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See detailConvivial ambient technologies: Requirements, ontology, and design
Caire, Patrice UL; van der Torre, Leon UL

in Computer Journal (2010), 53(8), 12291256

In this paper we discuss the use of the social concept ‘conviviality’ for computer science in general, and for the development of ambient technologies in particular. First, we give a survey of the use of ... [more ▼]

In this paper we discuss the use of the social concept ‘conviviality’ for computer science in general, and for the development of ambient technologies in particular. First, we give a survey of the use of the concept ‘conviviality’ in the social sciences. Conviviality is usually considered a positive concept related to sociability. However, further analysis reveals a negative side related to lack of diversity, privacy and ethical issues. Second, we argue that conviviality requirements for ambient intelligence are challenging, because ambient technologies give rise to a new virtual and social reality, and conviviality issues play a central role in applications that are concerned with the interaction of material, virtual and social realities. Conviviality highlights an important challenge that we illustrate with examples that emphasize ethical issues, such as privacy threats, surveillance of users and identity theft. Intelligent interfaces, for example, allow instant interactions and thereby create strong needs for coordination and regulation mechanisms that have to be addressed to ensure the safeguard of individuals against abuses, such as privacy intrusions and identity manipulations. Third, we propose a conviviality ontology by operationalizing the fuzzy concept of ‘conviviality,’ such that it can be used in computer science in the same way as other social concepts such as ‘service,’ ‘contract’ or ‘trust’ are used in this area. Conviviality is defined using dependence networks, and tools for conviviality are based on, what we call, conviviality masks. Fourth, we illustrate how convivial ambient intelligence applications can be designed using our operationalized concept of conviviality. We illustrate our arguments and contributions with a running example on the use of ambient technologies in digital cities, as a prototypical example where material reality such as ambient technologies interacts with virtual and social realities. [less ▲]

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See detailFive guidelines for normative multiagent systems
Boella, Guido UL; Pigozzi, Gabriella UL; van der Torre, Leon UL

in Proceedings of JURIX 2009 - The 22nd International Conference on Legal Knowledge and Information Systems (2009, December)

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

n this paper we introduce and discuss five guidelines for the use of normative systems in computer science. We adopt a multiagent systems perspective, because norms are used to coordinate, organize, guide, regulate or control interaction among distributed autonomous systems. They are derived from the computer science literature. From the so-called ‘normchange’ definition of the first workshop on normative 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 normative multiagent systems in 2007 we derive the guidelines to discuss the use and role of norms as a mechanism in a game-theoretic setting, and to clarify the role of norms in the multiagent system. [less ▲]

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See detailAlgorithms for finding coalitions exploiting a new reciprocity condition
Boella, Guido UL; Sauro, Luigi UL; van der Torre, Leon UL

in Logic Journal of the IGPL (2009), 17(3), 273297

We introduce a reciprocity criterion for coalition formation among goal-directed agents, which we call the indecomposable do-ut-des property. It refines an older reciprocity property, called the do-ut-des ... [more ▼]

We introduce a reciprocity criterion for coalition formation among goal-directed agents, which we call the indecomposable do-ut-des property. It refines an older reciprocity property, called the do-ut-des or give-to-get property by considering the fact that agents prefer to form coalitions whose components cannot be formed independently. A formal description of this property is provided as well as an analysis of algorithms and their complexity. We provide an algorithm to decide whether a coalition has the desired property, and we show that the problem to verify whether a single coalition satisfies the property is tractable. Moreover, we provide an algorithm to search all the sub-coalitions of a given coalition satisfying the new property. Even if this problem is not computationally tractable, we show that in several cases, also the complexity of this problem may decrease considerably. [less ▲]

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See detailA Middleware for modeling Organizations and Roles in Jade
Baldoni, Matteo UL; Boella, Guido UL; Genovese, Valerio UL et al

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 ▲]

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See detailInput/output logics
Parent, Xavier UL; van der Torre, Leon UL

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 ▲]

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See detailA complete conclusion-based procedure for judgment aggregation
Pigozzi, Gabriella UL; Slavkovik, Marija UL; van der Torre, Leon UL

in Proceedings of the First International Conference on Algorithmic Decision Theory (ADT) (2009)

Judgment aggregation is a formal theory reasoning about how a group of agents can aggregate individual judgments on connected propositions into a collective judgment on the same propositions. Three ... [more ▼]

Judgment aggregation is a formal theory reasoning about how a group of agents can aggregate individual judgments on connected propositions into a collective judgment on the same propositions. Three procedures for successfully aggregating judgments sets are: premise-based procedure, conclusion-based procedure and distance-based merging. The conclusion-based procedure has been little investigated because it provides a way to aggregate the conclusions, but not the premises, thus it outputs an incomplete judgment set. The goal of this paper is to present a conclusion-based procedure outputting complete judgment sets. [less ▲]

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See detailThe Design of Convivial Multiagent Systems
Caire, Patrice UL; van der Torre, Leon UL

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)

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See detailTemporal Dependence Networks for the Design of Convivial Multiagent Systems
Caire, Patrice UL; van der Torre, Leon UL

in Proceedings of the Eighth International Joint Conference on Autonomous Agents and Multiagent Systems, AAMAS (2009)

We show how to use TROPOS as a design methodology for convivial multi-agent systems. We introduce temporal dependence networks to measure the evolution of conviviality over time, and we compare them to ... [more ▼]

We show how to use TROPOS as a design methodology for convivial multi-agent systems. We introduce temporal dependence networks to measure the evolution of conviviality over time, and we compare them to dynamic dependence networks introduced for conviviality masks and internal dynamics. [less ▲]

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See detailNorm Negotiation in Online Multi-Player Games
Boella, Guido UL; Caire, Patrice UL; van der Torre, Leon UL

in Knowledge & Information Systems (2009), 18(2), 137156

In this paper, we introduce an agent communication protocol and speech acts for norm negotiation. The protocol creates individual or contractual obligations to fulfill goals of the agents based on the so ... [more ▼]

In this paper, we introduce an agent communication protocol and speech acts for norm negotiation. The protocol creates individual or contractual obligations to fulfill goals of the agents based on the so-called social delegation cycle. First, agents communicate their individual goals and powers. Second, they propose social goals which can be accepted or rejected by other agents. Third, they propose obligations and sanctions to achieve the social goal, which can again be accepted or rejected. Finally, the agents accept the new norm by indicating which of their communicated individual goals the norm achieves. The semantics of the speech acts is based on a commitment to public mental attitudes. The norm negotiation model is illustrated by an example of norm negotiation in multi-player online gaming. [less ▲]

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See detailA Conviviality Measure for Early Requirement Phase of Multiagent System Design
Caire, Patrice UL; van der Torre, Leon UL

in Normative Multiagent Systems (2009)

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See detailFour measures for the dynamics of coalitions in social networks
Boella, Guido UL; van der Torre, Leon UL; Villata, Serena

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 ▲]

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See detailMeta-Argumentation part 1
Boella, Guido UL; Gabbay, Dov M. UL; van der Torre, Leon UL et al

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 ▲]

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See detailChecking Consistency in role oriented Dependence Networks
Boella, Guido UL; Genovese, Valerio UL; van der Torre, Leon UL et al

in BNAIC 2009: 21th Belgian - Netherlands Conference on Artificial Intelligence (2009)

In this paper we first formalize dependence networks that can be automaticaly build to model goalbased relationships among agents. Then, we propose three algorithms to build and check the consistency of a ... [more ▼]

In this paper we first formalize dependence networks that can be automaticaly build to model goalbased relationships among agents. Then, we propose three algorithms to build and check the consistency of a dependence network. We start presenting the elements composing our ontology such as agents, goals, skills, dependencies with the addition of the institutional notions of roles, institutional goals, institutional skills. We investigate the reasons behind the possible inconsistencies in building the combined dependence network and we propose an algorithm to check them [less ▲]

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See detailThe Interplay between Relationships, Roles and Objects
Boella, Guido UL; van der Torre, Leon UL

in Proceedings of FSEN09 (2009)

In this paper we study the interconnection between relationships and roles. We start from the patterns used to introduce relationships in object oriented languages, and we show how the role model proposed ... [more ▼]

In this paper we study the interconnection between relationships and roles. We start from the patterns used to introduce relationships in object oriented languages, and we show how the role model proposed in powerJava can be used to define roles. In particular, we focus on how to implement roles in an abstract way in objects representing relationships, and to specify the interconnections between the roles. Abstract roles cannot be instantiated. To participate in a relationship, objects have to extend the abstract roles of the relationship. Only when roles are implemented in the objects offering them, they can be instantiated, thus allowing another object to play those roles. [less ▲]

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See detailOn the Acceptability of Meta-Arguments
Boella, Guido UL; van der Torre, Leon UL; Villata, Serena

in 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 ▲]

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See detailNormative framework for normative system change
Boella, Guido UL; Pigozzi, Gabriella UL; van der Torre, Leon UL

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 ▲]

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See detailFour Ways to Change Coalitions: Agents, Dependencies, Norms and Internal Dynamics
Boella, Guido UL; van der Torre, Leon UL; Villata, Serena

in Proceedings of COIN (2009)

We introduce a new formal approach to social networks in order to distinguish four ways in which coalitions change.First, the agents in the network change. Second, dependencies among the agents change ... [more ▼]

We introduce a new formal approach to social networks in order to distinguish four ways in which coalitions change.First, the agents in the network change. Second, dependencies among the agents change, for example due to addition or removal of powers and goals of the agents. Third, norms can introduce normative dependencies for obligations and prohibitions. Fourth, coalitions can change due to internal processes. We propose a number of stability measures to identify each one of the four proposed sources of coalitions ’dynamics and the consequences they induce on the stability of coalitions. [less ▲]

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See detailRepresenting Excuses in Social Dependence Networks
Boella, Guido UL; Broersen, Jan UL; van der Torre, Leon UL et al

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 ▲]

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See detailNormative systems in computer science. Ten guidelines for normative multiagent systems
Boella, Guido UL; Pigozzi, Gabriella UL; van der Torre, Leon UL

in Normative Multi-Agent Systems, Dagstuhl Seminar Proceedings 09121 (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 ▲]

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See detailDependency in Cooperative Boolean Games
Sauro, Luigi UL; van der Torre, Leon UL; Villata, Serena

in Agent and Multi-Agent Systems: Technologies and Applications, Third KES International Symposium, KES-AMSTA 2009, Uppsala, Sweden, June 3-5, 2009. Proceedings (2009)

Cooperative boolean games are coalitional games with both goals and costs associated to actions, and dependence networks for boolean games are a kind of social networks representing how the actions of ... [more ▼]

Cooperative boolean games are coalitional games with both goals and costs associated to actions, and dependence networks for boolean games are a kind of social networks representing how the actions of other agents have an influence on the achievement of an agent’s goal. In this paper, we introduce two new types of dependence networks, called the abstract dependence network and the refined dependence network. Moreover, we show that the notion of stability is complete with respect to the solution concept of the core in the case of cooperative boolean games with costly actions. We present a reduction, called Δ-reduction, to pass from a cooperative boolean game G to game G′ without loosing solutions. [less ▲]

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