Information Technology Reference
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system is sensitive to the context if it uses the context to provide information or
services that are relevant to the user; the relevance being evaluated according to the
user's ongoing task
”.
In the frame of an interactive application, consideration of the context can occur
on two levels:
- At the human-machine interface. In this case, we will speak of plasticity. Thus,
for [THE 99] plasticity is: “the ability of interfaces to adapt to their context of use
with respect to their usability. The context of use is defined as the triplet user,
platform and environment” (see also Chapter 11).
- In the content where we will talk about context awareness, defined as
[ABO 99]: “the use of context to provide appropriate information and/or services to
the user; the context being any information which can be used to characterize the
situation of an entity which can be a user, an environment, a physical or IT object”.
In the frame of an MDE-type approach, the question that arises is how to take
into account the context on a conceptual level, i.e. how to make the context
sufficiently abstract for it to be independent of the technology and sufficiently
practical for it to be used with conceptual models. Starting from existing works on
the subject, we were able to determine several different ways to deal with the
characterization of contexts:
- The first, used by [TAD 06], consists in only defining a limited and specified
number of contexts. By being based on an ensemble of rules, it then becomes
possible, all the time, to associate one and only one specified context to the
application.
- The second, used by [CHE 04], based on the previous solution, suggests
introducing the notion of context ontology. Each element of context (place, time,
technical ability, etc.) has its own ontology. It is the inference engine for all these
ontologies that enables the active context to be determined.
- The third consists in linking the notion of context to the user's ongoing
activities. Thus, certain works [BAR 04] propose basing the adaptation to context
according to the user's ongoing business processes. Other works propose integrating
the notion of intention at the user level in the adaptation to context [PAS 99]. It is,
according to these works, the only way of having a contextual adaptation that really
takes into account the needs and expectations of users.
If these solutions put forward different visions for the consideration of context,
they nonetheless have a certain number of similarities:
