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Michael J. Maher

Bio: Michael J. Maher is an academic researcher from University of New South Wales. The author has contributed to research in topics: Defeasible logic & Logic programming. The author has an hindex of 39, co-authored 154 publications receiving 7180 citations. Previous affiliations of Michael J. Maher include Australian Defence Force Academy & University of Texas at Austin.


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Journal ArticleDOI
TL;DR: This survey of CLP is to give a systematic description of the major trends in terms of common fundamental concepts and the three main parts cover the theory, implementation issues, and programming for applications.
Abstract: Constraint Logic Programming (CLP) is a merger of two declarative paradigms: constraint solving and logic programming. Although a relatively new field, CLP has progressed in several quite different directions. In particular, the early fundamental concepts have been adapted to better serve in different areas of applications. In this survey of CLP, a primary goal is to give a systematic description of the major trends in terms of common fundamental concepts. The three main parts cover the theory, implementation issues, and programming for applications.

1,571 citations

Journal ArticleDOI
TL;DR: In this article, transformations and normal forms in the context of defeasible logic have been investigated, a simple but efficient formalism for non-monotonic reasoning based on rules and priorities.
Abstract: 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 have two main benefits: on one hand they can be used as a theoretical tool that leads to a deeper understanding of the formalism, and on the other hand they have been used in the development of an efficient implementation of defeasible logic.

370 citations

01 Jun 1988

298 citations

Proceedings ArticleDOI
Michael J. Maher1
05 Jul 1988
TL;DR: The elementary equivalence of thegebra of rational trees and the algebra of infinite trees is obtained and forms the basis of decision procedures for the theories of the corresponding algebras.
Abstract: Complete axiomizations for the algebras of infinite trees and infinite trees are presented. The axiomizations are parameterized by the alphabet of function symbols for both the finite trees and infinite trees. There are two main cases, depending on whether the number of function symbols is finite or infinite. In the former case an extra axiom is necessary to obtain completeness. The method of proof is an elimination of quantifiers. Although a full elimination of quantifiers is not possible, the method forms the basis of decision procedures for the theories of the corresponding algebras. As a corollary to the results in infinite trees, the elementary equivalence of the algebra of rational trees and the algebra of infinite trees is obtained. >

283 citations

Journal ArticleDOI
TL;DR: Dung-like argumentation semantics is provided for two key defeasible logics, of which one is ambiguity propagating and the other ambiguity blocking, which provides the first ambiguity blocking Dung- like argumentation system.
Abstract: Defeasible reasoning is a simple but efficient rule-based approach to nonmonotonic reasoning. It has powerful implementations and shows promise to be applied in the areas of legal reasoning and the modelling of business rules. This paper establishes significant links between defeasible reasoning and argumentation. In particular, Dung-like argumentation semantics is provided for two key defeasible logics, of which one is ambiguity propagating and the other ambiguity blocking. There are several reasons for the significance of this work: (a) establishing links between formal systems leads to a better understanding and cross-fertilization, in particular our work sheds light on the argumentation-theoretic features of defeasible logic; (b) we provide the first ambiguity blocking Dung-like argumentation system; (c) defeasible reasoning may provide an efficient implementation platform for systems of argumentation; and (d) argumentation-based semantics support a deeper understanding of defeasible reasoning, especially in the context of the intended applications.

267 citations


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TL;DR: In this article, a professional services was launched having a hope to serve as a total on the internet electronic catalogue that gives usage of many PDF file guide assortment, including trending books, solution key, assessment test questions and answer, guideline sample, exercise guideline, test test, customer guide, user guide, assistance instruction, repair guidebook, etc.
Abstract: Our professional services was launched having a hope to serve as a total on the internet electronic catalogue that gives usage of many PDF file guide assortment. You will probably find many different types of e-guide as well as other literatures from our paperwork database. Distinct preferred topics that spread on our catalog are trending books, solution key, assessment test questions and answer, guideline sample, exercise guideline, test test, customer guide, user guide, assistance instruction, repair guidebook, etc.

6,496 citations

Proceedings ArticleDOI
22 Jun 2001
TL;DR: The development of a new complete solver, Chaff, is described which achieves significant performance gains through careful engineering of all aspects of the search-especially a particularly efficient implementation of Boolean constraint propagation (BCP) and a novel low overhead decision strategy.
Abstract: Boolean satisfiability is probably the most studied of the combinatorial optimization/search problems. Significant effort has been devoted to trying to provide practical solutions to this problem for problem instances encountered in a range of applications in electronic design automation (EDA), as well as in artificial intelligence (AI). This study has culminated in the development of several SAT packages, both proprietary and in the public domain (e.g. GRASP, SATO) which find significant use in both research and industry. Most existing complete solvers are variants of the Davis-Putnam (DP) search algorithm. In this paper we describe the development of a new complete solver, Chaff which achieves significant performance gains through careful engineering of all aspects of the search-especially a particularly efficient implementation of Boolean constraint propagation (BCP) and a novel low overhead decision strategy. Chaff has been able to obtain one to two orders of magnitude performance improvement on difficult SAT benchmarks in comparison with other solvers (DP or otherwise), including GRASP and SATO.

2,886 citations

Journal ArticleDOI
TL;DR: It is shown that the class of programs possessing a total well-founded model properly includes previously studied classes of "stratified" and "locally stratified" programs, and is compared with other proposals in the literature.
Abstract: A general logic program (abbreviated to "program" hereafter) is a set of roles that have both positive and negative subgoals. It is common to view a deductive database as a general logic program consisting of rules (IDB) slttmg above elementary relations (EDB, facts). It is desirable to associate one Herbrand model with a program and think of that model as the "meaning of the program, " or Its "declarative semantics. " Ideally, queries directed to the program would be answered in accordance with this model. Recent research indicates that some programs do not have a "satisfactory" total model; for such programs, the question of an appropriate partial model arises. Unfounded sets and well-founded partial models are introduced and the well-founded semantics of a program are defined to be its well-founded partial model. If the well-founded partial model is m fact a total model. it is called the well-founded model. It n shown that the class of programs possessing a total well-founded model properly includes previously studied classes of "stratified" and "locally stratified" programs, The method in this paper is also compared with other proposals in the literature, including Clark's "program completion, " Fitting's and Kunen's 3-vahred interpretations of it, and the "stable models" of Gelfond and Lifschitz.

1,908 citations