Normative Multiagent Systems

The majority of existing virtual heritage applications are focused on detailed 3D reconstruction of historically significant sites and ancient artifacts. Recreating the way of life of ancient people is only considered by some researchers, who employ crowd simulation for this task. Existing crowd simulation algorithms are not suitable for modeling complex individual behaviors and role dependent agent interactions with other participants in the Virtual World. To address this problem we suggest treating 3D Virtual Worlds as Normative Multiagent Systems and propose the Virtual Institutions Methodology that can be used for design and deployment of Virtual Worlds that require complex interactions involving both humans and autonomous agents. To highlight the usefulness of this approach we illustrate how Virtual Institutions are employed in the development of the Uruk prototype, which integrates 3D Virtual Worlds and Artificial Intelligence in the domain of cultural heritage.

The social and organisational aspects of agency have led to a good amount of theoretical work in terms of formal models and theories. From these different works normative multiagent systems and multiagent organisations are particularily considered in this paper. Embodying such models and theories in the conception and engineering of proper infrastructures that achieve requirements of openness and adaptation, is still an open issue. In this direction, this paper presents and discusses a framework for normative multiagent organisations. Based on the Agents and Artifacts meta-model (A&A), it introduces organisational artifacts as first class entities to instrument the normative organisation for supporting agents activities within it.

This paper is a contribution to the formalisation of Thagard's coherence theory. The term coherence is defined as the quality or the state of cohering, especially a logical, orderly, and aesthetically consistent relationship of parts. A coherent set is interdependent such that every element in it contributes to the coherence. We take Thagard's proposal of a coherence set as that of maximising satisfaction of constraints between elements and explore its use in normative multiagent systems. In particular, we interpret coherence maximisation as a decision-making criterion for norm adoption. We first provide a general coherence framework with the necessary computing tools. Later we introduce a proof-theoretic characterisation of a particular type of coherence, namely the deductive coherence based on Thagard's principles, and derive a mechanism to compute coherence values between elements in a deductive coherence graph. Our use of graded logic helps us to incorporate reasoning under uncertainty, which is more realistic in the context of multiagent systems. We then conduct a case study where agents deliberate about norm adoption in a multiagent system where there is competition for a common resource. We show how a coherence-maximising agent decides to violate a norm guided by its coherence.

If compliance with a norm does not achieve its purpose, then its applicability must dynamically be restricted or expanded. Legal interpretation is a mechanism from law allowing norms to be adapted to unforeseen situations. We model this mechanism for norms regulating computer systems by representing the purpose of norms by social goals and by revising the constitutive rules defining the applicability of norms. We illustrate the interpretation mechanism by examples.

Our belief is that conviviality is a concept of great depth that plays an important role in any social interaction. A convivial relation between individuals is one that allows participating individuals to behave and interact with each other following a set of conventions either shared, commonly agreed upon or at least understood. This presupposes implicit or an explicit regulation mechanism based on consensus or social contracts and applies to the behaviours and interactions of participating individuals. With respect to web-based systems, an applicable social attribute is to assist another user, to help him/her in situations that are unclear and to recommend him in finding the right decision whenever a conflict arises. Such a convivial social biotope deeply depends on both implicit and explicit cooperation and collaboration of natural users inside a community. An individual conviviality may benefit from the "wisdom of the crowd", which means that a dynamic understanding of the user's behaviours heavily influences the individual well being of another person(s). To achieve that, we present the system CUBA and target at user profiling while making a stay convivial through recommendations.

The ESSLLI course material has been compiled by Leon van der Torre and Jörg Hansen. Unless otherwise mentioned, the copyright lies with the individual authors of the material. Leon van der Torre and Jörg Hansen declare that they have obtained all necessary permissions for the distribution of this material. ESSLLI 2008 and its organizers take no legal responsibility for the contents of this booklet.

This report documents the program and the outcomes of Dagstuhl Seminar 12111 “Normative Multi-Agent Systems”. Normative systems are systems in the behavior of which norms play a role and which need normative concepts in order to be described or specified. A normative multi-agent system combines models for normative systems (dealing for example with obligations, permissions and prohibitions) with models for multi-agent systems. Norms have been proposed in multi-agent systems and computer science to deal with issues of coordination, security, electronic commerce and institutions, agent organization. However, due to the lack of a unified theory, many multi-agent system researchers are presently developing their own ad hoc concepts and applications. The aim of this Dagstuhl Seminar was to formulate a collective appraisal of the current perspectives in the field and the most promising venues for future activity. In particular, the seminar has been conceived for the writing of a volume ti...

This special issue contains the journal version of four contributions to the Handbook of Normative Multi-Agent Systems (NorMAS), which will appear at College Publications. The NorMAS initiative aims at providing a comprehensive coverage of both the state of the art and future research perspectives in the interdisciplinary field of normative multi-agent systems. It is meant to be an open community effort and a service to current and future students and researchers interested in this field. We invite the readers to buy the forthcoming handbook for a full view. Please visit the website for more information and feel free to send us comments, suggestions and proposals: http://normativemas.org/ The articles in this special issue and the chapters in the handbook give a survey of the area and may also contain a more personal view. For the survey part, at least the work reported in the NorMAS conference series is discussed. Instead of just a historical overview, the authors also address new developments, open topics and emerging areas. The handbooks appeal to all disciplines, including logic, computer science, law, philosophy, and linguistics. The articles in this special issue discuss the obtained results and open challenges in modeling normative multiagent systems during the last two decades. More information can be found in the handbook on deontic logic and normative systems, or the website http://deonticlogic.org/ The first paper in this special issue formally analyses the issue of modeling norm specification and verification in multiagent systems (MAS). In particular, for Alechina et al., violation conditions of regulative norms may correspond to conditions on states, actions, or arbitrary temporal patterns. They may be specified semantically or expressed syntactically in a suitable temporal logic, or in a programming language. Verification problems for norms or rather for normative systems involve verifying consistency of norms, verifying whether violation conditions hold, and finally verifying whether a system where norms are enforced satisfies some system objective.

Regarding the complexity of actual software systems, including web portals, it is becoming more and more difficult to develop software systems such that their real usage will satisfy their intended usage. To tackle this problem, we can compare the a priori assumptions about how the system should be used with the actual user behavior in order to decide how the system could be improved. For this aim, we propose to employ the same formalism to express the intended usage, the web portal model and the real usage extracted from system usage traces by data mining algorithms. Inspired from BioCham, we propose to use temporal logic and Kripke structure as such a common formalism.

In this paper, we consider the design of convivial multiagent systems. Conviviality has recently been proposed as a social concept to develop multi-agent systems. In this paper we introduce temporal dependence networks to model the evolution of dependence networks and conviviality over time, we introduce epistemic dependence networks to combine the viewpoints of stakeholders, and we introduce normative dependence networks to model the transformation of social dependencies by hiding power relations and social structures to facilitate social interactions. We show how to use these visual languages in design, and we illustrate the design method using an example on virtual children adoptions.

In this paper, we consider the design of convivial multi-agent systems. Conviviality has recently been proposed as a social concept to develop multi-agent systems. In this paper we introduce temporal dependence networks to model the evolution of dependence networks and conviviality over time, we introduce epistemic dependence networks to combine the viewpoints of stakeholders, and we introduce normative dependence networks to model the transformation of social dependencies by hiding power relations and social structures to facilitate social interactions. We show how to use these visual languages in design, and we illustrate the design method using an example on virtual children adoptions.

In agents systems, conviviality measures quantify interdependence in social dependence relations, representing the degree in which the system facilitates social interactions. Moreover, a normative system is a mechanism to change conviviality by changing social dependencies, for example by creating new obligations. With the pervasive development of socio-technical systems, modelling such social settings has become increasingly important. We distinguish design time from run time measures. At design time, roughly, more interdependence increases conviviality among groups of agents or coalitions, whereas larger coalitions may decrease the efficiency or stability of these involved coalitions. At run time, we consider the extension to temporal dependence networks, that is, sequences of dependence networks. We distinguish dominance, volatility and entropy requirements for conviviality measures. We illustrate the use of our conviviality measures with examples from gaming.

This special issue contains the journal version of four contributions to the Handbook of Normative Multi-Agent Systems (NorMAS), which will appear at College Publications. The NorMAS initiative aims at providing a comprehensive coverage of both the state of the art and future research perspectives in the interdisciplinary field of normative multi-agent systems. It is meant to be an open community effort and a service to current and future students and researchers interested in this field. We invite the readers to buy the forthcoming handbook for a full view. Please visit the website for more information and feel free to send us comments, suggestions and proposals: http://normativemas.org/ The articles in this special issue and the chapters in the handbook give a survey of the area and may also contain a more personal view. For the survey part, at least the work reported in the NorMAS conference series is discussed. Instead of just a historical overview, the authors also address new developments, open topics and emerging areas. The handbooks appeal to all disciplines, including logic, computer science, law, philosophy, and linguistics. The articles in this special issue discuss the obtained results and open challenges in modeling normative multiagent systems during the last two decades. More information can be found in the handbook on deontic logic and normative systems, or the website http://deonticlogic.org/ The first paper in this special issue formally analyses the issue of modeling norm specification and verification in multiagent systems (MAS). In particular, for Alechina et al., violation conditions of regulative norms may correspond to conditions on states, actions, or arbitrary temporal patterns. They may be specified semantically or expressed syntactically in a suitable temporal logic, or in a programming language. Verification problems for norms or rather for normative systems involve verifying consistency of norms, verifying whether violation conditions hold, and finally verifying whether a system where norms are enforced satisfies some system objective.

This report documents the program and the outcomes of Dagstuhl Seminar 12111 "Normative Multi-Agent Systems". Normative systems are systems in the behavior of which norms play a role and which need normative concepts in order to be described or specified. A normative multi-agent system combines models for normative systems (dealing for example with obligations, permissions and prohibitions) with models for multi-agent systems. Norms have been proposed in multi-agent systems and computer science to deal with issues of coordination, security, electronic commerce and institutions, agent organization. However, due to the lack of a unified theory, many multi-agent system researchers are presently developing their own ad hoc concepts and applications. The aim of this Dagstuhl Seminar was to formulate a collective appraisal of the current perspectives in the field and the most promising venues for future activity. In particular, the seminar has been conceived for the writing of a volume titled "A Prospective view of Normative Multi Agent Systems" aimed to become a standard reference in the field and to provide guidelines for future research in normative multi-agent systems.

This chapter presents a variety of applications of norms. These applications include governance in sociotechnical systems, data licensing and data collection, understanding software development teams, requirements engineering, assurance, natural resource allocation, wireless grids, autonomous vehicles, serious games, and virtual worlds.

In this chapter, we first provide a general introduction to the research area methodology and relevance, then we discuss normative reasoning for multiagent systems, and finally we discuss current research challenges. We cover the main issues in modern deontic logic, which is much broader than the traditional modal logic framework of deontic logic, with an emphasis to our in- tended audience. To emphasize this broadness, we typically refer to "deontic logic and normative systems" rather than deontic logic only.

Artificial intelligence and its applications have stood out over the last decade and presented effective solutions in the most diverse sectors and areas of knowledge. For example, in the environmental area, several challenges are faced, mainly in managing natural resources, due to numerous existing conflicts due to increased demand and scarcity of such resources. In this scenario, applications using multi-agent systems show promise. The main objective of this work is the presentation of modeling at the organizational level of agents to study the complexity and the functionalities of characters of a Role-Playing game. The case study of this work is the Gorim, an RPG Game developed in the scenario of the watershed of Lagoa Mirim and Canal Sao Gonc¸alo at ˜the Rio Grande do Sul, Brazil. The organization modeling was developed in the MOISE+ model and implemented to verify it in the JaCaMo platform through hypothetical scenarios. We demonstrated that the results of such scenarios validat...

Norm emergence is typically studied in the context of multiagent systems (MAS) where norms are implicit, and participating agents use simplistic decision-making mechanisms. These implicit norms are usually unconsciously shared and adopted through agent interaction. A norm is deemed to have emerged when a threshold or predetermined percentage of agents follow the "norm". Conversely, in normative MAS, norms are typically explicit and agents deliberately share norms through communication or are informed about norms by an authority, following which an agent decides whether to adopt the norm or not. The decision to adopt a norm by the agent can happen immediately after recognition or when an applicable situation arises. In this paper, we make the case that, similarly, a norm has emerged in a normative MAS when a percentage of agents adopt the norm. Furthermore, we posit that agents themselves can and should be involved in norm synthesis, and hence influence the norms governing the MAS, in line with Ostrom's eight principles. Consequently, we put forward a framework for the emergence of norms within a normative MAS, that allows participating agents to propose/request changes to the normative system, while special-purpose synthesizer agents formulate new norms or revisions in response to these requests. Synthesizers must collectively agree that the new norm or norm revision should proceed, and then finally be approved by an "Oracle". The normative system is then modified to incorporate the norm.

Norm emergence is typically studied in the context of multiagent systems (MAS) where norms are implicit, and participating agents use simplistic decision-making mechanisms. These implicit norms are usually unconsciously shared and adopted through agent interaction. A norm is deemed to have emerged when a threshold or predetermined percentage of agents follow the "norm". Conversely, in normative MAS, norms are typically explicit and agents deliberately share norms through communication or are informed about norms by an authority, following which an agent decides whether to adopt the norm or not. The decision to adopt a norm by the agent can happen immediately after recognition or when an applicable situation arises. In this paper, we make the case that, similarly, a norm has emerged in a normative MAS when a percentage of agents adopt the norm. Furthermore, we posit that agents themselves can and should be involved in norm synthesis, and hence influence the norms governing ...

Artificial intelligence and its applications have stood out over the last decade and presented effective solutions in the most diverse sectors and areas of knowledge. For example, in the environmental area, several challenges are faced, mainly in managing natural resources, due to numerous existing conflicts due to increased demand and scarcity of such resources. In this scenario, applications using multi-agent systems show promise. The main objective of this work is the presentation of modeling at the organizational level of agents to study the complexity and the functionalities of characters of a Role-Playing game. The case study of this work is the Gorim, an RPG Game developed in the scenario of the watershed of Lagoa Mirim and Canal Sao Gonc¸alo at ˜the Rio Grande do Sul, Brazil. The organization modeling was developed in the MOISE+ model and implemented to verify it in the JaCaMo platform through hypothetical scenarios. We demonstrated that the results of such scenarios validat...

From 31th August to 5th September, the Dagstuhl Seminar 08361 Programming Multi-Agent Systems was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The rst section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available.

Different approaches have investigated the syntax and semantic of agent communication. However, all these approaches (including : agent communication languages, conversation policies and dialogue games) have not indicated how agents should dynamically use communications. In fact, most of these approaches have mainly focused on "structure" of dialogues even though developers are more interested in agents' capabilities of having "useful" conversations in respect to their goals rather than in their abilities to structure dialogues. This leads us to propose a theory of use of conversations between agents. This pragmatic theory extends and adapts the cognitive dissonance theory (a major theory of social psychology) to multi-agent systems. In this paper, we show how this theory allows us to provide generic conceptual tools for the automation of both agent communicational behavior and attitude change processes. The cognitive coherence that we propose is formulated in terms of constraints and elements of cognition and allows us to define cognitive incoherences and dialogue utility measures. We show how these measures could be used to solve common problems and answer some critical questions concerning agent communication frameworks use. Finally, the theory is illustrated with an example of dialogue games automatic use.

Self-organisation and self-evolution is evident in physics, chemistry, biology, and human societies. Despite the existing literature on the topic, we believe self-organisation and self-evolution is still missing from the IT tools (whether online or offline) we are building and using. In the last decade, human interactions have been moving more and more towards social media. The time we spend interacting with others in virtual communities and networks is tremendous. Yet, the tools supporting those interactions remain rigid. This position paper argues the need for self-evolving software-enabled communities, and proposes a roadmap for achieving this required self-evolution. The proposal is based on building normative-based communities, where community interactions are regulated by norms and community members are free to discuss and modify their community's norms. The evolution of communities is then dictated by the evolution of its norms.

In Input/output (I/O) logic, one makes a distinction between three kinds of permission, called negative, positive static and positive dynamic permission. They have been studied semantically and axiomatically by Makinson and van der Torre in the particular case where the underlying I/O operation for obligation is one of the standard systems. In this paper, we investigate what happens when the underlying I/O operation is one of the constrained I/O operations recently introduced by Parent and van der Torre. Their distinctive feature is two-fold. First, they are not closed under logical consequence. Second they have a built-in consistency check, which filters out excess outputs and allows them to properly deal with contrary-to-duty reasoning. The main contribution of this paper is the characterization of the positive static permission with a set of rules, called subverse rules. Due to the fact that the studied logics are different from the original framework, although the proof of the c...

It is shown that I/O logic can be based on intuitionistic logic instead of classical logic. More specifically, it is established that, when going intuitionistic, a representation theorem is still available for three of the four (unconstrained) original I/O operations. The trick is to see a maximal consistent set as a saturated one. The axiomatic characterization is as in the classical case. Therefore, the choice between the two logics does not make any difference for the resulting framework.

Hierarchical structures have been widely used by human organizations because they provide the natural means to delegate tasks, to reduce communication lines and to control the activities performed within organizations. This has motivated the development of different approaches to automatize many of the activities that take place in hierarchical organizations. Recent frameworks, such as Gaia, Aalaadin, Har-monIA and OperA, among others, have considered the agent paradigm to do so. Since organizations are dynamic entities that evolve with the time, agents in organizations must adapt to changes. Here we develop a model for flexible and open hierarchical organizations where agents can dynamically adapt to organizational changes.

Intelligent agents and multi-agent systems (MAS) play an important role in today's software development. In fact, they constitute a new and interesting paradigm to implement complex systems, by offering relevant abstractions for the engineering of such intricate type of software. Several application domains, some at industrial level, take benefit from MAS technology. For almost two decades, the MAS community has developed and offers a large and rich set of concepts, architectures, interaction techniques, and general approaches to the analysis and the specification of MAS. One of the main challenges of the MAS community in recent years has been to combine the existing practical tools and theoretical approaches in order to provide practitioners with mature programming languages and platforms that help them to design, implement, and deploy efficiently a new generation of complex software built as MAS. The organisers of this seminar, and also the participants, share the conviction that the success of agent-based systems can only be guaranteed if expressive programming languages and well-developed platforms are available, so that the concepts and techniques of multi-agent systems can be easily and directly used in practice. The aim of this seminar was to bring together researchers from both academia and industry for bridging this gap and identifying interesting lines of research within multi-agent systems. In this respect, the seminar topic is also very relevant for industrial research and development.

In this chapter, we first provide a general introduction to the research area methodology and relevance, then we discuss normative reasoning for multiagent systems, and finally we discuss current research challenges. We cover the main issues in modern deontic logic, which is much broader than the traditional modal logic framework of deontic logic, with an emphasis to our in- tended audience. To emphasize this broadness, we typically refer to "deontic logic and normative systems" rather than deontic logic only.

Normative systems (norms) have been widely proposed as a technique for coordinating multi-agent systems. The automated synthesis of norms for coordination remains an open and complex problem, which we tackle in this paper. We propose a novel mechanism called IRON (Intelligent Robust On-line Norm synthesis mechanism), for the on-line synthesis of norms. IRON aims to synthesise conflict-free norms without lapsing into over-regulation. Thus, IRON produces norms that characterise necessary conditions for coordination, without over-regulation. In addition to defining the norm synthesis problem formally, we empirically show that IRON is capable of synthesising norms that are effective even in the presence of non-compliance behaviours in a system.

Most normative systems make use of explicit representations of norms (namely, obligations, prohibitions, and permissions) and associated mechanisms to support the self-regulation of open societies of self-interested and autonomous agents. A key problem in research on normative systems is that of how to synthesise effective and efficient norms. Manually designing norms is time consuming and error prone. An alternative is to automatically synthesise norms. However, norm synthesis is a computationally complex problem. We present a novel online norm synthesis mechanism, designed to synthesise compact normative systems. It yields normative systems composed of concise (simple) norms that effectively coordinate a multiagent system (MAS) without lapsing into overregulation. Our mechanism is based on a central authority that monitors a MAS, searching for undesired states. After detecting undesirable states, the central authority then synthesises norms aimed to avoid them in the future. We de...

The notion of 'coherence' plays an important but controversial role in moral theory. Usually, the concept of coherence is discussed in a framework of justifying moral beliefs. It is then faced with objections regarding circularity, vagueness, and impracticability when analyzing coherence of large belief sets. Most of this critique states that the normative relevance of coherence is tied to its descriptive use, i.e. one has to specify what exactly it means that a system of believes "coheres" in order to argue for the normative relevance of coherence. In our contribution, we present a descriptive notion of the concept of coherence that allows us to distinguishing qualitatively different system states with respect to coherence. We compare our notion with coherence concepts in psychology and Paul Thagard's definition of coherence as constraint satisfaction. We discuss the main differences between Thagard's definition and our proposal. Finally, we outline how our concept of coherence can be applied in moral psychology as a tool for understanding how the structure of moral beliefs an individual moral agent holds may influence the behavior of the agent. In particular, we show how our approach is able to integrate different types of coherence relationships between single beliefs. In this way, our definition of coherence allows us, for example, to analyze how cognitive and affective similarities between reasons used in moral decision making may interrelate. Furthermore, it can give novel insights into phenomena like practical irrationality in decision making. We finally sketch the relevance of our descriptive notion of coherence for its normative use.

In this paper we apply Boella and van der Torre's normative multiagent systems to analyze a model of transaction trust introduced by Tan and colleagues. We discuss the role of constitutive and regulative norms in party trust and control trust. Moreover, we use so called contract negotiation games to indicate when controls are needed. Though sometimes regulators focus exclusively on adding controls, a scenario analysis can be used to show when this is not needed. We illustrate these issues of transaction trust by a case study from international trade, namely the Letter of Credit procedure.

An important security aspect of Virtual Worlds (in particular Virtual Worlds oriented towards commercial activities) is controlling participants’ adherence to the social norms (rules of behavior) and making them follow the acceptable interaction patterns. Rules of behavior in the physical world are usually enforced through a post factum punishment, while in computer-controlled environments like Virtual Worlds we can simply block the actions that are inconsistent with the rules and eliminate rule violations as such. In order to facilitate enforcing the rules in such automatic manner and allow for frequent rule changes, the rules have to be expressed in a formal way, so that the software can detect both the rules and the actions that can potentially violate them. In this chapter the authors introduce the concept of Virtual Institutions that are Virtual Worlds with normative regulation of interactions. For development of such systems the authors employ the Virtual Institutions Methodol...

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.

We propose in this paper a framework for inter-agents dialogue to reach an agreement, which formalize a debate in which the divergent representations are discussed. For this purpose, we propose an argumentation-based representation framework which manages the conflicts between claims with different relevances for different audiences to compute their acceptance. Moreover, we propose a model for the reasoning of agents where they justify the claims to which they commit and take into account the claims of their interlocutors. This framework bounds a dialectics system in which agents play a dialogue to reach an agreement about a conflict of representation.

In this paper, we propose a coherence-driven approach to action selection in agents. The mechanism is inspired by the cognitive theory of coherence as proposed by Thagard. Based on a proposal to extend BDI agents with coherence, we interpret, how action selection can be viewed as a coherence-maximising problem. Contrasted against the classical BDI approach to action selection where actions are selected against a pre-determined set of beliefs and desires, this method provides us with a reasoning formalism that incorporates uncertainty and dynamism in the world model without loosing the type of formal qualities that make BDI-like architectures so attractive for testability and reliability reasons.

This chapter is concerned with the dynamics of social norms, that is the way that such norms change. In particular this chapter concentrates on the lifecycle that social norms go through, focusing on the generation of norms, the way that norms spread and stabilize, and the way that norms evolve. We also discuss the cognitive mechanisms behind norm compliance, the role of culture in norm dynamics, and the way that trust affects norm dynamics.

In this paper, we consider the design of convivial multi-agent systems. Conviviality has recently been proposed as a social concept to develop multi-agent systems. In this paper we introduce temporal dependence networks to model the evolution of dependence networks and conviviality over time, we introduce epistemic dependence networks to combine the viewpoints of stakeholders, and we introduce normative dependence networks to model the transformation of social dependencies by hiding power relations and social structures to facilitate social interactions. We show how to use these visual languages in design, and we illustrate the design method using an example on virtual children adoptions.

In agents systems, conviviality measures quantify interdependence in social dependence relations, representing the degree in which the system facilitates social interactions. Moreover, a normative system is a mechanism to change conviviality by changing social dependencies, for example by creating new obligations. With the pervasive development of socio-technical systems, modelling such social settings has become increasingly important. We distinguish design time from run time measures. At design time ...

Abstract. This work outlines the research activities carried out by our groups in the direction of the implementation of a tool for sharing nat-ural and cultural heritage on the web. The tool will serve as a support to teachers and people involved in scientific and cultural activities (for ...

In multi-agent systems, norms are a usual way to regulate the behaviour of autonomous agents. To be stable in different circumstances, norms are specified using high level terms, abstracting from the particular dynamics of the environment where the agents are situated. However, applying these norms requires a proper link with a concrete environment. Detaching that link from the norms themselves provides stability to the normative regulation but raises consistency and flexibility issues. Consistency is achieved when the abstract norms are coherent with the environment under regulation. Flexibility is achieved when different kinds of norms share the same interpretation about the environmental state. These properties are provided in some current works. However, since they are interrelated, there is not, to our knowledge, a single proposal providing all of them. This paper proposes the situated artificial institution (SAI) model to address these three issues-stability, consistency, and flexibility-by conceiving norms as part of institutions that provide, through the process of constitution, a social interpretation of the environmental state. After the presentation of the formalised model of SAI, a case study is used to illustrate and test this approach.

We address the problem of analysing the joint coherence of a number of concepts with respect to a background ontology. To address this problem, we explore the applicability of Paul Thagard’s computational theory of coherence, in combination with semantic similarity between concepts based on a generalisation operator. In particular, given the input concepts, our approach computes maximally coherent subsets of these concepts following Thagard’s partitioning approach, whilst returning a number of possible generalisations of these concepts as justification of why these concepts cohere.

This article presents a high-level overview of the literature on norms and their uses in multi-agent systems. We distinguish the main types of norms used in multi-agent systems, and the ways in which the behaviour of a system can be modified through the enforcement of norms. We first review the formal approaches used to study norms and norm enforcement mechanisms. We then explain the syntax and semantics of the key specification languages used to represent norms, and briefly survey some programming frameworks that support the implementation of normative multi-agent systems. Finally, we briefly review the key research questions and techniques in the important area of norm verification.

To understand Thagard's views on the nature of moral reasoning, we must first examine what he means by "coherence." The basic idea is that when we try to make sense of things, we select an interpretation that fits the available information better than any available alternative. The things we are trying to make sense of and the way we explain what fits the available information depends on the domain being modelled. Thagard has developed a general account of coherence that applies to a variety of domains. The following principles summarize, in a very general way, Thagard's views on setting up a coherence problem.

From 15.03. to 20.03.2009, the Dagstuhl Seminar 09121 ``Normative Multi-Agent Systems '' was held in Schloss Dagstuhl~--~Leibniz Center for Informatics. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general.

Software agents can be members of different institutions along their life; they might even belong to different institutions simultaneously. For these reasons, agents need capabilities that allow them to determine the repercussion that their actions would have within the different institutions. This association between the physical word, in which agents' interactions and actions take place, and the institutional world is defined by means of constitutive norms. Currently, the problem of how agents reason about constitutive norms has been tackled from a theoretical perspective only. Thus, there is a lack of more practical proposals that allow the development of software agents capable of reasoning about constitutive norms. In this article we propose an information model, knowledge representation and an inference mechanism to enable Belief-Desire-Intention (BDI) agents to reason about the consequences of their actions on the institutions and making decisions accordingly. Specifically, the information model, knowledge representation and inference mechanism proposed in this paper allows agents to keep track of the institutional state given that they have a physical presence in some real-world environment. Agents have a limited and not fully believable knowledge of the physical world (i.e., they are placed in an uncertain environment). Therefore, our proposal also deals with the uncertainty of the environment.

Abstract. From 15.03. to 20.03. 2009, the Dagstuhl Seminar 09121 Normative Multi-Agent Systems was held in Schloss Dagstuhl Leibniz Center for Informatics. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are ...

Abstract. Multi-Agent Systems require coordination mechanisms in order to assemble the behaviour of autonomous and heterogeneous agents and achieve the desired performance of the whole system. Norms are deontic statements employed by these coordination mechanisms which define constraints to the potential excesses of agents' autonomous behaviour. However, norms are only effective if agents are capable of understanding and managing them pragmatically. In this paper, we propose an extension of the BDI proposal ...