We show how to compile programs formalizing update plus preference reasoning into standard generalized logic programs and show the correctness of the transformation.
ISBN:
(纸本)3540441905
We show how to compile programs formalizing update plus preference reasoning into standard generalized logic programs and show the correctness of the transformation.
the aspps system is an answer-set programming system based on the extended logic of propositional schemata [2], which allows variables but not function symbols in the language. We denote this logic PS+. A theory in th...
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ISBN:
(纸本)3540441905
the aspps system is an answer-set programming system based on the extended logic of propositional schemata [2], which allows variables but not function symbols in the language. We denote this logic PS+. A theory in the logic PS+ is a pair (D,P), where D is a set of ground atoms (only constant symbols as arguments) representing an instance of a problem (input data), and P is a set of PS+-clauses representing a program (an abstraction of a problem). the meaning of a PS+-theory T = (D,P) is given by a family of PS+-models [2].
In this paper, we present a framework for agent negotiation based on abductive logicprogramming. the framework is based on an existing architecture for logic-based agents, and extends it by accommodating dialogues fo...
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ISBN:
(纸本)3540441905
In this paper, we present a framework for agent negotiation based on abductive logicprogramming. the framework is based on an existing architecture for logic-based agents, and extends it by accommodating dialogues for negotiation. As an application of negotiating agents, we propose a resource-exchanging problem. the innovative contribution of this work is in the definition of an operational model, including an agent cycle and dialogue cycle, and in the results that apply in the general case of abductive agents and in the specific case of a class of agent systems.
logic programs with ordered disjunction (LPODs) add a new connective to logicprogramming. this connective allows us to represent alternative, ranked options for problem solutions in the heads of rules: A x B intuitiv...
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ISBN:
(纸本)3540441905
logic programs with ordered disjunction (LPODs) add a new connective to logicprogramming. this connective allows us to represent alternative, ranked options for problem solutions in the heads of rules: A x B intuitively means: if possible A, but if A is not possible, then at least B. the semantics of logic programs with ordered disjunction is based on a preference relation on answer sets. In this paper we show how LPODs can be implemented using answer set solvers for normal programs. the implementation is based on a generator which produces candidate answer sets and a tester which checks whether a given candidate is maximally preferred and produces a better candidate if it is not. We also discuss the complexity of reasoning tasks based on LPODs.
Different many-valued logicprogramming frameworks have been proposed to manage uncertain information in deductive databases and logicprogramming. A feature of these frameworks is that they rely on a predefined assum...
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ISBN:
(纸本)3540441905
Different many-valued logicprogramming frameworks have been proposed to manage uncertain information in deductive databases and logicprogramming. A feature of these frameworks is that they rely on a predefined assumption or hypothesis, i.e. an interpretation that assigns the same default truth value to all the atoms of a program, e.g. in the open world assumption, by default all atoms have unknown truth value. In this paper we extend these frameworks along three directions: (i) we will introduce non-monotonic modes of negation;(ii) the default truth values of atoms need not necessarily to be all equal each other;and (iii) a hypothesis can be a partial interpretation. We will show that our approach extends the usual ones: if we restrict our attention to classical logic programs and consider total uniform hypotheses, then our semantics reduces to the usual semantics of logic programs. In particular, under the everything false assumption, our semantics captures and extends the well-founded semantics to these frameworks.
this paper focuses on the efficient computation of answer sets for normal logic programs. It concentrates on a recently proposed rule-based method (implemented in the noMoRe system) for computing answer sets. We show ...
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ISBN:
(纸本)3540441905
this paper focuses on the efficient computation of answer sets for normal logic programs. It concentrates on a recently proposed rule-based method (implemented in the noMoRe system) for computing answer sets. We show how noMoRe and its underlying method can be improved tremendously by extending the computation of deterministic consequences. Withthese changes noMoRe is able to deal with more challenging problem classes.
the procedural semantics of multi-adjoint logicprogramming is used for providing a model-theoretic semantics for a data model. A translation method for deductive logic databases is presented for obtaining a relationa...
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ISBN:
(纸本)3540441905
the procedural semantics of multi-adjoint logicprogramming is used for providing a model-theoretic semantics for a data model. A translation method for deductive logic databases is presented for obtaining a relational algebra with classical projection and enriched parametric join operator with aggregations. the use of non-commutative conjunctors allows for a model of different degrees of granulation and precision, whereas expressiveness is achieved by using multiple-valued connectives.
Answer set programming [8] is a new declarative programming paradigm suitable for solving a large range of problems related to knowledge representation and search. the paradigm is rooted in recent developments in seve...
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ISBN:
(纸本)3540441905
Answer set programming [8] is a new declarative programming paradigm suitable for solving a large range of problems related to knowledge representation and search. the paradigm is rooted in recent developments in several areas of artificial intelligence. Answer set programming starts by encoding relevant domain knowledge as a (possibly disjunctive) logic program, \8;. the connectives of this program are normally understood in accordance withthe answer set (stable model) semantics [4], [5]. the language’s ability to express defaults, i.e. statements of the form “normally, objects of class C have property P”, coupled with its natural treatment of recursion, and other useful features, often leads to a comparatively concise and clear representation of knowledge. Insights on the nature of causality and its relationship withthe answer sets of logic programs [6], [7],[10] allows description of the effects of actions which solves the frame, ramification, and qualification problems, which for a long time have caused difficulties in modeling knowledge about dynamic domains. In the second stage of the programming process, a programming task is reduced to finding the answer sets of a logic program \8; ∪ R where R is normally a simple and short program corresponding to this task. the answer sets are found withthe help of programming systems [9],[2], [3] implementing various answer set finding algorithms.
Solving a problem in the answer set programming approach means constructing a logic program so that the answer sets of the program correspond to the solutions to the problem. Typically, a programmer develops a series ...
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ISBN:
(纸本)3540441905
Solving a problem in the answer set programming approach means constructing a logic program so that the answer sets of the program correspond to the solutions to the problem. Typically, a programmer develops a series of improved formulations for a particular problem. Consequently, the programmer is confronted by another problem, namely ensuring that subsequent formulations are equivalent, i.e., give rise to the same answer sets. To ease answer set programming, we propose a methodology for testing the equivalence of logic programs. the basic idea is to translate the logic programs P and Q under consideration into a single logic program R whose answer sets (if such exist) yield counter-examples to the equivalence of P and Q. the translation function presented in the paper has been implemented as a translator program LPEQ that enables the equivalence testing of logic programs using the SMODELS system. Experiments performed with LPEQ and SMODELS suggest that establishing the equivalence of logic programs in this way is in certain cases much faster than explicit cross-checking of answer sets.
logicprogramming has often been considered less than adequate for modelling the dynamics of knowledge changing over time. In this paper we describe a simple though quite powerful approach to modelling the updates of ...
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ISBN:
(纸本)3540441905
logicprogramming has often been considered less than adequate for modelling the dynamics of knowledge changing over time. In this paper we describe a simple though quite powerful approach to modelling the updates of knowledge bases expressed by generalized logic programs, by means of a new language, hereby christened EVOLP (after EVOlving logic Programs). the approach was first sparked by a critical analysis of previous efforts and results in this direction [1, 2, 7, 11], and aims to provide a simpler, and at once more general, formulation of logic program updating, which runs closer to traditional logicprogramming (LP) doctrine. From the syntactical point of view, evolving programs are just generalized logic programs (i.e. normal LPs plus default negation also in rule heads), extended with (possibly nested) assertions, whether in heads or bodies of rules. From the semantics viewpoint, a model-theoretic characterization is offered of the possible evolutions of such programs. these evolutions arise both from self (or internal) updating, and from external updating too, originating in the environment. this formulation sets evolving programs on a firm basis in which to express, implement, and reason about dynamic knowledge bases, and opens up a number of interesting research topics that we brush on.
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