Cognitive Issues in Virtual Reality

Author(s):  
Christopher D. Wickens ◽  
Polly Baker

Virtual reality involves the creation of multisensory experience of an environment (its space and events) through artificial, electronic means; but that environment incorporates a sufficient number of features of the non-artificial world that it is experienced as “reality.” The cognitive issues of virtual reality are those that are involved in knowing and understanding about the virtual environment (cognitive: to perceive and to know). The knowledge we are concerned with in this chapter is both short term (Where am I in the environment? What do I see? Where do I go and how do I get there?), and long term (What can and do I learn about the environment as I see and explore it?). Given the recent interest in virtual reality as a concept (Rheingold, 1991; Wexelblat, 1993; Durlach and Mavor, 1994), it is important to consider that virtual reality is not, in fact, a unified thing, but can be broken down into a set of five features, any one of which can be present or absent to create a greater sense of reality. These features consist of the following five points. 1. Three-dimensional (perspective and/or stereoscopic) viewing vs. two-dimensional planar viewing. (Sedgwick, 1986; Wickens et al., 1989). Thus, the geography student who views a 3D representation of the environment has a more realistic view than one who views a 2D contour map. 2. Dynamic vs. static display. A video or movie is more real than a series of static images of the same material. 3. Closed-loop (interactive or learner-centered) vs. open-loop interaction. A more realistic closed-loop mode is one in which the learner has control over what aspect of the learning “world” is viewed or visited. That is, the learner is an active navigator as well as an observer. 4. Inside-out (ego-referenced) vs. outside-in (world-referenced) frame-of-reference. The more realistic inside-out frame-of-reference is one in which the image of the world on the display is viewed from the perspective of the point of ego-reference of the user (that point which is being manipulated by the control). This is often characterized as the property of “immersion.” Thus, the explorer of a virtual undersea environment will view that world from a perspective akin to that of a camera placed on the explorer’s head;

2021 ◽  
Vol 15 ◽  
Author(s):  
Neethu Robinson ◽  
Tushar Chouhan ◽  
Ernest Mihelj ◽  
Paulina Kratka ◽  
Frédéric Debraine ◽  
...  

Several studies in the recent past have demonstrated how Brain Computer Interface (BCI) technology can uncover the neural mechanisms underlying various tasks and translate them into control commands. While a multitude of studies have demonstrated the theoretic potential of BCI, a point of concern is that the studies are still confined to lab settings and mostly limited to healthy, able-bodied subjects. The CYBATHLON 2020 BCI race represents an opportunity to further develop BCI design strategies for use in real-time applications with a tetraplegic end user. In this study, as part of the preparation to participate in CYBATHLON 2020 BCI race, we investigate the design aspects of BCI in relation to the choice of its components, in particular, the type of calibration paradigm and its relevance for long-term use. The end goal was to develop a user-friendly and engaging interface suited for long-term use, especially for a spinal-cord injured (SCI) patient. We compared the efficacy of conventional open-loop calibration paradigms with real-time closed-loop paradigms, using pre-trained BCI decoders. Various indicators of performance were analyzed for this study, including the resulting classification performance, game completion time, brain activation maps, and also subjective feedback from the pilot. Our results show that the closed-loop calibration paradigms with real-time feedback is more engaging for the pilot. They also show an indication of achieving better online median classification performance as compared to conventional calibration paradigms (p = 0.0008). We also observe that stronger and more localized brain activation patterns are elicited in the closed-loop paradigm in which the experiment interface closely resembled the end application. Thus, based on this longitudinal evaluation of single-subject data, we demonstrate that BCI-based calibration paradigms with active user-engagement, such as with real-time feedback, could help in achieving better user acceptability and performance.


2021 ◽  
Vol 290 ◽  
pp. 02029
Author(s):  
ShiYu Zhang ◽  
YingHao Dong ◽  
Tingting Xie ◽  
Xinying Si ◽  
JinZe Li

In order to reproduce the grand look of Hanqing Stadium and restore the most realistic Hanqing Stadium internal layout and structure, a simulation system based on the virtual reality technology for the internal structure layout design of the stadium was designed and developed. Based on the current development trend of virtual reality technology, a three-dimensional dynamic space model was established to restore the real conditions of Hanqing Stadium. By integrating emerging technologies such as panoramic images, panoramic views, and stereo vision into virtual reality technology, the sense of reality was enhanced. 3Dmaxs was used to establish the Hanqing Stadium scene design model, the surrounding and internal scene models were reconstructed, and the experiencers’ feelings about the real scene were restored 1:1. The use of technologies such as panoramic images and views enhances the realism and three-dimensionality of the picture.


Author(s):  
Joseph M. Bari ◽  
Carl D. Crane ◽  
David B. Dooner ◽  
Javier Roldan Mckinley

A means has been discovered to apply gear pairing to create a one degree of freedom open-loop spatial mechanism. A specially chosen geometry consisting of three pairs of parallel joint axes is constricted by five sets of gears, three of which are parallel planar, allows for a reconfigurable mechanism that is suited for repetitive tasks. Previous work has examined three-dimensional rigid body guidance in closed-loop geared mechanisms, but has not come to a solution for the open-loop case. Gear pairs are designed based upon a desired position and orientation path for the end effector. Numerical optimization is performed to obtain physically realizable gear profiles. Non-circular gear centrodes must be continuous and smooth as well as mono-directional, that is, gear ratios of a given pair may not switch signs. These constraints eliminate non-realizable or non-optimal gears in favor of simple, more easily produced profiles. Variable parameters include link lengths, joint offsets and twist angles. Numerical examples are presented.


Author(s):  
Emanuele Bisso ◽  
Maria Salvina Signorelli ◽  
Michele Milazzo ◽  
Marilena Maglia ◽  
Riccardo Polosa ◽  
...  

(1) Background: Virtual Reality (VR) is a fully immersive computer simulated experience consisting of a three-dimensional interactive virtual environment, through a head-mounted display (HMD) and controller. The use of virtual reality has recently been proposed for the treatment of various psychiatric conditions, including the spectrum of schizophrenia. Our review aims to investigate the current available evidence regarding the use of immersive virtual reality in the treatment of psychotic symptoms. (2) Methods: From April 2019 to June 2020, we conducted a systematic review aimed at identifying therapeutic applications in immersive virtual reality for the spectrum of schizophrenia, searching for relevant studies on Web of Science, EMBASE, PsycINFO and CINHAL. (3) Results: We identified a total of 2601 unique records. Of these, 64 full-text articles were assessed for eligibility, and six out of these met the inclusion criteria and were included in the final systematic review. (4) Conclusions: The available data on immersive virtual reality are currently limited due to the few studies carried out on the topic; however, it has demonstrated its effectiveness and versatility in successfully treating various psychotic symptoms including delusions, hallucinations, or cognitive and social skills. Existing literature agrees on safe, tolerable, and long-term persistence of the therapeutic effects obtained by immersive VR. No serious side effects have been reported. In some specific cases, VR therapy was found to be very effective compared to usual treatment, allowing effective drug free interventions, and therefore without side effects for patients, even in those resistant to normal drug therapies.


Author(s):  
Michelle A. Vincow ◽  
Christopher D. Wickens

An experiment was conducted on navigation through three-dimensional visualizations of document databases. Subjects navigated through a 1000-document information space in which documents near each other were likely to be about a similar topic and keywords displayed in the space indicated the topic of nearby documents. The influence of frame of reference and use of a map on document search and spatial judgment tasks was investigated. The frame of reference distinction compared a more egocentric (inside-out, immersed) perspective and a more exocentric (outside-in, bird's eye) perspective. Performance was best with the exocentric display, with the egocentric display a close second. Use of a map hindered rather than supported performance. Results revealed tool/strategy choice as an important mediator of the influence of frame of reference, with non-optimal tool choices observed. Spatial ability correlated with performance. Results are accounted for in terms of mediating influences.


Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Robert M Levy

Abstract INTRODUCTION Spinal cord stimulation (SCS) is an established treatment for chronic pain; however, long-term success remains suboptimal. Current SCS therapies are fixed-output and do not account for large variation in electrical field strength due to changes in distance between the electrode and spinal cord (SC). METHODS In Avalon, 50 subjects were implanted and programmed in closed-loop; in Evoke, 134 subjects were randomized into open-loop (OL-SCS) or closed-loop (CL-SCS). ECAPs, a measure of SC activation, are recorded following each stimulation pulse in both groups. Each subject's therapeutic window (TW) is determined individually as the ECAP amplitude range between sensation perception threshold and discomfort. Without a measure of SC activation (eg, ECAPs), TW can only be based on perception of intensity; however, stimulation can produce variable SC activation (ECAP amplitude) as the electrode to SC distance varies with movement. RESULTS In the Evoke Study, each subjects' TW was determined in the clinic, along with the clinician prescribed level. There was no statistical difference between the 2 groups' TWs; however, CL-SCS subjects spent significantly more time in the TW despite having equivalent therapeutic ranges. Long-term data showed a similar percentage of stimuli in the TW (83%-97%). CONCLUSION TW can be individually defined by ECAP amplitudes (measure of SC activation), removing the need to rely on subjective reports of intensity, which can vary over time and with movement.


Author(s):  
C.L. Woodcock

Despite the potential of the technique, electron tomography has yet to be widely used by biologists. This is in part related to the rather daunting list of equipment and expertise that are required. Thanks to continuing advances in theory and instrumentation, tomography is now more feasible for the non-specialist. One barrier that has essentially disappeared is the expense of computational resources. In view of this progress, it is time to give more attention to practical issues that need to be considered when embarking on a tomographic project. The following recommendations and comments are derived from experience gained during two long-term collaborative projects.Tomographic reconstruction results in a three dimensional description of an individual EM specimen, most commonly a section, and is therefore applicable to problems in which ultrastructural details within the thickness of the specimen are obscured in single micrographs. Information that can be recovered using tomography includes the 3D shape of particles, and the arrangement and dispostion of overlapping fibrous and membranous structures.


2020 ◽  
Vol 26 ◽  
pp. 41
Author(s):  
Tianxiao Wang

This article is concerned with linear quadratic optimal control problems of mean-field stochastic differential equations (MF-SDE) with deterministic coefficients. To treat the time inconsistency of the optimal control problems, linear closed-loop equilibrium strategies are introduced and characterized by variational approach. Our developed methodology drops the delicate convergence procedures in Yong [Trans. Amer. Math. Soc. 369 (2017) 5467–5523]. When the MF-SDE reduces to SDE, our Riccati system coincides with the analogue in Yong [Trans. Amer. Math. Soc. 369 (2017) 5467–5523]. However, these two systems are in general different from each other due to the conditional mean-field terms in the MF-SDE. Eventually, the comparisons with pre-committed optimal strategies, open-loop equilibrium strategies are given in details.


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