Browsing by Author "Barrera MacHuca, Mayra Donaji"

Now showing 1 - 5 of 5

Citation - WoS: 40
Citation - Scopus: 53
The Effect of the Vergence-Accommodation Conflict on Virtual Hand Pointing in Immersive Displays
(Assoc Computing Machinery, 2022) Batmaz, Anil Ufuk; Machuca, Mayra Donaji Barrera; Sun, Junwei; Stuerzlinger, Wolfgang; Barrera MacHuca, Mayra Donaji
Previous work hypothesized that for Virtual Reality (VR) and Augmented Reality (AR) displays a mismatch between disparities and optical focus cues, known as the vergence and accommodation conflict (VAC), affects depth perception and thus limits user performance in 3D selection tasks within arm's reach (peri-personal space). To investigate this question, we built a multifocal stereo display, which can eliminate the influence of the VAC for pointing within the investigated distances. In a user study, participants performed a virtual hand 3D selection task with targets arranged laterally or along the line of sight, with and without a change in visual depth, in display conditions with and without the VAC. Our results show that the VAC influences 3D selection performance in common VR and AR stereo displays and that multifocal displays have a positive effect on 3D selection performance with a virtual hand.
Citation - WoS: 1
Citation - Scopus: 1
Evaluating Voxel-Based Graphical Passwords for Virtual Reality
(Ieee Computer Soc, 2024) Rawat, Prashant; Turkmen, Rumeysa; Nwagu, Chukwuemeka; Sunday, Kissinger; Machuca, Mayra Donaji Barrera; Barrera MacHuca, Mayra Donaji
Previous work has proposed using voxel-based graphical passwords (VGPs) for Virtual Reality (VR) as a secure, easy-to-remember way to authenticate users. Moreover, eye-tracking technology adds another level of security, as it avoids observational threats when entering the password. However, previous work has yet to evaluate the user performance, usability, and memorability of different combinations of VGPs. In two user studies, we first identified the best combination of shape and volume for VGPs. Then, we compare 3D versus 2D VGPs. Our results show that a cube is the best shape regarding usability and user preference. We also identified that 2D VGPs are easier to remember than 3D VGPs, as shown by a higher password accuracy and lower error rate. Our results inform the implementation of VGPs and other graphical passwords in VR.
Citation - WoS: 3
Citation - Scopus: 12
Exploring Discrete Drawing Guides To Assist Users in Accurate Mid-Air Sketching in Vr
(Assoc Computing Machinery, 2022) Turkmen, Rumeysa; Pfeuffer, Ken; Machuca, Mayra Donaji Barrera; Batmaz, Anil Ufuk; Gellersen, Hans; Barrera MacHuca, Mayra Donaji
Even though VR design applications that support sketching are popular, sketching accurately in mid-air is challenging for users. In this paper, we explore discrete visual guides that assist users' stroke accuracy and drawing experience inside the virtual environment. We also present an eye-tracking study that compares continuous, discrete, and no guide in a basic drawing task. Our experiment asks participants to draw a circle and a line using three different guide types, three different sizes and two different orientations. Results indicate that discrete guides are more user-friendly than continuous guides, as the majority of participants preferred their use, while we found no difference in speed/accuracy compared to continuous guides. Potentially, this can be attributed to distinct eye-gaze strategies, as discrete guides led users to shift their eyes more frequently between guide points and the drawing cursor. Our insights are useful for practitioners and researchers in 3D sketching, as they are a first step to inform future design applications of how visual guides inside the virtual environment affect visual behaviour and how eye-gaze can become a tool to assist sketching.
Citation - WoS: 8
Citation - Scopus: 9
I Consider Vr Table Tennis To Be My Secret Weapon!: an Analysis of the Vr Table Tennis Players' Experiences Outside the Lab
(Assoc Computing Machinery, 2023) Karatas, Eren; Sunday, Kissinger; Apak, Sude Erva; Li, Yiwei; Sun, Junwei; Batmaz, Anil Ufuk; Barrera MacHuca, Mayra Donaji
Thanks to stand-alone Virtual Reality (VR) advances, users can play realistic simulations of real-life sports at their homes. In these game simulations, players control their avatars by doing the same movements as in real life (RL) while playing against a person or AI opponent, making VR sports attractive for the players. In this paper, we surveyed a popular VR table tennis game community, focusing on understanding their demographics, challenges, and experiences with skill transfers between VR and RL. Our results show that, on average, VR table tennis players are primarily men, live in Europe/Asia, and are 38 years old. We also found that the current state of VR technology affects the player's experience and that players see VR as a convenient way to play matches but that RL is better for socialization. Finally, we identified skills like backhand and forehand strikes that players perceived to be transferred from VR to RL and vice versa. Our research findings have the potential to serve as a valuable resource for VR table tennis game developers seeking to integrate mid-air controllers into their future projects.
Citation - WoS: 19
Citation - Scopus: 20
Re-Investigating the Effect of the Vergence-Accommodation Conflict on 3d Pointing
(Assoc Computing Machinery, 2023) Batmaz, Anil Ufuk; Turkmen, Rumeysa; Sarac, Mine; Machuca, Mayra Donaji Barrera; Stuerzlinger, Wolfgang; Barrera MacHuca, Mayra Donaji
The vergence-accommodation conflict (VAC) limits user performance in current Virtual Reality (VR) systems. In this paper, we investigate the effects of the VAC in a single-focal VR system using three experimental conditions: with no VAC, with a constant VAC, and with a varying VAC. Previous work in this area had yielded conflicting results, so we decided to re-investigate this issue. Eighteen participants performed an ISO 9241:411 task in a study that closely replicates previous work, except that the angle of the task space was rotated 20 degrees downward, to make the task less fatiguing to perform, which addresses a potential confound in previous work. We found that the varying VAC condition had worse performance than the other conditions, which indicates that the contrasting results in previous work were very likely due to biomechanical factors. We hope that our work contributes to the understanding of the influence of the VAC in VR systems and potential strategies for improving user experience and performance in immersive virtual environments.