69 research outputs found
Automating the repair of faulty logical theories
This thesis aims to develop a domain-independent system for repairing faulty Datalog-like theories by combining three existing techniques: abduction, belief revision and conceptual change. Accordingly, the proposed system is named the ABC repair system (ABC). Given an observed assertion and a current theory, abduction adds axioms, or deletes preconditions, which explain that observation by making the corresponding assertion derivable from the expanded theory. Belief revision incorporates a new piece of information which conflicts with the input theory by deleting old axioms. Conceptual change uses the reformation algorithm for blocking unwanted proofs or unblocking wanted proofs. The former two techniques change an axiom as a whole, while reformation changes the language in which the theory is written. These three techniques are complementary. But they have not previously been combined into one system. We are working on aligning these three techniques in ABC, which is capable of repairing logical theories with better result than each individual technique alone. Datalog is used as the underlying logic of theories in this thesis, but the proposed system has the potential to be adapted to theories in other logics
Signature Entrenchment and Conceptual Changes in Automated Theory Repair
Human beliefs change, but so do the concepts that underpin them. The recent
Abduction, Belief Revision and Conceptual Change (ABC) repair system combines
several methods from automated theory repair to expand, contract, or reform
logical structures representing conceptual knowledge in artificial agents. In
this paper we focus on conceptual change: repair not only of the membership of
logical concepts, such as what animals can fly, but also concepts themselves,
such that birds may be divided into flightless and flying birds, by changing
the signature of the logical theory used to represent them. We offer a method
for automatically evaluating entrenchment in the signature of a Datalog theory,
in order to constrain automated theory repair to succinct and intuitive
outcomes. Formally, signature entrenchment measures the inferential
contributions of every logical language element used to express conceptual
knowledge, i.e., predicates and the arguments, ranking possible repairs to
retain valuable logical concepts and reject redundant or implausible
alternatives. This quantitative measurement of signature entrenchment offers a
guide to the plausibility of conceptual changes, which we aim to contrast with
human judgements of concept entrenchment in future work.Comment: Presented at The Ninth Advances in Cognitive Systems (ACS) Conference
2021 (arXiv:2201.06134
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