Alexis Nédélec

Effects of Coupling in Human-Virtual Agent Body Interaction

This paper presents a study of the dynamic coupling between a user and a virtual character during body interaction. Coupling is directly linked with other dimensions, such as co-presence, engagement, and believability, and was measured in an experiment that allowed users to describe their subjective feelings about those dimensions of interest. The experiment was based on a theatrical game involving the imitation of slow upper-body movements and the proposal of new movements by the user and virtual agent. The agent’s behaviour varied in autonomy: the agent could limit itself to imitating the user’s movements only, initiate new movements, or combine both behaviours. After the game, each participant completed a questionnaire regarding their engagement in the interaction, their subjective feeling about the co-presence of the agent, etc. Based on four main dimensions of interest, we tested several hypotheses against our experimental results, which are discussed here.

The INGREDIBLE Database: A First Step Toward Dynamic Coupling in Human-Virtual Agent Body Interaction

This paper presents the ANR Ingredible Project and the collection of a database of dyadic bodily expressive interactions.While there continues to be exciting developments in research related to virtual characters, improvements are still needed to create plausibly human-like behaviors. In this paper, we present a synthetic parameterized memory model which includes sensory, working, and long-term memories and mechanisms for acquiring and retrieving memories. With the aid of this model, autonomous virtual humans are able to perform more reasonable interactions with objects and agents in their environment. The memory model also facilitates emergent behaviors, enhances behavioral animation, and assists in creating heterogeneous populations. To demonstrate the effectiveness of the memory model, we also provide an example in a 3D game environment and have conducted a user study in which we found general guidance in determining parameter values for the memory model, resulting in NPCs with more human-like game playing performances.

Gesture Recognition in Flow in the Context of Virtual Theater

Our aim is to put on a short play featuring a real actor and a virtual actor, who will communicate through movements and choreography with mutual synchronization. Although the theatrical context is a good ground for multimodal communication between human and virtual actors, this paper will mainly deal with the ability to perceive the gestures of a real actor. During the performance, our goal is to match real-time observation with recorded examples. The recognition event will be sent to a virtual actor which reply with its own movements. We follow an approach similar to that proposed by [1] or [2]. They made the assumption that the first phase is to summarize the variation of the movement into a symbolic description. Then, the recognition phase is performed when a new trajectory is consistent with this description. The main section will describe our method of creating a signature from gestural data and the recognition system in real-time flow. To conclude, we shall present some results.

Using a multiagent language for collaborative interactive prototyping (poster session)

This paper introduces a Distributed Virtual Realit yplatform based on oRis, our dynamic and interpreted multi-agent language. This platform, called ARéViDis, has been designed for collaborative interactiv e protot yping. During an ARéViDis session, the dynamic properties of oRis allow the addition, modification or destruction of virtual agen ts in a distributed virtual environment. These modifications may either be introduced by the agents themselves or b y the users through various Computer Human Interfaces (CHI). These modifications may also be received accross the netw ork allowing communications in shared virtual worlds.

A model of an embodied emotional agent

We propose a model of embodied agent using SOAR rules engine to define believable behaviour of agents equipped with emotions, motivations, and episodical memory. The aim of our work is to create tools for simulation of virtual human with a believable behaviour which can be used in virtual environment for group meetings training or games.This work comes from a research project on relational groups of collaborative and emotional agents called GRACE. It is focused on the simulation of the behaviour of an autonomous character evolving in a virtual environment in which users can interact by controlling avatar. One of the goals of this project is to have a believable groups behaviour by modelling individual behaviour of characters. To improve believability, the modeling of an agent must take into account an emotional module which will introduce a skew into the decision, but also will allow to communicate in a nonverbal way between agents.The design of the model is done in an incremental way. The basic model will make it possible to select an action among a list of possible actions, and to apply it. Then to obtain a believable behavior one must eliminate the not-relevant actions according to the goals of the agent. Next by associating capacities of anticipation, we will allow it to envisage the consequences of its actions and thus to eliminate those which will have harmful results compared to these goals. The addition of an emotional state will allow to improve the evaluation of the anticipated situations. Taking into account the episodical memory will make it possible to remind the emotional impact of actions carried out in a similar situation. The attentional process will make possible for our model of agent to filter in a more significant way the actions suggested. And finally taking into account the motivations of the agent will make it possible to add and modify goals dynamically during simulation.

Gestural Coupling Between Humans and Virtual Characters in an Artistic Context of Imitation

We present a human-agent interaction based on a theatrical mirroring game. The user and the agent imitate each other’s body movements and introduce, from time to time, changes by proposing a new movement. The agent responses are linked to the game scenario but also to the user’s behavior, which makes each game session unique.

Recognition of gesture sequences in real-time flow, context of virtual theater

Our aim is to put on a short play featuring a real actor and a virtual actor, who will communicate through movements and choreography, with mutual synchronization. Gesture recognition in our context of Virtual Theater is mainly based on the ability of a virtual actor to perceive gestures made by a real actor. We present a method for real-time recognition. We use properties from Principal Component Analysis (PCA) to create signature for each gesture and a multiagent system to perform the recognition.