In this paper we analyse the benefits of incorporating interval-valued fuzzy sets into the Bousi-Prolog system. A syntax, declarative semantics and im- plementation for this extension is presented and formalised. We show, by using potential applications, that fuzzy logic programming frameworks enhanced with them can correctly work together with lexical resources and ontologies in order to improve their capabilities for knowledge representation and reasoning.
Ciao-Prolog and Bousi-Prolog have relevant differences at the semantic levels as well. Firstly, Bousi-Prolog implements the concept of cut-level, which allows to the user imposes a threshold in the system, and according to it you can be as precise as you want in your answer. This is a substantial change due to the introduction of a threshold operational semantics. Therefore, our operational mechanism behaves very much as the one of a Prolog system (obtaining correct answers one by one), while this option is not available in Ciao semantics. As we mentioned in section , a @math -cut for IVFS approximation degrees has been implemented. The concepts of interpretation, least model semantics, model, so on, are presented and defined in a different way, in Bousi-Prolog the operational semantics is based an extension of SLD Resolution. @cite_4 the type of resolution is based on the classical SLD Resolution of Prolog Systems.
@cite_4
2007452568
We present a definition of a Fuzzy Prolog Language that models B([0,1])-valued Fuzzy Logic, and subsumes former approaches because it uses a truth value representation based on a union of sub-intervals on [0,1] and is defined using general operators that can model different logics. This extension to Prolog is implemented by interpreting fuzzy reasoning as a set of constraints that are propagated through the rules by means of aggregation operators. Declarative and procedural semantics for Fuzzy Logic programs are given and their equivalence is proven. In addition, we present the implementation of an interpreter for this conceived language using constraint logic programming over real numbers.