PELACHAUD C.

In this paper we present a model of facial behaviour encompassing interpersonal relations for an Embodied Conversational Agent (ECA). Although previous solutions of this problem exist in ECA's domain, in our approach a variety of facial expressions (i.e. expressed, masked, inhibited, and fake expressions) is used for the first time. Moreover,...

Laughter is a strong social signal in human-human and human-machine communication. However, very few attempts to model it exist. In this paper we discuss several challenges regarding the generation of laughs. We focus, more particularly, on two aspects a) modeling laughter with different intensities and b) modeling respiration behavior during...

In this paper we propose an algorithm based on fuzzy similarity which models the concept of resemblance between facial expressions of an Embodied Conversational Agent (ECA). The algorithm measures the degree of visual resemblance between any two facial expressions. We also present an evaluation study in which we compared the users' perception...

In this paper we present our embodied conversational agent (ECA) capable of displaying a vast set of facial expressions to communicate its emotional states as well as its social relations. Our agent is able to superpose and mask its emotional states as well as fake or inhibit them. We defined complex facial expressions as expressions arising...

In this paper we present a system which allows a virtual character to display multimodal sequential expressions i.e. expressions that are composed of different signals partially ordered in time and belonging to different nonverbal communicative channels. It is composed of a language for the description of such expressions from real data and of...

The term "believability" is often used to describe expectations concerning virtual agents. In this paper, we analyze which factors influence the believability of the agent acting as the software assistant. We consider several factors such as embodiment, communicative behavior, and emotional capabilities. We conduct a perceptive study where we...

Believability is a key issue for virtual agents. Most of the authors agree that emotional behavior and personality have a high impact on agents' believability. The social capacities of the agents also have an effect on users' judgment of believability. In this paper we analyze the role of plausible and/or socially appropriate emotional displays...

A smile may communicate different meanings depending on subtle characteristics of the facial expression. In this article, we have studied the morphological and dynamic characteristics of amused, polite, and embarrassed smiles displayed by a virtual agent. A web application has been developed to collect virtual agent's smile descriptions corpus...

A model of multimodal sequential expressions of emotion for an Embodied Conversational Agent was developed. The model is based on video annotations and on descriptions found in the literature. A language has been derived to describe expressions of emotions as a sequence of facial and body movement signals. An evaluation study of our model is...

This paper focuses on the user's perception of virtual agents embedded in real and virtual worlds. In particular, we analyze the perception of spatial relations and the perception of coexistence. For this purpose, we measure the user's voice compensation which is one of the human automatic behaviors to their surrounding environment. The results...

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Recent research has shown that empathic virtual agents enable to improve human-machine interaction. Virtual agent's expressions of empathy are generally fixed intuitively and are not evaluated. In this paper, we propose a novel approach for the expressions of empathy using complex facial expressions like superposition and masking. An evaluation...

One of the challenges of designing virtual humans is the definition of appropriate models of the relation between realistic emotions and the coordination of behaviors in several modalities. In this paper, we present the annotation, representation and modeling of multimodal visual behaviors occurring during complex emotions. We illustrate our...

Emotional expressions play a very important role in the interaction between virtual agents and human users. In this paper, we present a new constraint-based approach to the generation of multimodal emotional displays. The displays generated with our method are not limited to the face, but are composed of different signals partially ordered in...

We propose a computational model of emotions that takes into account two aspects of emotions: the emotions triggered by an event and the expressed emotions (the displayed ones), which may differ in real life. More particularly, we present a formalization of emotion eliciting-events based on a model of the agent's mental state composed of...

We propose a computational model of emotions that takes into account two aspects of emotions: the emotions triggered by an event and the expressed emotions (the displayed ones), which may differ in real life. More particularly, we present a formalization of emotion eliciting-events based on a model of the agent's mental state composed of...

A smile may communicate different communicative intentions depending on subtle characteristics of the facial expression. In this article, we propose an algorithm to determine the morphological and dynamic characteristics of virtual agent's smiles of amusement, politeness, and embarrassment. The algorithm has been defined based on a virtual...

We propose an architecture of an embodied conversational agent that takes into account two aspects of emotions: the emotions triggered by an event (the felt emotions) and the expressed emotions (the displayed ones), which may differ in real life, In this paper, we present a formalization of emotion eliciting-events based on a model of the...

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In order to be believable, embodied conversational agents (ECAs) must show expression of emotions in a consistent and natural looking way across modalities. The ECA has to be able to display coordinated signs of emotion during realistic emotional behaviour. Such a capability requires one to study and represent emotions and coordination of...

Deception is a relevant issue for the theories of cognition and social interaction. When we deceive, we influence others through manipulating their beliefs. This paper presents a definition of deception and of its functions in terms of a model of cognition and social action. We define as deceptive any act or omission aimed at making others...

Deception is a relevant issue for the theories of cognition and social interaction. When we deceive, we influence others through manipulating their beliefs. This paper presents a definition of deception and of its functions in terms of a model of cognition and social action. We define as deceptive any act or omission aimed at making others...

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