Deductive question-answering systems generally evaluate queries under one of two possible assumptions which we in this paper refer to as the open and closed world assumptions. The open world assumption corresponds to the usual first order approach to query evaluation: Given a data base DB and a query Q, the only answers to Q are those which obtain from proofs of Q given DB as hypotheses. Under ...

In large document bases, hypertext retrieval techniques can be favourably used. However, for those bases, manual creation of links is not feasible. In this paper, we present a system that manages the automatic conversion of texts into hypertexts based on link type descriptions: it is discussed, where a standard database management system can be used for this goal directly and where additional o...

One of the important issues when designing effective expert systems is the validation and refinement of the acquired knowledge bases. The validation and refinement problem becomes more important and more difficult when the knowledge bases of expert systems consist of uncertain rules, e.g., probabilistic rules. In this paper, we first describe one type of inconsistency of knowledge bases called ...

We are interested in diminishing the aberrations in the lateral zones of a progressive lens. In order to achieve this, it is necessary to resolve a nonlinear optimization problem. In previous work [8], [9], this problem was modeled using bases with local control, particularly using Cubic B-Splines. However, the use of these bases in the model generates ill-conditioned problems. The illcondition...