Семиозис визуальных стимулов в интерактивных пользовательских интерфейсах медицинских приложений

In this paper, we provide an approach for authenticating users in virtual reality (VR) environments by tracking the behavior of users as they perform goal-oriented tasks, such as throwing a ball at a target. With the pervasion of VR in mission-critical applications such as manufacturing, navigation, military training, education, and therapy, validating the identity of users using VR systems is becoming paramount to prevent tampering of the VR environments, and to ensure user safety. Unlike prior work, which uses PIN and pattern based passwords to authenticate users in VR environments, our approach authenticates users based on their natural interactions within the virtual space by matching the 3D trajectory of the dominant hand gesture controller in a display-based head-mounted VR system to a library of trajectories. To handle natural differences in wait times between multiple parts of an action such as picking a ball and throwing it, our matching approach uses a symmetric sum-squared distance between the nearest neighbors across the query and library trajectories. Our work enables seamless authentication without requiring the user to stop their activity and enter specific credentials, and can be used to continually validate the identity of the user. We conduct a pilot study with 14 subjects throwing a ball at a target in VR using the gesture controller and achieve a maximum accuracy of 92.86% by comparing to a library of 10 trajectories per subject, and 90.00% by comparing to 6 trajectories per subject.

The ergonomic design of control elements in real life has been researched in detail. Various studies exist on the optimal dimensioning, their haptic and acoustic feedback to achieve high control accuracy and user experience. But the development of products is increasingly done with virtual prototypes. Virtual reality (VR) allows these prototypes to be tested in a highly immersive environment. However, the findings from reality cannot be transferred to VR directly. For example, users in VR interact with the prototypes using controllers, which affects haptic feedback. This study investigates how rotary dials and joysticks must be designed and programmed in VR so that control tasks can be performed efficiently and generate a high user experience and perceived presence.In user tests, subjects (n = 25) evaluate the control of a joystick and a rotary dial in VR. In a virtual crane operator's cabin or at a virtual table, the subjects (f = 10, m = 15, age: 24 +- 3) perform four predefined tasks per control element. On two screens in VR, subjects see a vertical bar graph with a scale from 0 to 100 % controlled by the joystick and separately a numerical value between 0 and 100 % which is controlled by the rotary dial. The screens display the task to the subjects, e.g., "Set the value from 0 % to 42 %". According to the method “design of experiments”, 14 factors, such as vibration feedback, acoustic feedback, position of the subject or the sensitivity of the control element are systematically varied on two respectively three levels (e.g., diameter of actuator 40 mm, 80 mm or 110 mm). For each trial, the control accuracy and the time required to complete the task are determined. In addition, the perceived presence is assessed using the Slater-Usoh-Steed-Questionnaire and the user experience is surveyed using the User Experience Questionnaire. The effect of a change of level on the response parameters is investigated using multifactorial ANOVA (α = .05). Linear regression is used to calculate a mathematical relationship between factor and response parameter. These mathematical models are used to calculate which factor values can be used to achieve a high level of control accuracy with a low time requirement and a high level of user experience and perceived presence. The factors angular resolution, inclination, shape of the rotary dial and position of the subject have a highly significant effect (p ≤ .001) on the time required to complete the tasks with the rotary dial. On the control accuracy of the rotary dial, the angular resolution, the VR-controller and the interaction of angular resolution and diameter of the rotary dial have a significant effect. On the user experience, a total of six factors and two interactions have a significant effect. On the perceived presence of the subjects, the VR environment and the diameter of the rotary dial have a significant effect. The calculated optimized design is a rotary dial with vibration feedback, without acoustic feedback, with visualization of a rough knurling, an angular resolution of 10-12 degree/value, a 40 mm diameter and no inclination. Visualization of the hand should be avoided.Sensitivity, size, subject position, VR environment, and the interaction of subject position and VR environment have a significant effect on the time required to perform the control tasks with the joystick. Three factors and one interaction have a significant effect on the control accuracy of the joystick. The interaction of the factors vibration feedback and visualization of the hand has a significant effect on the perceived presence of the subjects. On user experience, nine factors and five interactions have a significant effect. The calculated optimized levels of factors for the joystick are vibration and acoustic feedback, no visual feedback, vertical handle with a height of 20-24 cm, a five-level angular resolution, a maximum deflection angle of +- 15°, a sensitivity of 8 %/sec and a visualization of the hand.The trials show a high degree of scatter. The residuals show outliers in the experiments. These deviations are mainly due to the individual previous experience of the test subjects in handling VR systems. Nevertheless, significant effects could be identified. A screening experimental design was used in this study. In a follow-up study, detailed investigations with a full factorial experimental design must be performed with the significant factors. The factors will be tested at multiple levels and with a significantly increased number of trials to further increase the accuracy of the mathematical models.

Fitts’ Law posits that the time necessary for a user to move a pointer (such as a mouse or finger) to a target area is the function of the distance traveled and the size of the target. This translates to a simple rule that the smaller the target and larger the distance to the target, the longer it takes to reach and select. This principle is a fundamental consideration in the usability of any interface. Relatively little research has been done regarding the use of Fitts’ Law in Virtual Reality (VR) environments. This paper attempts to demonstrate that Fitts’ Law continues to hold when applied to VR interactions - specifically when a user is wearing a Head Mounted Display (HMD) and controlling a pointer with a VR controller. This oversight poses a significant problem as VR technology becomes increasingly prevalent in gaming, training, and many other applications. Understanding the applicability of Fitts' Law in VR is crucial for developing intuitive and efficient user interfaces in these immersive environments. This paper aims to bridge this gap by investigating whether Fitts' Law holds true in VR interactions. By measuring the time taken for participants to select a range of targets, a Fitts’ Law linear model was created to test if the law still applied. The experiment demonstrated that Fitts’ Law is still applicable in VR for pointing and selection with handheld controls, thereby filling an important gap in the understanding of user interactions in VR environments.

The personalization of user experiences through recommendation systems has been extensively explored in Internet applications, but this has yet to be fully addressed in Virtual Reality (VR) environments. The complexity of managing geometric 3D data, computational load, and natural interactions poses significant challenges in real-time adaptation in these immersive experiences. However, tailoring VR environments to individual user needs and interests holds promise for enhancing user experiences. In this paper, we present Virtual Reality Environment Adaptation through Recommendations (VR-EAR), a framework designed to address this challenge. VR-EAR employs customizable object metadata and a hybrid recommendation system modeling implicit user feedback in VR environments. We utilize VR optimization techniques to ensure efficient performance. To evaluate our framework, we designed a virtual store where product locations dynamically adjust based on user interactions. Our results demonstrate the effectiveness of VR-EAR in adapting and personalizing VR environments in real time. domains.

People often rely on workspace awareness to collaborate with one another, especially in learning and problem-solving tasks. Workspace awareness is defined as an understanding of a current state of the work environment and collaborators’ activities. However, workspace awareness is difficult to maintain in virtual environments (VE), since some information from the real world is missing. Fortunately, VEs are flexible and can be designed to compensate for a lack of real world cues. This thesis aims to improve collaborative workspace awareness through enhancing the design of VEs. Our proposed approaches improve workspace awareness in three ways. The first approach examines space configurations that could improve awareness in a collaboration. The second explores different strategies for updating the visual environment so that users are aware of their collaborators’ actions. The third focuses on finding visual cues that raise the user’s awareness when collaborating with multiple users. Prior research studies suggested that users operate in workspace to manage their attention and divide their tasks when working in the real world. The space within the users’ reach is often assigned as a private space and the space out of users’ reach is assigned as a group space. Following this approach, we propose to set up a virtual space in a desktop virtual reality environment by assigning the space in front of the desktop screen as a private space and the space behind the screen as a group space. According to our user study, this setup improves collaborations between users. To gain further insight into information sharing strategies in VEs, a user study was conducted to compare different strategies for updating the VEs in complex remote problem-solving tasks. From the study, real-time updating is found to be not suitable for workspace awareness, especially when users are performing different tasks. On the other hand, an updating strategy that updates only information that is relevant to the users’ actions performs the best. Moreover, users change collaboration strategies depending on the update timing. Design guidelines are proposed from the user study as a direction for different collaborative situations. While there are many research works that allow users to work together in one-to-one collaborations, less attention has been paid to one-to-many collaborations. This is due to the lack of visual awareness cues that allow users to spectate multiple users. To alleviate this limitation, a prototype system named ObserVAR is proposed. ObserVAR utilizes Augmented Reality (AR) technology to help an instructor in spectating multiple Virtual Reality (VR) users by augmenting the instructor’s environment with virtual awareness cues generated from the VR users. In the development of ObserVAR, different awareness cues are compared in a user study to determine its suitability under various circumstances. The virtual awareness cues are then optimized further using techniques derived from graph visualization to reduce visual clutter. Finally, the knowledge gained from improving workspace awareness using different approaches is used to formulate a collaborative framework for learning and problem-solving tasks. The contributions of this thesis include an enhanced design of desktop virtual reality for collaborations; multiple improvements in workspace awareness across different aspects; the design and development of the ObserVAR system for one-to-many collaborations; and a framework for collaborative problem-solving that utilizes the proposed designs. This thesis explores various enhancements of VEs, which lead to a better performance in collaborative learning and problem-solving tasks. The VE designs in this thesis can be used as guidelines for future collaborative problem-solving systems.

The effectiveness of the learning process in the virtual reality (VR) environment and the presence and immersion components of the VR environment are among the most important variables for students to feel as if they are part of the 3D environment and function in the environment. The objective of this chapter is to determine and compare the presence and usability levels of primary school students participating in VR environments with different immersion characteristics (immersive and non-immersive). According to the findings, there was no significant difference between immersive and non-immersive VR environments in terms of presence and usability. It was also determined that the level of presence of students in both groups did not vary depending on usability. The results are regarded to be useful to educators, researchers, and instructional designers who want to integrate VR technology into their educational environments.

Virtual reality (VR) provides a unique opportunity to simulate various environments, enabling the observation of human behavior in a manner that closely resembles real-world scenarios. This study aimed to explore the effects of anticipating reward or punishment, personality traits, and physiological arousal on risky decision-making within a VR context. A custom VR game was developed to simulate real-life experiences. The sample comprised 52 students (63.46% female) from the University of Novi Sad, Serbia. The study assessed four parameters within the VR environment: elapsed game time, number of steps taken, average score, and decision-making time. Three physiological signals, heart rate, skin conductance, and respiratory rate, were recorded. Results indicated that personality traits, specifically Fight (β = -0.33, p = 0.024) and Freeze (β = 0.431, p = 0.009), were significantly related to behavior in the VR environment (R = 0.572, R2_adj = 0.227, RMSE = 23.12, F(6, 40) = 3.25, p = 0.011). However, these effects were not significant after negative feedback. Emotional arousal, measured by respiratory rate amplitude (β = 0.276, p = 0.045), showed a more pronounced role after feedback (β = 0.337, p = 0.028). These findings indicate that personality traits primarily influence behavior in a VR environment prior to the actual threat, whereas environmental characteristics become more important afterwards. The results offer valuable insights for experimental and personality psychologists by revealing how risk-taking is influenced by situational, emotional, and personality factors. Additionally, they provide guidance for VR designers in creating more ecologically valid environments, highlighting VR's potential as a tool for psychological research, while also underscoring the critical importance of selecting objective VR measures to accurately capture the complexities of human behavior in immersive environments.

Cybersickness is a notoriously common problem experienced with virtual reality (VR) systems. While the symptoms produced in the user of these systems are similar to the symptoms of motion sickness, the reaction to cybersickness is largely unrelated to physical movement, since physical movement, if any, is realized by the user in VR. Detection of cybersickness in a VR environment is a substantial step towards providing a comfortable VR experience. Because cybersickness has many symptoms, it has proved to be difficult to develop a precise method to detect it. Visual discomfort is believed to be the foremost contributing factor to cybersickness. Detection of visual discomfort is currently performed by questionnaires. However, this approach is not reliable due to the subjective nature of the collected feedback. With the availability of mobile EEG devices which are wearable, portable and low cost compared to medical level EEG devices, it is possible to use them with head mounted VR displays without interference. In this study, we first review the methodology used in EEG-based cybersickness detection and prevention. Then, we present our precursor study for EEG-based visual comfort improvement in VR and demonstrate the preliminary results of an EEG-based analysis using a mobile EEG device supported with the responses to the user questionnaire.

Tracking motion sickness in dynamic VR environments with EDA signals

We present an experimental study evaluating the effectiveness of immersive virtual reality games (combined with stationary cycling) on health-related physical activity in comparison to stationary cycling with the same game in a non-immersive (2D) setting. In the experiment, participants were asked to play a cycling video game with a stationary bike either in the immersive virtual reality (3D VR) environment or in a traditional 2D (Non-VR) display setting. Based on several theories, we anticipate that users of immersive virtual reality will feel more present in the game be induced to physically performed better than when they played the same game with a traditional 2D screen. In addition, we also expect to see people who are eager to accept and use a new technology will show better cycling performance in an immersive virtual environment than people who think accepting the newest technology in a timely manner is not very important for their lives.

The current virtual reality (VR) techniques develop immersive environments via inducing illusions to our sense. Nowadays, most of VR focuses on inducing visual illusion. Hence, visual is the most important input channel for experiencing and exploring the VR environments. Recently, extensive research efforts have been put on eye-tracking studies. However, the development and growing trends of the VR-based eye-tracking studies are unrevealed due to the lack of a systematic literature review on it. In this study, we reviewed related literature from 2000 to 2019 and summarized them into two main categories, including eye tracking methods and eye-tracking-enabled applications, such as tracking gaze points to manipulate the VR environment, measuring user states, and evaluating the usability of VR based on eye-tracking data. Based on the literature review, we can find that eye-tracking can assist in developing adaptive VR systems and enhance users experience. While comparing with 2D environments, immersive VR environment still requires more deep studies in eye-tracking.

Background Sustained attention is essential for effective learning, especially in virtual reality (VR) environments with a high degree of operational freedom. Electroencephalogram (EEG) feedback has proven effective in terms of monitoring and regulating students' attentional states. However, EEG feedback faces implementation challenges in VR environments. Auditory feedback may interfere with voice‐based learning content, while visual feedback can exacerbate the cognitive load in visually rich environments. Objective The aim was to explore methods that would help students maintain attention in the VR learning environment (including voice learning or voice guidance from virtual characters), thereby enhancing learning effectiveness. Method This study proposed and integrated a vibration‐based EEG feedback mechanism into a VR learning system. Grounded in the Cognitive Theory of Multimedia Learning, this approach leverages tactile prompts to avoid sensory conflict. A quasi‐experiment involving 64 university students was subsequently conducted in an English for Geography course. Of the participants, 32 were exposed to a VR environment incorporating the vibration‐based EEG feedback, while the other 32 used the same VR environment without the feedback. The data collection included students' attention levels, performance, and learning behaviours. Systematic records and interviews were used to retrace the students' states when the vibration feedback was triggered. Results and Conclusions Results showed that students in the VR learning system with vibration‐based EEG feedback exhibited higher attention levels, improved vocabulary memory and retention, and more structured behaviour patterns such as review and evaluation, planned learning and refocusing after EEG feedback. This study innovates EEG feedback in VR environments, providing a design reference to promote VR‐based learning. In addition, the results of identified scenarios and subjective reasons for inattention will help in the design of future language VR environments and learning activities.

Controlling characters in a virtual reality (VR) environment can lead to the interiorization of their body dimensions by the recipients. The possible preservation of these distortions in their psyche will indicate a high degree of psychological impact of a VR on a person and the potential danger of developing depersonalization of the recipients and their dependence on such stimulation. The study of the stability of these distortions is necessary in the context of ensuring the safety of the impact of VR environments on the human psyche. The main focus of the study is on the perception distortions of human body dimensions, as they are sensed by people immersed in a VR environment, and their dynamics depending on the number of immersions. The impact of the virtual reality environment was simulated using the Freedom Locomotion VR application. One virtual reality immersion session took 15 minutes. To obtain psychometric indicators of the subjects perception of their own body dimensions, the technique Measurements according to M. Feldenkrais was used. All the participants (N = 45, three experimental groups) underwent a mandatory preliminary measurement using this technique (several hours before exposure) and a final measurement (one day after the last exposure). At the same time, the results of preliminary measurements were taken as indicators of the subjects habitual perception of their own body dimensions and were considered in each data processing as a comparison group. Free movement in a VR environment leads to distortions in the subjects perception of their own body dimensions. In all the experimental groups, there was a tendency to exaggerate body dimensions immediately after immersions, which indicates the qualitative similarity of these distortions. The effect of repetitive immersion in a VR environment on the perception of body dimensions is that it increases awareness in perceiving body parts that are least active at the time of immersion. Controlling an anthropomorphic character in a VR leads to an increase in the subjective significance of the recipients own body perception and an increased concentration of attention on the parameters least involved in immersion. The results of the study show that an increased level of awareness in perceiving their own bodies is characteristic of the subjects who have experience of repetitive immersions in a VR environment in the guise of an anthropomorphic character. Controlling a bodily projection in a VR headset does not cause its long-term interiorization, but has a positive effect on the formation of personal corporeality.

Building virtual reality fMRI paradigms: A framework for presenting immersive virtual environments

The development of virtual reality (VR) in enhancing the effectiveness of the learning process, with its interactive, immersive, and intuitive pedagogical environment, has become a necessity for corporations with increasingly complex operations. However, VR users’ perceptions, openness and learning effectiveness are seldom comprehensively evaluated, particularly in learning complex industrial operations. In this study, grounded in the technology acceptance model, a moderated mediation model of perceived usefulness, ease of use, openness to experience, and engagement in VR-based learning was developed. The model was empirically validated using responses collected from 321 users who were trained on aircraft and cargo terminal operations powered by a novel VR-based learning platform. A survey to measure openness to experience and a pre-training performance test were carried out, followed by a post-training survey of learners’ intrinsic factors, including the influence of perceived usefulness, openness to experience, and attitude towards learning. The study revealed that learners with an open attitude towards experiencing new technology tend to perceive VR technology as a useful platform for training. In addition, the learners with more positive views of VR technology-supported training were more engaged in learning.