In this paper we introduce a formal framework for the construction of normative multiagent systems, based on Searle's notion of the construction of social reality. Within the structure of normative multiagent systems we distinguish between regulative norms that describe obligations, prohibitions and permissions, and constitutive norms that regulate the creation of institutional facts as well as the modification of the normative system itself. Using the metaphor of normative systems as agents, we attribute mental attitudes to the normative system. In particular,

Abstract. We introduce a distributed architecture to endow multi-agent systems with a social layer in which norms are explicitly represented and managed via rules. We propose a class of rules (called institutional rules) that operate on a database of facts (called institutional states) representing the state of affairs of a multi-agent system. We define the syntax and semantics of the institutional rules and describe a means to implement them as a logic program. We show how the institutional rules and states come together in a distributed architecture in which a team of administrative agents employ a tuple space (i.e., a kind of blackboard system) to guide the execution of a multi-agent system. 1

In this paper we study the rational balance between local and global policies in web based distributed systems. We use a logical framework for multiagent systems to model obligations and permissions composing policies. In particular, a qualitative decision theory allows agents to trade off the decision of respecting a norm against the consequences of not respecting it: the possibility that they are considered violators and thus sanctioned. Global policies refer not to the existence of a local norm but to the fact that it is enforced by the local authority by recognizing and sanctioning violations.

In this paper we address the problem of defining roles in organizations like e-trade ones. The methodology we use is to model roles according to the agent metaphor: we attribute to roles mental attitudes, like beliefs, desires and goals, we relate them to the agent’s required expertise and responsibilities, and we model role behavior in game theoretic terms. Analogously, the organization is modelled as an agent which acts as a normative system: it imposes obligations to roles and to the agents playing the roles. 1.

Abstract. In this paper we introduce an ontology based on the notion of agent to represent and reason about social reality. We model social constructions as agents, for example, groups, organizations, normative systems, and roles, and we attribute mental attitudes to them. Roughly, we define obligations or regulative norms as goals of the normative system, constitutive norms as beliefs of the normative system, joint, shared, mutual and social beliefs, desires and goal as beliefs, desires and goals of group, responsibilities of an agent as goals of the role he plays, and the required expertise of an agent as beliefs and actions of the role he plays. In this way, we achieve a uniform framework for a large variety of concepts using a small vocabulary, and, in particular, basing it on notions, like mental attitudes, which are commonly used in agent theories. The proposed ontology is modelled using a description logic. 1

Abstract. Norms constitute a powerful coordination mechanism among heterogeneous agents. In this paper, we propose a rule language to specify and explicitly manage the normative positions of agents (permissions, prohibitions and obligations), with which distinct deontic notions and their relationships can be captured. Our rule-based formalism includes constraints for more expressiveness and precision and allows to supplement (and implement) electronic institutions with norms. We also show how some normative aspects are given computational interpretation. 1

Abstract. The paper discusses ten philosophical problems in deontic logic: how to formally represent norms, when a set of norms may be termed ‘coherent’, how to deal with normative conflicts, how contraryto-duty obligations can be appropriately modeled, how dyadic deontic operators may be redefined to relate to sets of norms instead of preference relations between possible worlds, how various concepts of permission can be accommodated, how meaning postulates and counts-as conditionals can be taken into account, and how sets of norms may be revised and merged. The problems are discussed from the viewpoint of input/output logic as developed by van der Torre & Makinson. We argue that norms, not ideality, should take the central position in deontic semantics, and that a semantics that represents norms, as input/output logic does, provides helpful tools for analyzing, clarifying and solving the problems of deontic logic.

This paper considers the problem of checking whether an organization conforms to a body of regulation. Conformance is cast as a trace checking trace or run representing the operations of an organization. We focus on the problem of designing a logic to represent regulation. A common phenomenon in regulatory texts is for sentences to refer to others for conditions or exceptions. We motivate the need for a formal representation of regulation to accomodate such references between statements. We then extend linear temporal logic to allow statements to refer to others. The semantics of the resulting logic is defined via a combination of techniques from Reiter’s default logic and Kripke’s theory of truth.

We are interested in the design of policies for virtual communities of agents based on the grid infrastructure. In a virtual community agents can play both the role of resource consumers and the role of resource providers, and they remain in control of their resources. We argue that this requirement imposes a distinction between the authorization to access a resource given by the virtual community and the permission to do so issued by the resource providers. Our model is based on a logical multiagent framework that distinguishes the three roles of resource consumption, provision, and of authorization.

Abstract. The use of norms is a well-known technique of co-ordination in multi-agent systems (MAS) adopted from human societies. A normative position is the “social burden ” associated with individual agents, that is, their obligations, permissions and prohibitions. Compound activities may be regulated by means of normative positions. However, conflicts may appear among normative positions of activities and subactivities. Recently several computational approaches have appeared to make norms operational in MAS but they do not cope with compound activities. In this paper, we propose an algorithm to determine the set of applicable normative positions, i.e., the largest set of normative positions without conflicts in the state of an activity, and propagate them to the sub-activities. 1