References of "Boella, Guido 30000076"
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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 detailA Normative Multiagent Approach to Requirements Engineering
Boella, Guido UL; Broersen, Jan UL; van der Torre, Leon UL et al

in Postproceedings COIN@AAMAS 2009 (2009)

In this paper we present a new model, called NorMAS-RE, for the requirements analysis of a system. NorMAS-RE is a new model based on the multiagent systems paradigm with the aim to support the ... [more ▼]

In this paper we present a new model, called NorMAS-RE, for the requirements analysis of a system. NorMAS-RE is a new model based on the multiagent systems paradigm with the aim to support the requirements analysis phase of systems design. This model offers a structured approach to requirements analysis, based on conceptual models defined following a visual modeling language, called dependence networks. The main elements of this visual language are the agents with their goals, capabilities and facts, similarly to the TROPOS methodology [10]. The normative component is present both in the ontology and in the conceptual metamodel, associating agents to roles they play inside the systems and a set of goals, capabilities and facts proper of these roles. This improvement allows to define different types of dependence networks, called dynamic dependence networks and conditional dependence networks, representing the different phases of the requirements analysis of the system. This paper presents a requirements analysis model based on normative concepts such as obligation and institution. The NorMAS-RE model is a model of semiformal specification featured by an ontology, a meta-model, a graphical notation and a set of constraints. Our model, moreover, allows the definition of the notion of coalition for the different kinds of network. We present our model using the scenario of virtual organizations based on a Grid network. [less ▲]

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See detailDynamics in Argumentation with Single Extensions: Abstraction Principles and the Grounded Extension
Boella, Guido UL; Kaci, Souhila UL; van der Torre, Leon UL

in Symbolic and Quantitative Approaches to Reasoning with Uncertainty, 10th European Conference, ECSQARU 2009, Verona, Italy, July 1-3, 2009. Proceedings (2009)

In this paper we consider the dynamics of abstract argumentation in Baroni and Giacomin’s framework for the evaluation of extension based argumentation semantics. Following Baroni and Giacomin, we do not ... [more ▼]

In this paper we consider the dynamics of abstract argumentation in Baroni and Giacomin’s framework for the evaluation of extension based argumentation semantics. Following Baroni and Giacomin, we do not consider individual approaches, but we define general principles or postulates that individual approaches may satisfy. In particular, we define abstraction principles for the attack relation, and for the arguments in the framework. We illustrate the principles on the grounded extension. In this paper we consider only principles for the single extension case, and leave the multiple extension case to further research. [less ▲]

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See detailAnalyzing Cooperation in Iterative Social Network Design
Boella, Guido UL; van der Torre, Leon UL; Villata, Serena

in Journal of Universal Computer Science (2009), 15(13),

We introduce an approach to iteratively design `small' social networks used in software engineering together with methods analyzing the cooperation in the system. The degree of cooperation is measured by ... [more ▼]

We introduce an approach to iteratively design `small' social networks used in software engineering together with methods analyzing the cooperation in the system. The degree of cooperation is measured by the emergence of coalitions and their stability over time. At the most abstract level, which we call the coalition view, coalitions are abstract entities that may dominate or attack other coalitions. During iterative design, these abstract entities are refined with agents and their dependencies constituting the coalitions (dependence view), the powers of sets of agents to see to goals (power view) and finally the beliefs, plans, tasks and goals of agents (agent view). The analysis methods predict the emergence of coalitions based on reciprocity and argumentation theory. [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 detailThe role of goals in belief selection
Boella, Guido UL; Pereira, Célia Da Costa UL; Pigozzi, Gabriella UL et al

in Logic Journal of the IGPL (2009)

In this paper we consider the relation between beliefs and goals in agent theory. Beliefs play three roles in reasoning about goals: they play a role in the generation of unconditional desires from ... [more ▼]

In this paper we consider the relation between beliefs and goals in agent theory. Beliefs play three roles in reasoning about goals: they play a role in the generation of unconditional desires from conditional ones, they play a role in adoption of desires as goals, and they play a role in the selection of plans to achieve goals. In this paper we consider the role of goals in reasoning about beliefs. Though we assume that goals do not play a role in the belief generation problem, we argue that they play a role in the belief selection problem. We show the rationality of the use of goals in belief selection, in the sense that there are cases in which agents that take their goals into account in selecting a belief set from a set of alternatives outperform agents that do not do so. We also formally distinguish between the rational role of goals in belief selection and irrational wishful thinking. [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 detailHow to Program Organizations and Roles in the JADE Framework
Baldoni, Matteo; Boella, Guido UL; Genovese, Valerio UL et al

in Multiagent System Technologies, 6th German Conference, MATES 2008, Kaiserslautern, Germany, September 23-26, 2008. Proceedings (2008)

The organization metaphor is often used in the design and implementation of multiagent systems. However, few agent programming languages provide facilities to define them. Several frameworks are proposed ... [more ▼]

The organization metaphor is often used in the design and implementation of multiagent systems. However, few agent programming languages provide facilities to define them. Several frameworks are proposed to coordinate MAS with organizations, but they are not programmable with general purpose languages. In this paper we extend the JADE framework with primitives to program in Java organizations structured in roles, and to enable agents to play roles in organizations. Roles facilitate the coordination of agents inside an organization and offer new abilities (powers) in the context of organizations to the agents which satisfy the requirements necessary to play the roles. To program organizations and roles, we provide primitives which enable an agent to enact a new role in an organization to invoke powers. [less ▲]

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See detailInteraction between Objects in powerJava
Baldoni, Matteo UL; Boella, Guido UL; van der Torre, Leon UL

in Journal of Object Technology (2007), 6(2),

In this paper we start from the consideration that high level interaction between entities like web services has very different properties with respect to the interaction between objects at the lower ... [more ▼]

In this paper we start from the consideration that high level interaction between entities like web services has very different properties with respect to the interaction between objects at the lower level of programming languages in the object oriented paradigm. In particular, web services, for security, usability and user adaptability reasons, offer different operations to different users by means of access control and keep track of the state of the interaction with each user by means of sessions. The current vision in object orientation, instead, considers attributes and operations of objects as being objective and independent from the interaction with another object, which is sessionless. To introduce these features in the interaction between objects directly in object oriented programming languages, we take inspiration from how access control is regulated by means of roles. Roles allow objects to offer different operations depending on the type of the role, of the type and identity of the player of the role, and to define session-aware interaction. We start from a definition of roles given in ontologies and knowledge representation and we discuss how this definition of roles can be introduced in Java, building our language powerJava [less ▲]

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See detailFrom Social Power to Social Importance
Boella, Guido UL; Sauro, Luigi UL; van der Torre, Leon UL

in Web Intelligence and Agent Systems Journal (2007), (5), 393404

In this paper we introduce a method to measure the social importance of an agent in a multiagent system, using a directed graph representing dependencies among agents to achieve their goals, so-called ... [more ▼]

In this paper we introduce a method to measure the social importance of an agent in a multiagent system, using a directed graph representing dependencies among agents to achieve their goals, so-called dependence graphs pioneered by Castelfranchi, Conte and Sichman. Our measure is derived from van den Brink and Gilles' β-measure to rank agents, using a directed graph representing an abstract dominance relation among agents. In particular, we show how to define power structures and dependence networks from the goals and skills of individual agents, and how to adapt the β-measure for such dependence networks based on their topological properties. Moreover, we show that our notion of social importance can be given an intuitive meaning: it measures the discontent of the other agents in case the agent would leave the society. [less ▲]

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See detailRelationships Meet Their Roles in Object Oriented Programming
Baldoni, Matteo UL; Boella, Guido UL; van der Torre, Leon UL

in International Symposium on Fundamentals of Software Engineering, International Symposium, FSEN 2007, Tehran, Iran, April 17-19 2007, Proceedings (2007)

In this paper we study how roles can be added to patterns modelling relationships in Object Oriented programming. Relationships can be introduced in programming languages either by reducing them to ... [more ▼]

In this paper we study how roles can be added to patterns modelling relationships in Object Oriented programming. Relationships can be introduced in programming languages either by reducing them to attributes of the objects which participate in the relationship, or by modelling the relationship itself as a class whose instances have the participants of the relationships among their attributes. However, even if roles have been recognized as an essential component of relationships, also in modelling languages like UML, they have not been introduced in Object Oriented programming when it is necessary to model relationships. Introducing roles allows to add attributes and behaviors to the participants in the relationship, rather than to the relationship itself, and to distinguish the natural types of the participants in the relationships from the roles the participants acquire in the relationships. We show how the role model of the language powerJava can be used to endow the relationship as attribute pattern with roles. [less ▲]

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See detailA Game-Theoretic Approach to Normative Multi-Agent Systems
Boella, Guido UL; van der Torre, Leon UL

in Normative Multi-agent Systems (2007)

We aim to explain our own approach, and we are therefore very brief with respect to recent related approaches in the area of normative multiagent sys- tems. For these other approaches, see the special ... [more ▼]

We aim to explain our own approach, and we are therefore very brief with respect to recent related approaches in the area of normative multiagent sys- tems. For these other approaches, see the special issue on normative multiagent systems in Computational and Mathematical Organization Theory[68], these DROPS proceedings, the proceedings of the biannual workshops on deontic logic in computer science (¢EON) and of the COIN workshop series. 1The layout of this paper follows the Øve questions above, addressing each of them in a new section. [less ▲]

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See detailBridging Agent Theory and Object Orientation: Agent-Like Communication Among Objects
Baldoni, Matteo UL; Boella, Guido UL; van der Torre, Leon UL

in Programming Multi-Agent Systems, 4th International Workshop, ProMAS 2006, Hakodate, Japan, May 9, 2006, Revised and Invited Papers (2007)

This paper begins with the comparison of the message- sending mechanism, for communication among agents, and the method-invocation mechanism, for communication among objects. Then, we describe an ... [more ▼]

This paper begins with the comparison of the message- sending mechanism, for communication among agents, and the method-invocation mechanism, for communication among objects. Then, we describe an extension of the method-invocation mechanism by introducing the notion of “sender” of a message, “state” of the interaction and “protocol” using the notion of “role”, as it has been introduced in the powerJava extension of Java. The use of roles in communication is shown by means of an example of protocol. [less ▲]

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See detailNorm negotiation in multiagent systems
Boella, Guido UL; van der Torre, Leon UL

in International Journal of Cooperative Information Systems (2007), 16(2),

Normative multiagent systems provide agents with abilities to autonomously devise societies and organizations coordinating their behavior via social norms and laws. In this paper we study how agents ... [more ▼]

Normative multiagent systems provide agents with abilities to autonomously devise societies and organizations coordinating their behavior via social norms and laws. In this paper we study how agents negotiate new social norms and when they accept them. We introduce a negotiation model based on what we call the social delegation cycle, which explains the negotiation of new social norms from agent desires in three steps. First individual agents or their representatives negotiate social goals, then a social goal is negotiated in a social norm, and finally the social norm is accepted by the agents when it leads to fulfilment of the desires the cycle started with. We characterize the allowed proposals during social goal negotiation as mergers of the individual agent desires, and we characterize the allowed proposals during norm negotiation as both joint plans to achieve the social goal (obligations associated with the norm) and the associated sanctions or rewards (a control system associated with the norm). The norm is accepted when the norm is stable in the sense that agents will act according to the norm, and effective in the sense that fulfilment of the norm leads to achievement of the agents’ desires. We also compare norm negotiation with contract negotiation and negotiation of the distribution of obligations [less ▲]

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See detailChoosing Your Beliefs
Boella, Guido UL; Pereira, Célia Da Costa UL; Pigozzi, Gabriella UL et al

in Normative Multi-agent Systems (2007)

This paper presents and discusses a novel approach to indeterministic belief revision. An indeterministic belief revision operator assumes that, when an agent is confronted with a new piece of information ... [more ▼]

This paper presents and discusses a novel approach to indeterministic belief revision. An indeterministic belief revision operator assumes that, when an agent is confronted with a new piece of information, it can revise its belief sets in more than one way. We define a rational agent not only in terms of what it believes but also of what it desires and wants to achieve. Hence, we propose that the agent's goals play a role in the choice of (possibly) one of the several available revision options. Properties of the new belief revision mechanism are also investigated. [less ▲]

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See detailWhat You should Believe
Boella, Guido UL; Pereira, Célia Da Costa UL; Pigozzi, Gabriella UL et al

in Proceedings of The 19th Belgian-Dutch Conference on Artificial Intelligence (BNAIC 2007) (2007)

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See detailFIPA Communicative Acts in Defeasible Logic
Boella, Guido UL; Hulstijn, Joris UL; Governatori, Guido UL et al

in Proceedings of NRAC'07 (2007)

In agent communication languages, the inferences that can be made on the basis of a communicative action are inherently conditional, and non-monotonic. For exam- ple, a proposal only leads to a commitment ... [more ▼]

In agent communication languages, the inferences that can be made on the basis of a communicative action are inherently conditional, and non-monotonic. For exam- ple, a proposal only leads to a commitment, on the con- dition that it is accepted. And in a persuasion dialogue, assertions may later be retracted. In this paper we there- fore present a defeasible logic that can be used to express a semantics for agent communication languages, and to efficiently make inferences on the basis of communica- tive actions. The logic is non-monotonic, allows nested rules and mental attitudes as the content of communica- tive actions, and has an explicit way of expressing per- sistence over time. Moreover, it expresses that mental attitudes are publicly attributed to agents playing roles in the dialogue. To illustrate the usefulness of the logic, we reformalize the meta-theory underlying the FIPA se- mantics for agent communication, focusing on inform and propose. We show how composed speech acts can be formalized, and extend the semantics with an account of persuasion [less ▲]

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See detailMerging Roles in Coordination and in Agent Deliberation
Boella, Guido UL; Genovese, Valerio UL; Grenna, Roberto UL et al

in PRIMA (2007)

In this paper we generalize and merge two models of roles used in multiagent systems which address complementary aspects: enacting roles and communication among roles in an organization or institution. We ... [more ▼]

In this paper we generalize and merge two models of roles used in multiagent systems which address complementary aspects: enacting roles and communication among roles in an organization or institution. We do this by proposing a metamodel of roles and specializing the metamodel to two existing models. We show how the two approaches can be integrated since they deal with complementary aspects: Boella [1] focuses on roles as a way to specify interactions among agents, and, thus, it emphasizes the public character of roles. [2] focuses instead on how roles are played, and thus it emphasizes the private aspects of roles: how the beliefs and goals of the roles become the beliefs and goals of the agents. The former approach focuses on the dynamics of roles in function of the communication process. The latter focuses on agents internal dynamics when they start playing a role or shift the role they are currently playing. [less ▲]

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See detailPower in Norm Negotiation
Boella, Guido UL; van der Torre, Leon UL

in Agent and Multi-Agent Systems: Technologies and Applications, First KES International Symposium, KES-AMSTA 2007, Wroclaw, Poland, May 31 – June 1, 2007, Proceedings (2007)

In social mechanism design, norm negotiation creates individual or contractual obligations fulfilling goals of the agents. The social delegation cycle distinguishes among social goal negotiation ... [more ▼]

In social mechanism design, norm negotiation creates individual or contractual obligations fulfilling goals of the agents. The social delegation cycle distinguishes among social goal negotiation, obligation and sanction negotiation and norm acceptance. Power may affect norm negotiation in various ways, and we therefore introduce a new formalization of the social delegation cycle based on power and dependence, without referring to the rule structure of norms, actions, decision variables, tasks, and so on. [less ▲]

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See detailA Common Ontology of Agent Communication Languages: Modeling Mental Attitudes and Social Commitments using Roles
Boella, Guido UL; Damiano, R. UL; Hulstijn, J. UL et al

in Applied Ontology (2007), (2), 217265

There are two main traditions in defining a semantics for agent communication languages, based either on mental attitudes or on social commitments. These traditions share speech acts as operators with ... [more ▼]

There are two main traditions in defining a semantics for agent communication languages, based either on mental attitudes or on social commitments. These traditions share speech acts as operators with preconditions and effects, and agents playing roles like speaker and hearer, but otherwise they rely on distinct ontologies. They refer not only to either belief and intention or various notions of social commitment, but also to distinct speech acts and distinct kinds of dialogue. In this paper, we propose a common ontology for both approaches based on public mental attitudes attributed to role instances. Public mental attitudes avoid the unverifiability problem of private mental states, while reusing the logics and implementations developed for FIPA compliant approaches. Moreover, a common ontology of communication primitives allows for the construction of agents which do not need separate reasoning modules to participate in dialogues with both mental attitudes and social commitments compliant agents. Moreover, a common ontology of communication primitives allows for the construction of agents participating in and combining the full range of dialogues covered by the individual approaches without having to redefine the existing protocols to cope with new dialog types. We illustrate how to extend the ontology to a semantics for agent communication and how to define mappings from existing semantics to the new one. [less ▲]

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