Jomi Fred Hübner

Developing organised multiagent systems using the MOISE + model: programming issues at the system and agent levels

Multiagent Systems (MASs) have evolved towards the specification of global constraints that heterogeneous and autonomous agents are supposed to follow when concerning open systems. A subset of these constraints is known as the MAS organisation. This article describes a set of computational tools that supports the development and the programming of such systems. At the system level, a middleware is provided which ensures that all agents will follow the organisational constraints. At the agent level, the AgentSpeak language is extended, using Jason features, so that the agents can perceive and act upon the organisation to which they belong.

A Model for the Structural, Functional, and Deontic Specification of Organizations in Multiagent Systems

A Multiagent System (MAS) that explicitly represents its organization normally focuses either on the functioning or the structure of this organization. However, addressing both aspects is a prolific approach when one wants to design or describe a MAS organization. The problem is to define these aspects in such a way that they can be both assembled in a single coherent specification. The MOISE+ model - described here through a soccer team example - intends to be a step in this direction since the organization is seen under three points of view: structural, functional, and deontic.

Instrumenting multi-agent organisations with organisational artifacts and agents

The social and organisational aspects of agency have led to a good amount of theoretical work in terms of formal models and theories. However, the conception and engineering of proper organisational infrastructures embodying such models and theories are still an open issue. The introduction of normative concerns with requirements of openness and adaptation stresses this issue. The corresponding mechanisms for the current infrastructures appear to be not appropriate for managing distributed and open normative organisations. There is still the need of proper abstractions and tools to facilitate application agents taking part in the monitoring of the organisation on one hand, and in the adaptation and definition of the organisation in which they are situated on the other hand. In this paper we present and discuss ORA4MAS (Organisational Artifacts for Multi-Agent Systems), a proposed approach aiming at these issues. Based on the Agents and Artifacts meta-model (A&A), it introduces organisational artifacts as first class entities to instrument the organisation for supporting agents activities within it.

MOISE+: towards a structural, functional, and deontic model for MAS organization

A Multi-Agent System (MAS) that represents explicitly its organization normally focuses either on the functioning or on the structure of this organization. However, addressing both aspects is a prolific approach when one wants to design or describe a MAS organization. The problem is to define these aspects in such a way that they can be both assembled in a single coherent specification. The MOISE+ model -- described here through a soccer team example -- intends to be a step in this direction since the organization is seen under three points of view: structural, functional, and deontic.

A logic of trust and reputation

The aim of this paper is to present a logical framework in which the concepts of trust and reputation can be formally characterized and their properties studied. We start from the definition of trust proposed by Castelfranchi & Falcone (C&F). We formalize this definition in a logic of time, action, beliefs and choices. Then, we provide a refinement of C&F’s definition by distinguishing two general types of trust: occurrent trust and dispositional trust. In the second part of the paper we present a definition of reputation that is structurally similar to the definition of trust but moves the basic concept of belief to a collective dimension of group belief.

Coo-AgentSpeak: Cooperation in AgentSpeak through Plan Exchange

This paper brings together two recent contributions to the area of declarative agent-oriented programming, made feasible in practice by the recent introduction of an interpreter for a BDI programming language. The work on Coo-BDI has proposed an approach to plan exchange which applies to BDI agents in general. The other contribution is the introduction of special illocutionary forces for plan exchange between AgentSpeak agents. This has been implemented in Jason, an interpreter for an extended version of that language. This paper shows how the elaborate plan exchange mechanism of Coo-BDI can be used by AgentSpeak agents implemented with Jason. It also discusses an application on PDA-based multi-media presentations in museum visits for which plan exchange is relevant.

Programming declarative goals using plan patterns

AgentSpeak is a well-known language for programming intelligent agents which captures the key features of reactive planning systems in a simple framework with an elegant formal semantics. However, the original language is too abstract to be used as a programming language for developing multi-agent system. In this paper, we address one of the features that are essential for a pragmatical agent programming language. We show how certain patterns of AgentSpeak plans can be used to define various types of declarative goals. In order to do so, we first define informally how plan failure is handled in the extended version of AgentSpeak available in Jason, a Java-based interpreter; we also define special (internal) actions used for dropping intentions. We then present a number of plan patterns which correspond to elaborate forms of declarative goals. Finally, we give examples of the use of such types of declarative goals and describe how they are implemented in Jason.

Using the \mathcal{M}oise + for a Cooperative Framework of MAS Reorganisation

Reorganisation within a multi-agent system may be managed by the agents themselves by adapting the organisation to both environmental changes and their own goals. In this paper, we propose an organisation-centred model for controlling this process. Using the \(\mathcal{M}\) oise + organisation model, we are able to define an organisational structure bearing on a reorganisation process along four phases: monitoring (when to reorganise), design (ways of building a new organisation), selection (how to choose an organisation), and implementation (how to change the current running organisation). The proposed reorganisation scheme is evaluated in the robot soccer domain where we have developed players that follow the team organisation specified in \(\mathcal{M}\) oise + . A special group of agents may change this organisation, and thus the team behaviour, using reinforcement learning for the selection phase.

Agent-Oriented programming with underlying ontological reasoning

Developing applications that make effective use of machine-readable knowledge sources as promised by the Semantic Web vision is attracting much of current research interest; this vision is also affecting important trends in computer science such as grid-based and ubiquitous computing. In this paper, we formally define a version of the BDI agent-oriented programming language AgentSpeak based on description logic rather than predicate logic. In this approach, the belief base of an agent contains the definition of complex concepts, besides specific factual knowledge. We illustrate the approach using examples based on the well-known smart meeting-room scenario. The advantages of combining AgentSpeak with description logics are: (i) queries to the belief base are more expressive as their results do not rely only on explicit knowledge but can be inferred from the ontology; (ii) the notion of belief update is refined given that (ontological) consistency of a belief addition can be checked; (iii) retrieving a plan for handling an event is more flexible as it is not based solely on unification but on the subsumption relation between concepts; and (iv) agents may share knowledge by using ontology languages such as OWL. Extending agent programming languages with description logics can have a significant impact on the development of multi-agent systems for the semantic web.

Organisational artifacts and agents for open multi-agent organisations: giving the power back to the agents

The social and organisational aspects of agency have become nowadays a major focus of interest in the MAS community, and a good amount of theoretical work is available, in terms of formal models and theories. However, the conception and engineering of proper organisational infrastructures embodying such models and theories is still an open issue, in particular when open MAS are considered. Accordingly, in this paper we discuss a model for an organisational infrastructure called ORA4MAS that aims at addressing these issues. By being based on the A&A (Agents and Artifacts) meta-model, the key and novel aspect introduced with ORA4MAS is that organisations and the organisation infrastructure itself are conceived in terms of agents and artifacts, as first-class abstractions giving body to the MAS from design to runtime.