Browsing by Author "Turkmen, Rumeysa"

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Citation Count: 0
Effect of Grip Style on Peripersonal Target Pointing in VR Head Mounted Displays
(Ieee Computer Soc, 2023) Batmaz, Anıl Ufuk; Turkmen, Rumeysa; Sarac, Mine; Machuca, Mayra Donaji Barrera; Stuerzlinger, Wolfgang
When working in Virtual Reality (VR), the user's performance is affected by how the user holds the input device (e.g., controller), typically using either a precision or a power grip. Previous work examined these grip styles for 3D pointing at targets at different depths in peripersonal space and found that participants had a lower error rate with the precision grip but identified no difference in movement speed, throughput, or interaction with target depth. Yet, this previous experiment was potentially affected by tracking differences between devices. This paper reports an experiment that partially replicates and extends the previous study by evaluating the effect of grip style on the 3D selection of nearby targets with the same device. Furthermore, our experiment re-investigates the effect of the vergence-accommodation conflict (VAC) present in current stereo displays on 3D pointing in peripersonal space. Our results show that grip style significantly affects user performance. We hope that our results are useful for researchers and designers when creating virtual environments.
Citation Count: 0
Evaluating Voxel-Based Graphical Passwords for Virtual Reality
(Ieee Computer Soc, 2024) Rawat, Prashant; Turkmen, Rumeysa; Nwagu, Chukwuemeka; Sunday, Kissinger; Machuca, Mayra Donaji Barrera
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 Count: 2
Exploring Discrete Drawing Guides to Assist Users in Accurate Mid-air Sketching in VR
(Assoc Computing Machinery, 2022) Batmaz, Anıl Ufuk; Pfeuffer, Ken; Machuca, Mayra Donaji Barrera; Batmaz, Anil Ufuk; Gellersen, Hans
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 Count: 0
EyeGuide & EyeConGuide: Gaze-based Visual Guides to Improve 3D Sketching Systems
(Assoc Computing Machinery, 2024) Batmaz, Anıl Ufuk; Gelmez, Zeynep Ecem; Batmaz, Anil Ufuk; Stuerzlinger, Wolfgang; Asente, Paul; Sarac, Mine
Visual guides help to align strokes and raise accuracy in Virtual Reality (VR) sketching tools. Automatic guides that appear at relevant sketching areas are convenient to have for a seamless sketching with a guide. We explore guides that exploit eye-tracking to render them adaptive to the user's visual attention. EYEGUIDE and EYECONGUIDE cause visual grid fragments to appear spatially close to the user's intended sketches, based on the information of the user's eye-gaze direction and the 3D position of the hand. Here we evaluated the techniques in two user studies across simple and complex sketching objectives in VR. The results show that gaze-based guides have a positive effect on sketching accuracy, perceived usability and preference over manual activation in the tested tasks. Our research contributes to integrating gaze-contingent techniques for assistive guides and presents important insights into multimodal design applications in VR.
Citation Count: 0
Put your glasses on: A voxel-based 3D authentication system in VR using eye -gaze
(IEEE Computer Soc, 2023) Turkmen, Rumeysa; Nwagu, Chukwuemeka; Rawat, Prashant; Riddle, Poppy; Sunday, Kissinger; Machuca, Mayra Barrera
Due to the current push of social Virtual Reality (VR) apps and mobile VR headsets, users are surrounded by people in real life and virtually. Users need a private method to authenticate payments or login into apps. In this paper, we propose VoxAuth, a novel voxel-based 3D authentication system, allowing users to input their password in a private way. By using eye-gaze as a secure, input method, people outside VR are prevented from observing the password. Sunglasses on the avatar appear during the authentication process both as a gaze observation prevention and as a signal that the user is still connected.
Citation Count: 2
Re-investigating the Effect of the Vergence-Accommodation Conflict on 3D Pointing
(Assoc Computing Machinery, 2023) Batmaz, Anıl Ufuk; Turkmen, Rumeysa; Sarac, Mine; Machuca, Mayra Donaji Barrera; Stuerzlinger, Wolfgang
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.