Normative Multi-Agent Systems

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 ▲]

Modelling defeasible and prioritized support in bipolar argumentation

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 ▲]

Logics for Security and Privacy

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 ▲]

A logic of argumentation for specification and verification of abstract argumentation frameworks

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 ▲]

Conditional acceptance functions

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 ▲]

Contrary-To-Duties in Games

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)

Towards Legal Knowledge Management Systems for Regulatory Compliance

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 ▲]

Multi-sorted Argumentation

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 ▲]

Neural Symbolic Architecture for Normative Agents

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 ▲]

Attack Semantics for Abstract Argumentation

in Attack Semantics for Abstract Argumentation (2011)

In this paper we conceptualize abstract argumentation in terms of successful and unsuccessful attacks, such that arguments are accepted when there are no successful attacks on them. We characterize the ... [more ▼]

In this paper we conceptualize abstract argumentation in terms of successful and unsuccessful attacks, such that arguments are accepted when there are no successful attacks on them. We characterize the relation between attack semantics and Dung’s approach, and we define an SCC recursive algorithm for attack semantics using attack labelings. [less ▲]