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REVIGIS Résumé de rapport

Project ID: IST-1999-14189
Financé au titre de: FP5-IST
Pays: France

Reversibility of fusion

In the context of GIS we deal with data coming from different sources providing data with various qualities. Revision holds in the case of two conflicting sources, one preferred, more plausible, more reliable than the other. Revision means restoring consistency while keeping the preferred observation and removing the least possible previous observations. Revision process can be seen as a special case of the fusion process, fusion of two weighted sources one assigned a weight more important than the other. Fusion is a more general process, which deals with merging several sources. Fusion generally is more complex than revision, anyway in case of conflicting data; restoring consistency is crucial, removing the least possible data from the different sources, the strategy depending on the relative reliability, plausibility, and preferences on the sources. Different fusion operators have been proposed according to priorities are available or not. However these operators are not reversible which is a real problem when dealing with real applications.

We add the property of reversibility to some known fusion operators (max, sum, lex, weighted sum), when priorities of propositional belief bases are explicit which generalizes the results obtained for the reversibility of revision. At a semantic level, epistemic states are represented by total pre-orders on interpretations, called local pre-orders, and the semantic fusion process constructs a global total pre-order on interpretations. Total pre-orders are represented by means of polynomials, which allow to recover the local pre-orders from the global pre-order. At a syntactic level, epistemic states are represented by weighted belief bases and the syntactic fusion process consists in constructing a global weighted belief base. Since weights are represented by polynomials they allow recovering the original belief bases from the global belief base. We show the equivalence between semantic and syntactic approaches of reversibility. We use this approach is a real application in the framework of submarine archaeology where the reversible fusion is applied to amphoras measurement.

J. Seinturier, P. Drap, O. Papini : Fusion reversible: application a l'information archeologique. Proceedings of JNMR'2003. Paris. 2003.


Odile PAPINI, (professor)
Tél.: +33-4-94142656
Fax: +33-4-94142897