In this paper, we extend our previous work on Resourced ASP, or for short RASP, where we have introduced the possibility of defining and using resources in ASP. In RASP, one can define resources with their amounts, Wh...
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In this paper, we extend our previous work on Resourced ASP, or for short RASP, where we have introduced the possibility of defining and using resources in ASP. In RASP, one can define resources with their amounts, Where available resources can be used for producing other resources and the remaining amount, if any, can be used in a different way. In this paper, we introduce P-RASP (RASP with Preferences) where it is possible to express preferences about which resources should be either consumed or produced. Moreover, conditional preferences, of different forms, allow one to express preferences according to certain conditions, that are to be evaluated "dynamically", namely, with respect to the specific answerset at hand. The semantic of conditional preferences is given in terms of (non-conditional) preferences, though the translation is not straightforward and thus the new features are not syntactic sugar. Complexity of P-RASP is also discussed. (C) 2009 Elsevier Inc. All rights reserved.
The paper introduces the notion of offline justification for answer set programming (ASP). Justifications provide a graph-based explanation of the truth value of an atom with respect to a given answerset. The paper e...
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The paper introduces the notion of offline justification for answer set programming (ASP). Justifications provide a graph-based explanation of the truth value of an atom with respect to a given answerset. The paper extends also this notion to provide justification of atoms during the computation of an answerset (on-line justification) and presents an integration of online justifications within the computation model Of SMODELS. Offline and online justifications provide useful tools to enhance understanding of ASP, and they offer a basic data structure to support methodologies and tools for debugging answerset programs. A preliminary implementation has been developed in ASP - PROLOG.
This note summarizes a dissertation that focuses on methods for solving structured real-world problems based on propositional satisfiability (SAT). The work contributes to the analysis and development of both complete...
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This note summarizes a dissertation that focuses on methods for solving structured real-world problems based on propositional satisfiability (SAT). The work contributes to the analysis and development of both complete search (DPLL and clause learning) and stochastic local search methods for SAT.
Enterprise/Corporate ontologies are widely adopted to conceptualize business enterprise information. In this area, the semantic peculiarities of answer set programming (ASP), like the Closed World Assumption (CWA) and...
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Enterprise/Corporate ontologies are widely adopted to conceptualize business enterprise information. In this area, the semantic peculiarities of answer set programming (ASP), like the Closed World Assumption (CWA) and the Unique Name Assumption (UNA), are more appropriate than the OntologyWeb Language (OWL) assumptions, also because such ontologies frequently stem from relational databases, where both CWA and UNA are adopted. This article presents OntoDLV, a system based on ASP for the specification and reasoning on enterprise ontologies. OntoDLV implements a powerful ontology representation language, called OntoDLP, extending (disjunctive) ASP with all the main ontology features including classes, inheritance, relations and axioms. OntoDLP is strongly typed, and includes also complex type constructors, like lists and sets. Importantly, OntoDLV supports a powerful interoperability mechanism with OWL, allowing the user to retrieve information from OWL ontologies, and build rule-based reasoning on top of OWL ontologies. The system is already used in a number of real-world applications including agent-based systems, information extraction, and text classification.
The goal of this article is to foster modular program development in answer set programming using a Gaifman-Shapiro-style module architecture. More specifically, a method for verifying the equivalence of logic program...
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The goal of this article is to foster modular program development in answer set programming using a Gaifman-Shapiro-style module architecture. More specifically, a method for verifying the equivalence of logic program modules is devised and proved correct. The idea is to adapt a translation-based verification technique, which was originally devised for complete programs only, for program modules. In addition, optimization strategies are addressed in order to exploit the modular structure of programs in verification tasks. A number of experiments on verification strategies are also conducted using lpeq which implements the verification method for the smodels system. The preliminary experimental results reported in this article suggest that the modularization of equivalence verification leads to potential time savings especially if the modules involved share a common context.
The goal of this article is to foster modular program development in answer set programming using a Gaifman-Shapiro-style module architecture. More specifically, a method for verifying the equivalence of logic program...
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The goal of this article is to foster modular program development in answer set programming using a Gaifman-Shapiro-style module architecture. More specifically, a method for verifying the equivalence of logic program modules is devised and proved correct. The idea is to adapt a translation-based verification technique, which was originally devised for complete programs only, for program modules. In addition, optimization strategies are addressed in order to exploit the modular structure of programs in verification tasks. A number of experiments on verification strategies are also conducted using lpeq which implements the verification method for the smodels system. The preliminary experimental results reported in this article suggest that the modularization of equivalence verification leads to potential time savings especially if the modules involved share a common context.
Implementation costs linked to processor memory subsystems (cache miss costs, stalls due to bandwidth limits, etc.) have been shown to be a factor in the performance of a variety of declarative programming tools. This...
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Implementation costs linked to processor memory subsystems (cache miss costs, stalls due to bandwidth limits, etc.) have been shown to be a factor in the performance of a variety of declarative programming tools. This article investigates their impact on answerset solvers and the factors that control them. Experiments independently altering the size and difficulty of input programs allow a qualitative assessment of whether input program or solver design is a greater factor and a quantitative assessment of how much of problem these issues create.A variety of processor performance metrics are recorded and used to provide a detailed picture of what limits solver performance and dispel a number of common *** demonstrate the degree to which these problems can be addressed, smodels-ie is presented. This is a version of the smodels solver with a number of implementation changes to improve cache utilisation, one major aspect of memory costs.
Reasoning in the presence of imprecision and vagueness is inevitable in many real-world applications including those in robotics and intelligent agents. Although, reasoning about actions is a major component in these ...
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ISBN:
(纸本)9789899507968
Reasoning in the presence of imprecision and vagueness is inevitable in many real-world applications including those in robotics and intelligent agents. Although, reasoning about actions is a major component in these real-world applications, current actions languages for reasoning about actions lack the ability to represent and reason about actions in the presence of imprecision and vagueness that stem from effects of actions in these real-world applications. In this paper we present a new action language called fuzzy action language, A(F), that allows the representation and reasoning about actions with vague (fuzzy) effects. In addition we define the notions of fuzzy planning and fuzzy plan in the fuzzy action language AF. Furthermore, we describe a fuzzy planner based on the fuzzy action language AF that is developed by translating a fuzzy action theory, FT, in A(F) into a normal logic program with answerset semantics, II, where trajectories in FT are equivalent to the answersets of II. In addition, we formally prove the correctness of our translation. Furthermore, we show that fuzzy planning problems can be encoded as a SAT problem.
Implementation costs linked to processor memory subsystems (cache miss costs, stalls due to bandwidth limits, etc.) have been shown to be a factor in the performance of a variety of declarative programming tools. This...
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Implementation costs linked to processor memory subsystems (cache miss costs, stalls due to bandwidth limits, etc.) have been shown to be a factor in the performance of a variety of declarative programming tools. This article investigates their impact on answerset solvers and the factors that control them. Experiments independently altering the size and difficulty of input programs allow a qualitative assessment of whether input program or solver design is a greater factor and a quantitative assessment of how much of problem these issues create.A variety of processor performance metrics are recorded and used to provide a detailed picture of what limits solver performance and dispel a number of common *** demonstrate the degree to which these problems can be addressed, smodels-ie is presented. This is a version of the smodels solver with a number of implementation changes to improve cache utilisation, one major aspect of memory costs.
This paper considers a semantic approach for merging logic programs under answerset semantics. Given logic programs P-1,...,P-n, the goal is to provide characterisations of the merging of these programs. Our formal t...
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ISBN:
(纸本)9783642028458
This paper considers a semantic approach for merging logic programs under answerset semantics. Given logic programs P-1,...,P-n, the goal is to provide characterisations of the merging of these programs. Our formal techniques are based on notions of relative distance between the underlying SE models of the logic programs. Two approaches are examined. The first informally selects those models of the programs that vary the least from the models of the other programs. The second approach informally selects those models of a program P-0 that are closest to the models of programs P-1,...,P-n. P-0 can be thought of as analogous to a set of database integrity constraints. We examine formal properties of these operators and give encodings for computing the rnergings of a multiset of logic programs within the same logic programming framework. As a by-product, we provide a complexity analysis revealing that our operators do not increase the complexity of the base formalism.
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