Context Architectures Using Web Services Candidate



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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:

  • 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/




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