Geodesic Merging

We pursue an account of merging through the use of geodesic semantics, the semantics based on the length of the shortest path on a graph. This approach has been fruitful in other areas of belief change such as revision and update. To this end, we introduce three binary merging operators of propositions defined on the graph of their valuations and we characterize them with a finite set of postulates. We also consider a revision operator defined in the extended language of pairs of propositions. This extension allows us to express all merging operators through the set of revision postulates

On the Difference between Merging Knowledge Bases and Combining them

We investigate the logical properties of knowledge base combination operators proposed in the literature. These operators are based on the selection of some maximal subsets of the union of the knowledge bases. We argue that they are not fully satisfactory to merge knowledge bases, since the source of information is lost in the combination process. We show that it is the reason why those operators do not satisfy a lot of logical properties. Then we propose to use more rened selection mechanisms in order to take the distribution of information into account in the combination process. That allows to dene merging operators with a more subtle behaviour. 1 INTRODUCTION In the elds of articial intelligence and databases, one is often faced with conicting information coming from several sources. Thus, an important problem in such cases is how to reach a coherent piece of information from these contradictory ones. For example, if one wants to build an expert system from a ..

Apports de la logique mathématique en ingénierie des exigences

This thesis deals with requirements engineering (RE). RE characterizes the process leading to consistent set of specifications about some product. We have identified three distinct phases in RE process: requirements modelling, inconsistency management and requirements distribution. In the modelling phase, we have used CO, a logic of preferences, which has allowed us to express each agent's requirements in an ordonned way, but also domain constraints and complex normative sentences. We have then defined the notion of consistency between those three notions. Concerning the possible conflicts between requirements emitted by different agents, we have developped MF, a modal logic allowing to reason on belief bases obtained by majority merging. We have also developped Prolog automatic prover for MF. We have then shown that our approach allows to reason on ordonned or unordonned requirements sets. Finally, we have proposed to include in the RE process a distribution phase. The requirements are distributed among a set of executive agents. We have defined a simple model of agency from which we can derive the agent's goals. We have then extended this approach to multiagents systems and defined a distribution model based on a central entity controlling the distribution process