Design Of Virtual Reality Systems Research Articles

Shaping corticospinal pathways in virtual reality: effects of task complexity and sensory feedback during mirror therapy in neurologically intact individuals

BackgroundRestoration of limb function for individuals with unilateral weakness typically requires volitional muscle control, which is often not present for individuals with severe impairment. Mirror therapy—interventions using a mirror box to reflect the less-impaired limb onto the more-impaired limb—can facilitate corticospinal excitability, leading to enhanced recovery in severely impaired clinical populations. However, the mirror box applies limitations on mirror therapy, namely that all movements appear bilateral and are confined to a small area, impeding integration of complex activities and multisensory feedback (e.g., visuo-tactile stimulation). These limitations can be addressed with virtual reality, but the resulting effect on corticospinal excitability is unclear.ObjectiveExamine how virtual reality-based unilateral mirroring, complex activities during mirroring, and visuo-tactile stimulation prior to mirroring affect corticospinal excitability.Materials and methodsParticipants with no known neurological conditions (n = 17) donned a virtual reality system (NeuRRoVR) that displayed a first-person perspective of a virtual avatar that matched their motions. Transcranial magnetic stimulation-induced motor evoked potentials in the nondominant hand muscles were used to evaluate corticospinal excitability in four conditions: resting, mirroring, mirroring with prior visuo-tactile stimulation (mirroring + TACT), and control. During mirroring, the movements of each participant’s dominant limb were reflected onto the nondominant limb of the virtual avatar, and the avatar’s dominant limb was kept immobile (i.e., unilateral mirroring). The mirroring + TACT condition was the same as the mirroring condition, except that mirroring was preceded by visuo-tactile stimulation of the nondominant limb. During the control condition, unilateral mirroring was disabled. During all conditions, participants performed simple (flex/extend fingers) and complex (stack virtual blocks) activities.ResultsWe found that unilateral mirroring increased corticospinal excitability compared to no mirroring (p < 0.001), complex activities increased excitability compared to simple activities during mirroring (p < 0.001), and visuo-tactile stimulation prior to mirroring decreased excitability (p = 0.032). We also found that these features did not interact with each other.DiscussionsThe findings of this study shed light onto the neurological mechanisms of mirror therapy and demonstrate the unique ways in which virtual reality can augment mirror therapy. The findings have important implications for rehabilitation for design of virtual reality systems for clinical populations.

Methods for Applying Matrices when Creating Models of Group Pursuit

Introduction. It is obvious that in the near future, the issues of equipping moving robotic systems with autonomous control elements will remain relevant. This requires the development of models of group pursuit. Note that optimization in pursuit tasks is reduced to the construction of optimal trajectories (shortest trajectories, trajectories with differential constraints, fuel consumption indicators). At the same time, the aspects of automated distribution by goals in group pursuit were not considered. To fill this gap, the presented piece of research has been carried out. Its result should be the construction of a model of automated distribution of pursuers by goals in group pursuit.Materials and Methods. A matrix was formed to study the multiple goal group pursuit. The control parameters for the movement of the pursuers were modified according to the minimum curvature of the trajectory. The methods of pursuit and approach were considered in detail. The possibilities of modifying the method of parallel approach were shown. Matrix simulation was used to build a scheme of multiple goal group pursuit. The listed processes were illustrated by functions in the given coordinate systems and animation. Block diagrams of the phase coordinates of the pursuer at the next step, the time and distance of the pursuer reaching the goal were constructed as a base of functions. In some cases, the location of targets and pursuers was defined as points on the circle of Apollonius. The matrix was formed by samples corresponding to the distribution of pursuers by goals.Results. Nine variants of the pursuit, parallel, proportional and three-point approach on the plane and in space were considered. The maximum value of the goal achievement time was calculated. There were cases when the speed vector of the pursuer was directed arbitrarily and to a point on the Apollonius circle. It was noted that the three-point approach method was convenient if the target was moving along a ballistic trajectory. To modify the method of parallel approach, a network of parallel lines was built on the plane. Here, the length of the arc of the line (which can be of any shape) and the array of reference points of the target trajectory were taken into account. An equation was compiled and solved with these elements. On an array of samples with corresponding time values, the minimum time was found, i.e., the optimal time for simultaneous group achievement of multiple goals was determined. For unified access to the library, the control vector was expressed through a one-parameter family of parallel planes. A library of calculations of control vectors was formed. An example of applying matrix simulation to group pursuit was shown. A scheme of group pursuit of multiple goals was presented. For two goals and three pursuers, six samples corresponding to the distribution of pursuers by goals were considered. The data was presented in the form of a matrix. Based on the research results, the computer program was created and registered – “Parallel Approach on Plane of Group of Pursuers with Simultaneous Achievement of the Goal”.Discussions and Conclusion. The methods of using matrices in modeling group pursuit were investigated. The possibility of modifying the method of parallel approach was shown. Matrix simulation of group pursuit enabled to build its scheme for a set of purposes. The matrix of the distribution of pursuers by goals would be generated at each moment of time. Methods of forming matrices of the distribution of pursuers and targets are of interest in the design of virtual reality systems, for tasks with simulating the process of group pursuit, escape, evasion. The dynamic programming method opens up the possibility of automating the distribution with optimization according to the specified parameters under the formation of the matrix of the distribution of pursuers by goals.

Interacting with Virtual Reality with a Controller Instead of the Body Benefits Performance and Perceptions

Methods of interaction within virtual environments, such as virtual reality (VR), typically include hand-held controllers, but recent advances in technology are making body-based interactions possible, such as eye and hand tracking. These modern interaction methods may prove to be more natural and intuitive for users and improve their experience by reducing the mental effort associated with learning a new interaction. In this within-subjects experiment, we compared users’ performance on a speeded button selection task and ratings of their experience in five different interaction methods: controller-based (Trigger, Push, and Raycasting) and body-based (Eyetracking and Handtracking). We found that participants performed best with controller-based interactions and rated their experiences more favorably than the body-based interactions. Participants reported higher mental and physical effort in the body-based conditions than the controller-based conditions. Implications for VR system design and future research are discussed.

Optimal Design of Virtual Reality Visualization Interface Based on Kansei Engineering Image Space Research

To effectively organize design elements in virtual reality (VR) scene design and provide evaluation methods for the design process, we built a user image space cognitive model. This involved perceptual engineering methods and optimization of the VR interface. First, we studied the coupling of user cognition and design features in the VR system via the Kansei Engineering (KE) method. The quantitative theory I and KE model regression analysis were used to analyze the design elements of the VR system’s human–computer interaction interface. Combined with the complex network method, we summarized the relationship between design features and analyzed the important design features that affect users’ perceptual imagery. Then, based on the characteristics of machine learning, we used a convolutional neural network (CNN) to predict and analyze the user’s perceptual imagery in the VR system, to provide assistance for the design optimization of the VR system design. Finally, we verified the validity and feasibility of the solution by combining it with the human–machine interface design of the VR system. We conducted a feasibility analysis of the KE model, in which the similarity between the multivariate regression analysis of the VR intention space and the experimental test was approximately 97% and the error was very small; thus, the VR intention space model was well correlated. The Mean Square Error (MSE) of the convolutional neural network (CNN) prediction model was calculated with a measured value of 0.0074, and the MSE value was less than 0.01. The results show that this method can improve the effectiveness and feasibility of the design scheme. Designers use important design feature elements to assist in VR system optimization design and use CNN machine learning methods to predict user image values in VR systems and improve the design efficiency. Facing the same design task requirements in VR system interfaces, the traditional design scheme was compared with the scheme optimized by this method. The results showed that the design scheme optimized by this method better fits the user’s perceptual imagery index, and thus the user’s task operation experience was better.

Investigating Age-Related Differences in Spatial Presence in Virtual Reality

Virtual reality (VR) has potential applications for promoting physical, cognitive, and socio-emotional well-being for users of all ages. The ability for individuals to develop a sense of being physically located in the virtual environment, referred to as spatial presence, is often an essential component of successful VR applications. Thus, it is necessary to understand the psychological aspects of the spatial presence process and identify methods of measuring presence formation and maintenance. This in-progress study addresses gaps in the spatial presence literature through an empirical evaluation of a conceptual model of spatial presence, which emphasizes users’ characteristics and abilities. Age will serve as a proxy for changes in a variety of presence-relevant cognitive and perceptual abilities. The results will have implications for the design of VR systems and applications and for selecting individuals best-suited for these applications.

The effect of user's perceived presence and promotion focus on usability for interacting in virtual environments

Technological advance in human–computer interaction has attracted increasing research attention, especially in the field of virtual reality (VR). Prior research has focused on examining the effects of VR on various outcomes, for example, learning and health. However, which factors affect the final outcomes? That is, what kind of VR system design will achieve higher usability? This question remains largely. Furthermore, when we look at VR system deployment from a human–computer interaction (HCI) lens, does user's attitude play a role in achieving the final outcome? This study aims to understand the effect of immersion and involvement, as well as users' regulatory focus on usability for a somatosensory VR learning system. This study hypothesized that regulatory focus and presence can effectively enhance user's perceived usability. Survey data from 78 students in Taiwan indicated that promotion focus is positively related to user's perceived efficiency, whereas involvement and promotion focus are positively related to user's perceived effectiveness. Promotion focus also predicts user satisfaction and overall usability perception.

3D Scene of Virtual Reality System Design and Research

The use of virtual reality technology on the objective world visualization and simulation, can provide the user some information hidden behind the data and realize humanized man-machine interaction. Based on the virtual reality system design process, classification, key technology and application areas of exploration, can grasp and understand the realization of virtual reality system design and development of the basic principles.

Multisensory interactions in the automatic control of postural sway

Visual motion signals are an important source of self-motion information that are used in postural control. Bronstein and Buckwell (Exp. Brain Res. 113, 243–248, 1997) showed that postural reactions to visual motion are not rigid responses to optokinetic stimulation but specific responses appropriate for stabilising posture in natural circumstances: body sway, for instance, was abolished when participants fixated a static object in front of a laterally moving background, which in itself induced sway. We test whether haptic and auditory as well as visual fixation points reduce body sway induced by a background that either moved left/right or forward/back on a large (3 × 7 m) 3D visual display. 10 participants were asked to respond when a fixation target, whichs was presented either on a background or foreground, changed colour. Body sway was measured using a VICON motion tracking system. We tested three conditions that replicated Bronstein and Buckwell’s original study and show that body sway, induced by lateral motion of the background is abolished when participant fixate on a (virtual) foreground object. We extended their study by showing that 3D motion (looming/receding background) has a similar effect to lateral motion and to show that body sway can be effectively reduced by providing either auditory (a loudspeaker emitting a white noise) and haptic (participants lightly touch a tripod with their index finger) cues. Our findings show that postural control draws auditory and haptic as well as visual cues. The findings are relevant to the design of virtual reality systems and provide a method for objective measures of presence in virtual environments.

Do-It-Yourself Interface Device Prototyping for Virtual Reality

the off-the-shelf virtual reality community is well aware of the wide variety of inexpensive and robust tracking and display technologies that have emerged from the entertainment industry in recent years. Alongside these developments, there has also been a vast improvement in the accessibility and usability of hobbyist-grade electronics components, which make incorporating lower-level sensing and actuation components into virtual reality systems feasible for even novices in electronics. Combined, these developments have formed the foundation for a renaissance of do-it-yourself interface device prototyping. Development of novel virtual reality interface devices has been simplified to the point that it can be commonplace in virtual reality system design, rather than an exception. This article discusses a variety of ways in which off-the-shelf electronics and devices can be leveraged and combined in virtual reality experiences, and the knowledge required to begin exploring possibilities, through case studies in prototyping virtual reality experiences.

Human Factors in Virtual Reality System Design for Mobility and Haptic Task Performance

In this chapter, we review research on the use of virtual reality (VR) and haptic technologies for studying human performance in tasks involving the tactile sense, including locomotion and upper-extremity motor-control training or rehabilitation. We present a general organizing framework of motor-control tasks and identify types of VR systems that have been developed for supporting the tactile sense in simulation of such tasks. We divide this coverage into gross motor tasks with a focus on locomotion and gait, in part because of the volume of research that has been conducted in this area, and fine motor skills with a focus on training for surgical tasks and upper-extremity rehabilitation. In covering VR technology, we review visual devices that facilitate hand-eye or body-eye coordination as well as physical task simulators (e.g., treadmill interfaces and haptic controllers). The directions of locomotion and motor-control task research exploiting these technologies are identified, and seminal studies representing each area are summarized. On this basis, we define a collection of VR simulation design recommendations from task and functional perspectives. The review also identifies the underlying cognitive and physical bases for specific observations on human performance made by previous research. Finally, the summaries of research studies are used as a basis for identifying future directions of research that should be addressed by the human factors community.

Virtual reality: A state-of-the-art survey

This paper presents a survey on virtual reality systems and provides an in-depth understanding toward the notion of immersion, according to the semantic meanings of the terms “virtual” and “reality”. The paper analyses the structure and functions of a virtual reality system and takes the three dimensional display as the immersive medium to identify the key issues for construction of virtual environments. The paper also reviews the development of virtual reality technology and introduces new image processing techniques into the design of virtual reality systems and virtual environments.

Analyzing the performance of a cluster-based architecture for immersive visualization systems

Cluster computing has become an essential issue for designing immersive visualization systems. This paradigm employs scalable clusters of commodity computers with much lower costs than would be possible with the high-end, shared memory computers that have been traditionally used for virtual reality purposes. This change in the design of virtual reality systems has caused some development environments oriented toward shared memory computing to require modifications to their internal architectures in order to support cluster computing. This is the case of VR Juggler, which is considered one of the most important virtual reality application development frameworks based on open source code. This paper not only describes in detail the mechanisms based on cluster computing included in the internal design of VR Juggler, but also proposes a new global performance evaluation methodology. The goal of this methodology is to test the graphical performance of immersive visualization systems based on clusters of computers in terms of both network latency and number of nodes in the cluster. In this sense, a performance evaluation of VR Juggler, both in an overall and a modular approach, is presented. The obtained results show that VR Juggler can be considered as an efficient tool to support immersive visualization systems on a cluster of computers.

Design for Presence: A Structured Approach to Virtual Reality System Design

The development and maintenance of a virtual reality (VR) system requires indepth knowledge and understanding in many different disciplines. Three major features that distinguish VR systems are real-time performance while maintaining acceptable realism and presence, objects with two clearly distinct yet inter-related aspects like geometry/structure and function/behavior, and the still experimental nature of multi-modal interaction design. Until now, little attention has been paid to methods and tools for the structured development of VR software that addresses these features. Many VR application development projects proceed by modeling needed objects on conventional CAD systems, then programming the system using simulation packages. Usually, these activities are carried out without much planning, which may be acceptable for only small-scale or noncritical demonstration systems. However, for VR to be taken seriously as a media technology, a structural approach to developing VR applications is required for the construction of large-scale VR worlds, and this will undoubtedly involve and require complex resource management, abstractions for basic system/object functionalities and interaction tasks, and integration and easy plug-ins of different input and output methods. In this paper, we assembled a comprehensive structured methodology for building VR systems, called CLEVR (Concurrent and LEvel by Level Development of VR System), which combines several conventional and new concepts. For instance, we employ concepts such as the simultaneous consideration of form, function, and behavior, hierarchical modeling and top-down creation of LODs (levels of detail), incremental execution and performance tuning, user task and interaction modeling, and compositional reuse of VR objects. The basic underlying modeling approach is to design VR objects (and the scenes they compose) hierarchically and incrementally, considering their realism, presence, behavioral correctness, performance, and even usability in a spiral manner. To support this modeling strategy, we developed a collection of computeraided tools called P-VoT (POSTECH-Virtual reality system development Tool). We demonstrate our approach by illustrating a step-by-step design of a virtual ship simulator using the CLEVR/P-VoT, and demonstrate the effectiveness of our method in terms of the quality (performance and correctness) of the resulting software and reduced effort in its development and maintenance.

Individual Characteristics and Experiences of Virtual Reality Induced Symptoms and Effects (Vrise)

Virtual Reality Induced Symptoms and Effects (VRISE) include both “positive” effects, such as the feeling of presence in a Virtual Environment (VE) or enjoyment of the use of Virtual Reality (VR), and “negative” effects, such as postural instability or sickness symptoms. The severity and nature of these effects can be influenced by VR system design, VE design, circumstances of use and individual participant characteristics. This paper presents an experiment that examines the effects experienced by 78 participants after a 30 minute period of VR use. The influence of a number of participant characteristics was assessed, and gender, motion sickness history, VR attitudes and immersive tendencies were found to have some influence on the experience of VRISE. Appropriate methods of minimising the level of negative effects experienced are discussed.

Design of Virtual Reality Systems for Education: A Cognitive Approach

One of the main problems with virtual reality as a learning tool is that there are hardly any theories or models upon which to found and justify the application development. This paper presents a model that defends the metaphorical design of educational virtual reality systems. The goal is to build virtual worlds capable of embodying the knowledge to be taught: the metaphorical structuring of abstract concepts looks for bodily forms of expression in order to make knowledge accessible to students. The description of a case study aimed at learning scientific categorization serves to explain and implement the process of metaphorical projection. Our proposals are based on Lakoff and Johnson's theory of cognition, which defends the conception of the embodied mind, according to which most of our knowledge relies on basic metaphors derived from our bodily experience.

An Agent-Based Approach for Constructing Software Systems of Virtual Simulation

The design and construction of virtual reality environments involve technologies such as computer graphics, image processing, pattern recognition, intelligent interface, artificial intelligence, voice recognition, network, parallel processing, and high-performance computing. Some researchers insist that object-oriented and agent-oriented technologies are fundamental for virtual reality system design. This paper applies artificial intelligence to the design of virtual reality systems. Agents are constructed by using object-oriented methods and a set of underlying computing models, such as neural networks, genetic algorithms, expert systems, and plan managers. Some object-oriented frameworks of these computing models are presented to illustrate this approach. The example of a spaceship game will illustrate interactions among environments, agents, and underlying computing models. The approach and reusable class library presented herein can be applied to various virtual reality environment simulations and intelligent applications.

A 'room' with a 'view'

An immersive virtual reality system called the CAVE is described. To match virtual reality to real tasks, researchers built this smoothly functioning walk-in system mostly from off-the-shelf components. The CAVE represents a new model for the design of virtual reality systems, one that offers several advantages over existing models. CAVE users do not need to wear helmets, don bulky gloves and heavy electronics packs, or be pushed about by movement restricting platforms. Instead, they put on a pair of lightweight glasses and walk into the Cave, a 27 m/sup 3/ room with an open side and no ceiling. The Cave is in fact a partial cube, with the top and one vertical side missing. The three vertical sides are 3 m by 3 m rear projection screens facing the viewer, and the floor is a front projection screen. The glasses trick a user's mind into seeing the screen images as three-dimensional objects.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>