Most SAT solvers and Answer Set programming (ASP) systems employ a backtracking search by repeatedly assuming the truth of literals. The choice of these branching literals is crucial for the performance of these syste...
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Trailing of bindings in the PARMA variable representation is expensive in time and space. Two schemes are presented that lower its cost: the first is a technique that halves the space cost of trailing in PARMA. It can...
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ISBN:
(纸本)1581135289
Trailing of bindings in the PARMA variable representation is expensive in time and space. Two schemes are presented that lower its cost: the first is a technique that halves the space cost of trailing in PARMA. It can be used with conditional and unconditional trailing. It is illustrated and evaluated in the context of dProlog and in the Mercury backend of HAL. The second scheme combines a variant of a previously developed trailing analysis with the first technique. Empirical evidence shows the usefulness of these schemes and that the combination is more effective than each scheme apart.
We build upon recent work by Lierler that defines an abstract framework for describing the algorithm underlying many of the existing answer set solvers (for answer set programs, based upon the Answer Set Semantics), c...
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We build upon recent work by Lierler that defines an abstract framework for describing the algorithm underlying many of the existing answer set solvers (for answer set programs, based upon the Answer Set Semantics), considering in particular SMODELS and SUP. We define a particular class of programs and prove that the computation that the abstract solver performs actually represents a lower bound for deciding inconsistency of logic programs under the Answer Set Semantics. For that class of programs, given a program composed of n atoms a solver adopting this algorithm must perform no less than n steps. We then argue that this result can be extrapolated to every logic program.
This paper studies an abduction problem in formal argumentation frameworks. Given an argument, an agent verifies whether the argument is justified or not in its argumentation framework. If the argument is not justifie...
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ISBN:
(纸本)9783319100616;9783319100609
This paper studies an abduction problem in formal argumentation frameworks. Given an argument, an agent verifies whether the argument is justified or not in its argumentation framework. If the argument is not justified, the agent seeks conditions to explain the argument in its argumentation framework. We formulate such abductive reasoning in argumentation semantics and provide its computation in logic programming. Next we apply abduction in argumentation frameworks to reasoning by players in debate games. In debate games, two players have their own argumentation frameworks and each player builds claims to refute the opponent. A player may provide false or inaccurate arguments as a tactic to win the game. We show that abduction is used not only for seeking counter-claims but also for building dishonest claims in debate games.
We present an alternative approach to shortcut fusion based on the function unfoldr. Despite its simplicity the technique can remove intermediate lists in examples which are known to be difficult. We show that it can ...
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We present an alternative approach to shortcut fusion based on the function unfoldr. Despite its simplicity the technique can remove intermediate lists in examples which are known to be difficult. We show that it can remove all lists from definitions involving zip-like functions and functions using accumulating parameters.
The Janus programming language, viewed as the assembler for an abstract machine with a tree-based memory system, is of theoretical and practical interest, e.g., Pascal compilers. Many widely accepted theoretical formu...
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The dynamic flowgraph methodology (DFM) is a promising way to find the prime implicants of a top event for a dynamic system possibly containing digital subsystems. This paper demonstrates how to express dynamic flowgr...
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The systematic modelling of dynamic spatial systems is a key requirement in a wide range of application areas such as commonsense cognitive robotics, computer-aided architecture design, and dynamic geographic informat...
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An overview of today's automotive industry reminds us about an ever-increasing demand for passenger comfort, safety and zero emissions vehicles. Drivers are also seeking improvements in the handling stability at h...
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We study the problem of efficient, scalable set-sharing analysis of logic programs. We use the idea of representing sharing information as a pair of abstract substitutions, one of which is a worst-case sharing represe...
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We study the problem of efficient, scalable set-sharing analysis of logic programs. We use the idea of representing sharing information as a pair of abstract substitutions, one of which is a worst-case sharing representation called a clique set, which was previously proposed for the case of inferring pair-sharing. We use the clique-set representation for (1) inferring actual set-sharing information, and (2) analysis within a topdown framework. In particular, we define the abstract functions required by standard top-down analyses, both for sharing alone and also for the case of including freeness in addition to sharing. Our experimental evaluation supports the conclusion that, for inferring set-sharing, as it was the case for inferring pair-sharing, precision losses are limited, while useful efficiency gains are obtained. At the limit, the clique-set representation allowed analyzing some programs that exceeded memory capacity using classical sharing representations.
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