modeling and using context in adapting applications to pervasive environments
DESCRIPTION
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 PresentationTRANSCRIPT
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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OUTLINE
Introduction
The scope of this paper
Context Modeling
Adaptation strategy to context
Implementation
Conclusions
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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
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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
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Context – Awareness
Definition The ability of acquiring context knowledge adaptation to the context change
Requirements Capture Interpret Store/Disseminate Adapt
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Motivations
Existing solutions specific to particular concerns a lot of interest on how to capture context
Lack of a comprehensive context model formality expressiveness
Lack of a concrete approach to adapt applications to context
generic adaptation strategy dynamic adaptation
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OUTLINE
Introduction
The scope of this paper
Context Modeling
Adaptation strategy to context
Implementation
Conclusions
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SECAS Project
Simple Environment for Context – Aware Systems
Generic and comprehensive platform
Creating new context-aware applications
Adapting existing legacy applications to new contexts
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SECAS Architecture Domain definition
interface (DDI)
domain ontology
components
domain specific rules
Terminal
Adaptation
Application core
application data sources
core services
context consumer adapter
subscribe() push() pull()
Context management
context providers
context interp reters
context manager broker
Application’s UI
UI widgets
application manager
Data/control flow Is a
Adaptation services
Functional Model
context ontology, instance and history
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OUTLINE
Introduction
The scope of this paper
Context Modeling
Adaptation strategy to context
Implementation
Conclusions
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Context Modeling
Context = (Subject, Predicate, Value, Time, Certainty)
Example= (Bob, isLocatedIn, room305, Fri-23-jun-2006-12:00:00-GMT, 0.85)
Intelligence and semantics processing (VideoService, runsOn, PDA-01) (PDA-02, runs, VideoService) (realPlayer, runsOn, laptop-01)
devices that can run Video Services
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Ontology for context modeling
Static Low level Context
Dynamic Low level Context
Deduced High Level
Context
Context interpreter
Context manager Context to knowledge conversion
Domain Specific Rules
Context -aware
Service
Rule to ontology mapping
Context History DB
Context Ontology
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Example of a context ontology
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OUTLINE
Introduction
The scope of this paper
Context Modeling
Adaptation strategy to context
Implementation
Conclusions
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Application’s Functional Model
Functional Model = application services description + services dependences
XML deployment descriptor (extension of pnml)
Authentication
RecordInfo RecordImages
displayTemperatures
PatientList
userID is not null
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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
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Service adaptation entity
Adapter (proxy)
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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
Example
//context situation ¬acceptContentType(actual_device, ‘image’) hasService(actual_application, ?S) hasOutputVector(?S,?Ov) hasParameter(?Ov,?P) hasType(?P,’image’) //adaptation action hasAdaptation(actual_application, ?A) hasOperator(?A,”lockService”) hasAdaptationParemeter(?A,?S)
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OUTLINE
Introduction
The scope of this work
Context Modeling
Adaptation strategy to context
Implementation
Conclusions
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SECAS Administration User Interface
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Context1: Doctor1 using SICOM on a standard PC
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Context2: Doctor1 using SICOM on a smartPhone
E1 E2 E3 E4
E5 E6 E’6
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OUTLINE
Introduction
The scope of this paper
Context Modeling
Adaptation strategy to context
Implementation
Conclusions
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Conclusions
A comprehensive Context model based on ontology representation
An extensible adaptation platform to: create context – aware applications adapt existing applications to context
Platform under development Services adaptation module completed and validated Content adaptation module User interface adaptation module
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Question time !
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