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Towards dynamic consistency checking in goal-directed predicate answer set programming

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arXiv 2021年

作者： Arias, Joaquín Carro, Manuel Gupta, Gopal CETINIA Universidad Rey Juan Carlos Madrid Spain Universidad Politécnica de Madrid Spain IMDEA Software Institute Madrid Spain University of Texas at Dallas Richardson United States

Goal-directed evaluation of Answer Set Programs is gaining traction thanks to its amenability to create AI systems that can, due to the evaluation mechanism used, generate explanations and justifications. s(CASP) is one of these systems and has been already used to write reasoning systems in several fields. It provides enhanced expressiveness w.r.t. other ASP systems due to its ability to use constraints, data structures, and unbound variables natively. However, the performance of existing s(CASP) implementations is not on par with other ASP systems: model consistency is checked once models have been generated, in keeping with the generate-and-test paradigm. In this work, we present a variation of the top-down evaluation strategy, termed Dynamic Consistency Checking, which interleaves model generation and consistency checking. This makes it possible to determine when a literal is not compatible with the denials associated to the global constraints in the program, prune the current execution branch, and choose a different alternative. This strategy is specially (but not exclusively) relevant in problems with a high combinatorial component. We have experimentally observed speedups of up to 90× w.r.t. the standard versions of s(CASP). © 2021, CC BY.

关键词： logic programming

Knowledge-based stable roommates problem: A real-world application

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arXiv 2021年

作者： Fidan, Müge Erdem, Esra Faculty of Engineering and Natural Sciences Sabanci University Istanbul Turkey

The Stable Roommates problem with Ties and Incomplete lists (SRTI) is a matching problem characterized by the preferences of agents over other agents as roommates, where the preferences may have ties or be incomplete. SRTI asks for a matching that is stable and, sometimes, optimizes a domain-independent fairness criterion (e.g., Egalitarian). However, in real-world applications (e.g., assigning students as roommates at a dormitory), we usually consider a variety of domain-specific criteria depending on preferences over the habits and desires of the agents. With this motivation, we introduce a knowledge-based method to SRTI considering domain-specific knowledge, and investigate its real-world application for assigning students as roommates at a university dormitory. This paper is under consideration for acceptance in Theory and Practice of logic programming (TPLP). Copyright © 2021, The Authors. All rights reserved.

关键词： logic programming

Solution enumeration by optimality in answer set programming

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arXiv 2021年

作者： Pajunen, Jukka Janhunen, Tomi Department of Computer Science Aalto University P.O.Box 15400 AALTOFI-00076 Finland Computing Sciences Tampere University TAMPERE UNIVERSITY FI-33014 Finland

Given a combinatorial search problem, it may be highly useful to enumerate its (all) solutions besides just finding one solution, or showing that none exists. The same can be stated about optimal solutions if an objective function is provided. This work goes beyond the bare enumeration of optimal solutions and addresses the computational task of solution enumeration by optimality (SEO). This task is studied in the context of Answer Set programming (ASP) where (optimal) solutions of a problem are captured with the answer sets of a logic program encoding the problem. Existing answer-set solvers already support the enumeration of all (optimal) answer sets. However, in this work, we generalize the enumeration of optimal answer sets beyond strictly optimal ones, giving rise to the idea of answer set enumeration in the order of optimality (ASEO). This approach is applicable up to the best k answer sets or in an unlimited setting, which amounts to a process of sorting answer sets based on the objective function. As the main contribution of this work, we present the first general algorithms for the aforementioned tasks of answer set enumeration. Moreover, we illustrate the potential use cases of ASEO. First, we study how efficiently access to the next-best solutions can be achieved in a number of optimization problems that have been formalized and solved in ASP. Second, we show that ASEO provides us with an effective sampling technique for Bayesian networks. This article is under consideration for acceptance in *** Codes 68N17, 90C27 © 2021, CC BY-NC-ND.

关键词： logic programming

Quantitative and stream extensions of answer set programming

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arXiv 2021年

作者： Kiesel, Rafael TU Vienna Austria

Answer Set programming has separately been extended with constraints, to the streaming domain, and with capabilities to reason over the quantities associated with answer sets. We propose the introduction and analysis of a general framework that incorporates all three directions of extension by exploiting the strengths of Here-and-There logic and Weighted logic. Copyright © 2021, The Authors. All rights reserved.

关键词： logic programming

Harnessing incremental answer set solving for reasoning in assumption-based argumentation

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arXiv 2021年

作者： Lehtonen, Tuomo Wallner, Johannes P. Järvisalo, Matti University of Helsinki Finland Graz University of Technology Austria

Assumption-based argumentation (ABA) is a central structured argumentation formalism. As shown recently, answer set programming (ASP) enables efficiently solving NP-hard reasoning tasks of ABA in practice, in particular in the commonly studied logic programming fragment of ABA. In this work, we harness recent advances in incremental ASP solving for developing effective algorithms for reasoning tasks in the logic programming fragment of ABA that are presumably hard for the second level of the polynomial hierarchy, including skeptical reasoning under preferred semantics as well as preferential reasoning. In particular, we develop non-trivial counterexample-guided abstraction refinement procedures based on incremental ASP solving for these tasks. We also show empirically that the procedures are significantly more effective than previously proposed algorithms for the tasks. Copyright © 2021, The Authors. All rights reserved.

关键词： logic programming

An Alternative Option to Commercial Programmable logic Controllers

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An Alternative Option to Commercial Programmable Logic Contr...

International Conference on System Modeling & Advancement in Research Trends (SMART)

作者： Basharat Ahmad Garima Goswami M. Faisal Khan Teerthanker Mahaveer University Moradabad India Electrical Engineering Section Aligarh Muslim University Aligarh India

ISBN: (纸本)9781665439718

The Programmable logic Controllers (PLC) are widely used in control of Industrial Processes and Machinery. Numerous companies like Mitsubishi, Siemens, ABB, and Omron have developed commercial PLC’s and have launched them in the market. The buyer has to pay a considerable amount to buy commercial PLC’s available in the market. In this paper an AVR Microcontroller Based Circuitry is introduced that can be used as an alternative to commercial PLC’s. Only higher versions of Programmable logic Controllers contain analog input module. The developed Microcontroller based PLC can also provide a control for analog input signals. This alternative PLC is developed at a fraction of cost to PLC’s available in the market. The controller circuitry is programmed with the help of personal computer software. The LD-Micro Freely available Ladder logic programming Software is used to develop the code for the developed Programmable logic Controller.

关键词： Costs Microcontrollers Machine control logic programming Programmable logic devices Process control Microcomputers

Reasoning about counterfactuals and explanations: Problems, results and directions

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arXiv 2021年

作者： Bertossi, Leopoldo Santiago Chile

There are some recent approaches and results about the use of answer-set programming for specifying counterfactual interventions on entities under classification, and reasoning about them. These approaches are flexible and modular in that they allow the seamless addition of domain knowledge. Reasoning is enabled by query answering from the answer-set program. The programs can be used to specify and compute responsibility-based numerical scores as attributive explanations for classification results. Copyright © 2021, The Authors. All rights reserved.

关键词： logic programming

Application of Method for Constructing a Complex Hierarchical logic in Intelligent Agriculture Context

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Application of Method for Constructing a Complex Hierarchica...

Automatics and Informatics (ICAI), International Conference

作者： Todorka Glushkova Stanimir Stoyanov Vassil Sgurev Lyubka Doukovska Atanas Dukovski Faculty of Mathematics and Informatics Plovdiv University “Paisii Hilendarski” Plovdiv Bulgaria Institute of Information and Communication Technologies Bulgarian Academy of sciences Sofia Bulgaria

The paper considers the possibility of using complex logic to create shorter and clearer models for the purposes of intelligent agriculture. Some aspects for developing a suitable environment for program modeling of scenarios and processes of intelligent agriculture have been explored. Creating an interpreter of hierarchical complex logic will greatly facilitate modeling and decision making. Here is presented an opportunity to interpret complex logic using the logic programming language Prolog and its inference machine. The results are illustrated by an example of creating an irrigation plan.

关键词： Irrigation logic programming Decision making Intelligent systems Informatics Digital agriculture

Compilation of aggregates in ASP

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arXiv 2021年

作者： Mazzotta, Giuseppe University of Calabria Rende Italy

Answer Set programming (ASP) is a well-known problem-solving formalism in computational logic. Nowadays, ASP is used in many real world scenarios thanks to ASP solvers. Standard evaluation of ASP programs suffers from an intrinsic limitation, knows as Grounding Bottleneck, due to the grounding of some rules that could fit all the available memory. As a result, there exist instances of real world problems that are untractable using the standard Ground & Solve approach. In order to tackle this problem, different strategies have been proposed. Among them we focus on a recent approach based on compilation of problematic constraints as propagators, which revealed to be very promising but is currently limited to constraints without aggregates. Since aggregates are widely used in ASP, in this paper we extend such an approach also to constraints containing aggregates. Good results, that proof the effectiveness of the proposed approach, have been reached. © 2021, CC BY.

关键词： logic programming