (e.g., classification) and inference (i.e., rules)

7. Existing User Models GUMO ( General User Model Ontology)  Represents user dimensions (e.g., demographics, abilities) + Developed in OWL - Provides just a vocabulary (no axioms, restrictions) UserML –XML language –Provides just a syntax layer for higher level semantic models

8. User Navigation Ontology (UNO) An OWL ontology that specifies classes and properties for the components of a navigation user profile User classes are formally defined YoungWheelchairedUser ≡ ∃ hasAbility AutonomousWheelchairedMobility ∃ hasAge LessThan18 Enables dynamic classification of users through Description Logics reasoning UNO is aligned with GUMO ( where applicable )

9. UNO Elements Classes Properties

10. OntoNav Personalized indoor navigation, through the exploitation of user- and building-related semantics User Profile Creator UNO Building Blueprints INO Building graphUser-compatible graph Rules Path Computation and Ranking IF UNO:WheelchairedUser(u) AND INO:Stairway(s) THEN INO:isExcludedFor(s,u)

11. User Profile Creation Users can A) Choose from predefined profiles B) Create a custom profile through forms Both options demonstrate serious limitations –A is too coarse-grained –B is not automated and requires (substantial) user effort –Users may be reluctant to disclose (all of) their abilities/disabilities (A&B) Solution (+challenge): User Profile Inference and Calibration from user movement, history, published personal information (e.g., homepage), …

12. Conclusion A first attempt to define an “axiomatized” ontology for describing pedestrian users based on theories and existing work Integration of UNO with a navigation system (i.e., Location Based Services) Future Research Issues –User profile inference –Evaluation with real users –National project on Universal Access to Indoor LBS (GSRT MNISIKLIS)

13. Thank You! Questions??? UNO v0.1 available at: http://p-comp.di.uoa.gr/ont/UNO.owl