Knowledge revision in systems based on an informed tree search strategy : application to cartographic generalisation

Many real world problems can be expressed as optimisation problems. Solving this kind of problems means to find, among all possible solutions, the one that maximises an evaluation function. One approach to solve this kind of problem is to use an informed search strategy. The principle of this kind of strategy is to use problem-specific knowledge beyond the definition of the problem itself to find solutions more efficiently than with an uninformed strategy. This kind of strategy demands to define problem-specific knowledge (heuristics). The efficiency and the effectiveness of systems based on it directly depend on the used knowledge quality. Unfortunately, acquiring and maintaining such knowledge can be fastidious. The objective of the work presented in this paper is to propose an automatic knowledge revision approach for systems based on an informed tree search strategy. Our approach consists in analysing the system execution logs and revising knowledge based on these logs by modelling the revision problem as a knowledge space exploration problem. We present an experiment we carried out in an application domain where informed search strategies are often used: cartographic generalisation.Comment: Knowledge Revision; Problem Solving; Informed Tree Search Strategy; Cartographic Generalisation., Paris : France (2008

Using Computational Agents to Design Participatory Social Simulations

In social science, the role of stakeholders is increasing in the development and use of simulation models. Their participation in the design of agent-based models (ABMs) has widely been considered as an efficient solution to the validation of this particular type of model. Traditionally, "agents" (as basic model elements) have not been concerned with stakeholders directly but via designers or role-playing games (RPGs). In this paper, we intend to bridge this gap by introducing computational or software agents, implemented from an initial ABM, into a new kind of RPG, mediated by computers, so that these agents can interact with stakeholders. This interaction can help not only to elicit stakeholders' informal knowledge or unpredicted behaviours, but also to control stakeholders' focus during the games. We therefore formalize a general participatory design method using software agents, and illustrate it by describing our experience in a project aimed at developing agent-based social simulations in the field of air traffic management.Participatory Social Simulations, Agent-Based Social Simulations, Computational Agents, Role-Playing Games, Artificial Maieutics, User-Centered Design

Methods for Agent-Based Computer Modelling

International audiencePlenary Session of the Tam Dao University

The MICRoBES Project, an Experimental Approach towards 'Open Collective Robotics'

International audienceWe focus here on "Open Collective Robotics", a research domain interested in studying concepts and techniques which could lead to true collectivities between humans and robots. We also present the MICRobES project, a long-term experiment intended to investigate how to design such collectivities. Therefore, the MICRobES robots have no prior specific functionality, they have to develop individual competences, a social organization, and sociability towards humans in order to "survive" in a dynamic environment

Using Belief Theory to Diagnose Control Knowledge Quality. Application to cartographic generalisation

Both humans and artificial systems frequently use trial and error methods to problem solving. In order to be effective, this type of strategy implies having high quality control knowledge to guide the quest for the optimal solution. Unfortunately, this control knowledge is rarely perfect. Moreover, in artificial systems-as in humans-self-evaluation of one's own knowledge is often difficult. Yet, this self-evaluation can be very useful to manage knowledge and to determine when to revise it. The objective of our work is to propose an automated approach to evaluate the quality of control knowledge in artificial systems based on a specific trial and error strategy, namely the informed tree search strategy. Our revision approach consists in analysing the system's execution logs, and in using the belief theory to evaluate the global quality of the knowledge. We present a real-world industrial application in the form of an experiment using this approach in the domain of cartographic generalisation. Thus far, the results of using our approach have been encouraging.Comment: Best paper award, International Conference on Computing and Communication Technologies (IEEE-RIVF), Danang : Viet Nam (2009

Des données géographiques à la simulation à base d'agents : application de la plate-forme GAMA

International audienceCes dernières années, la simulation à base d’agents a révélé certains intérêts en géographie. Néanmoins, s’il existe aujourd’hui de nombreuses plates-formes permettant de faciliter le développement de modèle, celles-ci sont souvent trop complexes pour être utilisées par des non-informaticiens (par exemple Repast Symphony) ou trop limitées pour développer des modèles riches intégrant de nombreux agents et données (par exemple Netlogo). La plate-forme GAMA a pour objectif d’offrir aux modélisateurs une plate-forme à la fois puissante et simple d’accès grâce à langage de modélisation dédié. Dans cet article, nous présentons les capacités particulièrement avancées de la nouvelle version de la plate-forme GAMA pour la gestion de l’espace. Cette plate-forme permet en particulier de gérer simultanément plusieurs environnements basés sur trois types de topologie (continue, grille, graphe), d’intégrer très simplement des données géographiques (vectorielles et rasters) et de représenter des géométries dans un environnement 3D. Les capacités détaillées dans cet article sont illustrées par un modèle sur les problématiques de ségrégation urbaine