References of "van der Torre, Leon 50003247"
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See detailLogiKEy Workbench: Deontic Logics, Logic Combinations and Expressive Ethical and Legal Reasoning (Isabelle/HOL Dataset)
Benzmüller, Christoph UL; Farjami, Ali UL; Fuenmajor, David et al

in Data in Brief (2020), 33

The LogiKEy workbench and dataset for ethical and legal reasoning is presented. This workbench simultaneously supports development, experimentation, assessment and deployment of formal logics and ethical ... [more ▼]

The LogiKEy workbench and dataset for ethical and legal reasoning is presented. This workbench simultaneously supports development, experimentation, assessment and deployment of formal logics and ethical and legal theories at different conceptual layers. More concretely, it comprises, in form of a dataset (Isabelle/HOL theory files), formal encodings of multiple deontic logics, logic combinations, deontic paradoxes and normative theories in the higher-order proof assistant system Isabelle/HOL. The data were acquired through application of the LogiKEy methodology, which supports experimentation with different normative theories, in different application scenarios, and which is not tied to specific logics or logic combinations. Our workbench consolidates related research contributions of the authors and it may serve as a starting point for further studies and experiments in flexible and expressive ethical and legal reasoning. It may also support hands-on teaching of non-trivial logic formalisms in lecture courses and tutorials. [less ▲]

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See detailA bimodal simulation of defeasibility in thenormative domain
Libal, Tomer UL; van der Torre, Leon UL; Gabbay, Dov UL et al

in CEUR Workshop Proceedings (2020)

In the present work we illustrate how two sorts of defeasiblereasoning that are fundamental in the normative domain, that is, reasoning about exceptions and reasoning about violations, can be simulated ... [more ▼]

In the present work we illustrate how two sorts of defeasiblereasoning that are fundamental in the normative domain, that is, reasoning about exceptions and reasoning about violations, can be simulated via monotonic propositional theories based on a bimodal language with primitive operators representing knowledge and obligation. The proposed theoretical framework paves the way to using native theorem provers for multimodal logic, such as MleanCoP, in order to automate normative reasoning. [less ▲]

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See detailA Principle-Based Analysis of Weakly Admissible Semantics
Dauphin, Jérémie UL; Rienstra, Tjitze; van der Torre, Leon UL

in Computational Models of Argument - Proceedings of COMMA 2020, Perugia Italy, September 4-11, 2020 (2020)

Baumann, Brewka and Ulbricht recently introduced weak admissibility as an alternative to Dung’s notion of admissibility, and they use it to define weakly preferred, weakly complete and weakly grounded ... [more ▼]

Baumann, Brewka and Ulbricht recently introduced weak admissibility as an alternative to Dung’s notion of admissibility, and they use it to define weakly preferred, weakly complete and weakly grounded semantics of argumentation frameworks. In this paper we analyze their new semantics with respect to the principles discussed in the literature on abstract argumentation. Moreover, we introduce two variants of their new semantics, which we call qualified and semiqualified semantics, and we check which principles they satisfy as well. Since the existing principles do not distinguish our new semantics from the ones of Baumann et al., we also introduce some new principles to distinguish them. Besides selecting a semantics for an application, or for algorithmic design, our new principle-based analysis can also be used for the further search for weak admissibility semantics. [less ▲]

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See detailAttack-Defence Frameworks: Argumentation-Based Semantics for Attack-Defence Trees.
Gabbay, Dov M. UL; Horne, Ross James UL; Mauw, Sjouke UL et al

in Graphical Models for Security - 7th International Workshop (2020)

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See detailSCF2 - an Argumentation Semantics for Rational Human Judgments on Argument Acceptability
Cramer, Marcos; van der Torre, Leon UL

in Proceedings of the 8th Workshop on Dynamics of Knowledge and Belief (DKB-2019) and the 7th Workshop KI \& Kognition (KIK-2019) co-located with 44nd German Conference on Artificial Intelligence (KI 2019), Kassel, Germany, September 23, 2019 (2019)

In abstract argumentation theory, many argumentation semantics have been proposed for evaluating argumentation frameworks. This paper is based on the following research question: Which semantics ... [more ▼]

In abstract argumentation theory, many argumentation semantics have been proposed for evaluating argumentation frameworks. This paper is based on the following research question: Which semantics corresponds well to what humans consider a rational judgment on the acceptability of arguments? There are two systematic ways to approach this research question: A normative perspective is provided by the principle-based approach, in which semantics are evaluated based on their satisfaction of various normatively desirable principles. A descriptive perspective is provided by the empirical approach, in which cognitive studies are conducted to determine which semantics best predicts human judgments about arguments. In this paper, we combine both approaches to motivate a new argumentation semantics called SCF2. For this purpose, we introduce and motivate two new principles and show that no semantics from the literature satisfies both of them. We define SCF2 and prove that it satisfies both new principles. Furthermore, we discuss findings of a recent empirical cognitive study that provide additional support to SCF2. [less ▲]

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See detailFrom Classical to Non-monotonic Deontic Logic Using ASPIC+
Dong, Huimin; Liao, Beishui; Markovich, Réka UL et al

in Logic, Rationality, and Interaction - 7th International Workshop LORI 2019, Chongqing, China, October 18-21, 2019, Proceedings (2019)

In this paper we use formal argumentation to design non-monotonic deontic logics, based on two monotonic deontic logics. In particular, we use the structured argumentation theory ASPIC􀀀 to define non ... [more ▼]

In this paper we use formal argumentation to design non-monotonic deontic logics, based on two monotonic deontic logics. In particular, we use the structured argumentation theory ASPIC􀀀 to define non-monotonic variants of well-understood modal logics. We illustrate the approach using argumentation about free-choice permission. [less ▲]

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See detailA dynamic approach for combining abstract argumentation semantics
Dauphin, Jérémie UL; Cramer, Marcos; van der Torre, Leon UL

in Dynamics, Uncertainty and Reasoning (2019)

Abstract argumentation semantics provide a direct relation from an argumentation framework to corresponding sets of acceptable arguments, or equivalently to labeling functions. Instead, we study step-wise ... [more ▼]

Abstract argumentation semantics provide a direct relation from an argumentation framework to corresponding sets of acceptable arguments, or equivalently to labeling functions. Instead, we study step-wise update relations on argumentation frameworks whose fixpoints represent the labeling functions on the arguments. We make use of this dynamic approach in order to study novel ways of combining abstract argumentation semantics. In particular, we introduce the notion of a merge of two argumentation semantics, which is defined in such a way that the merge of the preferred and the grounded semantics is the complete semantics. Finally we consider how to define new semantics using the merge operator, in particular how meaningfully combine features of naive-based and complete-based semantics. [less ▲]

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See detailA geometrical view of I/O logic
Gabbay, Dov UL; Parent, Xavier UL; van der Torre, Leon UL

Report (2019)

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See detailMachine Argumentation. Can We Replace Taxi Drivers by Robots?
Gabbay, Dov M. UL; Cramer, Marcos; Dauphin, Jérémie UL et al

in Natural Argument, A tribute to John Woods (2019)

We need ethical non-monotonic action logics to control machines which interact heavily with humans. Such logics face special problems and require features which we need to recognise and to address. We ... [more ▼]

We need ethical non-monotonic action logics to control machines which interact heavily with humans. Such logics face special problems and require features which we need to recognise and to address. We believe that injecting argumentation methods into action pre-conditions is possibly the way to proceed to model what is needed. To get an idea of what is needed we must investigate a typical problem of replacing a human with a robot operating in a highly interactive environment. This paper focuses on replacing a human taxi driver by a robot. Robot driven cars are already under production and so there is an urgent need for modelling the kind of Artificial Intelligence/Logic/Norms/Ethics which is to be involved and installed in the mind of the Robot. This is research in progress. [less ▲]

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See detailIntroduction to Deontic Logic and Normative Systems
Parent, Xavier UL; van der Torre, Leon UL

Book published by College Publications (2018)

Deontic logic deals with obligation, permission and related normative concepts. This textbook introduces three frameworks that have dominated the landscape of deontic logic: monadic deontic logic, dyadic ... [more ▼]

Deontic logic deals with obligation, permission and related normative concepts. This textbook introduces three frameworks that have dominated the landscape of deontic logic: monadic deontic logic, dyadic deontic logic, and input/output logic. It describes their language, semantics, proof theory, and gives soundness and completeness theorems. The addition of exercises makes the book ideal for self-study or as a textbook in class. Deontic logic remains neutral on application issues. Over the years, it has been applied in a variety of fields, including philosophy, ethics, linguistics, computer science, and the law. This textbook will serve as a valuable resource for students and researchers wishing to gain a practical understanding of deontic logic for use in their work. [less ▲]

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See detailA Dynamic Approach for Combining Abstract Argumentation Semantics – Technical Report
Dauphin, Jérémie UL; Cramer, Marcos UL; van der Torre, Leon UL

Report (2018)

Abstract argumentation semantics provide a direct relation from an argumentation framework to corresponding sets of acceptable arguments, or equivalently to labeling functions. Instead, we study step-wise ... [more ▼]

Abstract argumentation semantics provide a direct relation from an argumentation framework to corresponding sets of acceptable arguments, or equivalently to labeling functions. Instead, we study step-wise update relations on argumentation frameworks whose fixpoints represent the labeling functions on the arguments. We make use of this dynamic approach in order to study novel ways of combining abstract argumentation semantics. In particular, we introduce the notion of a merge of two argumentation semantics, which is defined in such a way that the merge of the preferred and the grounded semantics is the complete semantics. Finally we consider how to define new semantics using the merge operator, in particular how meaningfully combine features of naive-based and complete-based semantics. [less ▲]

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See detailProceedings - 2017 ILILAS Distinguished Lectures
Bouvry, Pascal UL; Bisdorff, Raymond; Schommer, Christoph UL et al

Report (2018)

The Proceedings summarizes the 12 lectures that have taken place within the ILIAS Dinstguished Lecture series 2017. It contains a brief abstract of the talks as well as some additional information about ... [more ▼]

The Proceedings summarizes the 12 lectures that have taken place within the ILIAS Dinstguished Lecture series 2017. It contains a brief abstract of the talks as well as some additional information about each speaker. [less ▲]

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See detailArgumentation as Exogenous Coordination
van der Torre, Leon UL; Rienstra, Tjitze; Gabbay, Dov UL

in It's All About Coordination (2018)

Formal argumentation is one of the most popular approaches in modern logic and reasoning. The theory of abstract argumentation introduced by Dung in 1995 has shifted the focus from the internal structure ... [more ▼]

Formal argumentation is one of the most popular approaches in modern logic and reasoning. The theory of abstract argumentation introduced by Dung in 1995 has shifted the focus from the internal structure of arguments to relations among arguments, and temporal dynamics for abstract argumentation was proposed by Barringer, Gabbay and Woods in 2005. In this tradition, we see arguments as reasoning processes, and the interaction among them as a coordination process.We argue that abstract argumentation can adopt ideas and techniques from formal theories of coordination, and as an example we propose a model of sequential abstract argumentation loosely inspired by Reo’s model of exogenous coordination. We show how the argumentation model can represent the temporal dynamics of the liar paradox and predator-prey like behaviour. [less ▲]

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See detailArguing about constitutive and regulative norms
Pigozzi, Gabriella; van der Torre, Leon UL

in Journal of Applied Non-Classical Logics (2018), 28(2-3), 189--217

Formal arguments are often represented by (support, conclusion) pairs, but in this paper we consider normative arguments represented by sequences of (brute, institutional, deontic) triples, where ... [more ▼]

Formal arguments are often represented by (support, conclusion) pairs, but in this paper we consider normative arguments represented by sequences of (brute, institutional, deontic) triples, where constitutive norms derive institutional facts from brute facts, and regulative norms derive deontic facts like obligations and permissions from institutional facts. The institutional facts may be seen as the reasons explaining or warranting the deontic obligations and permissions, and therefore they can be attacked by other normative arguments too. We represent different aspects of normative reasoning by different kinds of consistency checks among these triples, and we use formal argumentation theory to resolve conflicts among such normative arguments. In particular, we introduce various requirements for arguing about norms concerning violations, contrary-to-duty obligations, dilemmas, conflict resolution and different kinds of norms, and we introduce a formal argumentation theory satisfying the requirements. In order to illustrate our framework, we introduce a running example based on university regulations for prospective and actual students. [less ▲]

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See detailAbstract and Concrete Decision Graphs for Choosing Extensions of Argumentation Frameworks - Technical Report
Dauphin, Jérémie UL; Cramer, Marcos UL; van der Torre, Leon UL

Report (2018)

Most argumentation semantics allow for multiple extensions, which raises the question of how to choose among extensions. We propose to study this question as a decision problem. Inspired by decision trees ... [more ▼]

Most argumentation semantics allow for multiple extensions, which raises the question of how to choose among extensions. We propose to study this question as a decision problem. Inspired by decision trees commonly used in economics, we introduce the notion of a decision graph for deciding between the multiple extensions of a given AF in a given semantics. We distinguish between abstract decision graphs and concrete instantiations thereof. Inspired by the principle-based approach to argumentation, we formulate two principles that mappings from argumentation frameworks to decision graphs should satisfy, the principle of decision-graph directionality and the one of directional decision-making. We then propose a concrete instantiation of decision graphs, which satisfies one of these principles. Finally, we discuss the potential for further research based on this novel methodology. [less ▲]

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See detailPresent and Future of Formal Argumentation (Dagstuhl Perspectives Workshop 15362)
Gabbay, Dov UL; Giacomin, Massimiliano; Liao, Beishui UL et al

in Dagstuhl Manifestos (2018), 7(1), 69--95

Formal Argumentation is emerging as a key reasoning paradigm building bridges among knowledge representation and reasoning in artificial intelligence, informal argumentation in philosophy and linguistics ... [more ▼]

Formal Argumentation is emerging as a key reasoning paradigm building bridges among knowledge representation and reasoning in artificial intelligence, informal argumentation in philosophy and linguistics, legal and ethical argumentation, mathematical and logical reasoning, and graph-theoretic reasoning. It aims to capture diverse kinds of reasoning and dialogue activities in the presence of uncertainty and conflicting information in a formal and intuitive way, with potential applications ranging from argumentation mining, via LegalTech and machine ethics, to therapy in clinical psychology. The turning point for the modern stage of formal argumentation theory, much similar to the introduction of possible worlds semantics for the theory of modality, is the framework and language of Dung’s abstract argumentation theory introduced in 1995. This means that nothing could remain the same as before 1995 — it should be a focal point of reference for any study of argumentation, even if it is critical about it. Now, in modal logic, the introduction of the possible worlds semantics has led to a complete paradigm shift, both in tools and new subjects of studies. This is still not fully true for what is going on in argumentation theory. The Dagstuhl workshop led to the first volume of a handbook series in formal argumentation, reflecting the new stage of the development of argumentation theory. [less ▲]

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See detailA comparison between a person and a robot in the attention, imitation, and repetitive and stereotypical behaviors of children with autism spectrum disorder.
Pinto Costa, Andreia UL; Charpiot, Louise UL; Lera, Francisco et al

Scientific Conference (2018)

The aim of the present study was to assess the usefulness of QT, a socially assistive robot, in interventions with children with autism spectrum disorder (ASD) by assessing children’s attention, imitation ... [more ▼]

The aim of the present study was to assess the usefulness of QT, a socially assistive robot, in interventions with children with autism spectrum disorder (ASD) by assessing children’s attention, imitation, and presence of repetitive and stereotyped behaviors. Fifteen children diagnosed with ASD, aged from 4 to 14 years participated in two short interactions, one with a person and one with QT robot. Statistical analyses revealed that children directed more attention towards the robot than to the person, imitated the robot as much as the person, and engaged in fewer repetitive or stereotyped behaviors with the robot than with the person. These results support previous research demonstrating the usefulness of robots in interventions with children with ASD and provide new evidence to the usefulness of robots in reducing repetitive and stereotyped behaviors in children with ASD, which can affect children’s learning. [less ▲]

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See detailPrioritized norms in formal argumentation
Liao, Beishui; Oren, Nir; van der Torre, Leon UL et al

in Journal of Logic and Computation (2018)

To resolve conflicts amongst norms, various non-monotonic formalisms can be used to perform prioritized normative reasoning. Meanwhile, formal argumentation provides a way to represent non-monotonic ... [more ▼]

To resolve conflicts amongst norms, various non-monotonic formalisms can be used to perform prioritized normative reasoning. Meanwhile, formal argumentation provides a way to represent non-monotonic logics. In this paper we propose a representation of prioritized normative reasoning by argumentation. Using hierarchical abstract normative systems (HANS), we define three kinds of prioritized normative reasoning approaches called Greedy, Reduction and Optimization. Then, after formulating an argumentation theory for a HANS, we show that for a totally ordered HANS, Greedy and Reduction can be represented in argumentation by applying the weakest link and the last link principles, respectively, and Optimization can be represented by introducing additional defeats capturing the idea that for each argument that contains a norm not belonging to the maximal obeyable set then this argument should be rejected. [less ▲]

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See detailPreference in Abstract Argumentation
Kaci, Souhila; van der Torre, Leon UL; Villata, Serena

in Computational Models of Argument (2018)

Consider an argument A that is attacked by an argument B, while A is preferred to B. Existing approaches will either ignore the attack or reverse it. In this paper we introduce a new reduction of ... [more ▼]

Consider an argument A that is attacked by an argument B, while A is preferred to B. Existing approaches will either ignore the attack or reverse it. In this paper we introduce a new reduction of preference and attack to defeat, based on the idea that in such a case, instead of ignoring the attack, the preference is ignored. We compare this new reduction with the two existing ones using a principle-based approach, for the four Dung semantics. The principle-based or axiomatic approach is a methodology to choose an argumentation semantics for a particular application, and to guide the search for new argumentation semantics. For this analysis, we also introduce a fourth reduction, and a semantics for preference-based argumentation based on extension selection. Our classification of twenty alternatives for preference-based abstract argumentation semantics using six principles suggests that our new reduction has some advantages over the existing ones, in the sense that if the set of preferences increases, the sets of accepted arguments increase as well. [less ▲]

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See detailRepresentation Equivalences among Argumentation Frameworks
Liao, Beishui; van der Torre, Leon UL

in Computational Models of Argument (2018)

In Dung’s abstract argumentation theory, an extension can be represented by subsets of it in the sense that from each of these subsets, the extension can be obtained again by iteratively applying the ... [more ▼]

In Dung’s abstract argumentation theory, an extension can be represented by subsets of it in the sense that from each of these subsets, the extension can be obtained again by iteratively applying the characteristic function. Such so-called regular representations can be used to differentiate argumentation frameworks having the same extensions. In this paper we provide a full characterization of relations between seven different types of representation equivalence. [less ▲]

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