Flexible authorization is a significant research realm in pervasive computing. logic program is a worthy approach for expressing and reasoning flexible authorization not only in theory but also in practice. This paper...
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(纸本)9781424442232
Flexible authorization is a significant research realm in pervasive computing. logic program is a worthy approach for expressing and reasoning flexible authorization not only in theory but also in practice. This paper mainly focuses on specifying flexible authorization policies using logic programs. The features of the flexible authorizations are analyzed. The conflicts resolution and dynamic authorization based on LPOD (logic Program with Ordered Disjunction) are studied.
This paper presents a Prolog interface to the MiniSat satisfiability solver. logicprogramming with satisfiability combines the strengths of the two paradigms: logicprogramming for encoding search problems into satis...
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This paper presents a Prolog interface to the MiniSat satisfiability solver. logicprogramming with satisfiability combines the strengths of the two paradigms: logicprogramming for encoding search problems into satisfiability on the one hand and efficient SAT solving on the other. This synergy between these two exposes a programming paradigm that we propose here as a logicprogramming pearl. To illustrate logicprogramming with SAT solving, we give an example Prolog program that solves instances of Partial MAXSAT.
In everyday life it happens that a person has to reason out what other people think and how they behave, in order to achieve his goals. In other words, an individual may be required to adapt his behavior by reasoning ...
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In everyday life it happens that a person has to reason out what other people think and how they behave, in order to achieve his goals. In other words, an individual may be required to adapt his behavior by reasoning about the others' mental state. In this paper we focus on a knowledge-representation language derived from logicprogramming which both supports the representation of mental states of individual communities and provides each with the capability of reasoning about others' mental states and acting accordingly. The proposed semantics is shown to be translatable into stable model semantics of logic programs with aggregates.
We introduce and study logic programs whose clauses are built out of monotone constraint atoms. We show that the operational concept of the one-step provability operator generalizes to programs with monotone constrain...
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We introduce and study logic programs whose clauses are built out of monotone constraint atoms. We show that the operational concept of the one-step provability operator generalizes to programs with monotone constraint atoms, but the generalization involves nondeterminism. Our main results demonstrate that our formalism is a common generalization of (1) normal logicprogramming with its semantics of models, supported models and stable models, (2) logicprogramming with weight atoms (Iparse programs) with the semantics of stable models, as defined by Niemela, Simons and Soininen, and (3) of disjunctive logicprogramming with the possible-model semantics of Sakama and Inoue.
Tabled Constraint logicprogramming is a powerful execution mechanism for dealing with Constraint logicprogramming without worrying about fixpoint computation. Various applications, e.g. in the fields of program anal...
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Tabled Constraint logicprogramming is a powerful execution mechanism for dealing with Constraint logicprogramming without worrying about fixpoint computation. Various applications, e.g. in the fields of program analysis and model checking, have been proposed. Unfortunately, a high-level system for developing new applications is lacking, and programmers are forced to resort to complicated ad hoc solutions. This papers presents TCHR, a high-level framework for tabled Constraint logicprogramming. It integrates in a light-weight manner Constraint Handling Rules (CHR), a high-level language for constraint solvers, with tabled logicprogramming. The framework is easily instantiated with new application-specific constraint domains. Various high-level operations can be instantiated to control performance. In particular, we propose a novel, generalized technique for compacting answer sets.
Building rules on top of ontologies is the ultimate goal of the logical layer of the Semantic Web. To this aim, an ad-hoc markup language for this layer is currently under discussion. It is intended to follow the trad...
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Building rules on top of ontologies is the ultimate goal of the logical layer of the Semantic Web. To this aim, an ad-hoc markup language for this layer is currently under discussion. It is intended to follow the tradition of hybrid knowledge representation and reasoning systems, such as,AL-log that integrates the description logic ALC and the function-free Horn clausal language DATALOG. In this paper, we consider the problem of automating the acquisition of these rules for the Semantic Web. We propose a general framework for rule induction that adopts the methodological apparatus of Inductive logicprogramming and relies on the expressive and deductive power of AL-log. The framework is valid whatever the scope of induction (description versus prediction) is. Yet, for illustrative purposes, we also discuss an instantiation of the framework which aims at description and turns out to be useful in Ontology Refinement.
The World Wide Web is nowadays the most famous and widespread information system. Its success is witnessed by its enormous size and rate of growth: however, the same success of the Web has brought to a situation where...
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The World Wide Web is nowadays the most famous and widespread information system. Its success is witnessed by its enormous size and rate of growth: however, the same success of the Web has brought to a situation where more sophisticated techniques are urgently needed to properly handle this mass of information. In this sense, the more ambitious plan for an evolution of a Web is the so called Semantic Web, envisioned by the inventor of the Web itself, Tim Berners-Lee. In this architectural vision, there is the need for further layers of semantics, properly enriching the data that now overflow the classic Web: ontologies, rules, logic, proofs, trust are all ingredients of this ambitious picture.
Extensible Markup Language (XML) is a simple, very flexible text format derived from SGML. Originally designed to meet the challenges of large-scale electronic publishing, XML is also playing an increasingly important...
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Extensible Markup Language (XML) is a simple, very flexible text format derived from SGML. Originally designed to meet the challenges of large-scale electronic publishing, XML is also playing an increasingly important role in the exchange of a wide variety of data on the Web and elsewhere. XPath language is the result of an effort to provide address parts of an XML document. In support of this primary purpose, it becomes in a query language against an XML document. In this paper we present a proposal for the implementation of the XPath language in logicprogramming. With this aim we will describe the representation of XML documents by means of a logic program. Rules and facts can be used for representing the document schema and the XML document itself. In particular, we will present how to index XML documents in logic programs: rules are supposed to be stored in main memory, however facts are stored in secondary memory by using two kind of indexes: one for each XML tag, and other for each group of terminal items. In addition, we will study how to query by means of the XPath language against a logic program representing an XML document. It evolves the specialization of the logic program with regard to the XPath expression. Finally, we will also explain how to combine the indexing and the top-down evaluation of the logic program.
We present an infinite-game characterization of the well-founded semantics for function-free logic programs with negation. Our game is a simple generalization of the standard game for negation-less logic programs intr...
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We present an infinite-game characterization of the well-founded semantics for function-free logic programs with negation. Our game is a simple generalization of the standard game for negation-less logic programs introduced by van Emden [M.H. van Emden, Quantitative deduction and its fixpoint theory, Journal of logicprogramming 3 (1) (1986) 37-53] in which two players, the Believer and the Doubter, compete by trying to prove (respectively disprove) a query. The standard game is equivalent to the minimum Herbrand model semantics of logicprogramming in the sense that a query succeeds in the minimum model semantics iff the Believer has a winning strategy for the game which begins with the Doubter doubting this query. The game for programs with negation that we propose follows the same rules as the standard one, except that the players swap roles every time the play "passes through" negation. We start our investigation by establishing the determinacy of the new game by using some classical tools from the theory of infinite-games. Our determinacy result immediately provides a novel and purely. game-theoretic characterization of the semantics of negation in logicprogramming. We proceed to establish the connections of the game semantics to the existing semantic approaches for logicprogramming with negation. For this purpose, we first define a refined version of the game that uses degrees of winning and losing for the two players. We then demonstrate that this refined game corresponds exactly to the infinite-valued minimum model semantics of negation [P. Rondogiannis,W.W. Wadge, Minimum model semantics for logic programs with negation-as-failure, ACM Transactions on Computational logic 6 (2) (2005) 441-467]. This immediately implies that the unrefined game is equivalent to the well-founded semantics (since the infinite-valued semantics is a refinement of the well-founded semantics). (c) 2007 Elsevier B.V. All rights reserved.
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