Existing interval constraint logic programming languages, such as BNR Prolog, work under the framework of interval narrowing and are deficient in solving systems of linear constraints over real numbers, which constitu...
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Existing interval constraint logic programming languages, such as BNR Prolog, work under the framework of interval narrowing and are deficient in solving systems of linear constraints over real numbers, which constitute an important class of problems in engineering and other applications. In this paper, we suggest to separate linear equality constraint solving from inequality and non-linear constraint solving. The implementation of an efficient interval linear constraint solver, which is based on the preconditioned interval Gauss-Seidel method, is proposed. We show how the solver can be adapted to incremental execution and incorporated into a constraint logic programming language already equipped with a non-linear solver based on interval narrowing. The two solvers share common interval variables, interact and cooperate in a round-robin fashion during computation, resulting in an efficient interval constraint arithmetic language CIAL. The CIAL prototypes, based on CLP(R), are constructed and compared favorably against several major interval constraint logic programming languages.
The Gelfond-Lifschitz operator associated with a logic program (and likewise the operator associated with default theories by Reiter) exhibits oscillating behavior. In the case of logic programs, there is always at le...
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The Gelfond-Lifschitz operator associated with a logic program (and likewise the operator associated with default theories by Reiter) exhibits oscillating behavior. In the case of logic programs, there is always at least one finite, nonempty collection of Herbrand interpretations around which the Gelfond-Litschitz operator 'bounces around'. The same phenomenon occurs with default logic when Reiter's operator GAMMA(DELTA) is considered. Based on this, a 'stable class' semantics and 'extension class' semantics has been proposed. The main advantage of this semantics was that it was defined for all logic programs (and default theories), and that this definition was modelled using the standard operators existing in the literature such as Reiter's GAMMA(DELTA) operator. In this paper our primary aim is to prove that there is a very interesting duality between stable class theory and the well-founded semantics for logic programming. In the stable class semantics, classes that were minimal with respect to Smyth's power-domain ordering were selected. We show that the well-founded semantics precisely corresponds to a class that is minimal w.r.t. Hoare's power domain ordering: the well-known dual of Smyth's ordering. Besides this elegant duality, this immediately suggests how to define a well-founded semantics for default logic in such a way that the dualities that hold for logic programming continue to hold for default theories. We show how the same technique may be applied to 'strong' autoepistemic logic: the logic of strong expansions proposed by Marek and Truszczynski.
Recently, Brass and Dir showed (J. Automat. Reason. 20(1) (1998) 143-165) that the well founded semantics WFS can be defined as a confluent calculus of transformation rules. This led not only to a simple extension to ...
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Recently, Brass and Dir showed (J. Automat. Reason. 20(1) (1998) 143-165) that the well founded semantics WFS can be defined as a confluent calculus of transformation rules. This led not only to a simple extension to disjunctive programs (J. logic programming 38(3) (1999) 167-213), but also to a new computation of the well-founded semantics which is linear for a broad class of programs. We take this approach as a starting point and generalize it considerably by developing a general theory of Confluent LP-systems CL. Such a system CL is a rewriting system on the set of all logic programs over a fixed signature L and it induces in a natural way a canonical semantics. Moreover, we show four important applications of this theory: (1) most of the well-known semantics are induced by confluent LP-sl sterns, (2) there are many more transformation rules that lean to confluent LP-systems, (3) semantics induced by such systems can be used to model aggregation, (4) the new systems can be used to construct interesting counterexamples to some conjectures about the space of well-behaved semantics. (C) 2001 Elsevier Science B.V. All rights reserved.
The Conference materials contain 61 papers on logic programming. Theory and foundations, applications of logic programming, implementations, machines and architectures, programming methodology and tools, relations wit...
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The Conference materials contain 61 papers on logic programming. Theory and foundations, applications of logic programming, implementations, machines and architectures, programming methodology and tools, relations with software engineering, relations with deductive databases, relations with artificial intelligence, extensions, constraints, and logical languages for parallelism are the main topics covered.
A logical system of inference rules intended to give the foundation of logic programs is presented. The distinguished point of the approach taken here is the application of the theory of inductive definitions, which a...
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A logical system of inference rules intended to give the foundation of logic programs is presented. The distinguished point of the approach taken here is the application of the theory of inductive definitions, which allows us to uniformly treat various kinds of induction schema and also allows us to regardnegation as failure as a kind of induction schema. This approach corresponds to the so-called least fixpoint semantics. Moreover, in our formalism, logic programs are extended so that a condition of a clause may be any first-order formula. This makes it possible to write a quantified specification as a logic program. It also makes the class of induction schemata much larger to include the usual course-of-values inductions.
The main research goal has been to evaluate significant factors affecting the in vivo magnetic resonance imaging (MRI) parameters T1, T2, and 1H density. This approach differs significantly from other such projects in...
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The main research goal has been to evaluate significant factors affecting the in vivo magnetic resonance imaging (MRI) parameters T1, T2, and 1H density. This approach differs significantly from other such projects in that the experimental data analysis is being performed while concurrently developing automated, computer-aided analysis software for such MRI tissue parameters. In the experimental portion of the project, statistical analyses, and a heuristic minimum/maximum discriminant analysis algorithm have been explored. Both methods have been used to classify tissue types from 1.5 Tesla transaxial MR images of the human brain. The developing program, written in the logic programming language Prolog, is similar in a number of ways to many existing expert systems now in use for other medical applications;inclusion of the underlying statistical data base and advanced statistical analyses is the main differentiating feature of the current approach. First results indicate promising classification accuracy of various brain tissues such as gray and white matter, as well as differentiation of different types of gray matter and white matter (e.g.: caudate-nucleus vs. thalamus, both representatives of gray matter;and, cortical white matter vs. internal capsule as representative of white matter). Taking all four tissue types together, the percentage of correct classifications ranges from 73 to 87%.
logic programming and Nonmonotonic Reasoning : 7Th International Conference, Lpnmr 2004, Fort Lauderdale, Fl, Usa, January 6-8, 2004 : Proceedings by Lpnmr 2004 (2004 : Fort Lauderdale, Fla.); Lifschitz, Vladimir; Nie...
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logic programming and Nonmonotonic Reasoning : 7Th International Conference, Lpnmr 2004, Fort Lauderdale, Fl, Usa, January 6-8, 2004 : Proceedings by Lpnmr 2004 (2004 : Fort Lauderdale, Fla.); Lifschitz, Vladimir; Niemelä, Ilkka, 1961-; published by Berlin ; New York : Springer
Computational nucleic acid devices show great potential for enabling a broad range of biotechnology applications, including smart probes for molecular biology research, in vitro assembly of complex compounds, high-pre...
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Computational nucleic acid devices show great potential for enabling a broad range of biotechnology applications, including smart probes for molecular biology research, in vitro assembly of complex compounds, high-precision in vitro disease diagnosis and, ultimately, computational theranostics inside living cells. This diversity of applications is supported by a range of implementation strategies, including nucleic acid strand displacement, localization to substrates, and the use of enzymes with polymerase, nickase, and exonuclease functionality. However, existing computational design tools are unable to account for these strategies in a unified manner. This paper presents a logic programming language that allows a broad range of computational nucleic acid systems to be designed and analyzed. The language extends standard logic programming with a novel equational theory to express nucleic acid molecular motifs. It automatically identifies matching motifs present in the full system, in order to apply a specified transformation expressed as a logical rule. The language supports the definition of logic predicates, which provide constraints that need to be satisfied in order for a given rule to be applied. The language is sufficiently expressive to encode the semantics of nucleic strand displacement systems with complex topologies, together with computation performed by a broad range of enzymes, and is readily extensible to new implementation strategies. Our approach lays the foundation for a unifying framework for the design of computational nucleic acid devices.
Disjunctive logic programming (DLP), also called answer set programming (ASP), is a convenient programming paradigm which allows for solving problems in a simple and highly declarative way. The language of DLP is very...
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Disjunctive logic programming (DLP), also called answer set programming (ASP), is a convenient programming paradigm which allows for solving problems in a simple and highly declarative way. The language of DLP is very expressive and able to represent even problems of high complexity (every problem in the complexity class Sigma(P)(2) = NPNP. During the last decade, efficient systems supporting DLP have become available. Virtually all of these systems internally rely on variants of the Davis-Putnam procedure (for deciding propositional satisfiability [SAT]), combined with a suitable model checker. The heuristic for the selection of the branching literal (i.e., the criterion determining the literal to be assumed true at a given stage of the computation) dramatically affects the performance of a DLP system. While heuristics for SAT have received a fair deal of research, only little work on heuristics for DLP has been done so far. In this paper, we design, implement, optimize, and experiment with a number of heuristics for DLP. We focus on different look-ahead heuristics, also called "dynamic heuristics" (the DLP equivalent of unit propagation [UP] heuristics for SAT). These are branching rules where the heuristic value of a literal Q depends on the result of taking Q true and computing its consequences. We motivate and formally define a number of look-ahead heuristics for DLP programs. Furthermore, since look-ahead heuristics are computationally expensive, we design two techniques for optimizing the burden of their computation. We implement all the proposed heuristics and optimization techniques in DLV-the state-of-the-art implementation of disjunctive logic programming, and we carry out experiments, thoroughly comparing the heuristics and optimization techniques on a large number of instances of well-known benchmark problems. The results of these experiments are very interesting, showing that the proposed techniques significantly improve the performance of the DLV syst
logic programming : 20Th International Conference, Iclp 2004, Saint-Malo, France, September 6-10, 2004 : Proceedings by International Conference on logic programming (20Th : 2004 Saint Malo, France); Demoen, Bart; Lif...
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logic programming : 20Th International Conference, Iclp 2004, Saint-Malo, France, September 6-10, 2004 : Proceedings by International Conference on logic programming (20Th : 2004 Saint Malo, France); Demoen, Bart; Lifschitz, Vladimir; published by Berlin ; New York : Springer
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