Context Architectures Using Web Services

1
Context Architectures Using Web Services

• Candidate
• Alvaro E. Escobar
• Advisors
• Dr. Maria Petrie
• Dr. Eduardo Fernandez

Department of Computer Science and
Engineering Florida Atlantic University, Boca
Raton FL. 01/04/2007
2
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

3
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.

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Design of Context-Aware Applications Based on Web
Services Cha04

• Steps to Context-awarenessDey01
• 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.

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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

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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.

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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.

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Design of Context-Aware Applications Based on Web
Services
2
3

• Service Oriented Architecture (SOA) Cha04
• Context Capturing
• Context Interpreting
• Context Modeling
• Context Dissemination
• Context Adaptation
• Data flow (content)
• Visualization (UI)
• Application behavior (service)

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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

10
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.

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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.

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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

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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.

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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.

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What can Context do for Web Services?Maa06
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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).

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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

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ContextAware Model
19
ContextAware Model
20
ContextAware Model using Web Services
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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

22
Context Architecture Using Web Services
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Conclusions

• Context is a fundamental concept in mobile
  systems.
• Different researchers use different variations of
  context.
• Web Services is the widespread approach to
  application integration.
• Integrated Web Services into our Context Model
  for easier application integration.
• Created a Context Architecture incorporating Web
  Services.

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Future Work

• Simulate the many context and location-aware
  scenarios through our model.
• Build sequence diagrams for some Use Cases.
• The 4th International Conference on Ubiquitous
  Intelligence and Computing (UIC-07). Hong Kong,
  China, July 11-13, 2007. (01/15/2007)
• ICPS'07 IEEE International Conference on
  Pervasive Services, July 15 - 20, 2007, Istanbul,
  Turkey (02/04/2007)
• ICWN'07- The 2007 International Conference on
  Wireless Networks. Monte Carlo Resort, Las Vegas,
  June 25-28, 2007 (02/20/2007)
• The Second International Conference on Pervasive
  Computing and Applications (ICPCA07) July 26-27,
  2007, Birmingham, UK (02/28/2007)
• First International Conference on Autonomic
  Computing and Communication Systems, 28-30
  October 2007, Rome Italy (04/18/2007)

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Context Architectures Using Web Services

• References
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  Resource Management in the Wireless Internet,
  IEEE Transactions on Software Engineering. Vol.
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• 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
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