Philippa, a Greek nineteen year old student at Patras University, has just discovered that Nikos and Angela are not her true parents; she was adopted when she was six months old from an orphanage in Sao Paulo. The news really shook Philippa. Much of what she used to believe all her life about herself and her family was wrong. After recovering from the initial shock she started putting her thoug...

Knowledge systems as currently configured are static in their concept sets. As knowledge maintenance becomes more sophisticated, the need to address issues concerning dynamic concept sets will naturally arise. Such dynamics is properly called ontology revision, or in the simpler case, expansion. A number of sub-disciplines in artificial intelligence, philosophy and recursion theory have results...

Background and purpose - Recurrent dislocation is the commonest cause of early revision of a total hip arthropasty (THA). We examined the effect of femoral head size and surgical approach on revision rate for dislocation, and for other reasons, after total hip arthroplasty (THA). Patients and methods - We analyzed data on 166,231 primary THAs and 3,754 subsequent revision THAs performed between...

We have proposed in previous work [11, 12] a construction that allows to define operators for iterated revision from classical AGM revision operators. We called those operators revision operators with memory and show that the operators obtained have nice logical properties. But those operators can be considered as too conservative, since the revision policy of the agent, encoded as a faithful a...

Alchourrón devoted his last years to the analysis of the notion of defeasible conditionalization. He developed a formal system capturing the essentials of this notion. His definition of the defeasible conditional is given in terms of strict implication operator and a modal operator f which is interpreted as a revision function at the language level. In this paper, we will point out that this un...

In this paper, we propose a new method for revising terminologies in description logic-based ontologies. Our revision method is a reformulation of the kernel revision operator in belief revision. We first define our revision operator for terminologies in terms of MIPS (minimal incoherence-preserving sub-terminologies), and we show that it satisfies some desirable logical properties. Second, two...

Fermé and Rott (‘Revision by Comparison’, Artificial Intelligence 157, 2004) introduced a binary operation of ‘revision by comparison’ and pointed out that this method of changing epistemic states has both characteristics of belief contraction (with respect to the ‘reference sentence’) and characteristics of belief revision (with respect to the ‘input sentence’). Using revision by comparison as...

We present a revision learning model for improving the accuracy of a dependency parser. The revision stage corrects the output of the base parser by means of revision rules learned from the mistakes of the base parser itself. Revision learning is performed with a discriminative classifier. The revision stage has linear complexity and preserves the efficiency of the base parser. We present empir...

In this work, we address the problem of revision of OWL-DL knowledge bases. We focus on belief bases revision as it has previously been shown that OWL-DL is not AGM-compliant for revision. Previously an algorithm for belief base semi-revision for propositional logic has been defined; in particular it has been shown how the diagnosis problem can be translated into a revision problem. In this wor...

Ontology is a formal explicit specification of shared conceptualisation. Ontology revision refers to revising the ontology as a result of learning or when new knowledge is gained. This paper discusses the possibility of using the concept of belief revision as a basis for ontology revision. Belief revision is concerned with the approach of updating and revising a belief set so that it remains co...