More than a decade has passed since Herbrand's theorem was first generalized to arbitrary institutions, enabling in this way the development of the logic-programming paradigm over formalisms beyond the conventiona...
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Event-based systems have been developed and used to implement networked and adaptive business environments based on loosely coupled systems in order to respond faster to critical business events. In this paper, we int...
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This paper presents a set of rules for reasoning about the truth values of states in knowledge systems using an interval-based representation of time. Two major sources of complexity, ambiguity in temporal networks an...
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ISBN:
(纸本)1932415122
This paper presents a set of rules for reasoning about the truth values of states in knowledge systems using an interval-based representation of time. Two major sources of complexity, ambiguity in temporal networks and the possibility of the persistence of states, are analyzed. Finally, both an exact though inefficient solution method and a more efficient approximate solution method are presented.
An operational semantics for functional logic programs is presented. In such programs functional terms provide for reduction of expressions, provided that they ground. The semantics is based on multi-pass evaluation t...
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ISBN:
(纸本)0897916360
An operational semantics for functional logic programs is presented. In such programs functional terms provide for reduction of expressions, provided that they ground. The semantics is based on multi-pass evaluation techniques originally developed for attribute grammars. Program execution is divided into two phases: (1) construction of an incomplete proof tree, and 92) its decoration into a complete proof tree. The construction phase applies a modified SLD-resolution scheme, and the decoration phase a partial (multipass) traversal over the tree. The phase partition is generated by static analysis where data dependencies are extracted for the functional elements of the program. The method guarantees that all the functional terms of a program can be evaluated, and no dynamic groundness checks are needed.
Capturing the uncertain aspects in cyber threat analyses is an important part of a wide range of efforts, including diagnostics, threat evaluation, and preventing attacks. However, there has been insufficient research...
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Over-approximating the descendants (successors) of a initial set of terms by a rewrite system is used in verification. The success of such verification methods depends on the quality of the approximation. To get bette...
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This paper studies computational issues related to the problem of reasoning about actions and change (RAC) by exploiting its link with the Answer Set programming paradigm. It investigates how increasing the expressive...
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ISBN:
(纸本)9783540207214
This paper studies computational issues related to the problem of reasoning about actions and change (RAC) by exploiting its link with the Answer Set programming paradigm. It investigates how increasing the expressiveness of a RAC formalism so that it can capture the three major problems of frame, ramification and qualification, affects its computational complexity, and how a solution to these problems can be implemented within Answer Set programming. Our study is carried out within the particular language Ε. It establishes a link between language Ε and Answer Set programming by presenting encodings of different versions of this language into logic programs under the answer set semantics. This provides a computational realization of solutions to problems related to reasoning about actions and change, that can make use of the recent development of effective systems for Answer Set programming.
In this paper we present a novel method for preprocessing complex non-ground rules in answer set programming (ASP). Using a well-known result from the area of conjunctive query evaluation, we apply hypertree decomposi...
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A hybrid query is a requirement of data produced by data services and a set of QoS preferences w.r.t. the query execution. In this paper we present the problem of the hybrid query optimization and, in particular, the ...
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A hybrid query is a requirement of data produced by data services and a set of QoS preferences w.r.t. the query execution. In this paper we present the problem of the hybrid query optimization and, in particular, the generation of the search space of hybrid query plans. We show how the constraints that characterize the generation of hybrid query plans are modeled arid validated by implementing them in an action language. We present graphs with the experiment results that show the complexity of this generation.
We introduce just enough tabling (JET), a mechanism to suspend and resume the tabled execution of logic programs at an arbitrary point. In particular, JET allows pruning of tabled logic programs to be performed withou...
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ISBN:
(纸本)1581138199
We introduce just enough tabling (JET), a mechanism to suspend and resume the tabled execution of logic programs at an arbitrary point. In particular, JET allows pruning of tabled logic programs to be performed without resorting to any recomputation. We discuss issues that are involved in supporting pruning in tabled resolution, how re-execution of tabled computations which were previously pruned can be avoided, and we describe the implementation of such a scheme based on an abstract machine like CHAT, which implements the suspension/resumption support that tabling requires through a combination of freezing and copying of execution states of suspended computations. Properties of just enough tabling and possible uses of the JET mechanism in a tabling system are also briefly discussed.
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