Humans have always been intrigued by their ability to reason. We have constantly attempted to emulate this process, trying almost everything, from physiological explanations, to sociological accounts. The approach with possibly the longest tradition conceives this process as a mere…

Collaborative systems are becoming a widely used tool particularly among professional communities and research groups. They provide a suitable context for distributed people working on the same subject to concentrate their work in a shared place to which everyone has…

There are many areas in Computer Science where time plays an important role. Artificial Intelligence is one of them. In this particular area Defeasible Logic Programming (DeLP) was developed to cope with incomplete and potentially inconsistent information. This formalism combines…

Defeasible Logic Programming (DeLP) is a suitable tool for knowledge representation and reasoning. Its operational semantics is based on a dialectical analysis where arguments for and against a literal interact in order to determine whether this literal is believed by…

The design of intelligent agents is a key issue for many applications. Since there is no universally accepted definition of intelligence, the notion of rational agency was proposed by Russell as an alternative for the characterization of intelligent agency.
A…

This article presents the confluence of two general ideas: Defeasible Logic Programming (DeLP, an argumentation based formalism for representing knowledge and reasoning) and Abduction in logic. In first place, we introduce a framework that formally states the problem of doing…

The notion of context and its importance in knowledge representation and nonmonotonic reasoning was first discussed in Artificial Intelligence by John McCarthy.
Ever since, contexts have found many applications in developing knowledge-based reasoning systems.
Defeasible argumentation has gained wide acceptance…

The problem of speeding up ínference has proved to be important in argumentative systems. When computing dialectical structures, several paths are searched (called argumentation lines), many of which will eventually prove useless. Morover, the performance of backward chainers degrades quickly…

In a defeasible argumentation formalism, an argument is used as a defeasible reason for supporting conclusions. A conclusion q will be considered valid only when the argument that supports it become a justification. Building a justification involves the construction of…