Abstract. It is generally accepted that the environment is an essential compound of multiagent systems (MASs). Yet the environment is typically assigned limited responsibilities, or even neglected entirely, overlooking a rich potential for the paradigm of MASs. Opportunities that environments offer, have mostly been researched in the domain of situated MASs. However, the complex principles behind the concepts and responsibilities of the environment and the interplay between agents and environment are not yet fully clarified. In this paper, we first give an overview of the state-of-the-art on environments in MASs. The survey discusses relevant research tracks on environments that have been explored so far. Each track is illustrated with a number of representative contributions by the research community. Based on this study and the results of our own research, we identify a set of core concerns for environments that can be divided in two classes: concerns related to the structure of the environment, and concerns related to the activity in the environment. To conclude, we list a number of research challenges that, in our opinion, are important for further research on environments for MAS. 1

Abstract. In this paper we propose a new role for the agent metaphor in the definition of the organizational structure of multiagent systems. The agent metaphor is extended to consider as agents also social entities like organizations, groups and normative systems, so that mental attitudes can be attributed to them- beliefs, desires and goals- and also an autonomous and proactive behavior. We show how the metaphor can be applied also to structure organizations in functional areas and roles, which are described as agents too. Thus, the agent metaphor can play a role similar to the object oriented metaphor which allows structuring objects in component objects. Finally, we discuss how the agent metaphor addresses the problems of control and communication in such structured organizations. 1

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Abstract. Several agent-oriented methodologies have been proposed over the last few years. Unlike the object-oriented domain and unfortunately for designers, most of the time, each methodology has its own purposes and few standardization works have been done yet, limiting the impact of agent design on the industrial world. By studying three existing methodologies- ADELFE, Gaia and PASSI- and the concepts related to them, this paper tries to find a means to unify their metamodels. Comparing a certain number of features at the agent or system level (such as the agent structure, its society or organization, its interactions capacities or how agents may be implemented) has enabled us to draw up a first version of a unified meta-model proposed as a first step toward interoperability between agent-oriented methodologies. 1

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.

Electronic markets, dispute resolution and negotiation protocols are three types of application domains that can be viewed as open agent societies. Key characteristics of such societies are agent heterogeneity, conflicting individual goals and unpredictable behaviour. Members of such societies may fail to, or even choose not to, conform to the norms governing their interactions. It has been argued that systems of this type should have a formal, declarative, verifiable, and meaningful semantics. We present a theoretical and computational framework being developed for the executable specification of open agent societies. We adopt an external perspective and view societies as instances of normative systems. In this paper we demonstrate how the framework can be applied to specifying and executing a contract-net protocol. The specification is formalised in two action languages, the C+ language and the Event Calculus, and executed using respective software implementations, the Causal Calculator and the Society Visualiser. We evaluate our executable specification in the light of the presented case study, discussing the strengths and weaknesses of the employed action languages for the specification of open agent societies.

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. For two years, we have been involved in a challenging project to develop a new architecture for an industrial transportation system. The motivating quality attributes to develop this innovative architecture were flexibility and openness. Taking these quality attributes into account, we proposed a decentralized architecture using multiagent systems (MASs). A MAS consists of multiple autonomous entities that coordinate with each other to achieve decentralized control. The typical advantages attributed to such decentralized architecture are flexibility and openness, the motivating quality attributes to apply MAS in this case. The Architecture Tradeoff Analysis Method (ATAM) was used to provide insights wether our architecture meets the expected flexibility and openness, and to identify tradeoffs with other quality attributes. Applying the ATAM proved to be a valuable experience. One of the main outcome of applying the ATAM was the identification of a tradeoff between flexibility and communication load that results from the use of a decentralized architecture. This paper describes our experiences in applying the ATAM to a MAS architecture, containing both the main outcomes of the evaluation and a critical reflection on the ATAM itself. 1

The Agent Modeling Language (AML) is a semi-formal visual modeling language for specifying, modeling and documenting systems that incorporate features drawn from multi-agent systems theory. It is specified as an extension to UML 2.0 in accordance with major OMG modeling frameworks (MDA, MOF, UML, and OCL). The ultimate objective of AML is to provide software engineers with a ready-to-use, complete and highly expressive modeling language suitable for the development of commercial software solutions based on multi-agent technologies. This paper presents an overview of AML. The scope of the language, its structure and extensibility mechanisms are discussed, and the core AML modeling constructs and mechanisms are introduced and demonstrated by examples.

Context-sensitive middleware-based software is an emerging kind of ubiquitous computing application. The components of such software communicate proactively among themselves according to the situational attributes of their environments, known as the ``contexts''. The actual process of accessing and updating the inter-component contexts lies with the middleware. The latter invokes the relevant local and remote operations whenever any context inscribed in the situation-aware interface is satisfied. Since the applications operate in a highly dynamic environment, the testing of context-sensitive software is complex and challenging. Metamorphic testing is a property-based testing strategy. It recommends that, even if a test case does not reveal any failure, follow-up test cases should be further constructed from the original to check whether the software satisfies some necessary conditions of the problem to be implemented. This paper proposes to use isotropic properties of contexts as metamorphic relations for testing context-sensitive software. For instance, distinct points on the same isotropic curve of contexts would entail comparable responses by the components. This notion of testing context relations is novel, robust, and intuitive to users.