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An application of ASP in nuclear engineering: Explaining the Three Mile Island Nuclear Accident Scenario

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arXiv 2020年

作者： Hanna, Botros N. Trieu, Ly L.Y.T. Son, Tran C. Dinh, Nam T. Computer Science Department New Mexico State University Las CrucesNM United States Department of Nuclear Engineering North Carolina State University RaleighNC United States

The paper describes an ongoing effort in developing a declarative system for supporting operators in the Nuclear Power Plant (NPP) control room. The focus is on two modules: diagnosis and explanation of events that happened in NPPs. We describe an Answer Set programming (ASP) representation of an NPP, which consists of declarations of state variables, components, their connections, and rules encoding the plant behavior. We then show how the ASP program can be used to explain the series of events that occurred in the Three Mile Island, Unit 2 (TMI-2) NPP accident, the most severe accident in the USA nuclear power plant operating history. We also describe an explanation module aimed at addressing answers to questions such as "why an event occurs?" or "what should be done?" given the collected data. Copyright © 2020, The Authors. All rights reserved.

关键词： logic programming

Belief Base Revision for Further Improvement of Unified Answer Set programming

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arXiv 2020年

作者： Ray, Kumar Sankar Paul, Sandip Saha, Diganta ECSU Indian Statistical Institute Kolkata India CSE Department Jadavpur University

A belief base revision is developed. The belief base is represented using Unified Answer Set Programs which is capable of representing imprecise and uncertain information and perform nonomonotonic reasoning with them. The base revision operator is developed using Removed Set Revision strategy. The operator is characterized with respect to the postulates for base revisions operator satisfies. Copyright © 2020, The Authors. All rights reserved.

关键词： logic programming

Toward a concept of derivation for Prolog 32

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Toward a concept of derivation for Prolog

32. Workshops fur (Constraint) Logische Programmierung, WCLP 2018 - 32nd Workshop on (Constraint) logic programming, WCLP 2018

作者： Kulaš, Marija FernUniversität Hagen Wissensbasierte Systeme Hagen58084 Germany

In logic programming, derivations are dependant on two kinds of implicit parameters: history of a derivation step, and (in case of implementation) also algorithms, which restrict the freedom of derivation and generate backtracking. On that basis, we propose a concept of derivation including backtracking and aggregation of steps. © Deklarative Ansatze zur Kunstlichen Intelligenz - Punktuelle Beitrage - Post-Proceedings des 32. Workshops fur (Constraint) Logische Programmierung, WCLP 2018. All rights reserved.

关键词： logic programming

Structural Decompositions of Epistemic logic Programs

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arXiv 2020年

作者： Hecher, Markus Morak, Michael Woltran, Stefan TU Wien Vienna Austria University of Potsdam Potsdam Germany University of Klagenfurt Klagenfurt Austria

Epistemic logic programs (ELPs) are a popular generalization of standard Answer Set programming (ASP) providing means for reasoning over answer sets within the language. This richer formalism comes at the price of higher computational complexity reaching up to the fourth level of the polynomial hierarchy. However, in contrast to standard ASP, dedicated investigations towards tractability have not been undertaken yet. In this paper, we give first results in this direction and show that central ELP problems can be solved in linear time for ELPs exhibiting structural properties in terms of bounded treewidth. We also provide a full dynamic programming algorithm that adheres to these bounds. Finally, we show that applying treewidth to a novel dependency structure—given in terms of epistemic literals—allows to bound the number of ASP solver calls in typical ELP solving *** Codes 68T27 Copyright © 2020, The Authors. All rights reserved.

关键词： logic programming

Verifying Tight logic Programs with anthem and vampire

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arXiv 2020年

作者： Fandinno, Jorge Lifschitz, Vladimir Lühne, Patrick Schaub, Torsten University of Potsdam Germany University of Texas Austin United States

This paper continues the line of research aimed at investigating the relationship between logic programs and first-order theories. We extend the definition of program completion to programs with input and output in a subset of the input language of the ASP grounder gringo, study the relationship between stable models and completion in this context, and describe preliminary experiments with the use of two software tools, anthem and vampire, for verifying the correctness of programs with input and output. Proofs of theorems are based on a lemma that relates the semantics of programs studied in this paper to stable models of first-order formulas. This paper is under consideration for acceptance in Theory and Practice of logic programming. Copyright © 2020, The Authors. All rights reserved.

关键词： logic programming

Constraint answer set programming without grounding and its applications 3

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Constraint answer set programming without grounding and its ...

3rd International Workshop on the Resurgence of Datalog in Academia and Industry, Datalog 2.0 2019

作者： Arias, Joaquin Carro, Manuel Chen, Zhuo Gupta, Gopal IMDEA Software Institute Spain Universidad Politécnica de Madrid Spain University of Texas at Dallas United States

Extending Datalog/ASP with constraints (CASP) enhances its expressiveness and performance but it is not straightforward as the grounding phase removes variables and the links among them. We incorporate constraints into s(ASP), a goal-directed, top-down execution model which implements predicate answer set programming without grounding. The resulting model, s(CASP), can constrain variables that, as in CLP, are kept during the execution and in the answer sets. We show the enhanced expressiveness of s(CASP) w.r.t. other CASP systems, through a non-trivial example of modeling the event calculus. © 2019 CEUR-WS. All rights reserved.

关键词： logic programming

An ASP-Based Approach to Counterfactual Explanations for Classification

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arXiv 2020年

作者： Bertossi, Leopoldo Universidad Adolfo Ibáñez ✶ RelationalAI’s Academic Network Millenium Institute on Foundations of Data UAI Faculty Eng. & Sciences Santiago Chile

We propose answer-set programs that specify and compute counterfactual interventions as a basis for causality-based explanations to decisions produced by classification models. They can be applied with black-box models and models that can be specified as logic programs, such as rule-based classifiers. The main focus in on the specification and computation of maximum responsibility causal explanations. The use of additional semantic knowledge is investigated. Copyright © 2020, The Authors. All rights reserved.

关键词： logic programming

eclingo: A solver for Epistemic logic Programs∗

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arXiv 2020年

作者： Cabalar, Pedro Fandinno, Jorge Garea, Javier Romero, Javier Schaub, Torsten University of Corunna Spain University of Potsdam Germany

We describe eclingo, a solver for epistemic logic programs under Gelfond 1991 semantics built upon the Answer Set programming system clingo. The input language of eclingo uses the syntax extension capabilities of clingo to define subjective literals that, as usual in epistemic logic programs, allow for checking the truth of a regular literal in all or in some of the answer sets of a program. The eclingo solving process follows a guess and check strategy. It first generates potential truth values for subjective literals and, in a second step, it checks the obtained result with respect to the cautious and brave consequences of the program. This process is implemented using the multi-shot functionalities of clingo. We have also implemented some optimisations, aiming at reducing the search space and, therefore, increasing eclingo’s efficiency in some scenarios. Finally, we compare the efficiency of eclingo with two state-of-the-art solvers for epistemic logic programs on a pair of benchmark scenarios and show that eclingo generally outperforms their obtained results. Copyright © 2020, The Authors. All rights reserved.

关键词： logic programming

Advancing lazy-grounding ASP solving techniques – restarts, phase saving, Heuristics, and more

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arXiv 2020年

作者： Weinzierl, Antonius Taupe, Richard Friedrich, Gerhard Austria Alpen-Adria-Universitt Klagenfurt Austria Siemens AG sterreich Austria

Answer-Set programming (ASP) is a powerful and expressive knowledge representation paradigm with a significant number of applications in logic-based AI. The traditional ground-and-solve approach, however, requires ASP programs to be grounded upfront and thus suffers from the so-called grounding bottleneck (i.e., ASP programs easily exhaust all available memory and thus become unsolvable). As a remedy, lazy-grounding ASP solvers have been developed, but many state-of-the-art techniques for grounded ASP solving have not been available to them yet. In this work we present, for the first time, adaptions to the lazy-grounding setting for many important techniques, like restarts, phase saving, domain-independent heuristics, and learned-clause deletion. Furthermore, we investigate their effects and in general observe a large improvement in solving capabilities and also uncover negative effects in certain cases, indicating the need for portfolio solving as known from other solvers. Under consideration for acceptance in TPLP. Copyright © 2020, The Authors. All rights reserved.

关键词： logic programming