1,721,239 research outputs found
Multimodal Communication and Context in Embodied Agents. Proceedings of the Workshop W7 at the 5th International Conference on Autonomous Agents
No full textSubtleties of facial expressions in embodied agents
No full textOur goal is to develop a believable embodied agent able to dialogue with a user. In particular, we aim at making an agent that can also combine facial expressions in a complex and subtle way, just like a human agent does. We first review a taxonomy of communicative functions that our agent is able to express non-verbally; but we point out that, due to the complexity of communication, in some cases different information can be provided at once by different parts and actions of an agent's face. In this paper we are interested in assessing and treating what happens, at the meaning and signal levels of behaviour, when different communicative functions have to be displayed at the same time and necessarily have to make use of the same expressive resources. In some of these cases the complexity of the agent's communication can give rise to conflicts between the parts or movements of the face. In this paper, we propose a way to manage the possible conflicts between different modalities of communication through the tool of belief networks, and we show how this tool allows us to combine facial expressions of different communicative functions and to display complex and subtle expressions. Copyright (C) 2002 John Wiley Sons, Ltd
Towards multimodal expression of laughter
No full textLaughter 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 laughter. Both of these models combine a data-driven approach with high-level animation control. Careful analysis and implementation of the synchronization mechanisms linking visual and respiratory cues has been undertaken. It allows us to reproduce the highly correlated multimodal signals of laughter on a 3D virtual agent. © 2012 Springer-Verlag Berlin Heidelberg
Fuzzy similarity of facial expressions of embodied agents
No full textIn 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 of similarity of facial expressions. Finally we describe an application of this algorithm to generate complex facial expressions of an ECA. © Springer-Verlag Berlin Heidelberg 2007
Model of facial expressions management for an embodied conversational agent
No full textIn 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, our rules of facial behaviour management are consistent with the predictions of politeness theory as well as the experimental data (i.e. annotation of the video-corpus). Knowing the affective state of the agent and the type of relations between interlocutors the system automatically adapts the facial behaviour of an agent to the social context. We present also the evaluation study we have conducted of our model. In this experiment we analysed the perception of interpersonal relations from the facial behaviour of our agent. © Springer-Verlag Berlin Heidelberg 2007
Performative faces
No full textThe paper presents a model for the construction of an artificial agent that can express performatives through facial expression. The performative of a speech act or communicative act is the particular communicative intention a Sender has to one's Addressee, the way one wants to socially relate oneself to the interlocutor. Performatives are decomposed both on the meaning and on the signal side: on the meaning side, a performative is represented as a cluster of cognitive units, that in turn include subclusters mentioning the Sender's general goal (informing, asking, requesting), the power relationship between Sender and Addressee, the Sender's affective state, and further information peculiar of specific performatives; on the signal side, facial expressions are decomposed into Action Units. The proposed system computes the appropriate performative of one's communicative acts through consideration of the context of communication, particularly of the Addressee's cognitive capacity, social relationship and personality traits, and then expresses the computed performatives through 3D facial displays. (C) 1998 Published by Elsevier Science B.V. All rights reserved
Affect expression in ECAs: Application to politeness displays
No full textIn 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 from these displays. In the following, we describe a model based on fuzzy methods that enables to generate complex facial expressions of emotions. It uses fuzzy similarity to compute the degree of resemblance between facial expressions of the ECA. We also present an algorithm that adapts the facial behaviour of the agent depending on its social relationship with the interactants. This last algorithm is based on the theory of politeness by Brown and Levinson (1987). It outputs complex facial expressions that are socially adequate. © 2010 Elsevier Ltd. All rights reserved
Persuasion and the expressivity of gestures in humans and machines
No full textL'articolo analizza l'espressività del gesto, individuandovi gli elementi di ampiezza, velocità, fluidità, ripetizione, e ne ipotizza il significato e la funzione nel discorso persuasivo. Prendendo in esame frammenti tratti dai discorsi elettorale di Romano Prodi e Achille Occhetto, mostra come i vari aspetti della gestualità possano svolgere una funzione persuasiva contribuendo alle strategie, già individuate da Aristotele, di lògos, ethos e pathos.The paper analyzes the expressivity of gesture, namely ist parameters of amplitude, velocity, fluidity and repetition, and wonder what its meaning and function may be in persuasive discourse. Taking into account fragments from electoral discourses by two Italian politicians, Romano Prodi and Achille Occhetto, it shows how the various aspects of gesture may fulfil a persuasive function contributing to the persuasive strategies singled out by Aristotle, logos, ethos and pathos
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