A Programming Language for Normative Multi-Agent Systems

A Programming Language for Normative Multi-Agent Systems

Mehdi Dastani (Utrecht University, The Netherlands), Nick A.M. Tinnemeier (Utrecht University, The Netherlands) and John-Jules Ch. Meyer (Utrecht University, The Netherlands)
DOI: 10.4018/978-1-60566-256-5.ch016
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Multi-agent systems are viewed as consisting of individual agents whose behaviors are regulated by an organizational artifact. This chapter presents a programming language that aims at facilitating the implementation of norm-based organizational artifacts. The programming language is presented in two steps. We first present a programming language that is designed to support the implementation of nonnormative organizational artifacts. These artifacts are specified in terms of non-normative concepts such as the identity of participating agents, the identity of the constituting environments in which individual agents can perform actions, and the agents’ access relation to the environments. The programming language is then modified and extended to support the implementation of norm-based artifacts. Such artifacts are specified in terms of norms being enforced by monitoring, regimenting, and sanctioning mechanisms. The syntax and operational semantics of the programming language are discussed and explained by means of a conference management system example.
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In this chapter, multi-agent systems are considered as consisting of individual agents that are autonomous and heterogeneous. The first assumption implies that each individual agent pursues its own design objectives and the second one implies that the internal states and operations of individual agents may not be known to external entities (Zambonelli, Jennings, & Wooldridge, 2003; Esteva, Rodríguez-Aguilar, Rosell, & Arcos, 2004). In order to achieve the overall goal of such multi-agent systems, the observable/external behavior of individual agents and their interactions should be regulated.

There are two main approaches to regulate the external behavior of individual agents. The first approach is based on coordination artifacts that are specified in terms of low-level coordination concepts such as synchronization of processes (Ricci, Viroli, & Omicini, 2007). The second approach is motivated by organizational models, normative systems, and electronic institutions (Searle, 1995; Jones & Sergot, 1993; Esteva et al., 2004; Grossi, 2007). In this approach, norms are used to regulate the behavior of individual agents.

Using a social and normative perspective is conceived as a way to make the development and maintenance of multi-agent systems easier to manage. A plethora of social concepts (e.g., roles, social structures, organizations, institutions, norms) has been introduced in multi-agent system methodologies, such as Gaia (Zambonelli et al., 2003), models such as OperA (Dignum, 2004), Moise+ (Hübner, Sichman, & Boissier, 2002), and electronic institutions and frameworks such as AMELI (Esteva et al., 2004) and S-Moise+ (Hübner et al., 2002). See also Chapters VI, VIII and XIV for other models that specify multi-agent systems in terms of social and organizational concepts.

Norms in multi-agent systems can be used to specify the standards of behavior that agents ought to follow in order for the overall objectives of the system to be met. However, to develop a multi-agent system does not boil down to state a number of standards of behavior in the form of a set of norms, but rather to organize the system in such a way that those standards of behavior are actually followed by the agents. This can be achieved by regimentation or enforcement mechanisms (Jones & Sergot, 1993).

When regimenting norms all agents’ external actions leading to a violation of those norms are made impossible. Via regimentation (e.g., gates) the system prevents an agent from performing a forbidden action (e.g., entering an underground train platform without a ticket). However, regimentation drastically decreases the agent’s autonomy. Instead, enforcement is based on the idea of responding after a violation of the norms has occurred. Such a response, which includes sanctions, aims to return the system to an acceptable state. Crucial for enforcement is that the actions that violate norms are observable by the system (e.g., fines can be issued only if the system can detect travelers entering the underground system without a ticket).

The main contribution of this chapter is to present and discuss a simplified version of a programming language that is designed to implement norm-based artifacts that can be used to regulate the behaviors of individual agents constituting a multi-agent system. Such artifacts are assumed to be used by individual agents to perform their external actions in the shared environment(s) and to pass messages to each other. In the next section, we present the syntax and semantics of a programming language that can be used to specify a (non-normative) multi-agent system. This programming language is then modified and extended to allow the implementation of norm-based artifacts. The modified programming language provides constructs to represent norms and mechanisms to enforce them. Then, an example is given to illustrate the use of the programming language. The chapter will be closed by discussing some norm-based approaches to multi-agent systems available at the moment in the literature, among which, ISLANDER/AMELI (Esteva et al., 2004) and S-MOISE+ (Hübner et al., 2002). The chapter will be concluded by some remarks and suggestions for future research directions.

Key Terms in this Chapter

Exchange: Sets of actions that two or more agents perform together in a coordinated way, so that objects or services provided by ones are made available to the others that need them.

Link: A set of standar interaction processes, that pairs (or, more generally, subsets of agents) in multiagent system may be assigned to, in order to help the system to fullfil some internal or external function.

Service: A coordinated set of actions that an agent performs in order to satisfy a specific need of another agent or set of agents.

Role: A set of standard behaviors, that agents in a multiagent system may be assigned to, in order to help the system to fullfil some internal or external function.

Organizational Growth: A process through which the structure of a multigent system organization increases the number of its roles and links. Organizational growth is essentially a quantitative process.

Multiagent System Organization: The structure inherent in a multiagent system, constituted essentially by roles and exchange links between roles, defining standard behaviors and interaction processes to be followed by the agents, in accordance with the way they were assigned to the roles.

Organizational Dynamics: The set of rules that govern the temporal changes in of the organization of a multiagent system.

Organizational Development: a process through which the structure of a multiagent system organization improves its quality and strength. Organizational development is essentially a qualitative process, with possible quantitative effects on the organization structure.

Complete Chapter List

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Editorial Advisory Board
Table of Contents
Liz Sonenberg
Virginia Dignum
Virginia Dignum
Chapter 1
Virgina Dignum
Agent Organization can be understood from two perspectives: organization as a process and organization as an entity. That is, organization is... Sample PDF
The Role of Organization in Agent Systems
Chapter 2
Luciano R. Coutinho, Jaime S. Sichman, Olivier Boissier
In this chapter, we discuss the concepts of agent organization, organizational model, and review some existing organizational models. Before the... Sample PDF
Modelling Dimensions for Agent Organizations
Chapter 3
Jacques Ferber, Tiberiu Stratulat, John Tranier
In this chapter, we stress the importance of thinking a MAS in all its aspects (agents, environment, interactions, organizations, and institutions)... Sample PDF
Towards an Integral Approach of Organizations in Multi-Agent Systems
Chapter 4
Scott A. DeLoach
This chapter introduces a suite of technologies for building complex, adaptive systems. It is based in the multi-agent systems paradigm and uses the... Sample PDF
OMACS: A Framework for Adaptive, Complex Systems
Chapter 5
Christopher Cheong, Michael Winikoff
Although intelligent agents individually exhibit a number of characteristics, including social ability, flexibility, and robustness, which make them... Sample PDF
Hermes: Designing Flexible and Robust Agent Interactions
Chapter 6
Viara Popova, Alexei Sharpanskykh
This chapter introduces a formal framework for modeling and analysis of organizations. It allows representing and reasoning about all important... Sample PDF
A Formal Framework for Organization Modeling and Analysis
Chapter 7
Maksim Tsvetovat
Agent-based approaches provide an invaluable tool for building decentralized, distributed architectures and tying together sets of disparate... Sample PDF
Describing Agent Societies: A Declarative Semantics
Chapter 8
Davide Grossi, Frank Dignum
In this chapter we investigate how organizations can be represented as graphs endowed with formal semantics. We distinguish different dimensions of... Sample PDF
Structural Aspects of Organizations
Chapter 9
Virgina Dignum, Frank Dignum
Organization concepts and models are increasingly being adopted for the design and specification of multi-agent systems. Agent organizations can be... Sample PDF
A Logic for Agent Organizations
Chapter 10
Cristiano Castelfranchi
This chapter presents organizations as a macro-micro notion and device; they presuppose autonomous proactive entities (agents) playing the... Sample PDF
Grounding Organizations in the Minds of the Agents
Chapter 11
Paolo Torroni, Pinar Yolum, Munindar P. Singh, Marco Alberti, Federico Chesani, Marco Gavanelli, Evelina Lamma, Paola Mello
Organizational models often rely on two assumptions: openness and heterogeneity. This is, for instance, the case with organizations consisting of... Sample PDF
Modelling Interactions via Commitments and Expectations
Chapter 12
Gita Sukthankar, Katia Sycara, Joseph A. Giampapa, Christopher Burnett
This chapter discusses the problem of agent aiding of ad-hoc, decentralized human teams so as to improve team performance on time-stressed group... Sample PDF
Communications for Agent-Based Human Team Support
Chapter 13
Bob van der Vecht, Frank Dignum, John-Jules Ch. Meyer
This chapter discusses how autonomous agents can adopt organizational rules into their reasoning process. Agents in an organization need to... Sample PDF
Autonomous Agents Adopting Organizational Rules
Chapter 14
Nicoletta Fornara, Marco Colombetti
The specification of open interaction systems is widely recognized to be a crucial issue, which involves the problem of finding a standard way of... Sample PDF
Specifying Artificial Institutions in the Event Calculus
Chapter 15
Francesco Viganò, Marco Colombetti
Institutions have been proposed to explicitly represent norms in open multi-agent systems, where agents may not follow them and which therefore... Sample PDF
Verifying Organizations Regulated by Institutions
Chapter 16
Mehdi Dastani, Nick A.M. Tinnemeier, John-Jules Ch. Meyer
Multi-agent systems are viewed as consisting of individual agents whose behaviors are regulated by an organizational artifact. This chapter presents... Sample PDF
A Programming Language for Normative Multi-Agent Systems
Chapter 17
Antônio Carlos da Rocha Costa, Graçaliz Pereira Dimuro
This chapter presents the Population-Organization model, a formal tool for studying the organization of open multi-agent systems and its functional... Sample PDF
A Minimal Dynamical MAS Organization Model
Chapter 18
Shaheen Fatima, Michael Wooldridge
This chapter presents an adaptive organizational policy for multi-agent systems called TRACE. TRACE allows a collection of multi-agent organizations... Sample PDF
A Framework for Dynamic Agent Organizations
Chapter 19
Alexander Artikis, Dimosthenis Kaponis, Jeremy Pitt
We have been developing a framework for executable specification of norm-governed multi-agent systems. In this framework, specification is a... Sample PDF
Dynamic Specifications for Norm-Governed Systems
Chapter 20
Marco Lamieri, Diana Mangalagiu
In this chapter we present a model of organization aimed to understand the effect of formal and informal structures on the organization’s... Sample PDF
Interactions Between Formal and Informal Organizational Networks
Chapter 21
Steven Okamoto, Katia Sycara, Paul Scerri
Intelligent software personal assistants are an active research area with the potential to revolutionize the way that human organizations operate... Sample PDF
Personal Assistants for Human Organizations
Chapter 22
Sachin Kamboj, Keith S. Decker
This chapter presents an approach to organizational-self design (OSD), a method of designing organizations at run-time in which the agents are... Sample PDF
Organizational Self-Design in Worth-Oriented Domains
Chapter 23
Olivier Bonnet-Torrès, Catherine Tessier
This chapter focuses on a Petri Net-based model for team organization and monitoring. The applications considered are missions performed by several... Sample PDF
A Formal Petri Net Based Model for Team Monitoring
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