References of "Boella, Guido 30000076"
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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 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 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 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 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 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 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 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 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 detailDistinguishing Propositional and Action Commitment in Agent Communication
Boella, Guido UL; Damiano, R. UL; Hulstijn, Joris UL et al

in Proceedings of CMNA'07 (2007)

Our goal is to extend agent communication lan- guages for persuasion dialogues. We distinguish action commitments from propositional commit- ments, because both limit future moves, but an action ... [more ▼]

Our goal is to extend agent communication lan- guages for persuasion dialogues. We distinguish action commitments from propositional commit- ments, because both limit future moves, but an action commitment is fulfilled when the hearer believes that the action is performed, whereas a propositional commitment is fulfilled only when the hearer concedes to the proposition – where con- cessions are the absence of a belief to the con- trary, and prevent further challenges. Using a com- mon model for both kind of commitments and a role-based semantics of agent communication lan- guages, we show how propositional commitments are related to public beliefs and action commit- ments to public goals [less ▲]

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See detailAdding Roles to Relationship Patterns
Baldoni, Matteo UL; Boella, Guido UL; van der Torre, Leon UL

in Proceedings of WOA07 (2007)

In this paper we study how roles can be added to patterns modelling relationships in Object Oriented programming, and which new relationship patterns can be introduced using roles. Relationships can be ... [more ▼]

In this paper we study how roles can be added to patterns modelling relationships in Object Oriented programming, and which new relationship patterns can be introduced using roles. 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 natural types as classes participating in the relationships from the roles the participants acquire in the relationships. In this paper we show how the role model proposed in powerJava can be used to endow relationships with roles, both in the relationship as attribute and in the relationship object pattern. Finally, since these patterns have different advantages and limitations, we propose a third pattern based on roles which benefits from the advantages of the two previous patterns when modelling relationships. [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 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 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 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 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 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 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 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 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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