Catálogo de publicaciones - libros

In this paper, we demonstrate a policy-driven approach for building and managing large scale agent based systems. We identify different classes of policies for agent based component integration. We also identify the system services and mechanisms that are required for policy-driven integration of components and their management. Policies are derived from the application level requirements and are used in dynamic configuration of agent based systems. Through case studies of two applications we demonstrate the utility of the policy-driven component integration approach in distributed agent systems.

Programming applications for highly dynamic environments such as mobile ad hoc networks (MANETs) is complex, since the working context of applications changes continuously. This paper presents “views” as abstractions for representing and maintaining context information, tailored to applications in MANETs. An application agent can define a view by declaratively describing the context information it is interested in. A supporting middleware platform, called ObjectPlaces, ensures that the information represented by a view continuously reflects the agent’s context information, despite the dynamic situation in a MANET. We elaborate on the distributed protocol that ObjectPlaces uses to maintain the information of views, and give an evaluation of the protocol’s correctness and overhead.

A multiagent application consists of an environment and a number of agents. The environment contains information that the agents use and manipulate to do their work. When a multiagent system is decentralized over a number of different hosts ( more than one execution platform is used), the environment has to be decentralized as well. The distributed layout of the environment can influence the performance of agents and of the system.

In this paper we discuss when a distributed system can dynamically change its distribution layout. Our focus is on a distributed environment in which mobile agents move around and are aware of the distributed nature of the system.

Changes to the layout of the distribution are not only triggered by the agents (like other, application-specific actions), but they can also be triggered by external events and the environment itself. A layer of meta-agents monitors those triggers. It has the ability to pro-actively change the distribution layout over the different hosts when this improves the behavior and efficiency of the application.

Using a specific application (solving distributed constraint satisfaction problems) as an example, we indicate the usefulness of changes to the distribution layout and how they can be incorporated easily into a multiagent application design. It turns out that for some problems, the improvement in efficiency can be more than 30%.

Large-scale multiagent systems will be the key software technology driving several future application scenarios. We envision a future in which clouds of microcomputers can be sprayed in an environment to provide, by spontaneously networking with each other, an endlessly range of futuristic applications. Beside this vision, similar kind of large-scale “spray” multiagent systems will be employed in several other scenarios ranging from ad-hoc networks of embedded and mobile devices to worldwide distributed computing. All of these scenarios present strong commonalities from the application development point of view, and new approaches and methodologies will be likely to apply, to some extent, to all of them. In particular, we argue that the issues related to the design and development of such spray multiagent systems call for novel approaches exploiting self-organization as first-class tools. With this regard, we survey a number of research projects around the world trying to apply self-organization to large-scale multiagent systems. Finally, we attempt at defining a rough research agenda that – in the long run – should integrate these ideas to develop a general and more assessed methodology for large-scale spray multiagent systems crosscutting several application domains.

According to social / psychological theories like Activity Theory (AT), plays a fundamental role in the context of human organisations for supporting cooperative work and, more generally, complex collaboration activities. Artifacts are either physical or cognitive tools that are shared and exploited by the collectivity of individuals for achieving individual as well as global objectives. The conceptual framework of is meant to bring the same sort of approach to multiagent systems (MAS).

In particular, are the entities used to shape the agent environment so as to fruitfully enable, promote and govern cooperative and social activities of agent ensembles. Thus, coordination artifacts also capture and extend the notion of coordination medium as coming from the distributed system and DAI fields, by generalising over abstractions like blackboards, tuple spaces and channels.

In this paper we account for the current state of the research on coordination artifacts. First we discuss the background from AT to artifact for MAS, then we summarise the model for the coordination artifact abstraction, and the state-of-the-art of the research on models, methods and technologies currently available for engineering MAS application with coordination artifacts.

The multi-agent paradigm promises to provide systems with the ability to adapt to changing external contexts. In this paper, we propose an approach for the model-driven design of context-aware multi-agent systems. We provide a classification for differentiating between different aspects of context and present a specification technique for modeling these aspects. We finally discuss the difficult transition from general requirements to implemented solution and propose some techniques.

In this paper, we examine the Multiagent Systems Engineering (MaSE) methodology and its applicability to developing organization-based multiagent systems, which are especially relevant to context aware systems. We discuss the inherent shortcomings of MaSE and then present our approach to modeling the concepts required for organizations including goals, roles, agents, capabilities, and the assignment of agents to roles. Finally, we extend MaSE to allow it to overcome its inherent shortcomings and capture the organizational concepts defined in our organization metamodel.

MAS development requires an appropriate methodology. Rather than seek a single, ideal methodology, we investigate the applicability of method engineering, which focuses on project-specific methodology construction from existing method fragments and provides an appealing approach to organize, appropriately access and effectively harness the software engineering knowledge of MAS methodologies. In this context, we introduce a generic metamodel to serve as a representational infrastructure to unify the work product component of MAS methodologies. The resultant metamodel does not focus on any class of MAS, nor does it impose any restrictions on the format of the system requirements; rather, it is an abstraction of how the work product elements in any MAS are structured and behave both at design time and run-time. Furthermore, in this paper we validate this representational infrastructure by analysing two well-known existing MAS metamodels. We sketch how they can be seen as subtypes of our generic metamodel, providing early evidence to support the use of our metamodel towards the construction of situated MAS methodologies.

Despite the relevance of the concept of for conceptual modeling and agent-orientation, there is still in the literature a lack of consensus on the meaning of this notion and how it should be incorporated in existing conceptual modeling languages and frameworks. In this paper, we offer a contribution to this problem by employing a well-founded reference ontology (UFO) to analyze and reconcile two competing notions of role existing in the conceptual modeling literature. Moreover, a modeling solution based on this ontology is proposed, which incorporates the benefit of the two approaches analyzed.

Software reuse technologies have been a driving force in significantly reducing both the time and cost of software specification, development, maintenance and evolution. However, the dynamic nature of highly autonomous agents in distributed systems is difficult to specify with existing requirements analysis and specification techniques. This paper offers an approach for open, agent-based distributed software systems to capture requirements specifications in such a way that they can be easily reused during the initial requirements phase as well as later if the software needs to be updated. The contribution of this paper is to provide a reusable requirements specification pattern to capture the dynamically changing design configurations of agents and reuse them for future similar systems. This is achieved by adopting a product-line approach for agent-based software engineering. We motivate and illustrate this work through a specific application, a phased deployment of an agent-based, distributed microsatellite constellation.