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We consider the problem of learning a user's ordinal preferences on a multiattribute domain, assuming that her preferences are lexicographic. We introduce a general graphical representation called LP-trees which captures various natural classes of such preference relations, depending on whether the importance order between attributes and/or the local(More)
For ontologies represented as Description Logic Tboxes, op-timised DL reasoners are able to detect logical errors, but there is comparatively limited support for resolving such problems. One possible remedy is to weaken the available information to the extent that the errors disappear, but to limit the weakening process as much as possible. The most obvious(More)
We look at the problem of revising fuzzy be­ lief bases, i.e., belief base revision in which both formulas in the base as well as revision­ input formulas can come attached with vary­ ing truth-degrees. Working within a very general framework for fuzzy logic which is able to capture certain types of uncertainty calculi as well as truth-functional fuzzy log­(More)
Standard belief contraction assumes an underlying logic containing full classical propositional logic, but there are good reasons for considering contraction in less expressive logics. In this paper we focus on Horn logic. In addition to being of interest in its own right, our choice is motivated by the use of Horn logic in several areas, including ontology(More)
We look at iterated non-prioritised belief revision, using as a starting point a model of non-prioritised revision, similar to Makinson's screened revision, which assumes an agent keeps a set of core beliefs whose function is to block certain revision inputs. We study postulates for the iteration of this operation. These postulates generalise some of those(More)
We develop a simple mathematical model for forced flow of culture medium through a porous scaffold in a tissue-engineering bioreactor. Porous-walled hollow fibres penetrate the scaffold and act as additional sources of culture medium. The model, based on Darcy's law, is used to examine the nutrient and shear-stress distributions throughout the scaffold. We(More)
We provide a formal study of belief retraction operators that do not necessarily satisfy the (Inclusion) postulate. Our intuition is that a rational description of belief change must do justice to cases in which dropping a belief can lead to the inclusion, or 'liberation', of others in an agent's corpus. We provide a few possible weakenings of the(More)