Input/output logics

in Abstract book of 9th De Morgan Workshop on Deontic Logic (2009)

In a range of contexts, one comes across processes resembling inference, but where input propositions are not in general included among outputs, and the operation is not in any way reversible. Exa mples ... [more ▼]

In a range of contexts, one comes across processes resembling inference, but where input propositions are not in general included among outputs, and the operation is not in any way reversible. Exa mples arise in contexts of conditional obligations, goals, ideals, preferences , actions, and beliefs. Our purpose is to develop a theory of such input/output operations . Four are singled out: simple- minded, basic (making intelligent use of disjunctiv e inputs), simple-minded reusable (in which outputs may be recycled as inputs), and b asic reusable. They are defined semantically and characterised by derivation rules, as well as in terms of relabeling procedures and modal operators. Their behaviour is studied on both semantic and syntactic levels [less ▲]

Meta-Argumentation part 1

in Studia Logica (2009)

In this paper, we introduce the methodology and techniques of meta-argumentation to model argumentation. The methodology of meta-argumentation instantiates Dung’s abstract argumentation theory with an ... [more ▼]

In this paper, we introduce the methodology and techniques of meta-argumentation to model argumentation. The methodology of meta-argumentation instantiates Dung’s abstract argumentation theory with an extended argumentation theory, and is thus based on a combination of the methodology of instantiating abstract arguments, and the methodology of extending Dung’s basic argumentation frameworks with other relations among abstract arguments. The technique of meta-argumentation applies Dung’s theory of abstract argumentation to itself, by instantiating Dung’s abstract arguments with meta-arguments using a technique called flattening. We characterize the domain of instantiation using a representation technique based on soundness and completeness. Finally, we distinguish among various instantiations using the technique of specification languages. [less ▲]

A Middleware for modeling Organizations and Roles in Jade

in Proceedings of PROMAS (2009)

Organizations and roles are often seen as mental constructs, good to be used during the design phase in Multi Agent Systems, but they have also been considered as first class citizens in MAS, when ... [more ▼]

Organizations and roles are often seen as mental constructs, good to be used during the design phase in Multi Agent Systems, but they have also been considered as first class citizens in MAS, when objective coordination is needed. Roles facilitate the coordination of agents inside an organization, and they give new abilities in the context of organizations, called powers, to the agents which satisfy the necessary requirements to play them. No general purpose programming languages for multiagent systems offer primitives to program organizations and roles as instances existing at runtime, so, in this paper, we propose our extension of the Jade framework, with Java primitives to program organizations structured in roles, and to enable agents to play roles in organizations. We provide classes and protocols which enable an agent to enact a new role in an organization, to interact with the role by invoking the execution of powers, and to receive new goals to be fulfilled. Roles and organizations can be on a different platform with respect to the role players, and communication is protocol-based. Since they can have complex behaviours, they are implemented by extending the Jade agent class. Our aim is to give to programmers a middle tier, built on the Jade platform, useful to solve with minimal implementative effort many coordination problems, and to offer a first, implicit, management of norms and sanctions. [less ▲]

Fibred security language

in Studia Logica (2009)

We study access control policies based on the says operator by introducing a logical framework called Fibred Security Language (FSL) which is able to deal with features like joint responsibility between ... [more ▼]

We study access control policies based on the says operator by introducing a logical framework called Fibred Security Language (FSL) which is able to deal with features like joint responsibility between sets of principals and to identify them by means of first-order formulas. FSL is based on a multimodal logic methodology. We first discuss the main contributions from the expressiveness point of view, we give semantics for the language both for classical and intuitionistic fragment), we then prove that in order to express well-known properties like ‘speaks-for’ or ‘hand-off’, defined in terms of says, we do not need second-order logic (unlike previous approaches) but a decidable fragment of first-order logic suffices. We propose a model-driven study of the says axiomatization by constraining the Kripke models in order to respect desirable security properties, we study how existing access control logics can be translated into FSL and we give completeness for the logic. [less ▲]

Normative framework for normative system change

in Normative framework for normative system change (2009)

Normative systems in a multiagent system must be able to evolve over time, for example due to actions creating or removing norms in the system. The only formal framework to evaluate and classify normative ... [more ▼]

Normative systems in a multiagent system must be able to evolve over time, for example due to actions creating or removing norms in the system. The only formal framework to evaluate and classify normative system change methods is the so-called AGM framework of theory change, which has originally been developed as a framework to describe and classify both belief and normative system change. However, it has been used for belief change only, since the beliefs or norms are represented as propositional formulas. We therefore propose, as a normative framework for normative system change, to replace propositional formulas in the AGM framework of theory change by pairs of propositional formulas, representing the rule based character of norms, and to add several principles from the input/output logic framework. In this new framework, we show that some of the AGM properties cannot be expressed, and other properties are consistent only for some logics, but not for others. [less ▲]

Normative systems in computer science. Ten guidelines for normative multiagent systems

in Normative Multi-agent Systems (2009)

In this paper we introduce and discuss ten guidelines for the use of normative systems in computer science. We adopt a multiagent sys- tems perspective, because norms are used to coordinate, organize ... [more ▼]

In this paper we introduce and discuss ten guidelines for the use of normative systems in computer science. We adopt a multiagent sys- tems perspective, because norms are used to coordinate, organize, guide, regulate or control interaction among distributed autonomous systems. The first six guidelines are derived from the computer science literature. From the so-called ‘normchange’ definition of the first workshop on nor- mative multiagent systems in 2005 we derive the guidelines to motivate which definition of normative multiagent system is used, to make explicit why norms are a kind of (soft) constraints deserving special analysis, and to explain why and how norms can be changed at runtime. From the so-called ‘mechanism design’ definition of the second workshop on nor- mative multiagent systems in 2007 we derive the guidelines to discuss the use and role of norms as a mechanism in a game-theoretic setting, clarify the role of norms in the multiagent system, and to relate the no- tion of “norm” to the legal, social, or moral literature. The remaining four guidelines follow from the philosophical literature: use norms also to resolve dilemmas, and in general to coordinate, organize, guide, regulate or control interaction among agents, distinguish norms from obligations, prohibitions and permissions, use the deontic paradoxes only to illustrate the normative multiagent system, and consider regulative norms in rela- tion to other kinds of norms and other social-cognitive computer science concepts. [less ▲]

Representing Excuses in Social Dependence Networks

in AI*IA (2009)

In this paper, we propose a representation of excuses in the context of multiagent systems. We distinguish five classes of excuses, taking as starting point both jurisprudential and philosophical studies ... [more ▼]

In this paper, we propose a representation of excuses in the context of multiagent systems. We distinguish five classes of excuses, taking as starting point both jurisprudential and philosophical studies about this topic, and we discuss their acceptance criteria. We highlight the following classes of excuses: epistemic excuses, power-based excuses, norm-based excuses, counts as-based excuses and social-based excuses and we represent them using social dependence networks. The acceptance criteria individuate those excuses which success in maintaining the trust of the other agents, e.g. in the context of social networks, excuses based on norms seem better than counts as-based ones in achieving this aim. [less ▲]

On the Acceptability of Meta-Arguments

in Proceedings of IAT 2009: Procs. of IEEE/WIC/ACM International Conference on Intelligent Agent Technology (2009)

In this paper we introduce a theory of meta-argumentation, by using Dung’s theory of abstract argumentation to reason about itself. Meta-arguments are generated from atomic arguments, and extensions of ... [more ▼]

In this paper we introduce a theory of meta-argumentation, by using Dung’s theory of abstract argumentation to reason about itself. Meta-arguments are generated from atomic arguments, and extensions of acceptable meta-arguments are based on Dung’s argumentation semantics. To illustrate our theory, we show how to represent Toulmin schemes in this theory by introducing meta-arguments using the Caminada labeling, and meta-arguments for support [less ▲]

The Design of Convivial Multiagent Systems

in Social Networks and Multiagent Systems symposium; Artificial Intelligence and Simulation of Behaviour, AISB, April 6-9, 2009 at the Heriot-Watt University, Edinburgh (Scotland). (2009)

Four measures for the dynamics of coalitions in social networks

in Four measures for the dynamics of coalitions in social networks (2009)

We introduce four measures for the change of coalitions in social networks. The first one measures the change of the agents in the network over time, The second one measures the change of dependencies ... [more ▼]

We introduce four measures for the change of coalitions in social networks. The first one measures the change of the agents in the network over time, The second one measures the change of dependencies among the agents, due to addition or removal of powers and goals of the agents. The third one measures the change in normative dependencies like obligations and prohibitions introduced by norms. The fourth one measures changes in coalitions. If one of the first three measures is high, then the fourth measure is probably high too, if the change in agents and dependencies is a cause for a change in coalitions. If the first three measures are low, but the change in coalitions is high, it is due to internal processes like violations of the coalition agreements. [less ▲]