Papers by Marc Parenthoen
Simulated radar observations of the sea surface dynamics as used in the MODENA project, are based... more Simulated radar observations of the sea surface dynamics as used in the MODENA project, are based on an original methodology for sea states : the "groupy" wave model (GWM). Random wave fields can have very different modulations but nearly identical spectra. Nevertheless, the response of a floating object to waves depends strongly on the likelihood of large wave encounters. Sea surface fluxes also depend on wave breaking and air-flow separation, both being consequences of large-amplitude events. So wave group structure is one key description to simulate radar clutter under various environmental and instrumental configurations. The GWM builds on random distributions of wave groups and conditionally distributed breaking waves over these groups. Each wave group travels across the simulated area, and breaking waves appear dynamically on the wave crest at the rear of a group, propagating and disappearing at the front of this group. The generation of sea states follows a prescribed sea wave directional spectrum, and any breaking wave statistical distribution such as Λ( c)d c describing the total length of breaker per unit area and time with phase speed between c and c + d c. Accordingly, the group density per surface unit can lead to very different sea state structures, and the results will be discussed.
This study lies in the context of virtual engineering and human information systems. We propose t... more This study lies in the context of virtual engineering and human information systems. We propose to model and implement the behaviour of believable virtual agents, using ideas from psychology (cognitive maps, affordances) and neurophysiology (active perception, movement prediction). Virtual worlds are peopled with autonomous entities improvising in free interaction. Autonomization of a model consists in giving to it a sensorimotor interface and also a decision module so that it could adapt its reactions to inner and extern stimuli. We propose in this article the basis for a behavioral model imitating human beings' perceptive operation. The psychological notion of "affordance" will help us in the construction of fuzzy cognitive maps for believable virtual human behaviour specification. Sensus Alain Berthoz, neurophysiologist, perception is not only an interpretation of sensorial messages: it is also an internal simulation of the action and an anticipation of the consequences of this simulated action. Following neurophysiological experiments on hippocampus in which were observed oscillations permitting prediction of trajectories, our virtual actor uses fuzzy cognitive maps in an imaginary space and simulate a behaviour. This simulation in the simulation allows him to predict the consequences of actions. The expected benefit from our affordance-based and proactive model consists in elaborating a believable virtual helmsman within the framework of a virtual sailing ship. We have implemented such a virtual actor in the multi-agent environment oRis.
Techniques De L Ingenieur Informatique, 2007
Cet article s'inscrit dans le cadre des histoires virtuelles interactives et propose l'utilisatio... more Cet article s'inscrit dans le cadre des histoires virtuelles interactives et propose l'utilisation des cartes cognitives floues comme outil de modélisation du comportementémotionnel d'acteurs virtuels improvisant en interaction libre dans le cadre d'un scénario "nouvelle vague"à la Godard. Nous décrivons l'implémentation réaliséeà partir de travaux en psychologie cognitive et l'illustrons par une improvisation entre un berger, un chien et des moutons virtuels.
Journal of Modern Mathematics Frontier, 2013
Within the framework of multi-interaction systems (MIS), we aim at proposing algorithms for solvi... more Within the framework of multi-interaction systems (MIS), we aim at proposing algorithms for solving some partial differential equations (PDE), that are commonly used for modeling phenomena like transport or diffusion, as they often occur in a complex system involving natural phenomena. Unlike classical synchronous ones, schemes for MIS have to be compatible with chaotic asynchronous iterations, which enable multi-model/scale, interactive and real-time simulations. In our context, the notion of asynchronous iteration expresses the fact that activities, each modeling a phenomenon, have their own lifetime and are processed one after the other. These activations are processed by cycles, in a random order -to avoid computation bias-, what we name chaotic iterations. We provide MIS-compatible schemes to simulate transport phenomena, thermal diffusion phenomena and the spreading phenomenon of a wave packet. Our schemes are based on interactions that represent sorts of Maxwell daemons: transfers of flows between several separate environments given by a spatial resolution grid. We establish formal proofs of convergence for our transport methods. We experiment an efficient asynchronous diffusion scheme, and couple both schemes for solving the advection-diffusion problem. We finally illustrate a multi-interaction method for the spreading of a wave packet described by the Schrödinger equation. Results are compared to classical numerical methods and they show that our methods are as accurate as classical ones, whilst respecting MIS constraints.
Techniques et sciences informatiques, 2005
Ces comportements doivent déterminer leurs réponses, en fonction des stimulus externes, mais auss... more Ces comportements doivent déterminer leurs réponses, en fonction des stimulus externes, mais aussi en fonction d'émotions internes. Nous proposons de décrire de tels comportements émotionnels à l'aide de cartes cognitives floues où ces états internes sont explicitement représentés. Nous détaillons comment les cartes cognitives floues permettent la spécification, le contrôle, la simulation interne et l'adaptation dynamique du comportement perceptif d'un animat. L'exécution parallèle et asynchrone du contrôle, de la simulation interne et de l'apprentissage débouche sur une architecture comportementale pour entités virtuelles autonomes. Nous illustrons notre démarche à travers un exemple académique non trivial de fiction interactive. ABSTRACT. 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. MOTS-CLÉS : acteur virtuel, perception active, apprentissage, carte cognitive, architecture d'agent KEYWORDS: virtual actor, active perception, learning, cognitive map, agent architecture RSTI -TSI. Volume 24 -n • 10/2005, pages 1259 à 1293 1. Nous n'avons pas la prétention de fournir un modèle de stress ou de paranoïa ; nous utilisons ces termes psychologiques par simple analogie comportementale, dans un but pédagogique.
behaviors specified by FCMs for simulating it-self and others in its imaginary space. FCMs can gi... more behaviors specified by FCMs for simulating it-self and others in its imaginary space. FCMs can give true per- ception & emotion. We propose a FCM-learning al- gorithm using meta-knowledge about learning in order to imitate a given behavior in real-time. The virtual actor autonomously selects training periods. This se- lection is inspired by neurophysiological experiments about active perception and hippocampus.
OCEANS 2007 - Europe, 2007
This paper describes IPAS (Interactive Phenomenological Animation of the Sea), a method for numer... more This paper describes IPAS (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 phenomenons, 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 acommonly used theoretical model, showing the ability of IPAS to represent actual sea state characteristics.
Mots-Clés: appentissage, autonomie, acteur virtuel, carte cognitive floue, imitation Résuméétendu... more Mots-Clés: appentissage, autonomie, acteur virtuel, carte cognitive floue, imitation Résuméétendu Le but de ce travail est de donner plus d'autonomieà des acteurs virtuels en les dotant d'une capacité d'imitation. Un acteur virtuel est un agent autonome ayant sa propre personnalité, ses propreémotions [Hayes-Roth 96]. Il posséde des capteurs et des effecteurs contrôlés par des Graphes Cognitifs Flous (GCFs, en anglais: Fuzzy Cognitive Maps ou FCMs [Kosko 86]) qui spécifient le comportement [Parenthoën 01]. Un expert en collabaration avec un ergonome peut fournir les prototypes de tels GCFs [Parenthoën 02]. La connexion entre l'agent autonome et un GCF se traduit par une fuzzification des capteurs pour déterminer l'activation forcée des concepts perceptifs de ce GCF et par une défuzzification des activations des concepts moteurs fixant les effecteurs. Les concepts internes peuvent traduire desémotions et sont utilisés selon le graphe d'influence lors de la dynamique du GCF convergeant vers son attracteur. Un acteur virtuel possèdeégalement un monde imaginaire, dans lequel il peut simuler son propre comportement mais aussi celui d'autres acteurs [Maffre 01]. Il imagine son comportement en utilisant ses propres GCFs, et celui des autres acteurs avec des GCFs prototypiques. Par exemple, un chien de berger voulant garder un troupeau de moutons possèdera ses GCFs lui permettant de regrouper des moutons, mais aussi des GCFs prototypiques d'une proie lui permettant de simuler dans son monde imaginaire le comportement de moutons et des GCFs prototypiques de chiens de berger pour simuler les autres chiens. Cette perception de lui-même et des autres implémentée par une simulation dans la simulation est l'une des clés pour l'autonomie d'apprentissage. Dans le cadre d'un apprentissage par imitation, l'acteur virtuel doit pouvoir modifier son comportement pour mimer le comportement observé d'un modèle qui peutêtre un autre acteur ou un avatar contrôlé par un opérateur humain [Stoffregen 99
Cet article s'inscrit dans le cadre des histoires virtuelles interactives et propose l'utilisatio... more Cet article s'inscrit dans le cadre des histoires virtuelles interactives et propose l'utilisation des cartes cognitives floues comme outil de modélisation du comportementémotionnel d'acteurs virtuels improvisant en interaction libre dans le cadre d'un scénario "nouvelle vague"à la Godard. Nous décrivons l'implémentation réaliséeà partir de travaux en psychologie cognitive et l'illustrons par une improvisation entre un berger, un chien et des moutons virtuels.
Computer Animation and Virtual Worlds, 2010
This paper focuses on the simulation of behavior for autonomous entities in virtual environments.... more 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 (FCM), whereby these internal states might be explicitly represented. This article presents the use of fuzzy cognitive maps as a tool to specify and control the behavior of individual agents. First, we describe how fuzzy cognitive maps can be used to model behavior. We then present a learning algorithm allowing the adaptation of FCMs through observation.
Proceedings of the 8th ACM SIGGRAPH Conference on Motion in Games - SA '15, 2015
International Society of …, 2004
No current real time animation model of the sea simultaneously holds account of a heterogeneous w... more No current real time animation model of the sea simultaneously holds account of a heterogeneous water plane up to 10 km2 with the local effects of breakings, winds, currents and shallow waters on wave groups, and this on all the wavelength scales, ...
A multi-agent architecture is proposed in order to build a physics laboratory in virtual reality.... more A multi-agent 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 multi-agent 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 medium. 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.
OCEANS 2008, 2008
ABSTRACT
Les modèles infographiques actuels pour l'animation interactive et temps réel de la mer sont basé... more Les modèles infographiques actuels pour l'animation interactive et temps réel de la mer sont basés sur la simplification de solutions approchées auxéquations de Navier-Stokes, selon diverses hypothèses physiques dans un but de photo-réalisme [AM02]. Ceséquations de Navier-Stokes n'ont en effet pas de solution explicite dans le cas général . La complexité algorithmique de leur résolution numérique directe ne permet pas l'animation d'un plan d'eau de plusieurs kilomètres carrés [Gom00] et le but de ceséquations différentielles n'est pas l'interactivité: il est nécessaire de donner des conditions aux limites avant de commencer les calculs [Tem84]. Pour l'animation d'un tel plan d'eau, on trouve deux approches principales inspirées de travaux océanographiques: l'approche particulaire [FR86, Pea86, GS00, CGG01] s'appuyant sur [Ger04, Bie52] et l'approche spectrale [MWM87, Tes01, PA01, CGG03]à partir de [Has62, PM64]. Récemment, ces deux approches ontété combinées entre elles [TDG00, HNC02] ou avec des résolutions numériques locales directes deséquations de Navier-Stokes [JG01, . Quelle que soit l'approche considérée, une grille de points géométrique représente la surface de l'eau et ce maillage est animé. Cependant, aucun des modèles actuels de l'animation interactive de la mer ne tient compte simultanément pour un plan d'eau hétérogèneà l'échelle de la dizaine de kilomètres carrés des effets locaux des déferlements, du vent, des courants et de la bathymétrie sur des groupes de vagues de toutes les longueurs d'onde, phénomènes pourtant essentiels pour que la simulation maritime ait du sens pour les marins et reste physiquement crédible aux yeux des océanographes .
10th IEEE International Conference on Fuzzy Systems. (Cat. No.01CH37297), 2001
This article lies within the interactive virtual stories telling scope and proposes the use of fu... more This article lies within the interactive virtual stories telling scope and proposes the use of fuzzy cognitive maps as a tool to model emotional behavior of virtual actors improvising in free interaction within the framework of a "nouvelle vague" scenario, as could Godard do. We show how fuzzy cognitive maps can be delocalized on each agent level to model autonomous agents within a virtual world. We describe the implementation carried out, starting from work in cognitive psychology and illustrate it by an improvisation between a shepherd, a dog and virtual sheep.
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Papers by Marc Parenthoen