Catálogo de publicaciones - libros

This is a short report about the first contest of Multi-Agent Systems (MASs) that are based on computational logic. The CLIMA workshop series (which started in 1999) is a forum to discuss techniques, based on computational logic, for representing, programming, and reasoning about Multi-Agent Systems in a formal way. Now in its seventh year, it was felt that organising a competition for evaluating MASs based on computational logic was appropriate. The authors took on this task, which turned out to be quite difficult under the given time frame. We believe that this competition is a first (modest) step towards (1) collecting important benchmarks, (2) identifying advantages/shortcomings and, finally, (3) advertising the use of Computational Logic to the broader MAS audience, and foster integration of Computational Logic into existing agent-oriented software engineering frameworks.

We describe an implementation of distributed, multi-threaded BDI-style [RG95] agents cooperating efficiently in a foraging scenario. Using ant-style pheromone trails as the basis for a pseudo-random walk procedure, they explore the world uniformly and negotiate to allocate collection and delivery tasks. Global information is disseminated via a publish/subscribe mechanism. The system is implemented using the concurrent logic programming language Qu-Prolog.

There is a recognized lack of Agent-Oriented Methodologies to translate a design into a computational logic implementation. In this paper we address this problem by extending Tropos, which is one of the most used methodologies to design agent systems. We show our proposal with the Food Collecting Agent Problem in which a team has to collect food in a grid-like world. Our solution includes autonomous behaviour, beliefs, multiple roles playing, communication and cooperation. The main contribution is the proposal to generate a Prolog implementation from a Tropos design by first extending the Tropos detailed design and second illustrating how to get a set of Prolog clauses for this design. In addition we show a performance evaluation of our Prolog implementation which confirms that our solution for the case study is effective and allows a simple configuration of the resulting program.

This short paper describes a simple agent system aimed at addressing the food gathering problem set for the 2005 CLIMA contest. Our system is implemented as a collection of reactive agents which dynamically switch between a number of behaviours depending on interaction with their environment. Our agents maintain no internal representation of their environment and operate purely in response to their immediate surroundings. The agents collectively map the environment co-operating indirectly via environmental markers and they use these markers to assist them in locating the depot when they discover food. The required behaviour emerges from the interaction between agents and the marked environment. Despite the simplicity of the agents and their behaviours formal description is difficult. We concentrate more on identifying interesting problems in characterising system exhibiting emergent behaviour and outline possible logic approaches to dealing with them. The application (and one or two other systems addressing the same problem in a different manner) can be downloaded from: http://219.1.164.219/~robert/pwBlog/wp-content/CLIMAbuild.zip

In this work, we describe strategies for multi-agent coordination, where adequate coordination means a system performance increase. In the main strategy, when an agent cannot perform an action, for whatever reason, it chooses the agent more capable in the environment to execute this action. All the specification of the multi-agent system, from the social strategy to the actions in the environment, is made using a particular Petri Net model. The results show the strategy efficacy especially when the environment increases the necessity for a reaction.

The SOCS project (A computational logic model for the description, analysis and verification of global and open SOcieties of heterogeneous ComputeeS), funded by the European Commission under the Fifth Framework, Future and Emerging Technologies programme, has been one of the main sponsors of CLIMA VI. This short article outlines the project’s main challenges and its main outcomes.