Features of the Postural Sway Signal as Indicators to Estimate and Predict Visually Induced Motion Sickness in Virtual Reality

Navigation in a 3D immersive virtual environment is known to be prone to visually induced motion sickness (VIMS). Several psychophysiological and behavioral methods have been used to measure the level of sickness of a user, among which is postural instability. This study investigates all the features that can be extracted from the body postural sway: area of the projection of the center of gravity (mainly considered in past studies) and its shape and the frequency components of the signal’s spectrum, in order to estimate and predict the occurrence of sickness in a typical virtual reality (VR) application. After modeling and simulation of the body postural sway, an experiment on 17 subjects identified a relation between the level of sickness and the variation both in the time and frequency domains of the body sway signal. The results support and go further into detail of findings of past studies using postural instability as an efficient indicator of sickness, giving insight to better monitor VIMS in a VR application.FUI Callist

La ‘vista in prima persona’ tra esperienza reale e fruizione digitale

Il contributo espone i termini di una riflessione critica sul tema della ’vista in prima persona‘ così come definita nell’ambito delle rappresentazioni tridimensionali digitali virtuali interattive. Il tema gemmato da considerazioni riguardanti la meraviglia percettiva, comunicativa, illusoria e narrativa, propria delle prospettive architettoniche, analizza alcuni scenari della fruizione prospettica digitale, confrontandoli con le caratteristiche fondamentali dell’esperienza naturale del movimento e della visione nel mondo reale. L’obiettivo cui mira la ricerca, oggetto di questo contributo, è di individuare alcune macroscopiche criticità e lacune funzionali, oggi singolarmente trascurate, sulle quali sia possibile intervenire qualitativamente per perfezionare l’esperienza percettiva e, per conseguenza, l’attività conoscitiva dello spazio virtuale digitale così come dell’informazione in esso contenuto.The contribution exposes the terms of a critical reflection on the theme of “first person view” as defined in the context of interactive virtual digital three-dimensional representations. The theme, gemmed by considerations regarding the perceptive, communicative, illusory and narrative wonder, typical of architectural perspectives, analyzes some scenarios of digital perspective use, comparing them with the fundamental characteristics of the natural experience of movement and vision in the real world. The aim of the research object of this contribution is to identify some macroscopic criticalities and functional gaps, today individually overlooked, on which it is possible to intervene qua- litatively to perfect the perceptual experience and, consequently, the cognitive activity of the digital virtual space , as well as the information it contains

VR Sickness Prediction for Navigation in Immersive Virtual Environments using a Deep Long Short Term Memory Model

International audienceThis paper proposes a new objective metric of visually induced motion sickness (VIMS) in the context of navigation in virtual environments (VEs). Similar to motion sickness in physical environments, VIMS can induce many physiological symptoms such as general discomfort, nausea, disorientation, vomiting, dizziness and fatigue. To improve user satisfaction with VR applications, it is of great significance to develop objective metrics for VIMS that can analyze and estimate the level of VR sickness when a user is exposed to VEs. One of the well-known objective metrics is the postural instability. In this paper, we trained a LSTM model for each participant using a normal-state postural signal captured before the exposure, and if the postural sway signal from post-exposure was sufficiently different from the pre-exposure signal, the model would fail at encoding and decoding the signal properly; the jump in the reconstruction error was called loss and was proposed as the proposed objective measure of simulator sickness. The effectiveness of the proposed metric was analyzed and compared with subjective assessment methods based on the simulator sickness questionnaire (SSQ) in a VR environment, achieving a Pearson correlation coefficient of .89. Finally, we showed that the proposed method had the potential to be deployed within a closed-loop system and get real-time performance to predict VR sickness, opening new insights to develop user-centered and customized VR applications based on physiological feedback

Development of a speed protector to optimize user experience in 3D virtual environments

Virtual walking in virtual environments (VEs) requires locomotion interfaces, especially when the available physical environment is smaller than the virtual space due to virtual reality facilities limitations; many navigation approaches have been proposed according to different input conditions, target selection and speed selection. With current technologies, the virtual locomotion speed for most VR systems relies primarily on rate-control devices (e.g., joystick). The user has to manage manual adaptation of the speed, based on the size of the VE and personal preferences. However, this method cannot provide optimal speeds for locomotion as the user tends to change the speed involuntarily due to non-desired issues including collisions or simulator sickness; in this case, the user may have to adjust the speed frequently and unsmoothly, worsening the situation. Therefore, we designed a motion protector that can be embedded into the locomotion system to provide optimal speed profiles. The optimization process aims at minimizing the total jerk when the user translates from an initial position to a target, which is a common rule of the human motion model. In addition to minimization, we put constraints on speed, acceleration and jerk so that they do not exceed specific thresholds. The speed protector is formulated mathematically and solved analytically in order to provide a smooth navigation experience with a minimum jerk of trajectory. The assessment of the speed protector was conducted in a user study measuring user experience with a simulator sickness questionnaire, event-related skin conductance responses (ER-SCR), and a NASA-TLX questionnaire, showing that the designed speed protector can provide more natural and comfortable user experience with appropriate acceleration and jerk as it avoids abrupt speed profiles.China Scholarship Council: No. 20170839001

가상현실에서 몸의 자세와 공간인지, 공간이동방법, 존재감, 사이버멀미의 상호작용에 대한 연구

학위논문 (박사) -- 서울대학교 대학원 : 인문대학 협동과정 인지과학전공, 2021. 2. 이경민.가상현실은 몸과 마음이 공간에 함께 존재한다는 일상적 경험에 대해 새로운 관점을 제시한다. 컴퓨터로 매개된 커뮤니케이션에서 많은 경우 사용자들은 몸은 배제되며 마음의 존재가 중요하다고 느끼게 된다. 이와 관련하여 가상현실은 사용자들에게 커뮤니케이션에 있어 물리적 몸의 역할과 비체화된 상호작용의 중요성에 대해 연구할 수 있는 기회를 제공한다. 기존 연구에 의하면 실행, 주의집중, 기억, 지각과 같은 인지기능들이 몸의 자세에 따라 다르게 작용한다고 한다. 하지만 이와 같은 인지기능들과 몸 자세의 상호연관성은 여전히 명확히 밝혀지고 있지 않다. 특히 가상현실에서 몸의 자세가 지각반응에 대한 인지과정에 어떤 작용을 하는지에 대한 이해는 매우 부족한 상황이다. 가상현실 연구자들은 존재감을 가상현실의 핵심 개념으로 정의하였으며 효율적인 가상현실 시스템 구성과 밀접한 관계가 있다고 한다. 존재감은 가상공간에 있다고 느끼는 의식상태를 말한다. 구체적으로 가상현실 속 경험을 실재 존재한다고 느끼는 의식상태를 말한다. 이런 존재감이 높을 수록 현실처럼 인지하기에 존재감은 가상현실 경험을 측정하는 중요한 지표이다. 따라서 가상공간에 존재하고 있다는 의식적 경험 ((거기에 있다(being there)), 즉 존재감은 매개된 가상경험들의 인지 연구에 중요한 개념이다. 가상현실은 사이버멀미를 유발하는 것으로 알려져 있다. 이 증상은 가상현실의 사용성을 제약하는 주요 요인으로 효과적인 가상현실 경험을 위해 사이버멀미에 대한 다양한 연구가 필요하다. 사이버멀미는 가상현실 시스템을 사용할때 나타나며 어지러움, 방향상실, 두통, 땀흘림, 눈피로도등의 증상을 포함한다. 이런 사이버멀미에는 개인차, 사용된 기술, 공간디자인, 수행된 업무등 매우 다양 요인들이 관여하고 있어 명확한 원인을 규정할 수 없다. 이런 배경으로 인해 사이버멀미 저감과 관련한 다양한 연구들이 필요하며 이는 가상현실 발전에 중요한 의미를 갖는다. 공간인지는 3차원 공간에서 신체 움직임과 대상과의 상호작용에 중요한 역할을 하는 인지시스템이다. 가상공간에서 신체 움직임은 네비게이션, 사물조작, 다른 에이전트들과 상호작용에 관여한다. 특히 가상공간에서 네비게이션은 자주 사용되는 중요한 상호작용 방식이다. 이에 가상공간을 네비게이션 할때 존재감에 영향을 주지 않고 멀미증상을 유발하지 않는 효과적인 공간이동 방법에 대한 다양한 연구들이 이루어지고 있다. 이전 연구들에 의하면 시점이 존재감과 체화감에 영향을 준다고 한다. 이는 시점에 따라 사용자의 행동과 대상들과의 상호작용 방식에 달라지기 때문이다. 따라서 가상공간에서 경험 또한 시점에 따라 달라진다. 이런 배경으로 몸의 자세, 공간인지, 이동방법, 존재감, 사이버멀미의 상호 연관성에 대한 연구를 시점에 따라 분류해서 연구할 필요가 있다. 이를 통해 가상현실 속 공간 네비게이션에 대한 인지과정을 보다 다각적으로 이해 할 수 있을 것이다. 그동안 존재감과 사이버 멀미에 내재된 매커니즘을 이해하기 위해 다양한 연구들이 진행되어 왔다. 하지만 몸의 자세에 따른 인지작용이 존재감과 사이버멀미에 어떤 영향을 주는지에 대한 연구는 거의 이루어지지 않았다. 이에 본 학위논문에서는 1인칭과 3인칭 시점으로 분류된 별도의 실험과 연구를 진행하여 가상현실에서 몸의 자세와 공간인지, 공간이동방법, 존재감, 사이버멀미의 상호연관성을 보다 심층적으로 이해하고자 한다. 제3장에서는 3인칭시점의 실험과 결과에 대한 내용을 기술했다. 3인칭시점 실험에서는 가상공간에서 몸의 자세와 존재감의 상호연관성 연구를 위해 세가지 몸의 자세 (서있는 자세, 앉은 자세, 다리를 펴고 앉은 자세)와 2가지 타입의 공간이동 자유도 (무한, 유한)를 상호 비교했다. 실험결과에 의하면 공간이동 자유도가 무한한 경우 서있는 자세에서 존재감이 높게 나타났다. 추가적으로 가상공간에서 몸의 자세와 존재감은 공간이동자유도와 관련이 있는 것으로 나타났으며 여러 인지기능 중 주의집중이 몸의 자세, 존재감, 공간인지의 통합적 상호작용을 이끌어 낸 것으로 파악되었다. 3인칭시점의 결과들을 종합해 보면 몸 자세의 인지적 영향은 공간이동자유도와 상관관계가 있는 것으로 추측할 수 있다. 제4장에서는 1인칭시점의 실험과 결과에 대한 내용을 기술했다. 1인칭시점 실험에서는 가상공간에서 몸의 자세, 공간이동방법, 존재감, 사이버멀미의 상호연관성 연구를 위해 두 조건의 몸의 자세 (서있는 자세, 앉아 있는 자세)와 네가지 타입의 이동방법 (스티어링 + 몸을 활용한 회전, 스티어링 + 도구를 활용한 회전, 텔레포테이션 + 몸을 이용한 회전, 텔레포테이션 + 도구를 활용한 회전)의 상호 비교가 이루어 졌다. 실험결과에 의하면 위치이동방식과 회전방식에 따른 공간이동자유도는 성공적인 네비게이션과 관련이 있으며 존재감에 영향을 주는 것으로 나타났다. 추가적으로 연속적으로 시각정보가 입력되는 스티어링 방법은 자가운동을 높여 비연속적 방법인 텔레포테이션보다 사이버멀미를 더 유발하는 것으로 나타났다. 1인칭시점의 결과들을 종합해 보면 가상공간에서 네비게이션을 할때 존재감과 사이버멀미는 공간이동방법과 관련이 있는 것으로 가정할 수 있다. 제3장의 3인칭 시점 실험결과에 의하면 몸의 자세와 존재감은 상관관계가 있는 것으로 제시되었다. 반면 제4장의 실험결과에 의하면 1인칭시점으로 가상공간을 네비게이션 할 때는 공간이동방법이 존재감과 사이버멀미에 영향을 주는 것으로 나타났다. 이 두 실험에 대한 연구 결과를 통해 가상현실에서 몸의 자세와 공간인지 (네비게이션)의 상호연관성에 대한 이해를 확대하고 존재감 및 사이버멀미와 공간이동방법의 관련성을 밝힐 수 있을 것으로 기대한다.Immersive virtual environments (VEs) can disrupt the everyday connection between where our senses tell us we are and where we are actually located. In computer-mediated communication, the user often comes to feel that their body has become irrelevant and that it is only the presence of their mind that matters. However, virtual worlds offer users an opportunity to become aware of and explore both the role of the physical body in communication, and the implications of disembodied interactions. Previous research has suggested that cognitive functions such as execution, attention, memory, and perception differ when body position changes. However, the influence of body position on these cognitive functions is still not fully understood. In particular, little is known about how physical self-positioning may affect the cognitive process of perceptual responses in a VE. Some researchers have identified presence as a guide to what constitutes an effective virtual reality (VR) system and as the defining feature of VR. Presence is a state of consciousness related to the sense of being within a VE; in particular, it is a ‘psychological state in which the virtuality of the experience is unnoticed’. Higher levels of presence are considered to be an indicator of a more successful media experience, thus the psychological experience of ‘being there’ is an important construct to consider when investigating the association between mediated experiences on cognition. VR is known to induce cybersickness, which limits its application and highlights the need for scientific strategies to optimize virtual experiences. Cybersickness refers to the sickness associated with the use of VR systems, which has a range of symptoms including nausea, disorientation, headaches, sweating and eye strain. This is a complicated problem because the experience of cybersickness varies greatly between individuals, the technology being used, the design of the environment, and the task being performed. Thus, avoiding cybersickness represents a major challenge for VR development. Spatial cognition is an invariable precursor to action because it allows the formation of the necessary mental representations that code the positions of and relationships among objects. Thus, a number of bodily actions are represented mentally within a depicted VR space, including those functionally related to navigation, the manipulation of objects, and/or interaction with other agents. Of these actions, navigation is one of the most important and frequently used interaction tasks in VR environments. Therefore, identifying an efficient locomotion technique that does not alter presence nor cause motion sickness has become the focus of numerous studies. Though the details of the results have varied, past research has revealed that viewpoint can affect the sense of presence and the sense of embodiment. VR experience differs depending on the viewpoint of a user because this vantage point affects the actions of the user and their engagement with objects. Therefore, it is necessary to investigate the association between body position, spatial cognition, locomotion method, presence, and cybersickness based on viewpoint, which may clarify the understanding of cognitive processes in VE navigation. To date, numerous detailed studies have been conducted to explore the mechanisms underlying presence and cybersickness in VR. However, few have investigated the cognitive effects of body position on presence and cybersickness. With this in mind, two separate experiments were conducted in the present study on viewpoint within VR (i.e., third-person and first-person perspectives) to further the understanding of the effects of body position in relation to spatial cognition, locomotion method, presence, and cybersickness in VEs. In Chapter 3 (Experiment 1: third-person perspective), three body positions (standing, sitting, and half-sitting) were compared in two types of VR game with a different degree of freedom in navigation (DFN; finite and infinite) to explore the association between body position and the sense of presence in VEs. The results of the analysis revealed that standing has the most significant effect on presence for the three body positions that were investigated. In addition, the outcomes of this study indicated that the cognitive effect of body position on presence is associated with the DFN in a VE. Specifically, cognitive activity related to attention orchestrates the cognitive processes associated with body position, presence, and spatial cognition, consequently leading to an integrated sense of presence in VR. It can thus be speculated that the cognitive effects of body position on presence are correlated with the DFN in a VE. In Chapter 4 (Experiment 2: first-person perspective), two body positions (standing and sitting) and four types of locomotion method (steering + embodied control [EC], steering + instrumental control [IC], teleportation + EC, and teleportation + IC) were compared to examine the relationship between body position, locomotion method, presence, and cybersickness when navigating a VE. The results of Experiment 2 suggested that the DFN for translation and rotation is related to successful navigation and affects the sense of presence when navigating a VE. In addition, steering locomotion (continuous motion) increases self-motion when navigating a VE, which results in stronger cybersickness than teleportation (non-continuous motion). Overall, it can be postulated that presence and cybersickness are associated with the method of locomotion when navigating a VE. In this dissertation, the overall results of Experiment 1 suggest that the cognitive influence of presence is body-dependent in the sense that mental and brain processes rely on or are affected by the physical body. On the other hand, the outcomes of Experiment 2 illustrate the significant effects of locomotion method on the sense of presence and cybersickness during VE navigation. Taken together, the results of this study provide new insights into the cognitive effects of body position on spatial cognition (i.e., navigation) in VR and highlight the important implications of locomotion method on presence and cybersickness in VE navigation.Chapter 1. Introduction 1 1.1. An Introductory Overview of the Conducted Research 1 1.1.1. Presence and Body Position 1 1.1.2. Navigation, Cybersickness, and Locomotion Method 3 1.2. Research Objectives 6 1.3. Research Experimental Approach 7 Chapter 2. Theoretical Background 9 2.1. Presence 9 2.1.1. Presence and Virtual Reality 9 2.1.2. Presence and Spatiality 10 2.1.3. Presence and Action 12 2.1.4. Presence and Attention 14 2.2. Body Position 16 2.2.1. Body Position and Cognitive Effects 16 2.2.2. Body Position and Postural Control 18 2.2.3. Body Position and Postural Stability 19 2.3. Spatial Cognition: Degree of Freedom in Navigation 20 2.3.1. Degree of Freedom in Navigation and Decision-Making 20 2.4. Cybersickness 22 2.4.1. Cybersickness and Virtual Reality 22 2.4.2. Sensory Conflict Theory 22 2.4.3. Postural Instability Theory 23 2.5. Self-Motion 25 2.5.1. Vection and Virtual Reality 25 2.5.2. Self-Motion and Navigation in a VE 27 2.6. Navigation in Virtual Environments 29 2.6.1. Translation and Rotation in Navigation 29 2.6.2. Spatial Orientation and Embodiment 32 2.6.3. Locomotion Methods 37 2.6.4. Steering and Teleportation 38 Chapter 3. Experiment 1: Third-Person Perspective 40 3.1. Quantification of the Degree of Freedom in Navigation 40 3.2. Experiment 3.2.1. Experimental Design and Participants 41 3.2.2. Stimulus Materials 42 3.2.2.1. First- and Third-person Perspectives in Gameplay 43 3.2.3. Experimental Setup and Process 44 3.2.4. Measurements 45 3.3. Results 45 3.3.1. Presence: two-way ANOVA 45 3.3.2. Presence: one-way ANOVA 46 3.3.2.1. Finite Navigation Freedom 46 3.3.2.2. Infinite Navigation Freedom 47 3.3.3. Summary of the Results 48 3.4. Discussion 49 3.4.1. Presence and Body Position 49 3.4.2. Degree of Freedom in Navigation and Decision-Making 50 3.4.3. Gender Difference and Gameplay 51 3.5. Limitations 52 Chapter 4. Experiment 2: First-Person Perspective 53 4.1. Experiment 53 4.1.1. Experimental Design and Participants 53 4.1.2. Stimulus Materials 54 4.1.3. Experimental Setup and Process 55 4.1.4. Measurements 56 4.2. Results 57 4.2.1. Presence: two-way ANOVA 58 4.2.2. Cybersickness: two-way ANOVA 58 4.2.3. Presence: one-way ANOVA 60 4.2.3.1. Standing Position 60 4.2.3.2. Sitting Position 60 4.2.4. Cybersickness: one-way ANOVA 62 4.2.4.1. Standing Position 62 4.2.4.2. Sitting Position 62 4.2.5. Summary of the Results 63 4.3. Discussion 65 4.3.1. Presence 4.3.1.1. Presence and Locomotion Method 66 4.3.1.2. Presence and Body Position 68 4.3.2. Cybersickness 4.3.2.1. Cybersickness and Locomotion Method 69 4.3.2.2. Cybersickness and Body Position 70 4.4. Limitations 71 Chapter 5. Conclusion 72 5.1. Summary of Findings 72 5.2. Future Research Direction 73 References 75 Appendix A 107 Appendix B 110 국문초록 111Docto

Application of Virtual Reality in the study of Human Behavior in Fire : Pursuing realistic behavior in evacuation experiments

Virtual Reality (VR) experiments are used to study human behavior in fire because they allow simulation of fire events with relatively low risks to the participants, while maintaining high levels of experimental control. Manystudies have used VR experiments to explore aspects of the human response to fire threats, but VR experiments as a research method are yet to be subjected to a systematic process of validation. One way to validate VR experiments is to compare VR data to data obtained using other research methods, e.g., case studies, laboratory experiments, and field experiments. Five independent VR experiments were designed to collect data that could be then compared to data collected using other research methods. Both datasets, VR and physical, are thencompared with each other to assess similarities and differences between them. Results show that participants in the VR experiments often acted like people did in the physical-world events. Moreover, Human Behavior in Fire theories that explain the behavior of victims in real fires were found to also explain the participants’ behavior in the VR experiments. There were differences between VR and physical-world samples, which highlighted limitations of VR experiments or aspects about realism that need to be considered when designing VR experiments. Visual realism is not enough for participants to interpret a virtual fire emergency as a threat. Therefore, VR experiments need to induce participants to take the virtual fire event seriously. Social norms that apply in physical world contexts may not emerge naturally in virtual environments, and measures should be taken to enhance behavioral realism in VR. These findings are a meaningful contribution to the development of the VR experiment method for collection of behavioral data

Методе за оцену електричне активности глатких мишића

Recording of the smooth stomach muscles' electrical activity can be performed by means of Electrogastrography (EGG), a non-invasive technique for acquisition that can provide valuable information regarding the functionality of the gut. While this method had been introduced for over nine decades, it still did not reach its full potential. The main reason for this is the lack of standardization that subsequently led to the limited reproducibility and comparability between different investigations. Additionally, variability between many proposed recording approaches could make EGG unappealing for broader application. The aim was to provide an evaluation of a simplified recording protocol that could be obtained by using only one bipolar channel for a relatively short duration (20 minutes) in a static environment with limited subject movements. Insights into the most suitable surface electrode placement for EGG recording was also presented. Subsequently, different processing methods, including Fractional Order Calculus and Video-based approach for the cancelation of motion artifacts – one of the main pitfalls in the EGG technique, was examined. For EGG, it is common to apply long-term protocols in a static environment. Our second goal was to introduce and investigate the opposite approach – short-term recording in a dynamic environment. Research in the field of EGG-based assessment of gut activity in relation to motion sickness symptoms induced by Virtual Reality and Driving Simulation was performed. Furthermore, three novel features for the description of EGG signal (Root Mean Square, Median Frequency, and Crest Factor) were proposed and its applicability for the assessment of gastric response during virtual and simulated experiences was evaluated. In conclusion, in a static environment, the EGG protocol can be simplified, and its duration can be reduced. In contrast, in a dynamic environment, it is possible to acquire a reliable EGG signal with appropriate recommendations stated in this Doctoral dissertation. With the application of novel processing techniques and features, EGG could be a useful tool for the assessment of cybersickness and simulator sickness.Снимање електричне активности глатких мишића желуца може се реализовати употребом електрогастрографије (ЕГГ), неинвазивне методе која пружа значајне информације везане за функционисање органа за варење. Упркост чињеници да је откривена пре више од девет деценија, ова техника још увек није остварила свој пун потенцијал. Основни разлог за то је недостатак стандардизације који условљава ограничења у смислу поновљивости и упоредивости између различитих истраживања. Додатно, варијабилност која је присутна у примени различитих препоручених поступака снимања, може смањити интерес за употребу ЕГГ-а код широког опсега потенцијалних корисника. Наш циљ је био да пружимо евалуацију поједностављене методе мерења тј. протокола који укључује само један канал током релативно кратког временског периода (20 минута) у статичким условима са ограниченим кретањем субјекта тј. у мировању. Такође, приказали смо наше ставове у вези најприкладније позиције површинских електрода за ЕГГ снимање. Презентовали смо и резултате испитивања метода, на бази обраде видео снимка као и фракционог диференцијалног рачуна, за отклањање артефаката помераја – једног од највећих изазова са којима је суочена ЕГГ метода. За ЕГГ је уобичајено да се користе дуготрајни протоколи у статичким условима. Наш други циљ био је да представимо и оценимо употребљивост супротног приступа – краткотрајних снимања у динамичким условима. Реализовали смо истраживање на пољу оцене активности желуца током појаве симптома мучнине изазване виртуелном реалношћу и симулацијом вожње. За потребе методе за оцену електричне активности желуца, предложили смо три нова параметра за квантификацију ЕГГ сигнала (ефективну вредност амплитуде, медијану и крест фактор) и извршили процену њихове прикладности за оцену гастроинтестиналног тракта током коришћења виртуелне реалности и симулатора вожње. Закључак је да ЕГГ протокол у статичким условима може бити упрошћен и његово трајање може бити редуковано, док је у динамичким условима могуће снимити одговарајући ЕГГ сигнал, али уз праћење препорука наведених у овој тези. Употребом нових техника за процесирање сигнала и прорачун одговарајућих параметара, ЕГГ може бити корисна техника за оцену мучнине изазване коришћењем симулатора и производа виртуелне реалност