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Proceedings of the 21st ACM International Conference on Intelligent Virtual Agents / ACM Special Interest Group on Artificial Intelligence ACM International Conference on Intelligent Virtual Agents, IVA'21, online, 14 Sep 2021 - 17 Sep 2021; New York : Association for Computing Machinery 33-40 (2021). doi:10.1145/3472306.3478339, Published by Association for Computing Machinery, New York

We introduce a novel methodology to study peer effects. Using virtual reality technology, we create a naturalistic work setting in an immersive virtual environment where we embed a computer-generated virtual human as the co-worker of a human subject, both performing a sorting task at a conveyor belt. In our setup, subjects observe the virtual peer, while the virtual human is not observing them. In two treatments, human subjects observe either a low productive or a highly productive virtual peer. We find that human subjects rate their presence feeling of “being there” in the immersive virtual environment as natural. Subjects also recognize that virtual peers in our two treatments showed different productivities. We do not find a general treatment effect on productivity. However, we find that competitive subjects display higher performance when they are in the presence of a highly productive peer - compared to when they observe a low productive peer. We use tracking data to learn about the subjects’ body movements. Analyzing hand and head data, we show that competitive subjects are more careful in the sorting task than non-competitive subjects. We also discuss some VR related methodological issues.

Proceedings of the 20th ACM International Conference on Intelligent Virtual Agents - ACM New York, NY, USA, 2020. - ISBN 9781450375863 - doi:10.1145/3383652.3423862 IVA '20: ACM International Conference on Intelligent Virtual Agents, Virtual Event Scotland UK; ACM New York, NY, USA (2020). doi:10.1145/3383652.3423862, Published by ACM New York, NY, USA

Generating natural embodied conversational agents within virtual spaces crucially depends on speech sounds and their directionality. In this work, we simulated directional filters to not only add directionality, but also directionally adapt each phoneme. We therefore mimic reality where changing mouth shapes have an influence on the directional propagation of sound. We conducted a study (n = 32) evaluating naturalism ratings, preference and distinguishability of omnidirectional speech auralization compared to static and dynamic, phoneme-dependent directivities. The results indicated that participants cannot distinguish dynamic from static directivity. Furthermore, participants' preference ratings aligned with their naturalism ratings. There was no unanimity, however, with regards to which auralization is the most natural.

Proceedings of the 20th ACM International Conference on Intelligent Virtual Agents - ACM New York, NY, USA, 2020. - ISBN 9781450375863 - doi:10.1145/3383652.3423883 IVA '20: ACM International Conference on Intelligent Virtual Agents, Virtual Event Scotland UK; ACM New York, NY, USA (2020). doi:10.1145/3383652.3423883, Published by ACM New York, NY, USA

Simulating a realistic navigation of virtual pedestrians through virtual environments is a recurring subject of investigations. The various mathematical approaches used to compute the pedestrians’ paths result, i.a., in different computation-times and varying path characteristics. Customizable parameters, e.g., maximal walking speed or minimal interpersonal distance, add another level of complexity. Thus, choosing the best-fitting approach for a given environment and use-case is non-trivial, especially for novice users.To facilitate the informed choice of a specific algorithm with a certain parameter set, crowd simulation frameworks such as Menge [3] provide an extendable collection of approaches with a unified interface for usage. However, they often miss an elaborated visualization with high informative value accompanied by visual analysis methods to explore the complete simulation data in more detail – which is yet required for an informed choice. Benchmarking suites such as SteerBench [14] are a helpful approach as they objectively analyze crowd simulations, however they are too tailored to specific behavior details. To this end, we propose a preliminary design of an advanced graphical user interface providing a 2D and 3D visualization of the crowd simulation data as well as features for time navigation and an overall data exploration.

Proceedings of the 20th ACM International Conference on Intelligent Virtual Agents - ACM New York, NY, USA, 2020. - ISBN 9781450375863 - doi:10.1145/3383652.3423888 IVA '20: ACM International Conference on Intelligent Virtual Agents, Virtual Event Scotland UK; ACM New York, NY, USA (2020). doi:10.1145/3383652.3423888, Published by ACM New York, NY, USA

In this paper, we report on the multi-year Intelligent Virtual Agents (IVA) community effort, involving more than 80 researchers worldwide, researching the IVA community interests and practises in evaluating human interaction with an artificial social agent (ASA). The effort is driven by previous IVA workshops and plenary IVA discussions related to the methodological crisis on the evaluation of ASAs. A previous literature review showed a continuous practise of creating new questionnaires instead of reusing validated questionnaires. We address this issue by examining questionnaire measurement constructs used in empirical studies between 2013 to 2018 published in the IVA conference. We identified 189 constructs used in 89 questionnaires that are reported across 81 studies. Although these constructs have different names, they often measure the same thing. In this paper, we, therefore, present a unifying set of 19 constructs that captures more than 80% of the 189 constructs initially identified. We established this set in two steps. First, 49 researchers classified the constructs in broad theoretically based categories. Next, 23 researchers grouped the constructs in each category on their similarity. The resulting 19 groups form a unifying set of constructs, which will be the basis for the future questionnaire instrument of human-ASA interaction.

Embodied conversational agents become more and more important in various virtual reality applications, e.g., as peers, trainers or therapists. Besides their appearance and behavior, appropriate speech is required for them to be perceived as human-like and realistic. Additionally to the used voice signal, also its auralization in the immersive virtual environment has to be believable. Therefore, we investigated the effect of adding directivity to the speech sound source. Directivity simulates the orientation dependent auralization with regard to the agent's head orientation. We performed a one-factorial user study with two levels (n=35) to investigate the effect directivity has on the perceived social presence and realism of the agent's voice. Our results do not indicate any significant effects regarding directivity on both variables covered. We account this partly to an overall too low realism of the virtual agent, a not overly social utilized scenario and generally high variance of the examined measures. These results are critically discussed and potential further research questions and study designs are identified.

When designing the behavior of embodied, computer-controlled, human-like virtual agents (VA) serving as temporarily required assistants in virtual reality applications, two linked factors have to be considered: the time the VA is visible in the scene, defined as presence time (PT), and the time till the VA is actually available for support on a user's calling, defined as approaching time (AT). Complementing a previous research on behaviors with a low VA's PT, we present the results of a controlled within-subjects study investigating behaviors by which the VA is always visible, i.e., behaviors with a high PT. The two behaviors affecting the AT tested are: following, a design in which the VA is omnipresent and constantly follows the users, and busy, a design in which the VA is self-reliantly spending time nearby the users and approaches them only if explicitly asked for. The results indicate that subjects prefer thefollowing VA, a behavior which also leads to slightly lower execution times compared to busy.

Technological innovations have a growing relevance for charitable donations, as new technologies shape the way we perceive and approach digital media. In a between-subjects study with sixty-one volunteers, we investigated whether a higher degree of immersion for the potential donor can yield more donations for non-governmental organizations. Therefore, we compared the donations given after experiencing a video-based, an augmented-reality-based, or a virtual-reality-based scenery with a virtual agent, representing a war victimized Syrian boy talking about his losses. Our initial results indicate that the immersion has no impact. However, the donor's perceived innovativeness of the used technology might be an influencing factor.

VISIGRAPP 2019 : proceedings of the 14th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications : Prague, Czech Republic, February 25-27, 2019 / sponsored by: INSTICC - the Institute for Systems and Technologies of Information, Control and Communication. - Volume 1: GRAPP / edited by Ana Paula Cláudio, Kadi Bouatouch and Jose Braz 14th International Conference on Computer Graphics Theory and Applications, GRAPP, Prague, Czech Republic, 25 Feb 2019 - 27 Feb 2019 14. International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications, VISIGRAPP 2019, Prague, Czech Republic, 25 Feb 2019 - 27 Feb 2019; [Sétubal] : SCITEPRESS - Science and Technology Publications, Lda. 255-261 (2019). doi:10.5220/0007373202550261, Published by SCITEPRESS - Science and Technology Publications, Lda., [Sétubal]

Controlling user-agent-interactions by means of an external operator includes selecting the virtual interaction partners fast and faultlessly. However, especially in immersive scenes with a large number of potential partners, this task is non-trivial. Thus, we present a score-based recommendation system supporting an operator in the selection task. Agents are recommended as potential partners based on two parameters: the user's distance to the agents and the user's gazing direction. An additional graphical user interface (GUI) provides elements for configuring the system and for applying actions to those agents which the operator has confirmed as interaction partners.

It is increasingly common to embed embodied, human-like, virtual agents into immersive virtual environments for either of the two use cases: (1) populating architectural scenes as anonymous members of a crowd and (2) meeting or supporting users as individual, intelligent and conversational agents. However, the new trend towards intelligent cyber physical systems inherently combines both use cases. Thus, we argue for the necessity of multiagent systems consisting of anonymous and autonomous agents, who temporarily turn into intelligent individuals. Besides purely enlivening the scene, each agent can thus be engaged into a situation-dependent interaction by the user, e.g., into a conversation or a joint task. To this end, we devise components for an agent's behavioral design modeling the transition between an anonymous and an individual agent when a user approaches.

Traditionally, experimental economics uses controlled and incentivized field and lab experiments to analyze economic behavior. However, investigating peer effects in the classic settings is challenging due to the reflection problem: Who is influencing whom? To overcome this, we enlarge the methodological toolbox of these experiments by means of Virtual Reality. After introducing and validating a real-effort sorting task, we embed a virtual agent as peer of a human subject, who independently performs an identical sorting task. We conducted two experiments investigating (a) the subject's productivity adjustment due to peer effects and (b) the incentive effects on competition. Our results indicate a great potential for Virtual-Reality-based economic experiments.