Visual stimulus disrupts the spatial localization of a tactile sensation in Virtual Reality

Phantom limb pain is a neuropathic condition in which a person feels pain in a limb that is not present. Cognitive treatments that visually recreate the limb in an attempt to create a cross modal interaction between vision, and touch/proprioception have shown to be effective at alleviating this pain. With improvements in technology, Virtual Mirror Therapy is starting to gain favor, however, there are currently no applications that utilize passive touch in the same way non-virtual reality applications do. This paper investigates whether a visual stimulus can relocate a tactile stimulus to a different location using principles from the rubber hand illusion and mirror therapy. We demonstrate that a displaced visual stimulus in virtual reality can disrupt accurate spatial perception of a physical vibrotactile sensation however the effects are small and require further investigation

The use of embedded context-sensitive attractors for clinical walking test guidance in virtual reality

Virtual reality is increasingly used in rehabilitation and can provide additional motivation when working towards therapeutic goals. However, a particular problem for patients regards their ability to plan routes in unfamiliar environments. Therefore, the aim of this study was to explore how visual cues, namely embedded context-sensitive attractors, can guide attention and walking direction in VR, for clinical walking interventions. This study was designed using a butterfly as the embedded context- sensitive attractor, to guide participant locomotion around the clinical figure of eight walk test, to limit the use of verbal instructions. We investigated the effect of varying the number of attractors for figure of eight path following, and whether there are any negative impacts on perceived autonomy or workload. A total of 24 participants took part in the study and completed six attractor conditions in a counterbalanced order. They also experienced a control VE (no attractors) at the beginning and end of the protocol. Each VE condition lasted a duration of 1 minute and manipulated the number of attractors to either singular or multiple alongside, the placement of turning markers (virtual trees) used to represent the cones used in clinical settings for the figure of eight walk test. Results suggested that embedded context-sensitive attractors can be used to guide walking direction, following a figure of eight in VR without impacting perceived autonomy, and workload. However, there appears to be a saturation point, with regards to effectiveness of attractors. Too few objects in a VE may reduce feelings of intrinsic motivation, and too many objects in a VE may reduce the effectiveness of attractors for guiding individuals along a figure of eight path. We conclude by indicating future research directions, for attractors and their use as a guide for walking direction

LoCoMoTe – a framework for classification of natural locomotion in VR by task, technique and modality

Virtual reality (VR) research has provided overviews of locomotion techniques, how they work, their strengths and overall user experience. Considerable research has investigated new methodologies, particularly machine learning to develop redirection algorithms. To best support the development of redirection algorithms through machine learning, we must understand how best to replicate human navigation and behaviour in VR, which can be supported by the accumulation of results produced through live-user experiments. However, it can be difficult to identify, select and compare relevant research without a pre-existing framework in an ever-growing research field. Therefore, this work aimed to facilitate the ongoing structuring and comparison of the VR-based natural walking literature by providing a standardised framework for researchers to utilise. We applied thematic analysis to study methodology descriptions from 140 VR-based papers that contained live-user experiments. From this analysis, we developed the LoCoMoTe framework with three themes: navigational decisions, technique implementation, and modalities. The LoCoMoTe framework provides a standardised approach to structuring and comparing experimental conditions. The framework should be continually updated to categorise and systematise knowledge and aid in identifying research gaps and discussions

Visual elements influence on navigation in virtual environments

Virtual rehabilitation often incorporates an element of travel in a virtual environment. Whether patients are transported automatically through the environment, or whether they have navigational control, it is important to understand how the design of the environment itself can supply navigational cues, and how the processing of these cues may influence perception, behaviour and task performance. This paper explores the literature, which might inform application design, and presents a case study using a think-aloud protocol to explore the perception of users to visual cues within a running game. We conclude with some preliminary suggestions for positive and negative navigational cues

Prediction of navigation by visual aesthetics when presented with binary choices

This preliminary study explored the possibility of influencing participant’s navigation when presented with 5 binary choices. Each participant experienced one trial of the 5 fixed ordered conditions. A think-aloud protocol and questionnaires were used to understand perception and behaviour. We conclude with suggestions of further research of understanding visual aesthetics and their influence of human movement behaviour on patient’s navigation

Revised Calibration Strategy for the CALIOP 532 nm Channel

The CALIPSO lidar (CALIOP) makes backscatter measurements at 532 nm and 1064 nm and linear depolarization ratios at 532 nm. Accurate calibration of the backscatter measurements is essential in the retrieval of optical properties. An assessment of the nighttime 532 nm parallel channel calibration showed that the calibration strategy used for the initial release (Release 1) of the CALIOP lidar level 1B data was acceptable. In general, the nighttime calibration coefficients are relatively constant over the darkest segment of the orbit, but then change rapidly over a short period as the satellite enters sunlight. The daytime 532 nm parallel channel calibration scheme implemented in Release 1 derived the daytime calibration coefficients from the previous nighttime coefficients. A subsequent review of the daytime 532 nm parallel channel calibration revealed that the daytime calibration coefficients do not remain constant, but vary considerably over the course of the orbit, due to thermally-induced misalignment of the transmitter and receiver. A correction to the daytime calibration scheme is applied in Release 2 of the data. Results of both nighttime and daytime calibration performance are presented in this paper

Rethinking climate engineering categorization in the context of climate change mitigation and adaptation

The portfolio of approaches to respond to the challenges posed by anthropogenic climate change has broadened beyond mitigation and adaptation with the recent discussion of potential climate engineering options. How to define and categorize climate engineering options has been a recurring issue in both public and specialist discussions. We assert here that current definitions of mitigation, adaptation, and climate engineering are ambiguous, overlap with each other and thus contribute to confusing the discourse on how to tackle anthropogenic climate change. We propose a new and more inclusive categorization into five different classes: anthropogenic emissions reductions (AER), territorial or domestic removal of atmospheric CO2 and other greenhouse gases (D-GGR), trans-territorial removal of atmospheric CO2 and other greenhouse gases (T-GGR), regional to planetary targeted climate modification (TCM), and climate change adaptation measures (including local targeted climate and environmental modification, abbreviated CCAM). Thus, we suggest that techniques for domestic greenhouse gas removal might better be thought of as forming a separate category alongside more traditional mitigation techniques that consist of emissions reductions. Local targeted climate modification can be seen as an adaptation measure as long as there are no detectable remote environmental effects. In both cases, the scale and intensity of action are essential attributes from the technological, climatic, and political viewpoints. While some of the boundaries in this revised classification depend on policy and judgement, it offers a foundation for debating on how to define and categorize climate engineering options and differentiate them from both mitigation and adaptation measures to climate change