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See detailNormative Multi-Agent Systems
Andrighetto, Giulia; Governatori, Guido; Noriega, Pablo et al

in Dagstuhl Reports (2012), 2(3), 23-49

Normative systems are systems in the behavior of which norms play a role and which need normative concepts in order to be described or specified. A normative multi-agent system combines models for ... [more ▼]

Normative systems are systems in the behavior of which norms play a role and which need normative concepts in order to be described or specified. A normative multi-agent system combines models for normative systems (dealing for example with obligations, permissions and prohibitions) with models for multi-agent systems. Norms have been proposed in multi-agent systems and computer science to deal with issues of coordination, security, electronic commerce and institutions, agent organization. However, due to the lack of a unified theory, many multi-agent system researchers are presently developing their own ad hoc concepts and applications. The aim of this Dagstuhl Seminar was to formulate a collective appraisal of the current perspectives in the field and the most promising venues for future activity. In particular, the seminar has been conceived for the writing of a volume titled "A Prospective view of Normative Multi Agent Systems" aimed to become a standard reference in the field and to provide guidelines for future research in normative multi-agent systems. [less ▲]

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See detailVisualizing Normative Systems: an Abstract Approach
Colombo Tosatto, Silvano UL; Boella, Guido; van der Torre, Leon UL et al

in Agotnes, Thomas; Broersen, Jan; Elgesem, Dag (Eds.) Deontic Logic in Computer Science - 11th International Conference, DEON 2012, Bergen, Norway, July 16-18, 2012. Proceedings (2012)

Abstract normative systems allow to reason with norms even when their content is not detailed. In this paper, we propose a our preliminary results to visualize abstract normative systems, in such a way ... [more ▼]

Abstract normative systems allow to reason with norms even when their content is not detailed. In this paper, we propose a our preliminary results to visualize abstract normative systems, in such a way that we are able to reason with institutional facts, obligations and permissions. Moreover, we detect meaningful patterns emerging from the proposed visualization, and we show how these patterns can be used to define commonly used reusable solutions. [less ▲]

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See detailOn Input/Output Argumentation Frameworks
Baroni, Pietro UL; Boella, Guido UL; Cerutti, Federico et al

in Proceedings of COMMA (2012)

This paper introduces Input/Output Argumentation Frameworks, a novel approach to characterize the behavior of an argumentation framework as a sort of black box exposing a well-defined external interface ... [more ▼]

This paper introduces Input/Output Argumentation Frameworks, a novel approach to characterize the behavior of an argumentation framework as a sort of black box exposing a well-defined external interface. As a starting point, we define the novel notion of semantics decomposability and analyze complete, stable, grounded and preferred semantics in this respect. Then we show as a main result that, under grounded, complete, stable and credulous preferred semantics, Input/Output Argumentation Frameworks with the same behavior can be interchanged without affecting the result of semantics evaluation of other arguments interacting with them [less ▲]

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See detailModelling defeasible and prioritized support in bipolar argumentation
Villata, Serena; Boella, Guido; Gabbay, Dov M. UL et al

in Annals of Mathematics & Artificial Intelligence (2012), 66(1-4), 163-197

Cayrol and Lagasquie-Schiex introduce bipolar argumentation frameworks by introducing a second relation on the arguments for representing the support among them. The main drawback of their approach is ... [more ▼]

Cayrol and Lagasquie-Schiex introduce bipolar argumentation frameworks by introducing a second relation on the arguments for representing the support among them. The main drawback of their approach is that they cannot encode defeasible support, for instance they cannot model an attack towards a support relation. In this paper, we introduce a way to model defeasible support in bipolar argumentation frameworks. We use the methodology of meta-argumentation in which Dung’s theory is used to reason about itself. Dung’s well-known admissibility semantics can be used on this meta-argumentation framework to compute the acceptable arguments, and all properties of Dung’s classical theory are preserved. Moreover, we show how different contexts can lead to the alternative strengthening of the support relation over the attack relation, and converse. Finally, we present two applications of our methodology for modeling support, the case of arguments provided with an internal structure and the case of abstract dialectical frameworks. [less ▲]

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See detailAgent Programming Languages Requirements for Programming Cognitive Robots (extended abstract)
Ziafati, Pouyan UL; Dastani, Mehdi; Meyer, John-Jules et al

Scientific Conference (2012)

This paper presents various requirements for BDI-based agent programming languages to provide better support for implementing autonomous robotic control systems. Examples of such requirements are: 1 ... [more ▼]

This paper presents various requirements for BDI-based agent programming languages to provide better support for implementing autonomous robotic control systems. Examples of such requirements are: 1- Built-in support for integration with existing robotic frameworks such as ROS, 2- Real-time reactivity to events, 3- Management of heterogeneous sensory data and reasoning on complex events, and 4- Representation of complex plans and coordination of the parallel execution of plans. [less ▲]

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See detailBeyond Maxi-Consistent Argumentation Operators
Vesic, Srdjan UL; van der Torre, Leon UL

in 13th European Conference on Logics in Artificial Intelligence, JELIA 2012 (2012)

The question whether Dung’s abstract argumentation theory can be instantiated with classical propositional logic has drawn a considerable amount of attention among scientists in recent years. It was shown ... [more ▼]

The question whether Dung’s abstract argumentation theory can be instantiated with classical propositional logic has drawn a considerable amount of attention among scientists in recent years. It was shown by Cayrol in 1995 that if direct undercut is used, then stable extensions of an argumentation system correspond exactly to maximal (for set inclusion) consistent subsets of the knowledge base from which the argumentation system was constructed. Until now, no other correspondences were found between the extensions of an argumentation framework and its knowledge base (except if preferences are also given at the input of the system). This paper’s contribution is twofold. First, we identify four intuitive conditions describing a class of attack relations which return extensions corresponding exactly to the maximal (for set inclusion) consistent subsets of the knowledge base. Second, we show that if we relax those conditions, it is possible to instantiate Dung’s abstract argumentation theory with classical propositional logic and obtain a meaningful result which does not correspond to the maximal consistent subsets of the knowledge base used for constructing arguments. Indeed, we define a whole class of instantiations that return different results. Furthermore, we show that these instantiations are sound in the sense that they satisfy the postulates from argumentation literature (e.g. consistency, closure). In order to illustrate our results, we present one particular instantiation from this class, which is based on cardinalities of minimal inconsistent sets a formula belongs to. [less ▲]

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See detailA logic of argumentation for specification and verification of abstract argumentation frameworks
Villata, Serena; Boella, Guido; Gabbay, Dov M. UL et al

in Annals of Mathematics & Artificial Intelligence (2012), 66(1-4), 199-230

In this paper, we propose a logic of argumentation for the specification and verification (LA4SV) of requirements on Dung’s abstract argumentation frameworks. We distinguish three kinds of decision ... [more ▼]

In this paper, we propose a logic of argumentation for the specification and verification (LA4SV) of requirements on Dung’s abstract argumentation frameworks. We distinguish three kinds of decision problems for argumentation verification, called extension verification, framework verification, and specification verification respectively. For example, given a political requirement like “if the argument to increase taxes is accepted, then the argument to increase services must be accepted too,” we can either verify an extension of acceptable arguments, or all extensions of an argumentation framework, or all extensions of all argumentation frameworks satisfying a framework specification. We introduce the logic of argumentation verification to specify such requirements, and we represent the three verification problems of argumentation as model checking and theorem proving properties of the logic. Moreover, we recast the logic of argumentation verification in a modal framework, in order to express multiple extensions, and properties like transitivity and reflexivity of the attack relation. Finally, we introduce a logic of meta-argumentation where abstract argumentation is used to reason about abstract argumentation itself. We define the logic of meta-argumentation using the fibring methodology in such a way to represent attack relations not only among arguments but also among attacks. [less ▲]

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See detailLogics for Security and Privacy
van der Torre, Leon UL

in 2012 (2012)

In this presentation I first review new developments of deontic logic in computer science, then I discuss the use of dynamic epistemic deontic logic to reason about privacy policies, and finally I discuss ... [more ▼]

In this presentation I first review new developments of deontic logic in computer science, then I discuss the use of dynamic epistemic deontic logic to reason about privacy policies, and finally I discuss the use of modal logic for access control. This presentation is based on joint work with Guillaume Aucher, Guido Boella, Jan Broersen, Dov Gabbay and Valerio Genovese. [less ▲]

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See detailConditional acceptance functions
Booth, Richard UL; Kaci, Souhila; Rienstra, Tjitze UL et al

in 4th International Conference on Computational Models of Argument (COMMA 2012) (2012)

Dung-style abstract argumentation theory centers on argumentation frameworks and acceptance functions. The latter take as input a framework and return sets of labelings. This methodology assumes full ... [more ▼]

Dung-style abstract argumentation theory centers on argumentation frameworks and acceptance functions. The latter take as input a framework and return sets of labelings. This methodology assumes full awareness of the arguments relevant to the evaluation. There are two reasons why this is not satisfactory. Firstly, full awareness is, in general, not a realistic assumption. Second, frameworks have explanatory power, which allows us to reason abductively or counterfactually, but this is lost under the usual semantics. To recover this aspect, we generalize conventional acceptance, and we present the concept of a conditional acceptance function. [less ▲]

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See detailDiscussion Paper: Changing Norms Is Changing Obligation Change
Broersen, Jan UL; Gabbay, Dov M. UL; van der Torre, Leon UL

in Deontic Logic in Computer Science (2012)

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See detailContrary-To-Duties in Games
Turrini, Paolo UL; Parent, Xavier UL; van der Torre, Leon UL et al

in Logic Programs, Norms and Action: Essays in Honor of Marek J. Sergot on the Occasion of His 60th Birthday (Lecture Notes in Computer Science / Lecture Notes in Artificial Intelligence) (2012)

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See detailDependence Networks for Agreement Technologies
Boella, Guido; Caire, Patrice UL; van der Torre, Leon UL et al

in AT2012, Agreement Technologies, Proceedings of the First International Conference on Agreement Technologies (2012)

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See detailTowards Legal Knowledge Management Systems for Regulatory Compliance
Boella, Guido; Hulstijn, Joris; Humphreys, Llio UL et al

in IX Conference of the Italian Chapter of AIS (2012)

Maintaining regulatory compliance is an increasing concern. Legal Knowledge Management systems could support the work of compliance managers. However, there are challenges to overcome, of interpreting ... [more ▼]

Maintaining regulatory compliance is an increasing concern. Legal Knowledge Management systems could support the work of compliance managers. However, there are challenges to overcome, of interpreting legal knowledge and mapping it onto business processes. In this discussion paper we determine requirements for Legal Knowledge Management systems that can handle these challenges. We argue that an approach to Legal Knowledge Management should consist of four pillars: (1) a legal ontology to express the legal concepts that are central to the interpretation of rules and regulations in practice, (2) natural language processing techniques, to semi-automatically populate the ontology, (3) a systematic method for mapping the legal concepts onto the actual data and business processes of a company, and (4) a method to construct an audit trail as part of the process design, providing legally acceptable evidence of compliance. The challenges are illustrated by an example of MIFID, a set of European regulations in the financial domain. [less ▲]

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See detailAbstract Normative Systems: Semantics and Proof Theory
Colombo Tosatto, Silvano UL; Boella, Guido; van der Torre, Leon UL et al

in PRINCIPLES OF KNOWLEDGE REPRESENTATION AND REASONING: PROCEEDINGS OF THE THIRTEENTH INTERNATIONAL CONFERENCE (2012)

In this paper we introduce an abstract theory of normative reasoning, whose central notion is the generation of obligations, permissions and institutional facts from conditional norms. We present various ... [more ▼]

In this paper we introduce an abstract theory of normative reasoning, whose central notion is the generation of obligations, permissions and institutional facts from conditional norms. We present various semantics and their proof systems. The theory can be used to classify and compare new candidates for standards of normative reasoning, and to explore more elaborate forms of normative reasoning than studied thus far. [less ▲]

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See detailComputational Logic in Multi-Agent Systems - 13th International Workshop, CLIMA XIII
Fisher, Michael; van der Torre, Leon UL; Dastani, Mehdi et al

in Computational Logic in Multi-Agent Systems - 13th International Workshop, CLIMA XIII (2012)

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See detailComputational Logic in Multi-Agent Systems - 14th International Workshop, CLIMA XIV
Leite, Joao; Son, Tran Cao; Torroni, Paolo et al

in Computational Logic in Multi-Agent Systems - 14th International Workshop, CLIMA XIV (2012)

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See detailMulti-sorted Argumentation
Rienstra, Tjitze UL; Perotti, Alan; Villata, Serena et al

in Proceedings of the 1st International Workshop on the Theory and Applications of Formal Argumentation (TAFA 2011) (2011, July 16), 7132

In the theory of abstract argumentation, the acceptance status of arguments is normally determined for the complete set of arguments at once, under a single semantics. However, this is not always desired ... [more ▼]

In the theory of abstract argumentation, the acceptance status of arguments is normally determined for the complete set of arguments at once, under a single semantics. However, this is not always desired. In this paper, we extend the notion of an argumentation framework to a multi-sorted argumentation framework, and we motivate this extension using an example which considers practical and epistemic arguments. In a multi-sorted argumentation framework, the arguments are partitioned into a number of cells, where each cell is associated with a semantics under which its arguments are evaluated. We prove the properties of the proposed framework, and we demonstrate our theory with a number of examples. Finally, we relate our theory to the theory of modal fibring of argumentation networks. [less ▲]

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See detailJudgment aggregation rules based on minimization.
Lang, J. UL; Pigozzi, Gabriella UL; Slavkovik, Marija UL et al

in Actes des Cinquièmes Journées Francophones Modèles Formel de l'Interaction (MFI 11) (2011, July 12), XIII

Many voting rules are based on some minimization principle. Likewise, in the field of logic-based knowledge representation and reasoning, many belief change or inconsistency handling operators also make ... [more ▼]

Many voting rules are based on some minimization principle. Likewise, in the field of logic-based knowledge representation and reasoning, many belief change or inconsistency handling operators also make use of minimization. Surprisingly, minimization has not played a major role in the field of judgment aggregation, in spite of its proximity to voting theory and logic-based knowledge representation and reasoning. Here we make a step in this direction and study six judgment aggregation rules; two of them, based on distances, have been previously defined; the other four are new, and all inspired both by voting theory and knowledge representation and reasoning. We study the inclusion relationships between these rules and address some of their social choice theoretic properties. [less ▲]

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See detailNeural Symbolic Architecture for Normative Agents
Boella, Guido; Colombo Tosatto, Silvano UL; d'Avila Garcez, Artur et al

in In Proceedings of The Seventh International Conference on Autonomous Agents and Multiagent Systems (AAMAS 2011). May, 2011 (2011)

In this paper we propose a neural-symbolic architecture to represent and reason with norms in multi-agent systems. On the one hand, the architecture contains a symbolic knowledge base to represent norms ... [more ▼]

In this paper we propose a neural-symbolic architecture to represent and reason with norms in multi-agent systems. On the one hand, the architecture contains a symbolic knowledge base to represent norms and on the other hand it contains a neural network to reason with norms. The interaction between the symbolic knowledge and the neural network is used to learn norms. We describe how to handle normative reasoning issues like contrary to duties, dilemmas and exceptions by using a priority-based ordering between the norms in a neural-symbolic architecture. [less ▲]

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See detailA Satisficing Agreements Model
Boella, Guido UL; Pigozzi, Gabriella UL; Slavkovik, Marija UL et al

in Proceedings of the 13th International Workshop on Coordination, Organization, Institutions and Norms (COIN@WI-IAT) (2011)

Satisficing, the concept proposed by Herbert Simon, as an approach to reaching agreements is little explored. We propose a model for satisficing agreement reaching for an adaptive collaborative group of ... [more ▼]

Satisficing, the concept proposed by Herbert Simon, as an approach to reaching agreements is little explored. We propose a model for satisficing agreement reaching for an adaptive collaborative group of agents. The group consists of one human agent familiar with the problem and arbitrarily many artificial agents. Our model raises to the team level the recognition-primed decision model constructed in the field of cognitive decision-making by using social choice for reaching group opinions. [less ▲]

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