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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
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Ontology-Based User Modeling for Pedestrian Navigation Systems Panayotis Kikiras, Vassileios Tsetsos, and Stathes Hadjiefthymiades Pervasive Computing Research Group Communication Networks Laboratory Department of Informatics and Telecommunications University of Athens – Greece UbiqUM ’06 @ Riva del Garda
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
What Is Wayfinding • A cognitive procedure for orientation and navigation of the user in huge and complex environments • Involves four main steps: • Orientation • Route Selection • Routing Control • Recognition of destination
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
User Profile Components Orientation disability Mental impairment Wheelchair Escort-aided mobility Hearing abilities Visual quality Mental/Cognitive Characteristics Sensory Abilities Motor Abilities User Profile Navigational Preferences User Interface Preferences User Demographics Avoid stairs Only audio info Only visual info Age Gender
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)
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
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)
UNO Elements Classes Properties
OntoNav • Personalized indoor navigation, through the exploitation of user- and building-related semantics User Profile Creator UNO Building graph User-compatible graph Path Computation and Ranking Rules Building Blueprints IF UNO:WheelchairedUser(u) AND INO:Stairway(s) THEN INO:isExcludedFor(s,u) INO
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), …
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)
Thank You! Questions??? UNO v0.1 available at: http://p-comp.di.uoa.gr/ont/UNO.owl