secure systems research group - fau context architectures using web services phd candidate: alvaro...

Secure Systems Research Group - FAU

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


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.


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.



• 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



• 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)



• System Domain Context:– Describes digital, software and hardware

resources available to users.– Processing power

– Hardware components

– Network interfaces

– Storage

– Software components



• 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)



• 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.



• 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)



• 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.



Context Sources



Context Consumption



Context-aware Services


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.


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/


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.


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)

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