Catálogo de publicaciones - libros

The use of norms is a well-known technique of co-ordination in multi-agent systems (MAS) adopted from human societies. A normative position is the “social burden” associated with individual agents, that is, their obligations, permissions and prohibitions. Compound activities may be regulated by means of normative positions. However, conflicts may appear among normative positions of activities and sub-activities. Recently several computational approaches have appeared to make norms operational in MAS but they do not cope with compound activities. In this paper, we propose an algorithm to determine the set of applicable normative positions, i.e., the largest set of normative positions without conflicts in the state of an activity, and propagate them to the sub-activities.

In this paper, we present our metamodeling approach for integrating semantic web services and semantic web enabled agents under view which defines a conceptual framework to realize model driven development. We believe that agents must have well designed environment specific capabilities to fully utilize the power of semantic web environment. Hence, we first define a conceptual architecture for semantic web enabled agents and then discuss how this conceptual architecture can form the basis of a metamodel that can be used in the development of semantic web enabled agents with a model driven approach. We then zoom into the specific part of the metamodel that defines the interactions between semantic web enabled agents and semantic web services since it is not possible to cover all the aspects of the metamodel at one time. So we extend the metamodel of the conceptual architecture from the point of entity aspect for the interaction between semantic agents and semantic web services. Finally, we discuss the mappings between the entities of this extended metamodel and the implemented entities of SEAGENT framework.

In this work, we report an experience that illustrates the interplay between formal methods and real software development. Starting from a Web-enable Coordination Service (WCS) based on JavaSpaces technology which had been successfully used in an industrial project, we built a formal model for the system in order to study its properties; specifically, our aim was to prove that Linda semantics was preserved in several layers of complex mappings from XML documents to Java objects. Once this objective was achieved (at least in a simplified, idealistic version), we observed several possibilities of extending the coordination system at the model level. In particular, we identified that it was possible to enhance the formal model with transactional capabilities, taking advantage of the similarity of our model to rule-based systems. At present, we are working on the translation of this theoretical result to practice, in order to improve our Web Coordination Service.

Current approaches to multi-agent interaction involve specifying protocols as sets of possible interactions, and hard-coding decision mechanisms into agent programs in order to decide which path an interaction will take. This leads to several problems, three of which are particularly notable: hard-coding the decisions about interaction within an agent strongly couples the agent and the protocols it uses, which means a change to a protocol involves a changes in any agent that uses such a protocol; agents can use only the protocols that are coded into them at design time; and protocols cannot be composed at runtime to bring about more complex interactions. To achieve the full potential of multi-agent systems, we believe that it is important that multi-agent interaction protocols exist at runtime in systems as entities that can be inspected, referenced, composed, and shared, rather than as abstractions that emerge from the behaviour of the participants. We propose a framework, called , which regards protocols as first-class entities. In this paper, we present the first step in this framework: a formal language for specification of agent interaction protocols as first-class entities, which, in addition to specifying the order of messages using a process algebra, also allows designers to specify the rules and consequences of protocols using constraints. In addition to allowing agents to reason about protocols at runtime in order to improve their the outcomes to better match their goals, the language allows agents to compose more complex protocols and share these at runtime.

A defining characteristic of Open Computational Societies is the unpredictable behaviour of their participants, resulting from their operational and architectural heterogeneity. This has led to the development of computational frameworks that facilitate the declaration of agent specifications in terms of normative relations. The frameworks offer modelling, simulation and validation, but typically have not supported dynamic modification of the specification at runtime by the agents themselves. This omission can be a limitation in certain scenarios, where agents might be capable of adaptation when faced with unexpected stimuli, but the specifications under which they operate did not allow for it. In this paper we extend an existing normative computational framework to facilitate well-defined dynamic normative modification of a specification by the agents themselves, given a well-defined meta-specification. We complement the framework with a mathematical model of the ‘specification space’. We argue that the introduced dynamism preserves several of the advantages of static normative frameworks while allowing for more flexible, highly autonomous systems, simpler specification authoring and generic protocol reuse.

Nowadays, challenge is to design complex systems that evolve in changing environments. Multi-agent systems (MAS) are an answer to implement them and many agent-oriented methodologies are proposed to guide designers. Self-organisation is a promising paradigm to make these systems adaptive: the collective function arises from the local interactions and the system design becomes thus bottom-up. The difficulty rests then in finding the right behaviours at the agent-level to make the adequate global function emerge. The aim of this paper is to show how simulation can help designers to find these correct behaviours during the design stage: by simulating a simplified system and observing it during execution, a designer can modify and improve the behaviour of agents. A model of cooperative agents was implemented under the SeSAm platform in order to be integrated into ADELFE, an agent-oriented methodology dedicated to adaptive MAS (AMAS). This model is described here and applied to show how the behaviour of a simple ecosystem can be improved.

Electronic institutions (EIs) have been proposed as a means of regulating open agent societies. EIs define the rules of the game in agent societies by fixing what agents are permitted and forbidden to do and under what circumstances. And yet, there is the need for EIs to adapt their regulations to comply with their goals despite coping with varying populations of self-interested external agents. In this paper we focus on the extension of EIs with autonomic capabilities to allow them to yield a dynamical answer to changing circumstances through norm adaptation and changes in institutional agents.

In the future electronic devices will permeate the environment where they will work invisibly and autonomously to deliver new and enhanced services that go far beyond the mandate of the desktop era. Intelligent agents will form the basis of many applications in this emergent ubiquitous domain. Agent Factory Micro Edition (AFME) is a framework that facilitates the construction of agent-based applications for computationally constrained devices, this paper outlines three enhancements introduced to AFME to enable resources to be managed more effectively, namely a new threading model, an extended rational decision making infrastructure, and a syntactic modification to the agent programming language that improves efficiency. The extended reasoning capabilities of AFME enable agents to choose the most appropriate course of action with respect to their finite resources in a social context.

This paper present a novel approach to modelling creative societies using curious design agents. The importance of modelling the social aspects of creativity are first presented and a novel agent-based approach is developed. Curious design agents are introduced as an appropriate model of individuals in a creative society. Some of the advantages of using curious design agents to model creative societies are discussed. Results from some initial investigations into self-organisation within creative societies using the model are given. This paper concludes by discussing some related work and exploring possible directions for future work.

In all user-centred agent-based applications, for instance in the context of ambient computing, the user agent is often faced to a difficult trade-off between the protection of its own privacy, and the fluidity offered by the services. In existing applications, the choice is almost never on the user’s side, even though the law grants him a number of rights in order to guarantee his privacy. We examine here different technical works that seem to be as many interesting ways of dealing with privacy policies. The problems already solved will be identified, as well as remaining technical challenges. Then we will propose directions of research based on the most interesting aspects of the underlined approaches.