Multicriteria Information Retrieval in Textual Corpora - Geographical Information Retrieval in Textual Corpora - page 74

advanced-level users assign modal operators to the search criteria in order to
modulate their range in a finer way. We propose the requirement operator of + and −
type and the preference operator of ˆ type. The ˆ operator gradually penalizes or
boosts a criterion by a weight coefficient ranging between [−1, 1]. Figure 3.6
illustrates the approach of an advanced user. The modal operators of requirement and
preference specify the role associated with each criterion, independently of the
dimension involved. The matching operators (intersection (∩), equality (=), etc.), on
the other hand, are dependent on the spatial, temporal or thematic dimension of the
criteria.
Figure 3.6. An example of advanced representation of a multicriteria
geographic query - illustration taken from [PAL 10a]
The correspondence between the five previously defined roles and the modal
operators of requirement and preference is shown in Figure 3.7. To each of the five
roles corresponds a combination of levels of requirement and preference defined by
default.
Figure 3.7. Detailed description of the predefined roles and
corresponding default values
Figures 3.4 and 3.6 illustrate two levels of formalization of the multicriteria query
which we have taken as an example. Let us note that, in this example, the temporal
criterion “1800-1900” is not required but promoted as soon as it is satisfied in a
document. The thematic criterion “mountain”, on the other hand, is at the same time
required and promoted; a Target role is associated with it.