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- Revision by comparisonPublication . Fermé, Eduardo; Rott, HansSince the early 1980s, logical theories of belief revision have offered formal methods for the transformation of knowledge bases or “corpora” of data and beliefs. Early models have dealt with unconditional acceptance and integration of potentially belief-contravening pieces of information into the existing corpus. More recently, models of “non-prioritized” revision were proposed that allow the agent rationally to refuse to accept the new information. This paper introduces a refined method for changing beliefs by specifying constraints on the relative plausibility of propositions. Like the earlier belief revision models, the method proposed is a qualitative one, in the sense that no numbers are needed in order to specify the posterior plausibility of the new information. We use reference beliefs in order to determine the degree of entrenchment of the newly accepted piece of information. We provide two kinds of semantics for this idea, give a logical characterization of the new model, study its relation with other operations of belief revision and contraction, and discuss its intuitive strengths and weaknesses.
- Lógica e inteligência artificialPublication . Fermé, Eduardo; Hansson, Sven Ove
- Revisión de creenciasPublication . Fermé, EduardoEn el presente artículo presentamos la teoría de cambio de creencias AGM: sus orígenes, su axiomática, su semántica y diferentes métodos para construir funciones de cambio. Mostramos la relación entre el modelo AGM y la lógica condicional.
- Credibility limited revisionPublication . Hansson, Sven Ove; Fermé, Eduardo Leopoldo; Cantwell, John; Falappa, Marcelo AlejandroFive types of constructions are introduced for non-prioritized belief revision, i.e., belief revision in which the input sentence is not always accepted. These constructions include generalizations of entrenchment-based and sphere-based revision. Axiomatic characterizations are provided, and close interconnections are shown to hold between the different constructions.
- On the implementation of the belief change operatorsPublication . Falappa, Marcelo A.; Fermé, Eduardo L.
- Domain-specific trust for context-aware BDI Agents: preliminary workPublication . Casals, Arthur; Fermé, Eduardo; Brandao, Anarosa A. F.Context-aware systems are capable of perceiving the physical environment where they are deployed and adapt their behavior accordingly. Multiagent systems based on the BDI architecture can be used to process contextual information in the form of beliefs. Contextual information can be divided and structured in the form of information domains. Information and experience sharing enables a single agent to receive data on different information domains from another agent. In this scenario, establishing a trust model between agents can take into account the relative perceptions each agent has of the others, as well as different trust degrees for different information domains. The objective of this work is to adapt an epistemic model to be used by agents with their belief revision in order to establish a mechanism of domain-specific relative trust attribution. Such mechanism will allow for each agent to possess different trust degrees associated with other agents regarding different information domains.
- Possible worlds semantics for partial meet multiple contractionPublication . Reis, Maurício D. L.; Fermé, EduardoIn the logic of theory change, the standard model is AGM, proposed by Alchourrón et al. (J Symb Log 50:510–530, 1985). This paper focuses on the extension of AGM that accounts for contractions of a theory by a set of sentences instead of only by a single sentence. Hansson (Theoria 55:114–132, 1989), Fuhrmann and Hansson (J Logic Lang Inf 3:39–74, 1994) generalized Partial Meet Contraction to the case of contractions by (possibly non-singleton) sets of sentences. In this paper we present the possible worlds semantics for partial meet multiple contractions.
- Belief revision and computational argumentation: a critical comparisonPublication . Baroni, Pietro; Fermé, Eduardo; Giacomin, Massimiliano; Simari, Guillermo RicardoThis paper aims at comparing and relating belief revision and argumentation as approaches to model reasoning processes. Referring to some prominent literature references in both fields, we will discuss their (implicit or explicit) assumptions on the modeled processes and hence commonalities and differences in the forms of reason ing they are suitable to deal with. The intended contribution is on one hand assessing the (not fully explored yet) relationships between two lively research fields in the broad area of defeasible reasoning and on the other hand pointing out open issues and potential directions for future research.
- Droide virtual: utilização de robôs na aprendizagem colaborativa da programação através da webPublication . Santos, Elci Alcione Almeida dos; Fermé, Eduardo Leopoldo; Fernandes, Elsa Maria dos SantosEste artigo apresenta o projecto DROIDE VIRTUAL, que tem por objectivo descrever, analisar e compreender o processo de construção do conhecimento sobre conceitos de programação e o desenvolvimento de competências nesta área. O projecto tem uma duração de três anos ― sendo este o primeiro ano ― e envolve estudantes do ensino secundário da Madeira, Açores, Canárias e Cabo Verde, os quais aprendem programação desenvolvendo pequenos projectos de robótica através da colaboração virtual em um ambiente de aprendizagem baseado na web.
- Construction of system of spheres-based transitively relational partial meet multiple contractions: an impossibility resultPublication . Reis, Maurício D. L.; Fermé, Eduardo; Peppas, PavlosIn this paper we show that, contrary to what is the case in what concerns contractions by a single sentence, there is not a system of spheres-based construction of multiple contractions which generates each and every transitively relational partial meet multiple contraction. Before proving the general result, we consider the class of system of spheres-based mul tiple contractions introduced in [17,5] and show that this class neither subsumes nor is subsumed by the class of transitively relational partial meet multiple contractions. Furthermore, we propose two system of spheres-based constructions of multiple con tractions which generate (only) transitively relational partial meet multiple contractions. Therefore we can conclude that, although it is impossible to obtain a system of spheres based definition of all the transitively relational partial meet multiple contractions, there are classes of system of spheres-based multiple contractions which are subsumed by the class of transitively relational partial meet multiple contractions.