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Publications

Publications by Hugo Rafael Mendes

2022

Virtual Reality For Training: A Computer Assembly Application

Authors
Rodrigues, P; Coelho, H; Melo, M; Bessa, M;

Publication
2022 INTERNATIONAL CONFERENCE ON GRAPHICS AND INTERACTION (ICGI)

Abstract
Virtual reality applications aimed at worker training to train professionals are more common with the virtual reality advancements observed in this day and age. More companies search for ways to improve the efficiency and efficacy of their training programs, whilst also reducing training costs. There are several training applications found in the literature, but not many focus on the theme of computer assembly, and only a few have options like an observer's menu or a scoring system. With that in mind, a training application for assembling computer towers was designed. This article will focus on the application's functionalities, the results of questionnaires made to evaluate its quality and usability and potential future work. The study realized had good results and a good, varied sample of volunteers, with a score of 93.4% in the custom-made questionnaire, a cyber-sickness (SSQ) score of 26.53%, a usability score (SUS) of 90% and a satisfaction (ASQ) score of 17.67%, being that a higher score is better in custom made and SUS questionnaires, and a lower score is better in the SSQ and ASQ questionnaires. Although this project is just a proof of concept, it focuses on a theme that will certainly be explored soon, with the rise of demand for training applications, the ever-growing gamer market, and workstations for the design of virtual reality applications, like the one described on this paper.

2023

Systematic Review of Comparative Studies of the Impact of Realism in Immersive Virtual Experiences

Authors
Goncalves, G; Coelho, H; Monteiro, P; Melo, M; Bessa, M;

Publication
ACM COMPUTING SURVEYS

Abstract
The adoption of immersive virtual experiences (IVEs) opened new research lines where the impact of realism is being studied, allowing developers to focus resources on realism factors proven to improve the user experience the most. We analyzed papers that compared different levels of realism and evaluated their impact on user experience. Exploratorily, we also synthesized the realism terms used by authors. From 1,300 initial documents, 79 met the eligibility criteria. Overall, most of the studies reported that higher realism has a positive impact on user experience. These data allow a better understanding of realism in IVEs, guiding future R&D.

2023

The role of different light settings on the perception of realism in virtual replicas in immersive Virtual Reality

Authors
Gonçalves, G; Melo, M; Monteiro, P; Coelho, H; Bessa, M;

Publication
COMPUTERS & GRAPHICS-UK

Abstract
Immersive Virtual Reality (IVR) provides a platform where the real world can be replicated to a point where users can act and react in the virtual world as they would in reality. However, rendering visual stimuli is computationally heavy. Thus, optimizations must be done to take advantage of computational systems by studying our perception of reality. This study investigated parameters related to light rendering (Global Illumination, Ambient Occlusion, Screen Space Reflections (SSR) and Direct Shadows) in real-time in a virtual replica of a real place using IVR. Participants experienced both virtual and real rooms with only one flashlight and changed the quality settings of the considered parameters so that their sense of reality would be the closest to the one they felt when they experienced the real room. Participants were given a budget to drive them to prioritize what parameters, and their level of quality, are the most important for their sense of reality. Results indicated that participants considered Global Illumination the most important factor, closely followed by Direct Shadows. Ambient Occlusion and Reflections (Screen Space Reflections) were the less prioritized parameters. We conclude that in a lighting setting where only dynamic lights are used, Global Illumination and Direct Shadows should be prioritized over SSR Reflections and Ambient Occlusion when computational power is limited.

2023

Exploring the user experience of hands-free VR interaction methods during a Fitts' task

Authors
Monteiro, P; Coelho, H; Gonçalves, G; Melo, M; Bessa, M;

Publication
COMPUTERS & GRAPHICS-UK

Abstract
Despite advancements in interaction with immersive Virtual Reality (VR) systems, using hand gestures for all interactions still imposes some challenges, especially in interactions with graphical user interfaces that are usually performed with point-and-click interfaces. Therefore, exploring the use of alternative hands-free methods for selection is essential to overcome usability problems and provide natural interaction for users. The results and insights gained from this exploration can lead to enhanced user experiences in VR applications. This study aims to contribute to the literature with the evaluation of the usability of the most commonly used hands-free methods for selection and system control tasks in immersive VR and their impact on standard and validated experience and usability metrics, namely the sense of presence, cybersickness, system usability, workload, and user satisfaction. A Fitts' selection task was performed using a within-subjects design by nine participants experienced in VR. The methods evaluated were the handheld controllers, the head gaze, eye gaze, and voice commands for pointing at the targets, and dwell time and voice commands to confirm the selections. Results show that the methods provide similar levels of sense of presence and low cybersickness while showing low workload values and high user satisfaction, matching the experience of traditional handheld controllers for non-multimodal approaches. The assisted eye gaze with dwell was the preferred hands-free method and the one with the highest values of usability. Still, developers should minimize the number of gaze movements to reduce fatigue. The evaluation also showed that using a multimodal approach for selections, especially using the voice, decreases user satisfaction and increases users' frustration.(c) 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

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