USING PRIORITIES TO COMBINE KNOWLEDGE BASES

Two or more companies, each with its own knowledge base, may merge. In that case one option is to merge the knowledge bases into one knowled ge base. It can happen that some of the information contained in one o r more knowledge bases may be in conflict with information in the othe r knowledge bases. There may be several such points of conflict and an y information may be involved in several different such points of conf lict. In that case, the integrator of the knowledge bases may prefer a certain claim to another in one conflict-point without necessarily pr eferring that claim in another conflict-point. Our work constructs a f ramework within which the consequences of a set of such preferences (e xpressed as priorities among sets of statements) can be computed. We g ive three types of semantics for priorities, two of which are shown to be equivalent to one another. The third type of semantics for priorit ies is shown to be more cautious than the other two. In terms of these semantics for priorities, we give a function for combining knowledge from different sources such that the combined knowledge is conflict-fr ee and satisfies all the priorities.