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
ComputingFou06

• 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
ComputingFou06

• 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
ComputingFou06

• User Domain Context
• Provide knowledge to enable applications adapt to
  the profile of their users.
• Subjective Includes users personality and
  psychology.
• User mood and feelings (fear, anger, sad)
• Objective Includes users 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
ComputingFou06

• System Domain Context
• Describes digital, software and hardware
  resources available to users.
• Processing power
• Hardware components
• Network interfaces
• Storage
• Software components

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Towards Ad-hoc Contextual Services for Pervasive
ComputingFou06

• 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
ComputingFou06

• 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
ComputingFou06

• 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)

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Towards Ad-hoc Contextual Services for Pervasive
ComputingFou06

• 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.

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Towards Ad-hoc Contextual Services for Pervasive
ComputingFou06 Context Sources
12
Towards Ad-hoc Contextual Services for Pervasive
ComputingFou06Context Consumption
13
Towards Ad-hoc Contextual Services for Pervasive
ComputingFou06Context-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/p
  ub/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,
  ICWCF07, 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.
• Rae05M. 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
• UbiComp07 - 9th International Conference on
  Ubiquitous Computing, 16-19 September 2007,
  Innsbruck, Austria. (June deadline)
• ACM Symposium on Applied Computing 2008, Special
  Track on Ubiquitous ComputingUbiquitous and
  Pervasive eCommerce and eBusiness. March 16-20,
  2008, Fortaleza, Brazil. (Sept deadline)
• MobiSys08 - The 6th International Conference on
  Mobile Systems. TBA
• MobiHoc08 - The 9th ACM International Symposium
  on Mobile Ad Hoc Networking and Computing. May
  26-30, 2008, Hong Kong (Nov/22 deadline)