Spatialized audio cues in Augmented Reality (AR) provide an alternative to visually dominated navigation systems, yet little is known about how device type and cue design jointly shape user experience and performance. This study presents a within-subject experiment comparing artificial versus nature sounds across two AR platforms: a smartphone and a mixed-reality headset. Thirty-four participants completed audio-only outdoor navigation tasks, with 27 included in the final analysis. Subjective measures (UEQ, NASA-TLX, custom items) and objective metrics (completion time, path efficiency) were collected. Results showed that nature sounds were rated significantly higher in efficiency, pleasantness, and overall navigation experience compared to artificial sounds, while device type had limited influence on subjective ratings. Participants with prior AR audio navigation experience completed tasks faster, suggesting training benefits. These findings highlight the importance of cue design and user adaptation for future AR navigation systems.

The usage of virtual avatars in healthcare applications has become widely popular; however, certain critical aspects, such as social distancing and avatar size, remain insufficiently explored. This research investigates user experience and preferences when interacting with a healthcare application utilizing virtual avatars displayed in different sizes. For our study, we had 23 participants interacting with five different avatars (a human-size avatar followed by four, respectively, smaller avatars in a randomized order) varying in size, projected on a wall in front of them. The avatars were fully integrated with an artificial intelligence chatbot to make them conversational. Users were asked to rate the usability of the system after interacting with each avatar and complete a survey regarding trust and an additional questionnaire on social presence. The results of this study show that avatar size significantly influences the perceived attractiveness and perspicuity with the medium-sized avatars having received the highest ratings. Social presence correlated strongly with stimulation and attractiveness, suggesting that an avatar’s visual appeal and interactivity influenced user engagement more than its physical size. Additionally, we observed a tendency for gender-specific differences on some of the UEQ+ scales, with male participants tending to prefer human-sized representations, while female participants slightly favored smaller avatars. These findings highlight the importance of avatar design and representation in optimizing user experience and trust in virtual healthcare environments.

As augmented reality (AR) becomes increasingly prevalent in mobile and context-aware applications, the role of auditory cues in guiding users through physical environments is becoming critical. This study investigates the effectiveness and user experience of various categories of audio cues, including fully non-verbal sounds and speech-derived Spearcons, during outdoor navigation tasks using the Meta Quest 3 headset. Twenty participants navigated five outdoor routes using audio-only cue types: Artificial Sounds, Nature Sounds, Spearcons, Musical Instruments, and Auditory Icons. Subjective evaluations were collected to assess the perceived effectiveness and user experience of each sound type. Results revealed significant differences in perceived novelty and stimulation across sound types. Artificial Sounds and Musical Instruments were rated higher than Spearcons in novelty, while Artificial Sounds were also rated higher than Spearcons in stimulation. Overall preference was evenly split between Nature Sounds and Artificial Sounds. These findings suggest that incorporating aspects of novelty and user engagement in auditory feedback design may enhance the effectiveness of AR navigation systems.

Virtual environments (VEs) are increasingly used for immersive experiences, training simulations, and entertainment, yet factors such as height perception and user stance can significantly influence user experience (UX). Height perception in VEs plays a crucial role in shaping UX, particularly in immersive applications such as climbing simulations. This study investigates the effects of height in various VEs and examines how user stance, sitting or standing, impacts immersion, perceived height, and motion sickness. A user study was conducted with 25 participants who played through five randomized climbing scenarios, ranging from indoor climbing gyms to outdoor cityscapes and mountainous terrains. Participants’ UX was assessed using standardized questionnaires, including the IPQ for general presence, spatial presence, involvement, and experienced realism; as well as the SSQ to evaluate motion sickness symptoms such as nausea, oculomotor strain, and disorientation. Results indicate that seated participants experienced slightly higher immersion but were also more susceptible to motion sickness compared to those standing. While standing participants maintained consistent scores across different environments, seated participants reported increased immersion and discomfort as the VEs became larger, more physically demanding, and visually complex.

Precise temporal and spatial alignment is critical in collaborative Augmented Reality (AR) where users rely on shared visual information to coordinate actions. System latency and object misalignment can disrupt communication, reduce task efficiency, and negatively impact the overall user experience. While previous research has primarily focused on individual AR interactions, the impact of these inconsistencies on collaboration remains underexplored. This article investigates how user experience and task load are affected by object misalignment and time delay in a shared AR space. To examine these factors, we conducted an experiment with 32 participants, organized into 16 pairs, who collaboratively completed a spatial placement task. Within each condition, both participants alternated roles, taking turns as the leader—providing verbal placement instructions—and the builder—executing the placement. Six conditions were tested, manipulating object alignment (perfectly aligned vs. randomly misaligned) and time delay (0s, 0.1s, 0.4s). The misalignment was applied randomly to each virtual object with a shift of ±20 cm on every axis to create a clear distinction in spatial perception. User experience and task load were assessed to evaluate how these factors influence collaboration and interaction in AR environments. Results showed that spatial misalignment significantly increased perceived workload (NASA-TLX) and lowered user ratings in Pragmatic quality and Attractiveness (UEQ), while time delay had a more limited effect. These findings highlight the critical role of spatial accuracy in maintaining collaboration quality in AR.

Controlling Unmanned Aerial Vehicles (UAVs) is a cognitively demanding task, with accidents often arising from insufficient situational awareness, inadequate training, and bad user experiences. Providing more intuitive and immersive visual feedback—particularly through Digital Twin technologies—offers new opportunities to enhance pilot awareness and the overall experience quality. In this study, we investigate how different virtual points of view (POVs) influence user experience and performance during UAV piloting in Virtual Reality (VR), utilizing a digital twin that faithfully replicates the real-world flight environment. We developed a VR application that enables participants to control a physical DJI Mini 4 Pro drone while immersed in a digital twin with four distinct camera perspectives: Baseline View (static external), First Person View, Chase View, and Third Person View. Nineteen participants completed a series of ring-based obstacle courses from each perspective. In addition to objective flight data, we collected standardized subjective assessments of user experience, presence, workload, cybersickness, and situational awareness. Quantitative analyses revealed that the First Person View was associated with significantly higher mental demand and effort, greater trajectory deviation, but smoother control inputs compared to the Third Person and Chase perspectives. Complementing these findings, preference data indicated that the Third Person View was most consistently favored, whereas the First Person View elicited polarized reactions.

Virtual reality (VR) objects react dynamically to users’ touch interactions in real-time. However, experiencing changes in weight through the haptic sense remains challenging with consumer VR controllers due to their limited vibrotactile feedback. While prior works successfully applied pseudo-haptics to perceive absolute weight by manipulating the control-display (C/D) ratio, we continuously adjusted the C/D ratio to mimic weight changes. Vibrotactile feedback additionally emphasises the modulation in the virtual object’s physicality. In a study (N=18), we compared our multimodal technique with pseudo-haptics alone and a baseline condition to assess participants’ experiences of weight changes. Our findings demonstrate that participants perceived varying degrees of weight change when the C/D ratio was adjusted, validating its effectiveness for simulating dynamic weight in VR. However, the additional vibrotactile feedback did not improve weight change perception. This work extends the understanding of designing haptic experiences for lightweight VR systems by leveraging perceptual mechanisms.

This study explored a concept for using Augmented Reality (AR) glasses to customize augmented table setup and lighting in a restaurant. The aim was to provide insights into AR usage in restaurants and contribute to existing research by introducing an extendable and versatile concept for scholars and restaurateurs. A controlled laboratory study, using a within-subjects design, was conducted to investigate the effects of a customizable augmented table setup and lighting on user experience (UX), perceived waiting time, psychological ownership and social acceptability. A simulated restaurant environment was created using 360° image in Virtual Reality (VR). The study implemented default and customizable table setup and lighting. Results from a paired samples t-test showed a statistically significant effect of table setup and lighting on pragmatic quality of UX, hedonic quality of UX, overall UX, Valence, Dominance, psychological ownership and affect. Furthermore, table setup had a significant effect on Arousal and perceived waiting time. Moreover, table setup significantly affected AR Interaction-, Isolation-, and Safety acceptability, while lighting only affected AR Interaction acceptability. Findings suggest that these investigated variables are worth considering for AR applications in a restaurant, especially when offering customizable augmented table setup and lighting.

Nowadays, Mixed Reality (MR) headsets are a game-changer for knowledge work. Unlike stationary monitors, MR headsets allow users to work with large virtual displays anywhere they wear the headset, whether in a professional office, a public setting like a cafe, or a quiet space like a library. This study compares four different layouts (eye level-close, eye level-far, below eye level-close, below eye level-far) of virtual displays regarding feelings of safety, perceived productivity, and social acceptability when working with MR in public. We test which layout is most preferred by users and seek to understand which factors affect users’ layout preferences. The aim is to derive useful insights for designing better MR layouts. A field study in a public library was conducted using a within-subject design. While the participants interact with a layout, they are asked to work on a planning task. The results from a repeated measure ANOVA show a statistically significant effect on productivity but not on safety and social acceptability. Additionally, we report preferences expressed by the users regarding the layouts and using MR in public.

One of the most promising technologies inside the Extended Reality (XR) spectrum is Augmented Reality. This technology is already in people’s pockets regarding Mobile Augmented Reality with their smartphones. The scientific community still needs answers about how humans could and should interact in environments where perceived stimuli are different from fully physical or digital circumstances. Moreover, it is still being determined if people accept these new technologies in different social environments and interaction settings or if some obstacles could exist. This paper explores the impact of the Social Environment and the Focus of social interaction on users while playing a location-based augmented reality game, measuring it with user experience and social acceptance indicators. An empirical study in a within-subject fashion was performed in different social environments and under different settings of social interaction focus with N = 28 participants compiling self-reported questionnaires after playing a Scavenger Hunt in Augmented Reality. The measures from two different Social Environments (Crowded vs. Uncrowded) resulted in statistically relevant mean differences with indicators from the Social Acceptability dimension. Moreover, the analyses show statistically relevant differences between the variances from different degrees of Social Interaction Focus with Overall Social Presence, Perceived Psychological Engagement, Perceived Attentional Engagement, and Perceived Emotional Contagion. The results suggest that a location-based AR game played in different social environments and settings can influence the user experience’s social dimension. Therefore, they should be carefully considered while designing immersive technological experiences in public spaces involving social interactions between players.

The collaboration in co-located shared environments has sparked an increased interest in immersive technologies, including Augmented Reality (AR). Since research in this field has primarily focused on individual user experiences in AR, the collaborative aspects within shared AR spaces remain less explored, and fewer studies can provide guidelines for designing this type of experience. This article investigates how the user experience in a collaborative shared AR space is affected by divergent perceptions of virtual objects and the effects of positional synchrony and avatars. For this purpose, we developed an AR app and used two distinct experimental conditions to study the influencing factors. Forty-eight participants, organized into 24 pairs, participated in the experiment and jointly interacted with shared virtual objects. Results indicate that divergent perceptions of virtual objects did not directly influence communication and collaboration dynamics. Conversely, positional synchrony emerged as a critical factor, significantly enhancing the quality of the collaborative experience. On the contrary, while not negligible, avatars played a relatively less pronounced role in influencing these dynamics. These findings can potentially offer valuable practical insights, guiding the development of future collaborative AR/VR environments.

This study investigates the feasibility of remote virtual reality (VR) studies conducted at home using VR headsets and video conferencing by deploying an experiment on emotion ratings. 20 participants used head-mounted displays to immerse themselves in 360° videos selected to evoke emotional responses. The research compares continuous ratings using a graphical interface to retrospective questionnaires on a digitized Likert Scale for measuring arousal and valence, both based on the self-assessment manikin (SAM). It was hypothesized that the two different rating methods would lead to significantly different values for both valence and arousal. The goal was to investigate whether continuous ratings during the experience would better reflect users’ emotions compared to the post-questionnaire by mitigating biases such as the peak-end rule. The results show significant differences with moderate to strong effect sizes for valence and no significant differences for arousal with low to moderate effect sizes. This indicates the need for further investigation of the methods used to assess emotion ratings in VR studies. Overall, this study is an example of a remotely conducted VR experiment, offering insights into methods for emotion elicitation in VR by varying the timing and interface of the rating.

The current research evaluates user experience and preference when interacting with a patient-reported outcome measure (PROM) healthcare application displayed on a single tablet in comparison to interaction with the same application distributed across two tablets. We conducted a within-subject user study with 43 participants who engaged with and rated the usability of our system and participated in a post-experiment interview to collect subjective data. Our findings showed significantly higher usability and higher pragmatic quality ratings for the single tablet condition. However, some users attribute a higher level of presence to the avatar and prefer it to be placed on a second tablet.

The EyeSight feature, introduced with the new Apple Vision Pro XR headset, promises to revolutionize user interaction by simulating real human eye expressions on a digital display. This feature could enhance XR devices’ social acceptability and social presence when communicating with others outside the XR experience. In this pilot study, we explore the implications of the EyeSight feature by examining social acceptability, social presence, emotional responses, and technology acceptance. Eight participants engaged in conversational tasks in three conditions to contrast experiencing the Apple Vision Pro with EyeSight, the Meta Quest 3 as a reference XR headset, and a face-to-face setting. Our preliminary findings indicate that while the EyeSight feature improves perceptions of social presence and acceptability compared to the reference headsets, it does not match the social connectivity of direct human interactions.

Preservation of private user data is of paramount importance for high Quality of Experience (QoE) and acceptability, particularly with services treating sensitive data, such as IT-based health services. Whereas anonymization techniques were shown to be prone to data re-identification, synthetic data generation has gradually replaced anonymization since it is relatively less time and resource-consuming and more robust to data leakage. Generative Adversarial Networks (GANs) have been used for generating synthetic datasets, especially GAN frameworks adhering to the differential privacy phenomena. This research compares state-of-the-art GAN-based models for synthetic data generation to generate time-series synthetic medical records of dementia patients which can be distributed without privacy concerns. Predictive modeling, autocorrelation, and distribution analysis are used to assess the Quality of Generating (QoG) of the generated data. The privacy preservation of the respective models is assessed by applying membership inference attacks to determine potential data leakage risks. Our experiments indicate the superiority of the privacy-preserving GAN (PPGAN) model over other models regarding privacy preservation while maintaining an acceptable level of QoG. The presented results can support better data protection for medical use cases in the future.

Although there are several aspects that might impact one's feeling of immersion or presence in a virtual environment, noises in the actual world are often overlooked. Distractions (such as noises or lights) may have an effect on a person's mental or emotional state in real life, and these interruptions can be disturbing while trying to focus on work. With a steady stream of distractions, one may eventually lose interest and make mistakes or stop the activity. The goal of this research is to better understand the impact of various ambient sounds on presence, immersion, and decision-making by using virtual reality and audio rendering technology. This study's sound sources were obtained and recorded from several real-life sources before being mixed into the virtual world. These audio recordings have been shown to influence a person's decision-making skills by generating a sudden shift in different emotional states (such as annoyance and anger). In certain circumstances, binaural recording is used to provide the listener with a 3D stereo sound experience. They were triggered at random intervals while the user was in the virtual environment. Based on the findings of the study presented in this paper, some types of noises, such as continuous and impulsive noise, have a negative impact on user experience by reducing immersion in the virtual reality environment. It was also discovered that the more interaction there was, the more mental work was required to complete the activities.

Nowadays, Augmented Reality (AR) is available on almost all smartphones creating some exciting interaction opportunities but also challenges. For example, already after the famous AR app Pokemon GO was released in July 2016, numerous accidents related to the use of the app were reported by users. At the same time, the spread of AR can be noticed in the tourism industry, enabling tourists to explore their surroundings in new ways but also exposing them to safety issues. This preliminary study explores users' sense of safety when manipulating the amount and UI elements visualization parameters of Point of Interest (POI) markers in a developed AR application. The results show that the amount of POI markers that are displayed is significant for participants' sense of safety. The influence of manipulating UI elements in terms of “transparency”, “color”, and “size” cannot be proven. Nevertheless, most tested people stated that manipulating transparency and size somehow influences their sense of safety, so a closer look at them should be taken in future studies.

To study people's natural behavior during different conditions of audiovisual quality, we usually invite people into a lab and let them talk to each other. In such conversation settings, not only the media quality impacts the quality perception, but, e.g., social aspects of a real conversation are reflected by individual conversational and rating behavior. Hence, to study quality perception in conversational settings, we try to create an environment that isolates the media quality from such outside factors and is consistent for each participant in the lab. Therefore, we created a dataset of simulated videotelephony clips to act as stimuli in quality perception research. The dataset consists of four different stories in the German language that are told through ten consecutive parts, each about 10 seconds long. Each of these parts is available in four different quality levels, ranging from perfect to stalling. All clips (FullHD, H.264 / AAC) are actual recordings from end-user video-conference software to ensure ecological validity and realism of quality degradation. To ensure consistency among different clips of the same quality level, each video has been scored using VMAF and POLQA and selected to match predefined selection criteria. To analyze the perceived quality of the clips, we conducted a user study (N=25) and evaluated perceived quality, interest in the stories, and speaker engagement. Results validate the consistency of the quality levels of the video clips. Apart from a detailed description of the methodological approach, we contribute the entire stimuli dataset containing 160 videos and all rating scores for each file.

Over the past five years, the interest in Augmented Reality (AR) technologies has significantly increased. Different industries adopted it, such as gaming, tourism, e-commerce, and entertainment, to name a few. Due to its non-fully immersive property, easy implementation, and compatibility with the most recent smartphones, AR seems to be suitable for daily usage. This poses a significant challenge in creating a good User Experience (UX), as this kind of technology needs to be designed for private scenarios and public ones. In its context, it is essential to understand how users are influenced in their social interactions while using AR. Through the use of humanoid Virtual Characters, this paper is intended to better the understanding of how people perceive personal space in AR. By varying Virtual Character Gender (male, female) and its Placement Modality (predefined, dynamic distance) in the real environment, the effects on UX, Emotions, and Social Presence are investigated. As Personal Space is a dynamic psychological construct, which could depend on individual factors, this paper further investigates some possible co-variant effects of users' preferences towards a female or a male character based on their Sexual Attraction. Results show that Placement Modality significantly affects Personal Space boundaries in terms of position, width, and hedonic quality of the experience. Moreover, an effect of Virtual Character Gender was found on users' Personal Space inner boundary, and Social Presence in its emotional contagion dimension. Finally, an effect of Sexual Attraction on UX, Social Presence in its emotional contagion dimension, and dominance were discovered.

Touch interaction has established a dominating role in the realisation of Human–Machine Interfaces. However, to be able to use touch effectively and efficiently, users have to comply with particular prerequisites. Due to age-related changes, such as the decline of tactile accuracy and speed, especially elderly users often struggle with the touch modality. Interfaces that adapt to specific user characteristics could be a promising solution to overcome this problem. Notwithstanding the advantages of adaptive systems, perceived changes in the user interface can reduce the system's predictability and transparency. The present study compares three approaches concerning the adaptation of touch button sizes: no adaptation and adaptation with visible and invisible feedback. Results show that especially elderly users substantially benefit from an adaptive approach. Furthermore, data shows that the type of adaptation supports different usage goals. While adaption with visual feedback enables a higher interaction speed, invisible adaptation leads to a higher degree of accuracy.

Nowadays, Virtual Reality (VR) technology can be potentially used everywhere through wearable head-mounted displays. Nevertheless, it is still uncommon to see VR devices used in public settings. In these contexts, unaware bystanders in the surroundings might influence the User Experience (UX) and create concerns about the social acceptability of this technology. The user acts in a Social Environment (SE), characterized by surrounding people's number, proximity, and behavior. Simultaneously, VR applications often require a different degree of interactivity concerning body movements and controllers interaction. In this paper, the influence of Social Environments, and degree of interactivity on User Experience and social acceptability is investigated. Four Social Environments were simulated employing 360° Videos, and two VR games developed with two levels of interactivity. Results showed a statistically significant influence of Social Environments on Overall UX as well as Public VR, Interaction, Isolation, Privacy and Safety acceptability, and of the degree of interactivity on Presence, Valence, Arousal, Overall UX, UX Hedonic quality, and Safety acceptability. Findings indicate that Social Environments and degree of interactivity should be taken into account while designing VR applications.

Advancing technology and higher availability of Virtual Reality (VR) devices sparked its application in various research fields. For instance, health-related research showed that simulated nature environments in VR could reduce arousal and increase valence levels. This study investigates how the amount of possible interactivity influences the presence in nature environments and consequences on arousal and valence. After inducing fear (high arousal and low valence) through a VR-horror game, it was tested how participants recovered if they played a VR-nature game with either no, limited, or extensive interaction. The horror game proved to be a valid stimulus for inducing high arousal and low valence with a successful manipulation check. Igroup presence questionnaire (IPQ) scores showed that more interaction with the virtual environment increases spatial presence. A beneficial effect of experiencing nature can also be concluded. Results from the Self-Assessment Manikin questionnaire (SAM) scores for valence indicate a significant increase in the conditions with extensive and limited interaction compared to the control group. The VR Nature experience did significantly decrease arousal and increase valence compared to the post-horror game ratings. The physiological responses support this finding. These results can increase the effectiveness of health-related VR-applications to elevate mood levels by either implementing plenty of interactions and consequently increasing spatial presence or doing the opposite and leaving out any interactions at all.

Combining interconnected wearables provides fascinating opportunities like augmenting exergaming with virtual coaches, feedback on the execution of sports activities, or how to improve on them. Breathing rhythm is a particularly interesting physiological dimension since it is easy and unobtrusive to measure and gained data provide valuable insights regarding the correct execution of movements, especially when analyzed together with additional movement data in real-time. In this work, we focus on indoor rowing since it is a popular sport that's often done alone without extensive instructions. We compare a visual breathing indication with haptic guidance in order for athletes to maintain a correct, efficient, and healthy breathing-movement-synchronicity (BMS) while working out. Also, user experience and acceptance of the different modalities were measured. The results show a positive and statistically significant impact of purely verbal instructions and purely tactile feedback on BMS and no significant impact of visual feedback. Interestingly, the subjective ratings indicate a strong preference for the visual modality and even an aversion for the haptic feedback, although objectively the performance benefited most from using the latter.

Technology can facilitate self-learning for academic and leisure activities such as music learning. In general, learning to play an unknown musical song at sight on the electric piano or any other instrument can be quite a chore. In a traditional self-learning setting, the musician only gets feedback in terms of what errors they can hear themselves by comparing what they have played with the score. Research has shown that reaching a flow state creates a more enjoyable experience during activities. This work explores whether principles from flow theory and game design can be applied to make the beginner's musical experience adapted to their need and create higher flow. We created and evaluated a tool oriented around these considerations in a study with 21 participants. We found that provided feedback and difficulty scaling can help to achieve flow and that the effects get more pronounced the more experience with music participants have. In further research, we want to examine the influence of our approach to learning sheet music.

Virtual Reality (VR) has an increasing impact on the market in many fields, from education and medicine to engineering and entertainment, by creating different applications that replicate or in the case of augmentation enhance real-life scenarios. Intending to present realistic environments, VR applications are including text that we are surrounded by every day. However, text can only add value to the virtual environment if it is designed and created in such a way that users can comfortably read it. With the aim to explore what values for text parameters users find comfortable while reading in virtual reality, a study was conducted allowing participants to manipulate text parameters such as font size, distance, and contrast. Therefore two different standalone virtual reality devices were used, Oculus Go and Quest, together with three different text samples: Short (2 words), medium (21 words), and long (51 words). Participants had the task of setting text parameters to the best and worst possible value. Additionally, participants were asked to rate their experience of reading in virtual reality. Results report mean values for angular size (the combination of distance and font size) and color contrast depending on the different device used as well as the varying text length, for both tasks. Significant differences were found for values of angular size, depending on the length of the displayed text. However, different device types had no significant influence on text parameters but on the experiences reported using the self-assessment manikin (SAM) scale.

This paper describes the development and validation of a continuous pictographic scale for self-reported assessment of affective states in virtual environments. The developed tool, called Morph A Mood (MAM), consists of a 3D character whose facial expression can be adjusted with simple controller gestures according to the perceived affective state to capture valence and arousal scores. It was tested against the questionnaires Pick-A-Mood (PAM) and Self-Assessment Manikin (SAM) in an experiment in which the participants (N = 32) watched several one-minute excerpts from music videos of the DEAP database within a virtual environment and assessed their mood after each clip. The experiment showed a high correlation with regard to valence, but only a moderate one with regard to arousal. No statistically significant differences were found between the SAM ratings of this experiment and MAM, but between the valence values of MAM and the DEAP database and between the arousal values of MAM and PAM. In terms of user experience, MAM and PAM hardly differ. Furthermore, the experiment showed that assessments inside virtual environments are significantly faster than with paper-pencil methods, where media devices such as headphones and display goggles must be put on and taken off.

With the rising interest in Virtual Reality and the fast development and improvement of available devices, new features of interactions are becoming available. One of them that is becoming very popular is hand tracking, as the idea to replace controllers for interactions in virtual worlds. This experiment aims to compare different interaction types in VR using either controllers or hand tracking. Participants had to play two simple VR games with various types of tasks in those games — grabbing objects or typing numbers. While playing, they were using interactions with different visualizations of hands and controllers. The focus of this study was to investigate user experience of varying interactions (controller vs. hand tracking) for those two simple tasks. Results show that different interaction types statistically significantly influence reported emotions with Self-Assessment Manikin (SAM), where for hand tracking participants were feeling higher valence, but lower arousal and dominance. Additionally, task type of grabbing was reported to be more realistic, and participants experienced a higher presence. Surprisingly, participants rated the interaction type with controllers where both where hands and controllers were visualized as statistically most preferred. Finally, hand tracking for both tasks was rated with the System Usability Scale (SUS) scale, and hand tracking for the task typing was rated as statistically significantly more usable. These results can drive further research and, in the long term, contribute to help selecting the most matching interaction modality for a task.

In recent years 360° videos have been becoming more popular. For traditional media presentations, e.g., on a computer screen, a wide range of assessment methods are available. Different constructs, such as perceived quality or the induced emotional state of viewers, can be reliably assessed by subjective scales. Many of the subjective methods have only been validated using stimuli presented on a computer screen. This paper is using 360° videos to induce varying emotional states. Videos were presented 1) via a head-mounted display (HMD) and 2) via a traditional computer screen. Furthermore, participants were asked to rate their emotional state 1) in retrospect on the self-assessment manikin scale and 2) continuously on a 2-dimensional arousal-valence plane. In a repeated measures design, all participants (N = 18) used both presentation systems and both rating systems. Results indicate that there is a statistically significant difference in induced presence due to the presentation system. Furthermore, there was no statistically significant difference in ratings gathered with the two presentation systems. Finally, it was found that for arousal measures, a statistically significant difference could be found for the different rating methods, potentially indicating an underestimation of arousal ratings gathered in retrospect for screen presentation. In the future, rating methods such as a 2-dimensional arousal-valence plane could offer the advantage of enabling a reliable measurement of emotional states while being more embedded in the experience itself, enabling a more precise capturing of the emotional states.

This article investigates the possibility to estimate the perceived Quality of Experience (QoE) automatically and unobtrusively by analyzing the face of the consumer of video streaming services, from which facial expression and gaze direction are extracted. If effective, this would be a valuable tool for the monitoring of personal QoE during video streaming services without asking the user to provide feedback, with great advantages for service management. Additionally, this would eliminate the bias of subjective tests and would avoid bothering the viewers with questions to collect opinions and feedback. The performed analysis relies on two different experiments: i) a crowdsourcing test, where the videos are subject to impairments caused by long initial delays and re-buffering events; ii) a laboratory test, where the videos are affected by blurring effects. The facial Action Units (AU) that represent the contractions of specific facial muscles together with the position of the eyes' pupils are extracted to identify the correlation between perceived quality and facial expressions. An SVM with a quadratic kernel and a k-NN classifier have been tested to predict the QoE from these features. These have also been combined with measured application-level parameters to improve the quality prediction. From the performed experiments, it results that the best performance is obtained with the k-NN classifier by combining all the described features and after training it with both the datasets, with a prediction accuracy as high as 93.9% outperforming the state of the art achievements.

With the rise of Virtual Reality (VR) as trend in technology - also available for end users - came many opportunities for serious and gaming applications. One domain of games for virtual environments are exergames - a combination of exercising and gaming. For many exergames, users need to be instructed on how the exercise has to be performed correctly. In this study, a rowing simulation is extended by visualizations in VR that show constant live biofeedback information about the rowers current breathing patterns. In order to compare the effects of such additional information, several visualizations of biofeedback were designed: animation of lungs, line chart, and numerical breathing synchronization feedback. The main goal of the game for participants was to focus on their breathing rhythm and maintain it. Results show that helpfulness and sympathy were rated statistically significantly higher for the case of combined instructional elements compared to no elements. Moreover, participants rated rowing in VR statistically significantly higher on the sympathy scale compared to rowing without VR. Furthermore, flow was rated statistically significantly higher for the conditions including all instruction types. There was a significant decrease of task performance for conditions with performance visualizations. For future studies we are planning to use longer stimulus duration, greater than 10 minutes, due to this change we expect that a potential increase of task performance will manifest.

One of the fields where Virtual Reality (VR) is finding a potentially growing market is in the combination of exercising and gaming - also called exergaming. When it comes to competition in gaming, is important to investigate how different levels of delay influence overall quality of experience (QoE) in VR multiplayer exergames. The experimental setup consisted of a VR application coupled with a rowing ergometer, allowing races between the user and an artificially created opponent that is following the player with a similar speed and keeping the race tight. To investigate the influence of the delay, on both user's and opponent's side three levels of network delay were introduced (30ms, 100ms, and 500ms) and mixed throughout different conditions. After each session, participants rated perceived flow, sense of presence, and the degree to which they have noticed the delay in their or the opponent's system. Interestingly, results show different perception of delay and QoE depending on user's own delay. Participants perceived the opponent's player as being delayed even if only the player itself had network delay along with significantly lower rating of QoE only when their delay was high.

In past years, as virtual reality (VR) technology is extensively developing, more and more people are using it in different fields. One of the fast developing fields in VR are exergames, a combination of physical exercise and game. With a goal to engage people in physical activity, VR exergames should look and feel good for users. Therefore, user interface (UI) in VR is important and has to be built in a way to enhance user experience. In this paper, ergometer is used together with VR rowing environment as VR exergame for a study aiming to explore possibilities of UI in VR. Accordingly, different metrics commonly used to quantify rowing action (e.g, speed and distance) were visualized. The visualizations that were created had different positioning (closer or further away from the player) and different level of complexity (more or less metrics shown as only numbers or in a gamified design). Participants (N = 27) during experiment for this study rowed four times in different conditions depending were metrics of the game were shown: 1) as a cockpit at the front of the rowing e.g, with gamified visualization of metrics; 2) as a coach boat that follows the player with gamified visualization of metrics on a screen; 3) as a cockpit at the front of the rowing e.g, with digital visualization of metrics; 4) as a coach boat that follows the player with digital visualization of metrics on a screen. Results show that level of UI complexity has a significant influence on readability, while positioning of UI elements significantly influences users' perception of support from system. Furthermore, participants preferred the opposite level of complexity depending on the position where metrics were shown.

As known from everyday contexts of multimedia usage, suddenly occurring quality impairments are capable of causing strong negative emotions in human users. This is particularly the case if the displayed content is highly relevant to current motives and behavioral goals. The present study investigated the effects of visual degradations on quality perception and emotional state of participants who were exposed to a series of short video clips. After each video playback, participants had to decide whether a certain event happened in the video. For data collection, subjective measures of quality and emotion were complemented by behavioral measures derived from capturing participants' spontaneous facial expressions. For data analysis, two general approaches were combined: First, a multivariate analysis of variance approach allowed to examine the effects of visual degradation factors on perceived quality and subjective emotional dimensions. It mainly revealed that perceived quality and emotional valence were both sensitive to degradation intensity, whereas the impact of degradation length was limited when task-relevant video content had already been obscured. Second, using a machine learning approach, an automatic Video Quality of Experience (VQoE) prediction system based on the recorded facial expressions was derived, demonstrating a strong correlation between facial expressions and perceived quality. Hereby, estimates of VQoE might be delivered in an objective, continuous and concealed manner, thus diminishing any further need for subjective self-reports.

Video games and sport are an essential part in the life of millions of people. With recent advances of immersive virtual reality devices such as the HTC Vive, Oculus Rift, or PlayStation VR, the use of virtual environments (VE) for exergames is becoming more and more popular. An exergame combines a physical activity with video game elements by tracking body movements or reactions of user, attempting to engage users in a more enjoyable system. In this paper, we present the results of a subjective experiment carried out with the aim to compare different kinds of virtual environments with each other. A rowing ergometer, connected either to a virtual reality system using a head-mounted display (HMD) or to a CAVE environment, was used as an exergame device. While for rowing experts, fitness and performance improvements are of major interest, we wanted to focus on the motivation and engagement of non-professionals. By means of a series of questionnaires and a follow-up interview, the Quality of Experience of participants using the system was assessed. Measurements include concepts such as flow, presence, video quality and well-being. Results show significant advantages of the HMD as well as of the CAVE compared to a system without a VE for the overall quality, system feedback, and flow. While the CAVE and HMD system mainly differed in their autotelic experience, the HMD was favored by the majority of participants due to a superior feeling of presence.

Virtual Reality (VR) multiplayer games are currently developed more frequently, while in parallel VR is becoming more accessible to the broader public. Also exergames, which refer to computer games combined with a physical activity, are getting widely available, driven by developments in sensor technologies. In this paper, we present results of a multiplayer exergame experiment where two players race against each other four times on two rowing ergometers. Experimental conditions were type of environment (with VR vs. without VR) and the possibility of conversation with the opponent (conversation enabled vs. conversation disabled). To measure subjective experience, participants rated perceived flow, sense of presence and social presence on standardized questionnaires. Results show that the type of environment has a significant influence on the perceived presence, as participants rated the presence higher in VR. The possibility of conversation resulted in a perception of a significantly higher social presence. This illustrates that the usage of virtual environments as well as the possibility of conversations between users are highly valuable to increase the Quality of Experience during exergames. In our future research, we plan to further investigate means to improve the user experience by applying gamification, different representations of opponents, and to assess the impact of network impairments during multiplayer scenarios.

Human influence factors can have a strong impact on how users perceive the quality of a given system. Traditional measures such as questionnaires can be a time consuming and partially invasive means to assess human influence factors like personality. In this paper, we investigate whether an individual's personality traits can be classified based solely upon the characteristics of their touchscreen usage. We record the tablet input of 75 subjects using a cognitive training application. The application requires the user to spell words by tapping on letters and dragging them to their denoted position on the screen. The task is presented in two conditions: in one with normal functionality of the program, the other with the usability of the application impaired. The subject's personality is measured with the NEO-FFI questionnaire and captured in the five dimensions of the five-factor model (Big 5). The personality scores and 68 features (touch-behavior and task-performance), as well as statistical metrics derived from them, are fed to a number of classification algorithms. Our results show that in a binary classification task with normal usability, high levels of `Neuroticism' can be distinguished from low levels with a mean accuracy of 66 percent. The extent to which a personality dimension can be predicted is dependent on the usability of the test system. In a normal setting, `Extraversion' can be predicted with an accuracy of 61 percent. However, with impaired usability, the prediction rises to an average of 67 percent. The experiment shows that records of touchscreen interactions allow for the prediction of personalities significantly better than random. The study of the human influence factor personality and its relation to perceived quality would be facilitated by using touchscreen interaction data as a fast and easily accessible estimate of a user's personality.

Obtaining reliable quality ratings for applications is a time-consuming and expensive process. Touch interaction data, however, can be recorded without additional effort when using mobile applications. It could be used to assess usability without having to conduct dedicated tests. This work investigates the possibility to estimate quality ratings for two mobile games solely from touch interactions without relying on performance or game logic measures. To capture pragmatic as well as hedonic quality aspects of usability as ground truth, the AttrakDiff Mini questionnaire was chosen. Two different simple mobile games were used to capture a variety of touch interactions (taps and swipes). To influence the user ratings, three versions of the games were presented: one in original quality, the two others with manipulated interaction quality. Touch interaction features were extracted from the recorded interaction data and used for training models using linear regression and multivariate adaptive regression splines (MARS). The models were built with three times 10-fold cross-validation on each game data set separately. The results indicate that the ratings for pragmatic quality are estimated significantly better than for hedonic quality and attractiveness. Furthermore, the transferability of the models from one game to the other was examined and the touch features that were most important for estimating quality ratings in this study were identified. Touch interactions seem to carry some information on usability, especially pragmatic quality, and it seems to be possible to estimate a broad direction of the user's usability perception. Just a few touch features carry the most information and can be used for simple but fast and powerful models. This could be applied as an automatic analytic tool for mobile applications as well as in adaptive applications that optimize themselves in terms of usability perceived by individual users.

End-to-end delay is an important factor when studying the quality of modern packet-based telephone conversations. Other than most degradations, delay cannot be assessed by listen-only tests and mainly impacts the structure and interactivity of the conversation. Because of this, the modeling of the perceived quality of conversation under delay is dependent on various instrumental as well as human-related influencing factors. Physiological methods in particular might provide additional insights into how human participants are affected by such quality degradations during natural conversations. In the present experiment, a novel dual-electroencephalo-graphy (dual-EEG) method was employed to investigate the effects of delay on 10 pairs of participants engaging in dyadic conversations. In each test session, neurophysiological activity was registered simultaneously in both interlocutors, who interacted in accordance with short conversation test scenarios (SCIs) through an audio network. Meanwhile, delays of different magnitudes (0, 800, 1600 ms) were inserted into the network, which was expected to interfere with the conversation and cause changes in the participants' internal processing and state. Analysis of subjective and behavioral measures shows a decrease in perceived quality and of conversational interactivity with higher levels of delay. Moreover, an initial intra-brain analysis of the recorded dual-EEG data (N = 18) revealed significant modulations in beta and gamma frequency bands by varying delay level. This suggests that attentional load increased with high delay, probably due to less amounts of single talk and focusing more on the adaptation of the own turn-taking behavior.

The present study utilized electroencephalography (EEG) to explore the neuro-electrical correlates of perceptual dimensions underlying speech quality. Specific focus lay on the P300 event-related brain potential (ERP) component to provide indication for internal processes related to attention and stimulus categorization. A high-quality (HQ) recording of a spoken word was impaired on each of three perceptual dimensions at a time, “discontinuity” (F), “noisiness” (N) and “coloration” (C), with F being realized through random erasure of distinct frames in the speech signal parts of the audio file. In an active three-stimulus oddball task, repeated presentations of the HQ stimulus led to the formation of a sensory/perceptual HQ reference, which was interrupted by infrequent occurrences of degraded “oddball” stimuli (F, N, C). Initial analysis of the obtained subjective and electrophysiological data suggested the following conclusions: 1) Participants perceived the three degraded stimuli as clearly impaired, but equal in terms of degradation intensity. Thus, variations in neural responses were assumed to reflect changes in the perceptual dimension along which the speech degradation had been induced. 2) Timing of the evoked P300 corresponded with temporal differences in the impairments, implying a later onset for “discretely” (F) compared to “continuously” (N, C) degraded stimuli after being categorized as task-irrelevant. Hence, P300 peak latency might prove useful to dissociate both classes of speech quality impairments on a neural level of analysis.

The experience of web services depends on multiple factors such as the usability of the service itself as well as influences on Quality of Experience (QoE) like waiting times. Existing studies so far have investigated both experimental factors (usability and QoE) in isolation, thus it is not possible to investigate dependencies between the two. In this study, we manipulated the usability and QoE of a news web page in the same experiment. Participants had to solve 9 tasks (three usability level and three QoE level, all combinations). Data (N=44) from two different sessions with different QoE manipulations were recorded: Simulation of initial page display delay via 1) a complete overlay and 2) a semi-transparent overlay. Our preliminary results show that the usability manipulation resulted in significant effects along multiple dimensions (QoE, aesthetic, and usability). Furthermore, also the implementation of the QoE manipulation had an effect on, e.g., performance parameters. Surprisingly, our results reveal that participants seem to be unable to rate the constructs usability and QoE independently from each other. Even after adding pronounced explanations of the constructs to the introductory phase of the second session of the experiment, the results still show a strong correlation between the two constructs. We thus recommend for similar future experiments to check beforehand whether Quality of Experience and Usability can be reliably judged and distinguished by naive participants.

Enabling high Quality of Experience (QoE) with video-conferencing solutions based on Web Real-Time Communication (WebRTC) protocols anywhere, anytime, is challenging and triggers the exploration of new ways to gain QoE insights. In this paper, we share initial observations from a within-subjects experiment (N = 22) in which 2-party WebRTC-based audiovisual conversations took place under varying technical conditions. We collected self-report data, peripheral physiological data and application-level performance statistics with the overall aim of exploring their usefulness and compatibility for assessing QoE in the context of WebRTC. Our preliminary findings indicate that the varying quality is well-reflected in the self-reported overall quality and annoyance. However, this might not apply when considering the emotional valence ratings and ECG data, implying that other factors may play a role here.

Subjective speech quality assessment depends on listener “quality” opinions after hearing a particular test speech stimulus. Subjective scores are given based on a perception and quality judgment process that is unique to a particular listener. These processes are postulated to be dependent on the listener's internal reference of what good and bad quality sounds like, as well as their mental and emotional states. To overcome this variability, subjective listening tests often average scores over several listeners. In this paper, we use electroencephalography (EEG) and self-assessment tools to investigate the neural and affective correlates of speech quality perception of reverberant speech, with the goal of obtaining new insights into human speech quality perception in complex listening environments. We show that EEG event related potentials (ERP) are a useful tool to monitor the conscious stages of neural-processing during a speech quality assessment task. Significant correlations were obtained between the so-called P300 ERP component and the reverberation time of the room, as well as between the P300 peak amplitude and emotional self-assessment ratings. These insights could lead to more effective ways of characterizing room acoustics for improved speech quality and intelligibility.

Video quality has turned out to be a crucial aspect of multimodal transmission services. Most common video quality tests rely on a conscious judgment of test participants reflecting their internal quality perception. But it is not completely clear how this conscious rating is formed, neither in the auditory nor in the visual domain. Initial audio tests with Electroencephalography (EEG) have shown that EEG recordings can be used as a sensitive and non-intrusive method for quality assessment. In this paper we conducted first experiments of pure video quality tests with EEG to complement this approach in the visual domain. One of the goals for this experiment was to show that there is a different pattern in the EEG data for cases with no distortion compared to cases when there was a distortion and the subject recognized this in the subjective test.