Abstract Normative Systems: Semantics and Proof Theory

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 ▲]

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)

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 ▲]

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

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

Selecting judgment aggregation rules for NAO robots: an experimental approach

in Selecting judgment aggregation rules for NAO robots: an experimental approach (2012)

Social choice rules can be used to reach group decisions in multiagent systems. We consider judgment aggregation, the problem of aggregating answers to binary logically related questions. In general ... [more ▼]

Social choice rules can be used to reach group decisions in multiagent systems. We consider judgment aggregation, the problem of aggregating answers to binary logically related questions. In general "fairness" is usually considered to be the main concern when selecting a social choice rule, however we believe that in judgment aggregation often a more relevant property is how efficient the rule is in truth tracking, that is, how often does it return the correct answer to the binary questions. Whereas "fairness" can be studied axiomatically, truth tracking efficiency needs to be studied experimentally. We accomplish the experimental analysis by constructing a multi-robot system. [less ▲]

Beyond Maxi-Consistent Argumentation Operators

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 ▲]

Learning and Reasoning about Norms using Neural-Symbolic Systems

in International Conference on Autonomous Agents and Multiagent Systems, AAMAS 2012, Valencia, Spain, June 4-8, 2012 (2012)

In this paper we provide a neural-symbolic framework to model, reason about and learn norms in multi-agent systems. To this purpose, we define a fragment of Input/Output (I/O) logic that can be embedded ... [more ▼]

In this paper we provide a neural-symbolic framework to model, reason about and learn norms in multi-agent systems. To this purpose, we define a fragment of Input/Output (I/O) logic that can be embedded into a neural network. We extend d’Avila Garcez et al. Connectionist Inductive Learning and Logic Programming System (CILP) to translate an I/O logic theory into a Neural Network (NN) that can be trained further with examples: we call this new system Normative- CILP (N-CILP). We then present a new algorithm to handle priorities between rules in order to cope with normative issues like Contrary to Duty (CTD), Priorities, Exceptions and Permissions. We illustrate the applicability of the framework on a case study based on RoboCup rules: within this working example, we compare the learning capacity of a network built with N-CILP with a non symbolic neural net- work, we explore how the initial knowledge impacts on the overall performance, and we test the NN capacity of learn- ing norms, generalizing new Contrary to Duty rules from examples. [less ▲]

Agent Programming Languages Requirements for Programming Cognitive Robots (extended abstract)

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 ▲]

Judgment aggregation rules based on minimization.

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 ▲]

A Satisficing Agreements Model

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 ▲]