Lyon Research Center for Images and Intelligent Information Systems IEEE International Conference on Pervasive Services 2006 FRE 2672 INSA Lyon ICPS, 27 June 2006 Modeling and Using Context in Adapting Applications to Pervasive Environments Tarak Chaari, Dejene Ejigu, Frédérique Laforest and Vasile-Marian Scuturici
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Modeling and Using Context in Adapting Applications to Pervasive Environments
Modeling and Using Context in Adapting Applications to Pervasive Environments. Tarak Chaari, Dejene Ejigu, Frédérique Laforest and Vasile-Marian Scuturici. OUTLINE. Introduction The scope of this paper Context Modeling Adaptation strategy to context Implementation Conclusions. - PowerPoint PPT Presentation
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Lyon Research Center for Images and Intelligent Information Systems
IEEE International Conference on Pervasive Services 2006
FRE 2672
INSA Lyon
ICPS, 27 June 2006
Modeling and Using Context in Adapting Applications to Pervasive Environments
Tarak Chaari, Dejene Ejigu,
Frédérique Laforest and Vasile-Marian Scuturici
ICPS 2006 2
OUTLINE
Introduction
The scope of this paper
Context Modeling
Adaptation strategy to context
Implementation
Conclusions
ICPS 2006 3
What is context?
Fuzzy and general word
Where are we? What we are doing? …
1996, Brown’s definitionLocation, identity, application and time
2001, Dey’s definitionAny information characterizing an entityAn entity is a person, a location, an object… The most general and adopted definition Too vague and it does not help modelling the context
ICPS 2006 4
context definition and properties
Definition: context is the set of external parameters that can modify the behaviour of an application by defining new views on its data and services
Wingorad: something is context because of the way it is used in interpretation, not due to its inherent properties
Example: GPS coordinates in a healthcare application / in traffic regulation application
Context parameters are transparent to the user
New instance = new contextual situation
These precisions help adding context – awareness to non adapted application
ICPS 2006 5
Context – Awareness
Definition The ability of acquiring context knowledge adaptation to the context change
Functional Model = application services description + services dependences
XML deployment descriptor (extension of pnml)
Authentication
RecordInfo RecordImages
displayTemperatures
PatientList
userID is not null
ICPS 2006 16
Service Adaptation strategy
Initial Functional Model
Adapted Functional Model 1
Adaptation entities
Adapted Functional Model 2
Adapted Functional Model 3
Context situation 1
Context situation 3
Context situation 2
ICPS 2006 17
Service adaptation entity
Adapter (proxy)
ICPS 2006 18
Service adaptation rules
Pairs (context situation, adaptation action)Context situation = Logical expressions of context predicatesAdaptation action = a list of adaptation operators
Operators on the functional model Operators on the inputs and outputs of services Operators on service versions