2022 IEEE Conference on Virtual Reality and 3D User Interfaces (VR)
By definition, nonverbal communication refers to any interpersonal exchange that does not use spo... more By definition, nonverbal communication refers to any interpersonal exchange that does not use spoken language. It relies on different
2022 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)
In this study, we expand upon recent evidence that the motion of virtual characters affects the p... more In this study, we expand upon recent evidence that the motion of virtual characters affects the proximity of users who are immersed with them in virtual reality (VR). Attractive motions decrease proximity, but no effect of character gender on proximity was found. We designed a similar experiment where users observed walking motions in VR which were displayed on male and female virtual characters. Our results show similar patterns found in previous studies, while some differences related to the model of the character emerged.
Understanding whether observers are sensitive to physical distor-tions in dynamic events is impor... more Understanding whether observers are sensitive to physical distor-tions in dynamic events is important in order to develop plausible simulations while saving time on details that observers cannot per-ceive [Barzel et al. 1996]. In this experiment, we evaluated ob-
IEEE Transactions on Visualization and Computer Graphics, 2020
Fig. 1. Our objective is to understand whether and to what extent providing haptic rendering of c... more Fig. 1. Our objective is to understand whether and to what extent providing haptic rendering of collisions during navigation through a virtual crowd (right) makes users behave more realistically. Whenever a collision occurs (center), armbands worn on the arms locally vibrate to render this contact (left). We carried out an experiment with 23 participants, testing both subjective and objective metrics regarding the users' path planning, body motion, kinetic energy, presence, and embodiment.
Proceedings of the 2018 Federated Conference on Computer Science and Information Systems, 2018
The selection of relevant features in large databases is one of the most important and challengin... more The selection of relevant features in large databases is one of the most important and challenging problems in data mining. Samples forming a given database are generally described by a predefined set of features, and the situation where not all such features can be used for classification purposes needs very often to be faced in real applications. This situation is very typical when the database is related to a phenomenon whose characteristics are not well known. In this context, the extraction of relevant features can therefore also provide additional information on the studied phenomena. We tackle the feature selection problem from an optimization point of view, by reducing it to the problem of finding a maximal consistent "clustering" grouping together the samples and the features of the database. In this work, we extend this approach to dynamical databases, where features are not represented by only one real value, but they are rather given as sequences of a predefined number of real values. Our main contribution consists in proposing an alternative representation of the database so that it fits with a tridimensional matrix with no missing entries, from which a consistent triclustering can be obtained.
When walking, vision is the main source of information that allows us to navigate safely by detec... more When walking, vision is the main source of information that allows us to navigate safely by detecting potential collisions with other walkers. In order to gain a better understanding of the relationship between gaze activity and kinematics of motion during pedestrian interactions, we present in this paper a preliminary study towards designing a more comprehensive experimental platform. In this study, participants are asked to avoid collisions with an upcoming virtual character using a joystick, while we measure their gaze behaviours using an eye-tracker. As we are interested in the effects of potential collisions on gaze activity, i.e., where and when participants look to avoid potential future collisions, we display in our experiment a virtual character for which we vary the initial Time To Closest Approach (ttca) and Distance of Closest Approach (dca) values, to change its risk of collision with our participant. We then measure participant trajectory adjustments and gaze activity ...
2020 IEEE Conference on Virtual Reality and 3D User Interfaces (VR), 2020
Figure 1: Our objective is to analyze eye-gaze activity within a crowd to better understand walke... more Figure 1: Our objective is to analyze eye-gaze activity within a crowd to better understand walkers' interaction neighborhood and simulate crowd behaviour. We designed 2 experiments where participants physically walked both in a real and virtual street populated with other walkers, while we measured their eye-gaze activity (red circle). We evaluated the effect of virtual reality on eye-gaze activity by comparing real and virtual conditions (left and middle-right) and investigated the effect of crowd density (right).
Does virtual threat harm the Virtual Reality (VR) experience? In this paper, we explored the pote... more Does virtual threat harm the Virtual Reality (VR) experience? In this paper, we explored the potential impact of threat occurrence and repeatability on users' Sense of Embodiment (SoE) and threat response. The main findings of our experiment are that the introduction of a threat does not alter users' SoE but might change their behaviour while performing a task after the threat occurrence. In addition, threat repetitions did not show any effect on users' subjective SoE, or subjective and objective responses to threat. Taken together, our results suggest that embodiment studies should expect potential change in participants behaviour while doing a task after a threat was introduced, but that threat introduction and repetition do not seem to impact the subjective measure of the SoE (user responses to questionnaires) nor the objective measure of the SoE (behavioural response to threat towards the virtual body).
En realite virtuelle, un certain nombre d'etudes ont ete menees pour evaluer l'influence ... more En realite virtuelle, un certain nombre d'etudes ont ete menees pour evaluer l'influence de l'apparence de l'avatar, du controle de l'avatar et du point de vue de l'utilisateur sur le sentiment d'incarnation d'un avatar virtuel. Cependant, ces etudes ont tendance a explorer chaque facteur de maniere isolee. Cet article vise a mieux comprendre les interrelations entre ces trois facteurs en menant une experience d'appariement subjectif. Dans l'experience presentee (n=40), les participants devaient retrouver un sentiment d'incarnation eleve resenti dans une configuration d'avatar optimale (avatar realiste, capture de mouvements du corps entier, point de vue a la premiere personne), en commencant par une configuration minimale (avatar minimal, aucun controle, point de vue de la troisieme personne), et en augmentant iterativement le niveau de chaque facteur. Les choix des participants donnent un apercu de leurs preferences et de leur percep...
En 2016 une nouvelle realisation de Ben-Hur, roman de Lewis Wallace, est proposee 57 ans apres l’... more En 2016 une nouvelle realisation de Ben-Hur, roman de Lewis Wallace, est proposee 57 ans apres l’adaptation cinematographique la plus connue du peplum emblematique par William Wyler. Nous laissons a la critique les avis sur cette readaptation, nous nous interessons ici a une difference technique majeure qui oppose ces deux versions : le tournage de la mythique scene de la course de chars.
Proceedings of the 2021 CHI Conference on Human Factors in Computing Systems, 2021
Avatars, the users' virtual representations, are becoming ubiquitous in virtual reality applicati... more Avatars, the users' virtual representations, are becoming ubiquitous in virtual reality applications. In this context, the avatar becomes the medium which enables users to manipulate objects in the virtual environment. It also becomes the users' main spatial reference, which can not only alter their interaction with the virtual environment, but also the perception of themselves. In this paper, we review and analyse the current state-of-the-art for 3D object manipulation and the sense of embodiment. Our analysis is twofold. First, we discuss the impact that the avatar can have on object manipulation. Second, we discuss how the diferent components of a manipulation technique (i.e. input, control and feedback) can infuence the user's sense of embodiment. Throughout the analysis, we crystallise our discussion with practical guidelines for VR application designers and we propose several research topics towards "avatar-friendly" manipulation techniques. CCS CONCEPTS • Human-centered computing → Interaction design theory, concepts and paradigms.
We explored the potential impact of threat occurrence and repeatability on users' Sense of Embodi... more We explored the potential impact of threat occurrence and repeatability on users' Sense of Embodiment (SoE) and threat response. To that aim, we conducted an experiment in which participants were embodied in a virtual avatar, and performed a task in which a threat towards the virtual body was introduced a first time, then repeated several times through the experiment (in total 5 times). The SoE of participants as well as their subjective response to the threat were assessed through subjective questionnaires before the introduction of the threat, after a first introduction of the threat and at the end of the experiment. A control group did the same experiment with no threat introduced during the task. The main findings of our experiment are that the introduction of a threat does not alter users' SoE but might change their behaviour while performing a task after the threat occurrence. In addition, threat repetitions did not show any effect on users' subjective SoE, or subjective and objective responses to threat. Taken together, our results suggest that embodiment studies should expect potential change in participants behaviour while doing a task after a threat was introduced, but that threat introduction and repetition do not seem to impact the subjective measure of the SoE (subective ratings) nor the objective measure of the SoE (physical reaction to threat).
2022 IEEE Conference on Virtual Reality and 3D User Interfaces (VR)
By definition, nonverbal communication refers to any interpersonal exchange that does not use spo... more By definition, nonverbal communication refers to any interpersonal exchange that does not use spoken language. It relies on different
2022 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)
In this study, we expand upon recent evidence that the motion of virtual characters affects the p... more In this study, we expand upon recent evidence that the motion of virtual characters affects the proximity of users who are immersed with them in virtual reality (VR). Attractive motions decrease proximity, but no effect of character gender on proximity was found. We designed a similar experiment where users observed walking motions in VR which were displayed on male and female virtual characters. Our results show similar patterns found in previous studies, while some differences related to the model of the character emerged.
Understanding whether observers are sensitive to physical distor-tions in dynamic events is impor... more Understanding whether observers are sensitive to physical distor-tions in dynamic events is important in order to develop plausible simulations while saving time on details that observers cannot per-ceive [Barzel et al. 1996]. In this experiment, we evaluated ob-
IEEE Transactions on Visualization and Computer Graphics, 2020
Fig. 1. Our objective is to understand whether and to what extent providing haptic rendering of c... more Fig. 1. Our objective is to understand whether and to what extent providing haptic rendering of collisions during navigation through a virtual crowd (right) makes users behave more realistically. Whenever a collision occurs (center), armbands worn on the arms locally vibrate to render this contact (left). We carried out an experiment with 23 participants, testing both subjective and objective metrics regarding the users' path planning, body motion, kinetic energy, presence, and embodiment.
Proceedings of the 2018 Federated Conference on Computer Science and Information Systems, 2018
The selection of relevant features in large databases is one of the most important and challengin... more The selection of relevant features in large databases is one of the most important and challenging problems in data mining. Samples forming a given database are generally described by a predefined set of features, and the situation where not all such features can be used for classification purposes needs very often to be faced in real applications. This situation is very typical when the database is related to a phenomenon whose characteristics are not well known. In this context, the extraction of relevant features can therefore also provide additional information on the studied phenomena. We tackle the feature selection problem from an optimization point of view, by reducing it to the problem of finding a maximal consistent "clustering" grouping together the samples and the features of the database. In this work, we extend this approach to dynamical databases, where features are not represented by only one real value, but they are rather given as sequences of a predefined number of real values. Our main contribution consists in proposing an alternative representation of the database so that it fits with a tridimensional matrix with no missing entries, from which a consistent triclustering can be obtained.
When walking, vision is the main source of information that allows us to navigate safely by detec... more When walking, vision is the main source of information that allows us to navigate safely by detecting potential collisions with other walkers. In order to gain a better understanding of the relationship between gaze activity and kinematics of motion during pedestrian interactions, we present in this paper a preliminary study towards designing a more comprehensive experimental platform. In this study, participants are asked to avoid collisions with an upcoming virtual character using a joystick, while we measure their gaze behaviours using an eye-tracker. As we are interested in the effects of potential collisions on gaze activity, i.e., where and when participants look to avoid potential future collisions, we display in our experiment a virtual character for which we vary the initial Time To Closest Approach (ttca) and Distance of Closest Approach (dca) values, to change its risk of collision with our participant. We then measure participant trajectory adjustments and gaze activity ...
2020 IEEE Conference on Virtual Reality and 3D User Interfaces (VR), 2020
Figure 1: Our objective is to analyze eye-gaze activity within a crowd to better understand walke... more Figure 1: Our objective is to analyze eye-gaze activity within a crowd to better understand walkers' interaction neighborhood and simulate crowd behaviour. We designed 2 experiments where participants physically walked both in a real and virtual street populated with other walkers, while we measured their eye-gaze activity (red circle). We evaluated the effect of virtual reality on eye-gaze activity by comparing real and virtual conditions (left and middle-right) and investigated the effect of crowd density (right).
Does virtual threat harm the Virtual Reality (VR) experience? In this paper, we explored the pote... more Does virtual threat harm the Virtual Reality (VR) experience? In this paper, we explored the potential impact of threat occurrence and repeatability on users' Sense of Embodiment (SoE) and threat response. The main findings of our experiment are that the introduction of a threat does not alter users' SoE but might change their behaviour while performing a task after the threat occurrence. In addition, threat repetitions did not show any effect on users' subjective SoE, or subjective and objective responses to threat. Taken together, our results suggest that embodiment studies should expect potential change in participants behaviour while doing a task after a threat was introduced, but that threat introduction and repetition do not seem to impact the subjective measure of the SoE (user responses to questionnaires) nor the objective measure of the SoE (behavioural response to threat towards the virtual body).
En realite virtuelle, un certain nombre d'etudes ont ete menees pour evaluer l'influence ... more En realite virtuelle, un certain nombre d'etudes ont ete menees pour evaluer l'influence de l'apparence de l'avatar, du controle de l'avatar et du point de vue de l'utilisateur sur le sentiment d'incarnation d'un avatar virtuel. Cependant, ces etudes ont tendance a explorer chaque facteur de maniere isolee. Cet article vise a mieux comprendre les interrelations entre ces trois facteurs en menant une experience d'appariement subjectif. Dans l'experience presentee (n=40), les participants devaient retrouver un sentiment d'incarnation eleve resenti dans une configuration d'avatar optimale (avatar realiste, capture de mouvements du corps entier, point de vue a la premiere personne), en commencant par une configuration minimale (avatar minimal, aucun controle, point de vue de la troisieme personne), et en augmentant iterativement le niveau de chaque facteur. Les choix des participants donnent un apercu de leurs preferences et de leur percep...
En 2016 une nouvelle realisation de Ben-Hur, roman de Lewis Wallace, est proposee 57 ans apres l’... more En 2016 une nouvelle realisation de Ben-Hur, roman de Lewis Wallace, est proposee 57 ans apres l’adaptation cinematographique la plus connue du peplum emblematique par William Wyler. Nous laissons a la critique les avis sur cette readaptation, nous nous interessons ici a une difference technique majeure qui oppose ces deux versions : le tournage de la mythique scene de la course de chars.
Proceedings of the 2021 CHI Conference on Human Factors in Computing Systems, 2021
Avatars, the users' virtual representations, are becoming ubiquitous in virtual reality applicati... more Avatars, the users' virtual representations, are becoming ubiquitous in virtual reality applications. In this context, the avatar becomes the medium which enables users to manipulate objects in the virtual environment. It also becomes the users' main spatial reference, which can not only alter their interaction with the virtual environment, but also the perception of themselves. In this paper, we review and analyse the current state-of-the-art for 3D object manipulation and the sense of embodiment. Our analysis is twofold. First, we discuss the impact that the avatar can have on object manipulation. Second, we discuss how the diferent components of a manipulation technique (i.e. input, control and feedback) can infuence the user's sense of embodiment. Throughout the analysis, we crystallise our discussion with practical guidelines for VR application designers and we propose several research topics towards "avatar-friendly" manipulation techniques. CCS CONCEPTS • Human-centered computing → Interaction design theory, concepts and paradigms.
We explored the potential impact of threat occurrence and repeatability on users' Sense of Embodi... more We explored the potential impact of threat occurrence and repeatability on users' Sense of Embodiment (SoE) and threat response. To that aim, we conducted an experiment in which participants were embodied in a virtual avatar, and performed a task in which a threat towards the virtual body was introduced a first time, then repeated several times through the experiment (in total 5 times). The SoE of participants as well as their subjective response to the threat were assessed through subjective questionnaires before the introduction of the threat, after a first introduction of the threat and at the end of the experiment. A control group did the same experiment with no threat introduced during the task. The main findings of our experiment are that the introduction of a threat does not alter users' SoE but might change their behaviour while performing a task after the threat occurrence. In addition, threat repetitions did not show any effect on users' subjective SoE, or subjective and objective responses to threat. Taken together, our results suggest that embodiment studies should expect potential change in participants behaviour while doing a task after a threat was introduced, but that threat introduction and repetition do not seem to impact the subjective measure of the SoE (subective ratings) nor the objective measure of the SoE (physical reaction to threat).
Uploads
Papers by Ludovic Hoyet