Context Architectures Using Web Services Candidate

Context Architectures Using Web Services

• Candidate:

• Alvaro E. Escobar

• Advisors:

• Dr. Maria Petrie

• Dr. Eduardo Fernandez

Agenda

• Review the following papers:

• [Cha04] T. Chaari, F.Laforest, A. Celentano. “Design of Context-Aware Applications Based on Web Services”. LIRIS. Dipartimento di Informatica. INSA Lyon, France
• [Maa06] Z. Maamar, D.Benslimane, N. Narendra. “What can Context do for Web Services?”. Communications of the ACM, December 2006/Vol. 49, No. 12.

• Review our Context-aware Model

• Context Architecture Using Web Services

Design of Context-Aware Applications Based on Web Services [Cha04]

• Context:

• A way to adapt the behavior and the interface of an application, to the user situation and equipment.

• Adaptation vs Context-awareness:

• Adaptation: Capability to provide different versions/presentations of a service in order to suite the needs of the user.
• Context-awareness: Capability of perceiving the user situation and of adapting the system behavior, as a consequence.

Design of Context-Aware Applications Based on Web Services [Cha04]

• Steps to Context-awareness:[Dey01]

• Capture low level contextual data from sensors.
• Build high level contextual information by interpreting data captured on step one.
• Carry interpreted information to the application and provide possible ways on how it can adapt to context changes.

Design of Context-Aware Applications Based on Web Services [Cha04]

• Context representations:

• Simple set of Attribute/Value pairs. [Bel03,Cor04,Dey01,Fer07]
• Use of RDF (Resource Description Framework). [Bra01, Hel02]
• As Ontologies. [Che03,Gu04]

Design of Context-Aware Applications Based on Web Services [Cha04]

• How the application can adapt to context changes.

• Four approaches:

• Conceptual Frameworks: Focus on the architectural aspect of context-aware systems. [Dey01]
• Service Platforms: Focus on providing pertinent services to a user, depending on context.
• Appliance Environments: Focus on giving solutions to the heterogeneity problem by providing interoperability techniques and frameworks.
• Computing Environments: Focus on designing the physical and logical infrastructure to hold ubiquitous systems.

Design of Context-Aware Applications Based on Web Services [Cha04]

• Development of context-aware apps.

• Architecture supporting context-awareness at run-time.
• design the application to be context-aware.

• Web Services

• is widespread and “loosely coupling” approach to integration of applications.

• Adopt Web Services for context-aware application design.

Design of Context-Aware Applications Based on Web Services

• Service Oriented Architecture (SOA) [Cha04]

• Context Capturing
• Context Interpreting
• Context Modeling
• Context Dissemination
• Context Adaptation
• Data flow (content)
• Visualization (UI)
• Application behavior (service)

Agenda

• Review the following papers:

• [Cha04] T. Chaari, F.Laforest, A. Celentano. “Design of Context-Aware Applications Based on Web Services”. LIRIS. Dipartimento di Informatica. INSA Lyon, France
• [Maa06] Z. Maamar, D.Benslimane, N. Narendra. “What can Context do for Web Services?”. Communications of the ACM, December 2006/Vol. 49, No. 12.

• Review our Context-aware Model

• Context Architecture Using Web Services

What can Context do for Web Services?[Maa06]

• Web Services (WS):

• provide a language-neutral, loosely-coupled, and platform independent way for linking applications within organizations or enterprises across the Internet.
• facilitates composite services (CWS):
• describes list of component WS involved.
• describes execution order of WS involved.
• describes corrective strategy in case of an exception.

What can Context do for Web Services?[Maa06]

• WS limitations:

• processes the requests it receives without considering its execution status, before committing to another request.
• lacks self-management to satisfy requirements of:
• Scalability: capacity of WS to interact with small or large community of WS without reducing its performance.
• Flexibility: capacity of WS to adapt behavior according to the situation in which it operates.
• Autonomy: capacity of WS to accept/reject/propose alternative demands of participation in CWS.

What can Context do for Web Services?[Maa06]

• A WS must assess its current capabilities, its ongoing commitments and its surrounding environment prior to binding to any CWS.

• Therefore WS must be context-aware:

• Consider the following contextual aspects.
• Users: Stationary or mobile
• Expertise: Expert or novice
• Resources: Fixed or handheld
• Time: Morning or afternoon
• Location: Cafeteria or meeting room

What can Context do for Web Services?[Maa06]

• Applying context awareness on deploying WS.

• Participation perspective: is about overseeing the multiple composition scenarios in which a WS participates.
• Execution perspective: is about looking for the computing resources on which a WS operates and monitoring them.
• Preference perspective: is about ensuring that user preferences are integrated into the specification of the CWS.

• Context supports WS in their decision-making process to whether accept or reject participation in a CWS.

What can Context do for Web Services?[Maa06]

• Applying context awareness on CWS semantics.

• WS must agree on the meaning of the exchanged data.
• Semantic conflicts must be resolved automatically using context.
• Languages OWL-S (Ontology Web Language for WS) and WSDL-S (WS Description Language) can handle data conflicts of type structure but cannot handle data conflicts of type value.

What can Context do for Web Services?[Maa06]

What can Context do for Web Services?[Maa06]

• Applying context awareness on WS conciliation.

• W-Context: for context of WS (fine-grain content).
• C-Context: for context of CWS (course-grain content).

Agenda

• Review the following papers:

• [Cha04] T. Chaari, F.Laforest, A. Celentano. “Design of Context-Aware Applications Based on Web Services”. LIRIS. Dipartimento di Informatica. INSA Lyon, France
• [Maa06] Z. Maamar, D.Benslimane, N. Narendra. “What can Context do for Web Services?”. Communications of the ACM, December 2006/Vol. 49, No. 12.

• Review our Context-aware Model

• Context Architecture Using Web Services

Context–Aware Model

Context–Aware Model

Context–Aware Model using Web Services

Agenda

• Review the following papers:

• [Cha04] T. Chaari, F.Laforest, A. Celentano. “Design of Context-Aware Applications Based on Web Services”. LIRIS. Dipartimento di Informatica. INSA Lyon, France
• [Maa06] Z. Maamar, D.Benslimane, N. Narendra. “What can Context do for Web Services?”. Communications of the ACM, December 2006/Vol. 49, No. 12.

• Review our Context-aware Model

• Context Architecture Using Web Services

Context Architecture Using Web Services

Conclusions

Future Work

Context Architectures Using Web Services

• 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/