Tarak Chaari, Dejene Ejigu, Frédérique Laforest and Vasile-Marian Scuturici

• Tarak Chaari, Dejene Ejigu,

• Frédérique Laforest and Vasile-Marian Scuturici

Introduction

• Introduction

• The scope of this paper

• Context Modeling

• Adaptation strategy to context

• Implementation

• Conclusions

Fuzzy and general word

• Fuzzy and general word

• Where are we? What we are doing? …

• 1996, Brown’s definition

• Location, identity, application and time

• 2001, Dey’s definition

• Any information characterizing an entity
• An entity is a person, a location, an object…
• The most general and adopted definition
• Too vague and it does not help modelling the context

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

• 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

Definition

• Definition

• The ability of acquiring context knowledge
• adaptation to the context change

• Requirements

• Capture
• Interpret
• Store/Disseminate
• Adapt

Existing solutions

• 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

Introduction

• Introduction

• The scope of this paper

• Context Modeling

• Adaptation strategy to context

• Implementation

• Conclusions

Simple Environment for Context – Aware Systems

• Simple Environment for Context – Aware Systems

• Generic and comprehensive platform

• Creating new context-aware applications
• Adapting existing legacy applications to new contexts

Introduction

• Introduction

• The scope of this paper

• Context Modeling

• Adaptation strategy to context

• Implementation

• Conclusions

Context = (Subject, Predicate, Value, Time, Certainty)

• 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

Introduction

• Introduction

• The scope of this paper

• Context Modeling

• Adaptation strategy to context

• Implementation

• Conclusions

Functional Model = application services description + services dependences

• Functional Model = application services description + services dependences

• XML deployment descriptor (extension of pnml)

Adapter (proxy)

• Adapter (proxy)

Pairs (context situation, adaptation action)

• Pairs (context situation, adaptation action)

• Context situation = Logical expressions of context predicates
• Adaptation action = a list of adaptation operators
• Operators on the functional model
• Operators on the inputs and outputs of services
• Operators on service versions

• Example

Introduction

• Introduction

• The scope of this work

• Context Modeling

• Adaptation strategy to context

• Implementation

• Conclusions

E1 E2 E3 E4

• E1 E2 E3 E4

• E5 E6 E’6

Introduction

• Introduction

• The scope of this paper

• Context Modeling

• Adaptation strategy to context

• Implementation

• Conclusions

A comprehensive Context model based on ontology representation

• 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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