Marc Parenthoën

Fuzzy cognitive maps for the simulation of individual adaptive behaviors

This paper focuses on the simulation of behavior for autonomous entities in virtual environments. The behavior of these entities must determine their responses not only to external stimuli, but also with regard to internal states. We propose to describe such behavior using fuzzy cognitive maps (FCMs), whereby these internal states might be explicitly represented. This paper presents the use of FCMs as a tool to specify and control the behavior of individual agents. First, we describe how FCMs can be used to model behavior. We then present a learning algorithm allowing the adaptation of FCMs through observation. Copyright

Multiscale multiagent architecture validation by virtual instruments in molecular dynamics experiments

A multiagent architecture is proposed in order to build a physics laboratory in virtual reality. Thermodynamics experiments are used for its validation. Classical numerical resolution of thermodynamics problems comes up against the number and variability of boundary conditions. Based on molecular dynamics, a multiagent approach is proposed, resting upon agent spatial and temporal autonomy. This approach grants each particle a capacity to identify its environment using both its own clock and perceptive area. Individual molecular properties are injected into thermal and mechanical models, and macroscopic gas behaviors can be detected and quantified by 3D virtual instruments, created in order to involve the user into the simulation. In order to assess its ability to simulate thermodynamic experiments, our method is applied to classical situations, such as the Joule-Gay Lussac experiment or the maxwellian relaxation in a hard-sphere gas. The simulated gas behavior is in good agreement with theoretical results for gases without interaction. Taking into account the volume of the molecules, our method also allows to quantify the mean free path and the average collision time for Neon and Xenon hard-sphere gases at equilibrium. Dynamic speed relaxation from uniform to maxwellian distribution is simulated successfully, and molecular covolume are also measured with such virtual gases.

Comparison of sea state statistics between a phenomenological model and field data

This paper describes IPAS [13] (Interactive Phenomenological Animation of the Sea), a method for numerical interactive phenomenological animation of the sea, and it aims to validate this method by confrontation with field data. As IPAS is a phenomenological animation, it does not involve computation of hydrodynamic equations on a mesh or a grid of points. Instead, autonomous agents, modeling oceanographic phenomena, are combined and animated using enaction-based multi-agents simulation. A large number of such simulations has been carried out, and the resulting statistics are compared to a commonly used theoretical model, showing the ability of IPAS to represent actual sea state characteristics.

Comportements perceptifs d'acteurs virtuels autonomes Une application des cartes cognitives

We are interested here in the perceptive behaviors of autonomous virtual actors. These behaviors must determine their answers, not only according to the external stimuli, but also according to internal emotions. We propose to describe such emotional behaviors using fuzzy cognitive maps, where these internal states are explicitly represented. We detail how fuzzy cognitive maps allow the specification, the control, the internal simulation and the dynamic adaptation of the perceptive behavior of an animat. Their parallel and asynchronous execution leeds to the proposal of a behavioral architecture for virtual autonomous entities. All these are illustrated by the academic example of a non-trivial interactive fiction.