We propose a model

In this paper we present a systematic study of abductive consequence relations. We show that a monotone abductive consequence relation satisfies the properties of a cumulative monotonic system as defined by Kraus, Lehmann and Magidor when the disjunction of all abductive explanations is the explanation used to justify the observations. We also show that, in general, for this class of abductive consequence relations the Or rule does not hold. We present an example that shows that when there are preferences between different abductive explanations monotonicity does not hold. We show that non-monotonic abductive systems preserve a partial version of rational monotonicity and in fact are very similar to rational relations. We also present semantic characterizations of both monotonic and non-monotonic abductive systems in terms of cumulative models as defined by Kraus, Lehmann and Magidor. Keywords: Abduction, non-monotonic consequence relations, non-monotonic logic, belief revision. 1 I...

OF THE DISSERTATION The Complexity of Querying Indefinite Information: Defined Relations, Recursion and Linear Order by Ronald van der Meyden, Ph.D. Dissertation Director: L.T. McCarty This dissertation studies the computational complexity of answering queries in logical databases containing indefinite information arising from two sources: facts stated in terms of defined relations, and incomplete information about linearly ordered domains. First, we consider databases consisting of (1) a DATALOG program and (2) a description of the world in terms of the predicates defined by the program as well as the basic predicates. The query processing problem in such databases is related to issues in database theory, including view updates and DATALOG optimization, and also to the Artificial Intelligence problems of reasoning in circumscribed theories and sceptical abductive reasoning. If the program is non-recursive, the meaning of the database can be represented by Clark's Predicate Completion,...

ion in Diagnosis: A Schema Based Account Carl R. Stern University of New Mexico and George F. Luger University of New Mexico Address correspondence to: Carl R. Stern Department of Computer Science University of New Mexico Albuquerque, New Mexico 87131 (505) 345-4147 ostern@cs.unm.edu Abstract We present a schema-based architecture for semiconductor failure analysis. Schemas serve to guide the application of scientific domain knowledge in the construction of causal explanations. They organize data gathering and provide a road map for the detailed investigation of causal processes. They shape the form of explanations, ensuring that explanations satisfy not only theoretical requirements, e.g. consistency with applicable causal laws, but also practical requirements, in particular the need to support a specific range of remedial practices. Our work is based on the observation and analysis of expert performance in the area of semiconductor component failure analysis. We have worked with fiv...

this paper we will show that the two problems mentioned above are formally equivalent. That is to say, there are sets of rationality postulates (as in [1, 8]) for abduction that are, in a very precise way, equivalent to rationality postulates (as in [4, 3]) for j¸ ab . Moreover, we show that j¸ ab satisfies certain rationality postulates if and only if PE(ff) is given by certain types of preference relation among formulas. We will also show that every consequence relation satisfying certain rationality postulates is of the form j¸ ab . We can summarize our results by saying that abduction and non-monotonic reasoning are interdefinable

This paper deals with the problem of providing assistance to a Bridge player using Artificial Intelligence techniques. In order to achieve this goal, we propose an approach that consists in making assumptions about the honor cards location, then to gradually eliminating the inconsistent assumptions until locating all honor cards. Based on the bids, assumptions about honor cards distribution are made using abduction reasoning. The consistency of these assumptions is managed by an Assumption-based Truth Maintenance System (ATMS). As the game progresses, playing a card generates facts, thereby invalidating some assumptions that cause contradiction and transforming some others into facts corresponding to the location of honor cards.