Studying the performance of logic tools on solving a specific problem can bring new insights on the use of different paradigms. This paper provides an empirical evaluation of logic-based encodings for a well known boa...
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ISBN:
(纸本)9783319653402;9783319653396
Studying the performance of logic tools on solving a specific problem can bring new insights on the use of different paradigms. This paper provides an empirical evaluation of logic-based encodings for a well known board game: Ricochet Robots. Ricochet Robots is a board game where the goal is to find the smallest number of moves needed for one robot to move from the initial position to a target position, while taking into account the existing barriers and other robots. Finding a solution to the Ricochet Robots problem is NP-hard. In this work we develop logic-based encodings for the Ricochet Robots problem to feed into Boolean Satisfiability (SAT) solvers. When appropriate, advanced techniques are applied to further boost the performance of a solver. A comparison between the performance of SAT solvers and an existing ASP solution clearly shows that SAT is by far the more adequate technology to solve the Ricochet Robots problem.
In contrast to simple autonomous vacuum cleaners, multi-purpose robots that fetch a cup of coffee and clean up rooms require cognitive skills such as learning, planning, and reasoning. Especially reasoning in dynamic ...
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ISBN:
(纸本)9789897582202
In contrast to simple autonomous vacuum cleaners, multi-purpose robots that fetch a cup of coffee and clean up rooms require cognitive skills such as learning, planning, and reasoning. Especially reasoning in dynamic and human populated environments demands for novel approaches that can handle comprehensive and fluent knowledge bases. A promising approach is answer set programming (ASP), offering multi-shot solving techniques and non-monotonic stable model semantics. Our objective is to equip multi-agent systems with ASP-based reasoning capabilities, enabling a team of robots to cope with dynamic environments. Therefore, we combined ALICA - A Language for Interactive Cooperative Agents - with the ASP solver Clingo and chose topological path planning as our evaluation scenario. We utilised the Region Connection Calculus as underlying formalism of our evaluation and investigated the scalability of our implementation. The results show that our approach handles dynamic environments and scales up to appropriately large problem sizes.
We give an account of stable reasoning, a recent and novel approach to problem solving from a formal, logical point of view. We describe the underlying logic of stable reasoning and illustrate how it is used to model ...
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We describe the first automatic approach for merging coreference annotations obtained from multiple annotators into a single gold standard. Merging is subject to hard constraints (consistency) and optimization criteri...
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ISBN:
(纸本)9783319616605;9783319616599
We describe the first automatic approach for merging coreference annotations obtained from multiple annotators into a single gold standard. Merging is subject to hard constraints (consistency) and optimization criteria (minimal divergence from annotators) and involves an equivalence relation over a large number of elements. We describe two representations of the problem in answer set programming and four objective functions suitable for the task. We provide two structurally different real-world benchmark datasets based on the METU-Sabanci Turkish Treebank, and we report our experiences in using the Gringo, Clasp, and Wasp tools for computing optimal adjudication results on these datasets.
In dynamic service-oriented architectures, services and service compositions underlie constant evolution that may not only affect the own workflow but dependent services too. Subsequently, required adaptations necessi...
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ISBN:
(纸本)9783319596655;9783319596648
In dynamic service-oriented architectures, services and service compositions underlie constant evolution that may not only affect the own workflow but dependent services too. Subsequently, required adaptations necessitate an effective detection of the changes and their effects. Merely capturing a sequence of low-level changes and analyzing each of them demands much coordination and may lead to an incomplete picture. An abstraction that summarizes a combination of low-level changes will facilitate the detection and reduce the number of changes that shall be considered for adaptation. In this paper, we propose an abstraction that is formulated through graph-based patterns, since service compositions are workflows that can be mapped to directed labeled graphs. The characteristics and granularity of a graph pattern can be adjusted by domain experts to the respective workflow language and application case. In particular, graph-based patterns are crucial when workflows are represented in two different formats. This could be the case if there exists one representation for the execution and one for the verification. We present implementation details and a detailed example that shows the feasibility and simplicity of our solution.
We introduce an approach to detecting inconsistencies in large biological networks by using answer set programming. To this end, we build upon a recently proposed notion of consistency between biochemical/genetic reac...
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We introduce an approach to detecting inconsistencies in large biological networks by using answer set programming. To this end, we build upon a recently proposed notion of consistency between biochemical/genetic reactions and high-throughput profiles of cell activity. We then present an approach based on answer set programming to check the consistency of large-scale data sets. Moreover, we extend this methodology to provide explanations for inconsistencies by determining minimal representations of conflicts. In practice, this can be used to identify unreliable data or to indicate missing reactions.
In this paper we propose an extension of answer set programming (ASP) to deal with (possibly partial) evaluable functions. To this aim, we start from the most general logical counterpart of ASP, Quantified Equilibrium...
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In this paper we propose an extension of answer set programming (ASP) to deal with (possibly partial) evaluable functions. To this aim, we start from the most general logical counterpart of ASP, Quantified Equilibrium Logic (QEL), and propose a variant QEL(F)(=) where the set of functions is partitioned into Herbrand functions (or constructors) and evaluable functions (or operations). We show how this extension has a direct connection to Scott's Logic of Existence, and introduce several useful derived operators, some of them directly borrowed from Scott's formalisation. Using this general framework for arbitrary theories, we proceed to focus on a syntactic subclass that corresponds to normal logic programs with evaluable functions and equality. We provide a translation of this class into function-free normal programs and consider a safety condition so that the resulting program is also safe, under the usual meaning in ASP. Finally, we also establish a formal comparison to Lin and Wang's approach (FASP) dealing with evaluable total functions.
We introduce an approach to detecting inconsistencies in large biological networks by using answer set programming. To this end, we build upon a recently proposed notion of consistency between biochemical/genetic reac...
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We introduce an approach to detecting inconsistencies in large biological networks by using answer set programming. To this end, we build upon a recently proposed notion of consistency between biochemical/genetic reactions and high-throughput profiles of cell activity. We then present an approach based on answer set programming to check the consistency of large-scale data sets. Moreover, we extend this methodology to provide explanations for inconsistencies by determining minimal representations of conflicts. In practice, this can be used to identify unreliable data or to indicate missing reactions.
In complex reasoning tasks, as expressible by answer set programming (ASP), problems often permit for multiple solutions. In dynamic environments, where knowledge is continuously changing, the question arises how a gi...
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In complex reasoning tasks, as expressible by answer set programming (ASP), problems often permit for multiple solutions. In dynamic environments, where knowledge is continuously changing, the question arises how a given model can be incrementally adjusted relative to new and outdated information. This paper introduces Ticker, a prototypical engine for well-defined logical reasoning over streaming data. Ticker builds on a practical fragment of the recent rule-based language LARS, which extends ASP for streams by providing flexible expiration control and temporal modalities. We discuss Ticker's reasoning strategies: first, the repeated one-shot solving mode calls Clingo on an ASP encoding. We show how this translation can be incrementally updated when new data is streaming in or time passes by. Based on this, we build on Doyle's classic justification-based truth-maintenance system to update models of non-stratified programs. Finally, we empirically compare the obtained evaluation mechanisms.
We introduce dlv2, a new answer set programming (ASP) system. dlv2 combines I-dlv, a fully-compliant ASP-Core-2 grounder, with the well-assessed solver wasp. Input programs may be enriched by annotations and directive...
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ISBN:
(纸本)9783319616605;9783319616599
We introduce dlv2, a new answer set programming (ASP) system. dlv2 combines I-dlv, a fully-compliant ASP-Core-2 grounder, with the well-assessed solver wasp. Input programs may be enriched by annotations and directives that customize heuristics of the system and extend its solving capabilities. An empirical analysis conducted on benchmarks from past ASP competitions shows that dlv2 outperforms the old dlv system and is close to the state-of-the-art ASP system CLINGO.
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