David Billington

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Defeasible reasoning is a simple but efficient rule-based approach to nonmonotonic reasoning. It has<lb>powerful implementations and shows promise to be applied in the areas of legal reasoning and the<lb>modeling of business rules. This paper establishes significant links between defeasible reasoning and<lb>argumentation. In particular, Dung-like(More)
The importance of transformations and normal forms in logic programming, and generally in computer science, is well documented. This paper investigates transformations and normal forms in the context of Defeasible Logic, a simple but efficient formalism for nonmonotonic reasoning based on rules and priorities. The transformations described in this paper(More)
For many years, the non-monotonic reasoning community has focussed on highly expressive logics. Such logics have turned out to be computationally expensive, and have given little support to the practical use of non-monotonic reasoning. In this work we discuss defeasible logic, a less-expressive but more efficient non-monotonic logic. We report on two new(More)
Oxidation of low-density lipoprotein (LDL) has been recognized as playing an important role in the development and progression of atherosclerotic heart disease. Human LDL was isolated and challenged with a range of oxidants either in the presence or absence of AGE or its diethyl ether extract. Oxidative modification of the LDL fraction using CuSO(4),(More)
Recently there has been increased interest in logic programming-based default reasoning approaches which are not using negation-as-failure in their object language. Instead, default reasoning is modelled by rules and a priority relation among them. In this paper we compare the expressive power of two approaches in this family of logics: Defeasible Logic,(More)
Defeasible reasoning is a direction in nonmonotonic reasoning that is based on the use of rules that may be defeated by other rules. It is a simple, but often more efficient approach than other nonmonotonic reasoning systems. This paper presents a family of defeasible reasoning formalisms built around Nute’s defeasible logic. We describe the motivations of(More)
The major metabolites of morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), possess significant pharmacological properties. Whilst both metabolites bind to mu-opioid binding sites, M6G is a potent agonist whereas M3G antagonizes some of the effects of morphine and M6G. An inter-species comparison of in vitro hepatic morphine processing(More)
Logics for knowledge representation suffer from overspecialization: while each logic may provide an ideal representation formalism for some problems, it is less than optimal for others. A solution to this problem is to choose from several logics and, when necessary, combine the representations. In general, such an approach results in a very difficult(More)