Context Architectures Using Web Services

1. Context Architectures Using Web Services PhD Candidate: Alvaro E. Escobar Advisors: Dr. Maria Petrie Dr. Eduardo Fernandez Department of Computer Science and Engineering Florida Atlantic University, Boca Raton FL. 07/27/2007

2. Agenda • Review the following papers: • [Fou06] D Fournier, S B Mokhtar, N Georgantas,VIssarny. “Towards Ad-hoc Contextual Services for Pervasive Computing”. Proceedings of the 1st workshop on Middleware for Service Oriented Computing (MW4SOC 2006) Melbourne, Australia • [Bar05]J E Bardram.“The Java Context Awareness Framework (JCAF) – A Service Infrastructure and Programming Framework for Context-Aware Applications”. Centre for Pervasive Computing, Department of Computer Science, University of Aarhus. Denmark. • [Dom07]KM Dombroviak, R Ramnath. “A taxonomy of mobile and pervasive applications”. Proceedings of the 2007 ACM symposium on Applied computing.Seoul, Korea. • [Bha05]R Bhatti, E Bertino, A Ghafoor. “A Trust-Based Context-Aware Access Control Model for Web-Services”. Distributed and Parallel Databases, 2005 - Springer.

3. Towards Ad-hoc Contextual Services for Pervasive Computing[Fou06] • Main Idea: • How to incorporate context-aware concepts into SOA to enable context-aware services for pervasive computing. • Managing Context Information: • managed by centralized system and devices are consumers of context in a specific physical environment (pervasive spaces). • managed by devices so they have access to context in any environment.

4. Towards Ad-hoc Contextual Services for Pervasive Computing[Fou06] • Taxonomy of Context Information: • User Domain • System Domain • Environment (physical) Domain • Context Representation: • Key-Value models • Markup models • Graphical models • Object-Oriented models • Logic models • Ontologies

5. Towards Ad-hoc Contextual Services for Pervasive Computing[Fou06] • User Domain Context: • Provide knowledge to enable applications adapt to the profile of their users. • Subjective: Includes user’s personality and psychology. • User mood and feelings (fear, anger, sad…) • Objective: Includes user’s personal information. • Personal information (name, last name, birth date…) • Physiology information (height, weight, health…) • Agenda information (user activities over time)

6. Towards Ad-hoc Contextual Services for Pervasive Computing[Fou06] • System Domain Context: • Describes digital, software and hardware resources available to users. • Processing power • Hardware components • Network interfaces • Storage • Software components

7. Towards Ad-hoc Contextual Services for Pervasive Computing[Fou06] • Environmental Domain Context: • Deals with the description of location and of conditions of the physical environment. • Physical geography (GPS coor, room, building….) • Physical conditions (windy, sunny, rainy…) • Chronology (time, time zone, time of the day)

8. Towards Ad-hoc Contextual Services for Pervasive Computing[Fou06] • Context Representation : • Key-Value models: use a set of attributes and their associated values. • Markup models: structure context into a hierarchy using tags. • Graphical models: express relationships between context entities. • Object-Oriented models: structure context into object classes and their implicit relationships. • Logic models: express context in terms of facts and rules. • Ontologies: combination of logic models and O-O models they structure context into object classes and their explicit relationships.

9. Towards Ad-hoc Contextual Services for Pervasive Computing[Fou06] • Context Management : • Initially application-specific context managers (limited re-use; built for app-specific context). • Location-aware systems like Active Badge and Cyberguide. • Then dedicated Context Frameworks allowed more general (re-usable) context managers. • Context Toolkit (Dey), Contextors (Coutaz) • JCAF (Bardram)

10. Towards Ad-hoc Contextual Services for Pervasive Computing[Fou06] • Context Management (continue): • Lately is the Server-Oriented approach to context managers ( deployment of context servers within the network). • SOCAM (Service-Oriented Context Aware Middleware) • CoBra (Context Broker Architecture) • More recently the P2P architecture of context managers (devices responsible for managing subset of context). • AWARENESS project, where mobile and desktop devices acquire, interpret and exchange context even in the absence of a context server.

11. Towards Ad-hoc Contextual Services for Pervasive Computing[Fou06] Context Sources

12. Towards Ad-hoc Contextual Services for Pervasive Computing[Fou06]Context Consumption

13. Towards Ad-hoc Contextual Services for Pervasive Computing[Fou06]Context-aware Services

14. Conclusions • Context is a fundamental concept in mobile systems. • Service-Oriented computing has emerged as a promising paradigm for pervasive computing. • One challenge is making services contextual, so that the pervasive computing environment gets knowledge about the context and the services adapt their behavior accordingly. • Contextual Services may be composed in an ad hoc way.

15. Towards Ad-hoc Contextual Services for Pervasive Computing • References: • [Bel03] P. Bellavista, A. Corradi, R. Montanari, C. Stefanelli, “Context-Aware Middleware for Resource Management in the Wireless Internet”, IEEE Transactions on Software Engineering. Vol. 29, No. 12, December 2003. Page 1086. • [Bra01] T. Bray. What is RDF? http://www.xml.com/pub/a/2001/01/24/rdf.html, • January 24, 2001 • [Cha04] T. Chaari, F.Laforest, A. Celentano. “Design of Context-Aware Applications. Based on Web Services”. LIRIS. Dipartimento di Informatica. INSA Lyon, France • [Che03] H. Chen, T. Finin and A. Joshi. “An Ontology for Context-Aware Pervasive Computing Environments”. IJCAI Workshop on Ontologies and Distributed Systems, IJCAI 2003, Acapulco, Mexico, 2003. • [Cor04] A. Corradi, R. Montanari, D. Tibaldi, “Context-Based Access Control Management in Ubiquitous Environments”, Network Computing and Applications, Proceedings of the Third IEEE International Symposium on (NCA'04), August 30 - September 01, 2004, Boston, MA. • [Dey01] A. Dey, G. Abowd, D. Salber, “A Conceptual Framework and a Toolkit for Supporting the Rapid Prototyping of Context-Aware Applications” - Human-Computer Interaction, 2001 - Lawrence Earlbaum • [Fer07] E. B. Fernandez, A. E. Escobar, M. Larrondo-Petrie. “Contexts and Context-Based Access Control”. The Third International Conference on Wireless and Mobile Communications, ICWCF’07, March 2007. Guadeloupe, French Caribbean. • [Fer05] E.B. Fernandez, T. Sorgente, N. Delessy, and M.M.Larrondo-Petrie, "A survey of web services security", Technical report to DISA (Defense Information Systems Agency), grant # ?????, 2005 • [Fer04] E.B. Fernandez, "Web services security: An overview of standards and industrial practice", 2004 • [Gu04] T. Gu, X.H. Wang, H.K. Pung, D.Q. Zhang. “An Ontology-based Context Model in Intelligent Environments”, Proceedings of Communication Networks and Distributed Systems, 2004. • [Hel02] A. Held, S. Buchholz, A. Schill, "Modeling of Context Information for Pervasive Computing Applications", In Proceedings of the 6th World Multiconference on Systemics, Cybernetics and Informatics (SCI), Orlando, FL, July 2002. • [Rae05]M. Raento, A. Oulasvirta, R. Petit, H. Toivonen. “ContextPhone: A Prototyping Platform for Context-Aware Mobile Applications”. IEEE Pervasive Computing, 2005. • [Sil05] J. Siljee, S. Vintges, J. Nijhuis. “A Context Architecture for Service-Centric Systems”. Context Modelling and Management in Ambient-Aware Pervasive Environments. LoCA 2005, Oberpfaffenhofen, Germany, May 12-13, 2005. • [W3C04] http://www.w3.org/TR/ws-arch/

16. Agenda • Review the following papers: • [Fou06] D Fournier, S B Mokhtar, N Georgantas,VIssarny. “Towards Ad-hoc Contextual Services for Pervasive Computing”. Proceedings of the 1st workshop on Middleware for Service Oriented Computing (MW4SOC 2006) Melbourne, Australia • [Bar07] J E Bardram.“The Java Context Awareness Framework (JCAF) – A Service Infrastructure and Programming Framework for Context-Aware Applications”. Centre for Pervasive Computing, Department of Computer Science, University of Aarhus. Denmark. • [Dom07]KM Dombroviak, R Ramnath . “A taxonomy of mobile and pervasive applications”. Proceedings of the 2007 ACM symposium on Applied computing.Seoul, Korea.

17. Future Work • Develop a service oriented context-aware middleware that will enrich the JCAF. • Updating our Context-aware model to incorporate Web Services. • Simulate the many context and location-aware scenarios through that model. • Build sequence diagrams for some Use Cases to validate our model. • Paper submission for: • UbiComp’07 - 9th International Conference on Ubiquitous Computing, 16-19 September 2007, Innsbruck, Austria. (June deadline) • ACM Symposium on Applied Computing 2008, Special Track on Ubiquitous Computing:Ubiquitous and Pervasive eCommerce and eBusiness. March 16-20, 2008, Fortaleza, Brazil. (Sept deadline) • MobiSys’08 - The 6th International Conference on Mobile Systems. TBA • MobiHoc’08 - The 9th ACM International Symposium on Mobile Ad Hoc Networking and Computing. May 26-30, 2008, Hong Kong (Nov/22 deadline)