Daniel Rocacher

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The expression of user preferences into queries addressed to a relational database management system allows to obtain more appropriate answers. In this context, it is possible to consider fuzzy bipolar conditions which are made of two parts: i) a fuzzy constraint to represent a mandatory requirement, ii) a fuzzy wish to represent an optional requirement.(More)
Previously studied fuzzy bipolar conditions of type ”and if possible” are made of a mandatory condition c and an optional condition w. They allow expressing complex preferences of a conjunctive nature. We define in this paper, a new kind of fuzzy bipolar conditions of the form ”or else” which express complex preferences of a disjunctive nature. We show that(More)
The role and properties of the division operator are well known in the framework of queries addressed to regular relational databases. However, Boolean queries may turn out to be too restrictive to answer some user needs and it is desirable to consider extended queries by introducing preferences inside selection conditions. In this paper, the extension of(More)
Linguistic quantifiers are quantifiers defined by linguistic expressions like “around 5” or “most of,” and many types of linguistic quantifiers can be found in the literature (Diaz-Hermida, Bugarin, & Barro, 2003; Glockner, 1997, 2004a, 2004b; Losada, Díaz-Hermida, & Bugarín, 2006) (as semifuzzy quantifiers which allow modeling expressions like “there are(More)
Flexible querying of information systems dedicated to multimodal transport networks aims to help user organizing his/her trips by promoting public transport networks (bus, subway, train, boat, plane, etc.). In this context, it is necessary to provide an integrated environment in which it is possible for the user to express queries with complex preferences(More)
In this paper, we propose a novel approach for service retrieval that takes into account the service behavior (described as process model) and relies both on preference satisfiability and structural similarity. User query and target process models are represented as annotated graphs, where user preferences on QoS (Quality of Service) attributes (such as(More)
A fuzzy bag is a bag in which each occurrence of an element is associated with a grade of membership. This notion can be viewed as a generalization of the concepts of set, fuzzy set and bag. The set of fuzzy integers (Nf ) provides a general characterization in which all these different concepts are treated in a uniform way and can then be composed. In the(More)
Fuzzy queries addressed to a relational database management system are based on the expression of user preferences which leads to obtain more appropriate answers. Fuzzy set theory provides powerful tools to define such conditions (fuzzy conditions). In this context, it is possible to consider fuzzy bipolar conditions which are made of two fuzzy sets to(More)