Implementation of Ontology Based Context-awareness Framework Ki-Chul Lee, Jung-Hoon Kim International Conference on Multimedia and Ubiquitous Engineering Summarized by Gong GI Hyun, IDS Lab., Seoul National University

Copyright  2008 by CEBT Introduction  Well designed context model is a key accessor to the context in any context-aware system.  Some models take the users current situation, e.g. “in a meeting” into account, others model the physical environment, i.e. locations IDS Lab. Seminar - 2Center for E-Business Technology

Copyright  2008 by CEBT Context Model Requirements  Requirements for the Context-awareness context model Distributed composition Partial validation Richness and quality of information Incompleteness Level of formality Applicability to existing environment – Context model must be applicable within existing the infrastructure such as Web Services IDS Lab. Seminar - 3Center for E-Business Technology

Copyright  2008 by CEBT Context Modeling methods  Some Modeling Methods Key-Value model Graphical Model Object Oriented Models Ontology based Model IDS Lab. Seminar - 4Center for E-Business Technology

Copyright  2008 by CEBT Existing Context Ontologies  GAS Ontology Based on DAML+OIL Gas Core – Expresses the basic semantic and Relation. Gas Higher Ontology – Extended Semantic in domain  SOUPA SOUPA core – Basic semantic and Relation SOUPA extension – Extension semantic IDS Lab. Seminar - 5Center for E-Business Technology

Copyright  2008 by CEBT Existing Context Ontology Frameworks  CoBrA (Context Broker Architecture) CoBrA Ontology has interoperability and extensibility by having to exchange RDF/XML structured information. Need more consideration of the extension of domain ontology and intelligent service, and its expression and algorithm.  SOCAM(Service-Oriented Context-Aware Middleware) Represent general context information through the upper-level ontology. Extend detailed domain information using the ‘import’ tag of the ontology. This structure can easily implement variable Domain Ontology and can also reduce the time to implement the Context- Awareness System. IDS Lab. Seminar - 6Center for E-Business Technology

Copyright  2008 by CEBT SWRL  SWRL (Semantic Web Rule Language) is a proposal for a Semantic Web rules-language. Combining the OWL Web Ontology Language (OWL DL and Lite) with Rule Markup Language.  SWRL is extended from OWL and Rule-ML It can be expressed in OWL with Rules.  SWRL example parent(?x, ?y) ∧ brother(?y, ?z) ⇒ uncle(?x, ?z) IDS Lab. Seminar - 7Center for E-Business Technology

Copyright  2008 by CEBT Rule Based Inference Engine  Bossam Bossam is made by the ETRI in Korea. It is a Rule-Based engine that supports RDF, OWL and SWRL inference.  Jess Jess is also a rule-based inference engine that can support RDF, OWL and SWRL inference. SWRLTab – Extension for Protégé-OWL editor IDS Lab. Seminar - 8Center for E-Business Technology

Copyright  2008 by CEBT Our approach  Need more extensible structure, more powerful expression and more intelligent service. Define the context-type Upper level ontology based on the context-type Define SWRL rule IDS Lab. Seminar - 9Center for E-Business Technology

Copyright  2008 by CEBT The Context Model - 4 types of context  Sensed-Context Gathered from the sensor Base type for other context-types.  Combined-Context Calculated by Sensed-Context. It is calculated by the Rule-Based Inference Engine. This representation of calculation formula is represented by SWRL  Inferred-Context Inferred by Sensed-Context.  Learned-Context Made by a learning algorithm like DT (Decision-Tree) or NN (Neural-Network). IDS Lab. Seminar - 10Center for E-Business Technology

Copyright  2008 by CEBT The Context Ontology  3 Classes Compound – Used to define the domain ontology Elementary – Context type Learning – Learning module IDS Lab. Seminar - 11Center for E-Business Technology

Copyright  2008 by CEBT The Context Ontology -Simple example IDS Lab. Seminar - 12Center for E-Business Technology

Copyright  2008 by CEBT The Context Ontology  Using SWRL language define the SWRL rule for the combined Context and Inferred Context IDS Lab. Seminar - 13Center for E-Business Technology

Copyright  2008 by CEBT Instance of Domain Ontology IDS Lab. Seminar - 14Center for E-Business Technology

Copyright  2008 by CEBT The Context-Ontology Architecture  3 Components Context Manager Learning Manger Ontology Manager IDS Lab. Seminar - 15Center for E-Business Technology

Copyright  2008 by CEBT The Definition of Process IDS Lab. Seminar - 16Center for E-Business Technology

Copyright  2008 by CEBT Conclusion  We define the Context-Type / Context-Ontology  Our architectures has extensibility to the domain, information sharing, reusability and extensibility.  We are now developing health-care service, crime prevention service. IDS Lab. Seminar - 17Center for E-Business Technology