Eyes on teleporting: comparing locomotion techniques in Virtual Reality with respect to presence, sickness and spatial orientation

This work compares three locomotion techniques for an immersive VR environment: two different types of teleporting (with and without animation) and a manual (joystick-based) technique. We tested the effect of these techniques on visual motion sickness, spatial awareness, presence, subjective pleasantness, and perceived difficulty of operating the navigation. We collected eye tracking and head and body orientation data to investigate the relationships between motion, vection, and sickness. Our study confirms some results already discussed in the literature regarding the reduced invasiveness and the high usability of instant teleport while increasing the evidence against the hypothesis of reduced spatial awareness induced by this technique. We reinforce the evidence about the issues of extending teleporting with animation. Furthermore, we offer some new evidence of a benefit to the user experience of the manual technique and the correlation of the sickness felt in this condition with head movements. The findings of this study contribute to the ongoing debate on the development of guidelines on navigation interfaces in specific VR environments

Anthropometric prediction of DXA-measured percentage of fat mass in athletes with unilateral lower limb amputation

To date there is no anthropometric equation specific to athletes with unilateral lower limb amputation to estimate the percentage of fat mass (%FM). This study investigated the accuracy of a set of anthropometric equations validated on able-bodied populations to predict the %FM assessed by-means of dual-energy x-ray absorptiometry (DXA) in athletes with unilateral lower limb amputation. Furthermore, a predictive anthropometric equation specific to athletes with unilateral lower limb amputation was developed from skinfold thickness measurements using DXA as the reference method for the estimation of the %FM. Twenty-nine white male athletes with unilateral lower limb amputation underwent a DXA scan and an anthropometric assessment on the same day. The %FM, calculated through several existing anthropometric equations validated upon able-bodied populations, was compared with the DXA-measured %FM (%FM_DXA). Accuracy and agreement between the two methods was computed with two-tailed paired-sample t-test, concordance correlation coefficient, reduced major axis regression and Bland-Altman analysis. A stepwise multiple regression analysis with the %FM_DXA as the dependent variable and age and nine skinfold thicknesses as potential predictors was carried out and validated using a repeated 10-fold cross-validation. A linear regression analysis with the sum of nine skinfolds as the independent variable was also carried out and validated using a repeated 10-fold cross-validation. The results showed that the anthropometric equations validated on able-bodied populations are inaccurate in the estimation of %FM_DXA with an average bias ranging from 0.51 to -13.70%. Proportional bias was also found revealing that most of the anthropometric equations considered, tended to underestimate/overestimate the %FM_DXA as body fat increased. Regression analysis produced two statistically significant models (P < 0.001 for both) which were able to predict more than 93% of total variance of %FM_DXA from the values of four skinfold measurements (i.e., thigh, abdominal, subscapular and axillary skinfold measurements) or from the sum of 9 skinfolds. Repeated cross-validation analysis highlighted a good predictive performance of the proposed equations. The predictive equations proposed in this study represent a useful tool for clinicians, nutritionists, and physical conditioners to evaluate the physical and nutritional status of athletes with unilateral lower limb amputation directly in the field

Real vs Simulated Foveated Rendering to Reduce Visual Discomfort in Virtual Reality

In this paper, a study aimed at investigating the effects of real (using eye tracking to determine the fixation) and simulated foveated blurring in immersive Virtual Reality is presented. Techniques to reduce the optical flow perceived at the visual field margins are often employed in immersive Virtual Reality environments to alleviate discomfort experienced when the visual motion perception does not correspond to the body's acceleration. Although still preliminary, our results suggest that for participants with higher self-declared sensitivity to sickness, there might be an improvement for nausea when using blurring. The (perceived) difficulty of the task seems to improve when the real foveated method is used.Comment: 9 pages, 2 figures, 1 table, to be published in proceedings of the 18th International Conference promoted by the IFIP Technical Committee 13 on Human Computer Interaction, INTERACT 2021. August 30th September 3rd, 2021, Bari, Ital

An authoring environment for smart objects in museums : the meSch approach

The meSch project addresses the challenges of creating a personally meaningful, sensorily rich, and socially expanded museum visitor experience through tangible and embodied interaction with digital content. It is of paramount importance that cultural heritage professionals are directly involved in the design of those experiences. The meSch approach is to empower cultural heritage professionals with tools that guide them through a do-it-yourself process of creating or adapting digitally augmented experiences for their own museum spaces, therefore reducing the barriers of introducing Internet of Things technology in cultural heritage spaces

(Non-)Participation in deliberation at work: a case study of online participative decision-making

Social media are implemented by organisations to enhance productivity and knowledge sharing among employees, but they can also support group deliberation and employee voice. This paper presents a case study of an online deliberation initiative involving the discussion of a contentious internal policy within an organisation of around 550 knowledge workers. The deliberation process lasted 5 weeks and actively involved 167 employees. Different sources of information (user interaction logs, activity patterns, questionnaire responses) were analysed to investigate the impact of participation, or non‐participation, on the level of satisfaction with the deliberation, and on the understanding of the issue discussed. The findings suggest that (1) interest is a driver for participation, but it does not explain active participation, (2) participation, either active or passive, positively influences the understanding of the issue and (3) satisfaction with the outcome is not related to participation, but it may support participation in future initiatives

FROM A RESEARCH PROTOTYPE TO A DEPLOYED SYSTEM: THE CASE OF THE HECHT MUSEUM VISITOR\u27S GUIDE

Cultural heritage, Deployment, Mobile guides, Research prototype