Frank Dignum

Organizing Multiagent Systems

Despite all the research done in the last years on the development of methodologies for designing MAS, there is no methodology suitable for the specification and design of MAS in complex domains where both the agent view and the organizational view can be modeled. Current multiagent approaches either take a centralist, static approach to organizational design or take an emergent view in which agent interactions are not pre-determined, thus making it impossible to make any predictions on the behavior of the whole systems. Most of them also lack a model of the norms in the environment that should rule the (emergent) behavior of the agent society as a whole and/or the actions of individuals. In this paper, we propose a framework for modeling agent organizations, Organizational Model for Normative Institutions (OMNI), that allows the balance of global organizational requirements with the autonomy of individual agents. It specifies global goals of the system independently from those of the specific agents that populate the system. Both the norms that regulate interaction between agents, as well as the contextual meaning of those interactions are important aspects when specifying the organizational structure.

A Programming Language for Cognitive Agents: Goal-Directed 3APL

This paper presents the specification of a programming language for cognitive agents. This programming language is an extension of 3APL (An Abstract Agent Programming Language) and allows the programmer to implement agents’ mental attitudes like beliefs, goals, plans, and actions, and agents’ reasoning rules by means of which agents can modify their mental attitudes. The formal syntax and semantics of this language is presented as well as a discussion on the deliberation cycle and an example.

Towards socially sophisticated BDI agents

We present an approach to social reasoning that integrates prior work on norms and obligations with the BDI approach to agent architectures. Norms and obligations can be used to increase the efficiency of agent reasoning, and their explicit representation supports reasoning about a wide range of behaviour types in a single framework. We propose a modified BDI interpreter loop that takes norms and obligations into account in an agents deliberation.

OMNI: introducing social structure, norms and ontologies into agent organizations

In this paper, we propose a framework for modelling agent organizations, Omni, that allows the balance of global organizational requirements with the autonomy of individual agents. It specifies global goals of the system independently from those of the specific agents that populate the system. Both the norms that regulate interaction between agents, as well as the contextual meaning of those interactions are important aspects when specifying the organizational structure. Omni integrates all this aspects in one framework. In order to make design of the multi-agent system manageable, we distinguish three levels of abstraction with increasing implementation detail. All dimensions of Omni have a formal logical semantics, which ensures consistency and possibility of verification of the different aspects of the system. Omni is therefore utmost suitable for the modelling of all types of MAS from open to closed environments.

Autonomous Norm Acceptance

It is generally acknowledged that norms and normative action emphasize autonomy on the side of decision. But what about the autonomous formation of normative goals? This paper is intended to contribute to a theory of how agents form normative beliefs and goals, and to formulate general but non exhaustive principles of norm based autonomous agent-hood - namely goal generation and decision making- upon which to construct software agents.

Advances in Agent Communication

This article aims to provide foundations for a new approach to Agent Communication Languages (ACLs). First, we outline the theory of signalling acts. In contrast to current approaches to communication, this account is neither intention-based nor commitment-based, but convention-based. Next, we outline one way of embedding that theory within an account of conversation. We move here from an account of the basic types of communicative act (the statics of communication) to an account of their role in sequences of exchanges in communicative interaction (the dynamics of communication). Finally, we apply the framework to the analysis of a conversational protocol.

TRENDS IN AGENT COMMUNICATION LANGUAGE

Agent technology is an exciting and important new way to create complex software systems. Agents blend many of the traditional properties of AI programs—knowledge–level reasoning, flexibility, proactiveness, goal–directedness, and so forth—with insights gained from distributed software engineering, machine learning, negotiation and teamwork theory, and the social sciences. An important part of the agent approach is the principle that agents (like humans) can function more effectively in groups that are characterized by cooperation and division of labor. Agent programs are designed to autonomously collaborate with each other in order to satisfy both their internal goals and the shared external demands generated by virtue of their participation in agent societies. This type of collaboration depends on a sophisticated system of inter–agent communication. The assumption that inter–agent communication is best handled through the explicit use of an agent communication language (ACL) underlies each of the articles in this special issue. In this introductory article, we will supply a brief background and introduction to the main topics in agent communication.

Agent Theory for Team Formation by Dialogue

The process of cooperative problem solving can be divided into four stages. First, finding potential team members, then forming a team followed by constructing a plan for that team. Finally, the plan is executed by the team. Traditionally, protocols like the Contract Net protocol are used for performing the first two stages of the process. In an open environment however, there can be discussion among the agents in order to form a team that can achieve the collective intention of solving the problem. For these cases fixed protocols like contract net do not suffice. In this paper we present a theory for agents that are able to discuss the team formation and subsequently work as a team member until the collective goal has been fulfilled.We also present a solution, using structured dialogues, with an emphasis on persuasion, that can be shown to lead to the required team formation. The dialogues are described formally using modal logics and speech acts.

Designing a Deontic Logic of Deadlines

This paper studies the logic of a dyadic modal operator for being obliged to meet a condition ρ before a condition δ becomes true. Starting from basic intuitions we arrive at a simple semantics for deadline obligations in terms of branching time models. We show that this notion of deadline obligation can be characterized in the branching time logic CTL. The defined operator obeys intuitive logic properties, like monotony w.r.t. ρ and anti-monotony w.r.t. δ, and avoids some counter-intuitive properties like agglomeration w.r.t ρ and’weak agglomeration’ w.r.t. δ. However, obligations of this type are implied by the actual achievement of ρ before the deadline. We argue that this problem is caused by the fact that we model the obligation only from the point of view of its violation conditions. We show that the property might be eliminated by considering success conditions also.

Programming agent deliberation: an approach illustrated using the 3APL language

This paper presents the specification of a programming language for implementing the deliberation cycle of cognitive agents. The mental attitudes of cognitive agents are assumed to be represented in an object language. The implementation language for the deliberation cycle is considered as a meta-language the terms of which denote formulae from the object language. Without losing generality, we use the agent programming language 3APL as the object language. Using the meta-deliberation language, one can program the deliberation process of a cognitive agent. We discuss a set of programming constructs that can be used to program various aspects of the deliberation cycle including the planning constructs.