[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.
