Brian Ravenet

• Professor (Associate) at University of Paris-Saclay

Research on non-verbal behavior generation for social interactive agents focuses mainly on the believability and synchronization of non-verbal cues with speech. However, existing models, predominantly based on deep learning architectures, often perpetuate biases inherent in the training data. This raises ethical concerns, depending on the intended...

Despite both WHO's recommendation to increase the levels of physical activity, and the existence of numerous intervention programs, there is still a lack of sustainable tools to help people adopt and maintain a healthy level of physical activity. Currently, motivational technologies aimed at positively influencing user behavior seem to be relevant....

Transactive memory system (TMS) is a team emergent state representing the knowledge of each member about “who knows what” in a team performing a joint task. We present a study to show how the three TMS dimensions Credibility, Specialisation, Coordination, can be modelled as a linear combination of the nonverbal multimodal features displayed by the...

Sedentary lifestyles and lack of physical activity place a financial burden on health services. Although the World Health Organization (WHO) recommends people to increase levels of physical activity, more than 80% of adolescents and 27% of adults do not meet such WHO recommendations (Global status report on physical activity, 2022). Running is an a...

This paper is a condensed overview of Touché: the fourth edition of the lab on argument and causal retrieval that was held at CLEF 2023. With the goal to create a collaborative platform for research on computational argumentation and causality, we organized four shared tasks: (a) argument retrieval for controversial topics, where participants retri...

This paper introduces a new model to generate rhythmically relevant non-verbal facial behaviors for virtual agents while they speak. The model demonstrates perceived performance comparable to behaviors directly extracted from the data and replayed on a virtual agent, in terms of synchronization with speech and believability. Interestingly, we found...

The goal of Touché is to foster and support the development of technologies for argument and causal retrieval and analysis. For the fourth time, we organize the Touché lab featuring four shared tasks: (a) argument retrieval for controversial topics, where participants retrieve web documents that contain high-quality argumentation and detect the arg...

Clinician-patient communication is essential to successful care and treatment. However, health training programs do not provide sufficient clinical exposure to practice communication skills that are pivotal when interacting with patients exhibiting mental health or age-related disorders. Recently, virtual reality has been used to develop simulation...

This research covers the design of a digital simulation tool, from identification of training needs to analysis of the simulation produced by testers from a demonstration scenario. It is based on the development of a simulation tool for training caregivers in geriatrics in France, as part of a multidisciplinary research and development project know...

In social interactions between humans and Embodied Conversational Agents (ECAs) conversational interruptions may occur. ECAs should be prepared to detect, manage and react to such interruptions in order to keep the interaction smooth, natural and believable. In this paper, we examined nonverbal reactions exhibited by an interruptee during conversat...

In this paper we highlight the different challenges in modeling communicative gestures for Embodied Conversational Agents (ECAs). We describe models whose aim is to capture and understand the specific characteristics of communicative gestures in order to envision how an automatic communicative gesture production mechanism could be built. The work i...

Humans lie every day, from the least harmful lies to the most impactful ones. Therefore, in an attempt to design virtual agents endowed with advanced decision-making abilities , researchers not only focused their effort in designing cooperative and truthful agents but also deceptive and lying ones. In this paper we propose a model capable of engagi...

Within this chapter, we are presenting how game developers could take inspiration from the research in Embodied Conversational Agent to develop non-player characters capable of expressing believable emotional and social reactions. Inspired by the social theories about human emotional and social reactions, the researchers working with Embodied Conve...

Virtual Reality and immersive experiences, which allow players to share the same virtual environment as the characters of a virtual world, have gained more and more interest recently. In order to conceive these immersive virtual worlds, one of the challenges is to give to the characters that populate them the ability to express behaviors that can s...

In the everyday world people form small conversing groups where social interaction takes place, and much of the social behavior takes place through managing interpersonal space (i.e., proxemics) and group formation, signaling their attentio to others (i.e., through gaze behavior), and expressing certain attitudes, for example, friendliness, by smil...

Les Agents Conversationnels Animés sont des personnages virtuels dont la fonction principale est d'interagir avec l'utilisateur. Ils sont utilisés dans différents domaines tels que l'assistance personnelle, l'entrainement social ou les jeux vidéo et afin d'améliorer leur potentiel, il est possible de leur donner la capacité d'exprimer des comportem...

In this paper we propose a computational model for the real time generation of nonverbal behaviors supporting the expression of interpersonal attitudes for turn-taking strategies and group formation in multi-party conversations among embodied conversational agents. Starting from the desired attitudes that an agent aims to express towards every othe...

In this paper, we describe the enactment of autonomous agents and avatars in the web-based social collaborative virtual environment of REVERIE that supports natural, human-like behavior, physical interaction and engagement. Represented by avatars, users feel immersed in this virtual world in which they can meet and share experiences as in real life...

Virtual worlds are more and more populated with autonomous conversational agents embodying different roles like tutor, guide, or personal assistant. In order to create more engaging and natural interactions, these agents should be endowed with social capabilities such as expressing different social attitudes through their behaviors. In this paper,...

Embodied Conversational Agents have been widely used to simulate dyadic interactions with users. We want to explore the context of expression of interpersonal attitudes in simulated group conversations. We are presenting a model that allows agents to exhibit a variety of nonverbal behaviors (e.g gestures, facial expressions, proxemics) depending on...

This paper presents a computational model of social attitude for virtual agents. In our work, the agent acts as a virtual recruiter and interacts with a user during job interview training. Training sessions have a predefined level of difficulty, which is used along with the perceived user's anxiety at each speaking turn to compute the objectives of...

International audience In this article, we propose an architecture of a socio-affective Embodied Conversational Agent (ECA). The different computational models of the architecture enable an ECA to express emotions and social attitudes during an interaction with a user. Based on corpora of actors expressing emotions, models have been defined to comp...

Dans cet article, nous proposons une architecture d'un Agent Conversationnel Animé (ACA) socio-affectif. Les différents modèles computationnels sous-jacents à cette architecture, permettant de donner la capacité à un ACA d'exprimer des émotions et des attitudes sociales durant son interaction avec l'utilisateur, sont présentés.

Human’s non-verbal behavior may convey different meanings. They can reflect one’s emotional states, communicative intentions but also his social relations with someone else, i.e. his interpersonal attitude. In order to determine the non-verbal behavior that a virtual agent should display to convey particular interpersonal attitudes, we have collect...

Just as readers feel immersed when the story line adheres to their experiences, users will more easily feel immersed in a virtual environment if the behavior of the characters in that environment adheres to their expectations, based on their lifelong observations in the real world. This paper introduces a framework that allows authors to establish...

One of the key challenges in the development of social virtual actors is to give them the capability to display socio-emotional states through their non-verbal behavior. Based on studies in human and social sciences or on annotated corpora of human expressions, different models to synthesize virtual agent's non-verbal behavior have been developed....