Several practical inductivelogicprogramming systems efficiently learn 'determinate' clauses of constant depth. Recently it has been shown that while nonrecursive constant-depth determinate clauses are pac-le...
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Several practical inductivelogicprogramming systems efficiently learn 'determinate' clauses of constant depth. Recently it has been shown that while nonrecursive constant-depth determinate clauses are pac-learnable, most of the obvious syntactic generalizations of this language are not pac-learnable. In this paper we introduce a new restriction on logic programs called 'locality', and present two formal results. First, the language of nonrecursive clauses of constant locality is pac-learnable. Second, the language of nonrecursive clauses of constant locality is strictly more expressive than the language of nonrecursive determinate clauses of constant depth. Hence, constant-locality clauses are a pac-learnable generalization of constant-depth determinate clauses.
this is an expository article about the solution to the frame problem proposed in 1980 by Raymond Reiter. For years, his "frame default" remained untested and suspect. But developments in some seemingly unre...
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this is an expository article about the solution to the frame problem proposed in 1980 by Raymond Reiter. For years, his "frame default" remained untested and suspect. But developments in some seemingly unrelated areas of computer science-logicprogramming and satisfiability solvers-eventually exonerated the frame default and turned it into a basis for important applications.
We address a novel issue for logicprogramming, namely the problem of evaluating ranked top-k queries. the problem occurs for instance, when we allow queries such as '' find cheap hotels close to the conferenc...
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ISBN:
(纸本)9783540729174
We address a novel issue for logicprogramming, namely the problem of evaluating ranked top-k queries. the problem occurs for instance, when we allow queries such as '' find cheap hotels close to the conference location '' in which vague predicates like cheap and close occur. Vague predicates have the effect that each tuple in the answer set has now a score in [0,I]. We show how to compute the top-k answers in case the set of facts is huge, without evaluating all the tuples.
Withthe development of Web services, the quantity of services in clusters has increased rapidly, and the time complexity of service clustering becomes higher. To solve this problem, a new construction method of servi...
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Withthe development of Web services, the quantity of services in clusters has increased rapidly, and the time complexity of service clustering becomes higher. To solve this problem, a new construction method of service clusters is proposed based on service space in this paper. the main innovation is the construction of service space. Firstly, a mathematical space is defined. then, services are abstracted and quantized to the space based on ontology trees. the experiment illustrates that the time complexity of constructing service clusters is decreased. Moreover, the construction of service space and the mapping rules are shown in this paper. A service cluster and its dynamic library are constructed based on service space. the structure, updating mechanism and generation flows of service clusters are modeled by logic Petri nets. Finally, the validity and advantages of proposed methods are illustrated by some experiments and comparative analysis.
Access control provides the mean of restricting the access to a computer system by checking whether a legitimate user has the rights to perform certain actions on the resources. therefore it should rely on flexible ad...
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ISBN:
(纸本)9781479977000
Access control provides the mean of restricting the access to a computer system by checking whether a legitimate user has the rights to perform certain actions on the resources. therefore it should rely on flexible administrative mechanism. An important component of the administrative mechanism is delegation. Delegation is the process of granting a specific authorization from a user to another user of the same system to carry out some functions on his behalf. the delegation, although widely used, is modeled in very little security policies because this concept is very complex. What we tried to do in this work is to redefine delegation for OrBAC using description logic. OrBAC is an access control model;it provides the mean to specify contextual authorizations, which facilitates modeling the features of the delegation such as temporary delegation, multiple delegation, revocation, etc. the description logicthat we use for the re-formalization process is T-JClassicde. this logic is a temporal nonmonotonic description logic, it gives the mean to specify nonmonotonic authorizations, and a better representation of the temporal aspects specific to a given delegation. this new representation augments the expressivity of the model and therefore it facilitates even more the representation and the management of the delegation characteristics.
In recent work, we provided a formulation of ASP programs in terms of linear logictheories. Based on this work, in this paper we propose and discuss a modified Answer Set Semantics, "Resource-based Answer Set Se...
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ISBN:
(纸本)9783642405648
In recent work, we provided a formulation of ASP programs in terms of linear logictheories. Based on this work, in this paper we propose and discuss a modified Answer Set Semantics, "Resource-based Answer Set Semantics".
Defeasible logic is extended to programming languages for cognitive agents with preferences and actions for planning. We define rule-based agent theories that contain preferences and actions, together with inference p...
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ISBN:
(纸本)354030553X
Defeasible logic is extended to programming languages for cognitive agents with preferences and actions for planning. We define rule-based agent theories that contain preferences and actions, together with inference procedures. We discuss patterns of agent types in this setting. Finally, we illustrate the language by an example of an agent reasoning about web-services.
We consider using machine learning techniques to help understand a large software system. In particular, we describe how learning techniques can be used to reconstruct abstract Datalog specifications of a certain type...
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We consider using machine learning techniques to help understand a large software system. In particular, we describe how learning techniques can be used to reconstruct abstract Datalog specifications of a certain type of database software from examples of its operation. In a case study involving a large (more than one million lines of C) real-world software system, we demonstrate that off-the-shelf inductivelogicprogramming methods can be successfully used for specification recovery;specifically, Grendel2 can extract specifications for about one-third of the modules in a test suite with high rates of precision and recall. We then describe two extensions to Grendel2 which improve performance on this task: one which allows it to output a set of candidate hypotheses, and another which allows it to output specifications containing determinations. In combination, these extensions enable specifications to be extracted for nearly two-thirds of the benchmark modules with perfect recall, and precision of better than 60%.
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