Information Technology Reference
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surjective and not injective. Indeed, a solution proposal can be associated with
several distinct situations of use. The (
S
B
) function is therefore not injective.
Furthermore, a function is surjective when any element of the target ensemble can
be associated with an element of the domain. The function (
S
B
) is therefore
surjective, as for any proposition P
R
there is an associated situation of use. Thanks to
the formatting of this function and to the previous modeling, it becomes possible to
implement a specification aiding tool to be used by the designer. Indeed, modeling
enables us to build a view of the problem in terms of classes and objects linked by
methods. The implementation of these classes according to the function of
satisfaction of the need then leaves us to consider the generation of a tool enabling
us to search for and manage knowledge that qualifies the user needs and solutions
that are associated with them. These recommendations are expressed in terms of
entities of the domain model.
2.5. RAMSES in the context of the P@ss-ITS project
As was said in the introduction, the traveler information system design project,
P@ss-ITS
, offered a favorable ground for the implementation of the RAMSES
approach. Indeed, the highly iterative aspect of the application, the diversity of the
players involved and the variability of situations of use were of particular interest for
the collection and analysis of data.
The operational timeframe of the project was nonetheless constrained to an
implementation of RAMSES in two distinct phases. The first phase was integrated
in the project; it covered the steps of ergonomic collection and analysis, then it
contributed to the use-oriented specifications of
P@ss-ITS
. A second phase unfolded
in parallel to the realization of the project; based on real data, it consisted of
studying the phases of modeling, specification and evaluation of specifications via
the MASSIV application.
The initial phase of the project enabled us to identify the information that can
help users, both collectively and individually, to reach their destination and attenuate
the impact of possible disruptions. As for any design of a “general public” product,
this analysis phase implies taking into account the variability of the population,
contexts and objectives of use in order to put forward tools that are adapted to the
greatest number of potential situations. The preparation of collections therefore
required the definition of the samples to be studied: population, contexts, travels
[VAL 10a]. The collections were then carried out according to principles of an
ergonomic approach, by observation of the activity in an actual situation. Tools of
chronological re-transcription were then defined to keep the context of the observed
actions. Next, each step was analyzed to identify the information needs of the
travelers.
