logic programs with abstract constraint atoms provide a unifying framework for studying logic programs with various kinds of constraints. Establishing strong equivalence between logic programs is a key property for pr...
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ISBN:
(纸本)9783642208942;9783642208959
logic programs with abstract constraint atoms provide a unifying framework for studying logic programs with various kinds of constraints. Establishing strong equivalence between logic programs is a key property for program maintenance and optimization, and for guaranteeing the same behavior for a revised original program in any context. In this paper, we study strong equivalence of logic programs with abstract constraint atoms. We first give a general characterization of strong equivalence based on a new definition of program reduct for logic programs with abstract constraints. then we consider a particular kind of program revision-constraint replacements addressing the question: under what conditions can a constraint in a program be replaced by other constraints, so that the resulting program is strongly equivalent to the original one.
Answer Set programming, or ASP, is now becoming well-established as a declarative approach to problem-solving in AI and in an increasing number of practical, application domains. While a significant part of ASP resear...
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ISBN:
(纸本)9783642208942
Answer Set programming, or ASP, is now becoming well-established as a declarative approach to problem-solving in AI and in an increasing number of practical, application domains. While a significant part of ASP research is devoted to producing and applying faster and more user-friendly solvers, there is also a growing interest in studying extensions of the basic language of ASP. Additions to the language that are currently being developed include function symbols, temporal and causal operators, as well as devices to deal with aggregates, preferences, ontologies, resources, and many others.
We report on three recent advances in the distributed ASP solver claspar. First, we describe its flexible architecture supporting various search strategies, including competitive search using a portfolio of solver con...
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ISBN:
(纸本)9783642208942
We report on three recent advances in the distributed ASP solver claspar. First, we describe its flexible architecture supporting various search strategies, including competitive search using a portfolio of solver configurations. Second, we describe claspar's distributed learning capacities that allow for sharing learned nogoods among solver instances. Finally, we discuss claspar's approach to distributed optimization.
Answer Set programming (ASP) is a truly-declarative programming paradigm proposed in the area of non-monotonic reasoning and logicprogramming. In the last few years, several tools for ASP-program development have bee...
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ISBN:
(纸本)9783642208942;9783642208959
Answer Set programming (ASP) is a truly-declarative programming paradigm proposed in the area of non-monotonic reasoning and logicprogramming. In the last few years, several tools for ASP-program development have been proposed, including (more or less advanced) editors and debuggers. However, ASP still lacks an Integrated Development Environment (IDE) supporting the entire life-cycle of ASP development, from (assisted) programs editing to application deployment. In this paper we present ASPIDE, a comprehensive IDE for ASP, integrating a cutting-edge editing tool (featuring dynamic syntax highlighting, on-line syntax correction, autocompletion, code-templates, quick-fixes, refactoring, etc.) with a collection of user-friendly graphical tools for program composition, debugging, profiling, database access, solver execution configuration and output-handling.
Domains, such as Ambient Intelligence and Social Networks, are characterized by some common features including distribution of the available knowledge, entities with different backgrounds, viewpoints and operational e...
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ISBN:
(纸本)9783642208942;9783642208959
Domains, such as Ambient Intelligence and Social Networks, are characterized by some common features including distribution of the available knowledge, entities with different backgrounds, viewpoints and operational environments, and imperfect knowledge. Multi-Context Systems (MCS) has been proposed as a natural representation model for such environments, while recent studies have proposed adding non-monotonic features to MCS to address the issues of incomplete, uncertain and ambiguous information. In previous works, we introduced a non-monotonic extension to MCS and an argument-based reasoning model that handle imperfect context information based on defeasible argumentation. Here we propose alternative variants that integrate features such as partial preferences, ambiguity propagating and team defeat, and study the relations between the different variants in terms of conclusions being drawn in each case.
We consider a housekeeping domain with multiple cleaning robots and represent it in the action language C+. With such a formalization of the domain, a plan can be computed using the causal reasoner CCALC for each robo...
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ISBN:
(纸本)9783642208942
We consider a housekeeping domain with multiple cleaning robots and represent it in the action language C+. With such a formalization of the domain, a plan can be computed using the causal reasoner CCALC for each robot to tidy some part of the house. However, to find a plan that characterizes a feasible trajectory that does not collide with obstacles, we need to consider geometric reasoning as well. For that, we embed motion planning in the domain description using external predicates. For safe execution of feasible plans, we introduce a planning and monitoring algorithm so that the robots can recover from plan execution failures due to heavy objects that cannot be lifted alone. the coordination of robots to help each other is considered for such a recovery. We illustrate the applicability of this algorithm with a simulation of a housekeeping domain.
Heterogeneous nonmonotonic multi-context systems (MCS) permit different logics to be used in different contexts, and link them via bridge rules. We investigate the role of symmetry detection and symmetry breaking in s...
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ISBN:
(纸本)9783642208942;9783642208959
Heterogeneous nonmonotonic multi-context systems (MCS) permit different logics to be used in different contexts, and link them via bridge rules. We investigate the role of symmetry detection and symmetry breaking in such systems to eliminate symmetric parts of the search space and, thereby, simplify the evaluation process. We propose a distributed algorithm that takes a local stance, i.e., computes independently the partial symmetries of a context and, in order to construct potential symmetries of the whole, combines them withthose partial symmetries returned by neighbouring contexts. We prove the correctness of our methods. We instantiate such symmetry detection and symmetry breaking in a multi-context system with contexts that use answer set programs, and demonstrate computational benefit on some recently proposed benchmarks.
In this paper we present STeLP, a solver for Answer Set programming with temporal operators. Taking as an input a particular kind of logic program with modal operators (called Splitable Temporal logic Program), STeLP ...
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ISBN:
(纸本)9783642208942;9783642208959
In this paper we present STeLP, a solver for Answer Set programming with temporal operators. Taking as an input a particular kind of logic program with modal operators (called Splitable Temporal logic Program), STeLP obtains its set of temporal equilibrium models (a generalisation of stable models for this extended syntax). the obtained set of models is represented in terms of a deterministic Buchi automaton capturing the complete program behaviour. In small examples, this automaton can be graphically displayed in a direct and readable way. the input language provides a set of constructs which allow a simple definition of temporal logic programs, including a special syntax for action domains that can be exploited to simplify the graphical output. STeLP combines the use of a standard ASP solver with a linear temporal logic model checker in order to find all models of the input theory.
We propose External Transaction logic (or ET R), an extension of Transaction logic able to represent updates in internal and external domains whilst ensuring a relaxed transaction model. Withthis aim, ETR deals with ...
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ISBN:
(纸本)9783642208942;9783642208959
We propose External Transaction logic (or ET R), an extension of Transaction logic able to represent updates in internal and external domains whilst ensuring a relaxed transaction model. Withthis aim, ETR deals with two main components: an internal knowledge base where updates follow the strict ACID model, given by the semantics of Transaction logic;and an external knowledge base of which one has limited or no control and can only execute external actions. When executing actions in the external domain, if a failure occurs, it is no longer possible to simply rollback to the initial state before executing the transaction. For dealing withthis, similarly to what is done in databases, we define compensating operations for each external action to be performed to ensure a relaxed model of atomicity and consistency. By executing these compensations in backward order, we obtain a state considered to be equivalent to the initial one.
In this paper, we study a method for computing temporal equilibrium models, a generalisation of stable models for logic programs with temporal operators, as in Linear Temporal logic (LTL). To this aim, we focus on a s...
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ISBN:
(纸本)9783642208942;9783642208959
In this paper, we study a method for computing temporal equilibrium models, a generalisation of stable models for logic programs with temporal operators, as in Linear Temporal logic (LTL). To this aim, we focus on a syntactic subclass of these temporal logic programs called splitable and whose main property is satisfying a kind of "future projected" dependence present in most dynamic scenarios in Answer Set programming (ASP). Informally speaking, this property can be expressed as "past does not depend on the future." We show that for this syntactic class, temporal equilibrium models can be captured by an LTL formula, that results from the combination of two well-known techniques in ASP: splitting and loop formulas. As a result, an LTL model checker can be used to obtain the temporal equilibrium models of the program.
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