Existing ASP languages lack support for conveniently specifying objects, their sorts and the sorts of the parameters of relations in an application domain. However, such support may allow a programmer to better struct...
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ISBN:
(纸本)9783642405648
Existing ASP languages lack support for conveniently specifying objects, their sorts and the sorts of the parameters of relations in an application domain. However, such support may allow a programmer to better structure the program, to automatically determine some syntax and semantic errors and to avoid thinking about safety of ASP rules - non-declarative conditions on rules required by existing ASP systems. In this paper, we define the syntax and semantics of a knowledge representation language SPARC which offers explicit constructs to specify objects, relations, and their sorts. the language expands CR-Prolog - an extension of ASP by consistency restoring rules. We introduce an implementation of SPARC based on its translation to DLV with weak constraints. A syntax checking algorithm helps to avoid errors related to misspellings as well as simple type errors. Another type checking algorithm flags program rules which, due to type conflicts, have no ground instantiations.
In recent years, Answer Set programming (ASP), logicprogramming under the stable model or answer set semantics, has seen several extensions by generalizing the notion of an atom in these programs: be it aggregate ato...
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ISBN:
(纸本)9783642405648
In recent years, Answer Set programming (ASP), logicprogramming under the stable model or answer set semantics, has seen several extensions by generalizing the notion of an atom in these programs: be it aggregate atoms, HEX atoms, generalized quantifiers, or abstract constraints, the idea is to have more complicated satisfaction patterns in the lattice of Herbrand interpretations than traditional, simple atoms. In this paper we refer to any of these constructs as generalized atoms. It is known that programs with generalized atoms that have monotonic or antimonotonic satisfaction patterns do not increase complexity with respect to programs with simple atoms (if satisfaction of the generalized atoms can be decided in polynomial time) under most semantics. It is also known that generalized atoms that are nonmonotonic (being neither monotonic nor antimonotonic) can, but need not, increase the complexity by one level in the polynomial hierarchy if non-disjunctive programs under the FLP semantics are considered. In this paper we provide the precise boundary of this complexity gap: programs with convex generalized atom never increase complexity, while allowing a single non-convex generalized atom (under reasonable conditions) always does. We also discuss several implications of this result in practice.
Understanding why and how a given answer to a query is generated from a deductive or relational database is fundamental to obtain justifications, assess trust, and detect dependencies on contradictions. Propagating pr...
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While object-oriented programming languages are good at modelling real-world concepts and benefit from rich libraries and developer tools, logicprogramming languages are well suited for declaratively solving computat...
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the program verification tool SLAYER uses abstractions during analysis and relies on a solver for reachability to refine spurious counterexamples. In this context, we extract a reachability benchmark suite and evaluat...
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Answer Set programming (ASP) is a logicprogramming language for nonmonotonic reasoning. Propositional ASP programs are usually evaluated by DPLL algorithms combining unit propagation with operators that are specific ...
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We propose a rule-based framework for representing and reasoning about business processes from boththe procedural and ontological point of views. To this end we define a rule-based procedural semantics for a relevant...
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ISBN:
(纸本)9789898565389
We propose a rule-based framework for representing and reasoning about business processes from boththe procedural and ontological point of views. To this end we define a rule-based procedural semantics for a relevant fragment of BPMN, a very popular graphical notation for specifying business processes. Our semantics defines a state transition system by following an approach similar to the Fluent Calculus, and allows us to specify state change in terms of preconditions and effects of the enactment of activities. then we show how the procedural process knowledge can be seamlessly integrated withthe domain knowledge specified by using the OWL-RL rule-based ontology language. Our framework provides a wide range of reasoning services by using standard logicprogramming inference engines. In particular, we can perform very sophisticated reasoning tasks by combining both procedural and domain dependent knowledge. A preliminary implementation shows that our approach is effective in practice.
In the past few years, several approaches for revision (and update) of logic programs have been studied. None of these however matched the generality and elegance of the original AGM approach to revision in classical ...
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ISBN:
(纸本)9783642405648
In the past few years, several approaches for revision (and update) of logic programs have been studied. None of these however matched the generality and elegance of the original AGM approach to revision in classical logic. One particular obstacle is the underlying nonmonotonicity of the semantics of logic programs. Recently however, specific revision operators based on the monotonic concept of SE-models (which underlies the answer-set semantics of logic programs) have been proposed. Basing revision of logic programs on sets of SE-models has the drawback that arbitrary sets of SE-models may not necessarily be expressed via a logic program. this situation is similar to the emerging topic of revision in fragments of classical logic. In this paper we show how nonetheless classical AGM-style revision can be extended to various classes of logic programs using the concept of SE-models. that is, we rephrase the AGM postulates in terms of logic programs, provide a semantic construction for revision operators, and then in a representation result show that these approaches coincide. this work is interesting because, on the one hand it shows how the AGM approach can be extended to a seemingly nonmonotonic framework, while on the other hand the formal characterization may provide guiding principles for the development of specific revision operators.
the proceedings contain 26 papers. the topics discussed include: inconsistency management for description logic programs and beyond;reasoning about pattern-based XML queries;answer set programming: language, applicati...
ISBN:
(纸本)9783642396656
the proceedings contain 26 papers. the topics discussed include: inconsistency management for description logic programs and beyond;reasoning about pattern-based XML queries;answer set programming: language, applications and development tools;a variant of earley deduction with partial evaluation;verification and synthesis in description logic based dynamic systems;towards an efficient algorithm to reason over description logics extended with nominal schemas;computing incoherence explanations for learned ontologies;an ontology-based reasoning approach for electric power utilities;conjunctive queries with negation over DL-lite: a closer look;on the exploration of the query rewriting space with existential rules;incomplete information in RDF;RIO: minimizing user interaction in ontology debugging;and eliminating nonmonotonic DL-atoms in description logic programs.
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