1. GAS ontology: an ontology for collaboration among ubiquitous computing devices International Journal of Human-Computer Studies (May 2005) Presented By Eleni Christopoulou, Achilles Kameas Research Academic Computer Technology Institute Design of Ambient Intelligent Systems Group, Greece Summerized By Jaeseok Myung

2. Copyright  2008 by CEBT Introduction  eGadget Project A research project funded by EU IST/FET The goal of this project is to deliver an architectural framework that supports the composition of ubiquitous computing systems – GAS (Gadgetware Architectural Style) A key issue in the project is the heterogeneity of the devices  GAS Ontology Represents basic concepts and their inter-relations – A common language – Semantic interoperability among the heterogeneous devices Should be flexible and extensible – so that new concepts can be added and represented Center for E-Business Technology

3. Copyright  2008 by CEBT Basic Concepts  eGadgets (eGts) Everyday physical objects enhanced with sensing, acting, processing and communication abilities Building blocks to form GadgetWorlds  Plugs Software classes that make visible the eGt capabilities to people and to other eGts  Synapses Associations between two plugs  eGadgetWorlds Dynamic, distinguishable, and functional configurations of associated eGts, which communicate and/or collaborate in order to realized a collective behaviour. Center for E-Business Technology

4. Copyright  2008 by CEBT  Constructing eGadgetWorlds The Notion of eGadgetWorlds Center for E-Business Technology

5. Copyright  2008 by CEBT Need for GAS Ontology  Conceptualization of eGadgetWorlds Provide a new world view constituted of the set of basic terms, their definitions and their inter-relations which are defined by the GAS  Semantic Interoperability among eGadgets The eGts have to use the same language and a common vocabulary – Although each may implement a different mechanism to interpret them  Dynamic Nature of eGadgetWorlds Synapses between eGts can be created and removed dynamically We need formal rules in order to handle some changes and failures  Semantic Service Discovery We can use the semantic description of the eGts’ capabilities – so that we can discover all the relevant services Center for E-Business Technology

6. Copyright  2008 by CEBT GAS Ontology Design  Ontology Layers GAS Core Ontology(GAS-CO) GAS Higher Ontology(GAS-HO) The GAS-CO provides eGts with the necessary common language that we need in order to describe their acquired knowledge represented by the GAS-HO Center for E-Business Technology

7. Copyright  2008 by CEBT GAS Core Ontology  As a Common Language All eGts must have same GAS-CO to communicate each other Cannot be changed either from the manufacturer or from an user Should contain only the necessary information in order to be small Center for E-Business Technology

8. Copyright  2008 by CEBT GAS Higher Ontology  Describes instances of the classes defined from the GAS-CO  Represents the private knowledge of each eGadget The size can be ‘unlimited’ and depending on eGt’s memory Can be changed dynamically  GAS-HO-static eGt’s plugs, services  GAS-HO-volatile Synapses Center for E-Business Technology

9. Copyright  2008 by CEBT GAS Ontology Development  GAS ontology is written in DAML+OIL  Protégé-2000 is selected as an ontology development tool Center for E-Business Technology

10. Copyright  2008 by CEBT Summary  The ontologies can help us to address some key issues of ubiquitous computing environments Knowledge representation Semantic interoperability Service discovery  The GAS Ontology Describes the semantics of the basic concepts and their relations Provides a common language for the communication and collaboration among the heterogeneous devices Supports the service discovery mechanism Center for E-Business Technology

11. Copyright  2008 by CEBT Paper Evaluation  Strong Points Provide a new world view (eGadgetWorlds) Provide a new way for layering ontologies – general and domain-specific vs. common and private  Weak Points Too simple example Explanation is poor – for the architecture – for the development tools and languages Center for E-Business Technology

12. Copyright  2008 by CEBT Discussion  GAS vs. CONON vs. SOUPA As a candidate for representing real-world contexts  Who can make a standard ontology? How the standard ontology is maintained? Center for E-Business Technology