Serban R. Pop

Technical Section: A review of virtual environments for training in ball sports

There is growing interest in utilising virtual environments (VEs) in the context of sports. In particular there is a desire to be able to improve sensorimotor skills rather than just using a VE as a tool for strategy analysis, or entertainment. The range of skills required across all different sports is very large and varied. This review of the state-of-the-art, therefore focuses on just ball sports, and was carried out as part of a current project developing training tools for rugby. A VE needs to provide realistic rendering of the sports scene to achieve good perceptual fidelity. More important for a sport-themed VE is high functional fidelity, which requires an accurate physics model of a complex environment, real time response, and a natural user interface. The goal is to provide multiple scenarios to players at different levels of difficulty, providing them with improved skills that can be applied directly to the real sports arena. The typical hardware and software components needed are identified in the paper, and important psychological factors that should be considered are discussed. The challenges that need to be overcome are identified and illustrated with examples from recent projects in this area.

Storyboarding for visual analytics

Analysts wish to explore different hypotheses, organize their thoughts into visual narratives and present their findings. Some developers have used algorithms to ascertain key events from their data, while others have visualized different states of their exploration and utilized free-form canvases to enable the users to develop their thoughts. What is required is a visual layout strategy that summarizes specific events and allows users to layout the story in a structured way. We propose the use of the concept of ‘storyboarding’ for visual analytics. In film production, storyboarding techniques enable film directors and those working on the film to pre-visualize the shots and evaluate potential problems. We present six principles of storyboarding for visual analytics: composition, viewpoints, transition, annotability, interactivity and separability. We use these principles to develop epSpread, which we apply to VAST Challenge 2011 microblogging data set and to Twitter data from the 2012 Olympic Games. We present technical challenges and design decisions for developing the epSpread storyboarding visual analytics tool that demonstrate the effectiveness of our design and discuss lessons learnt with the storyboarding method.

The Implementation and Validation of a Virtual Environment for Training Powered Wheelchair Manoeuvres

Navigating a powered wheelchair and avoiding collisions is often a daunting task for new wheelchair users. It takes time and practice to gain the coordination needed to become a competent driver and this can be even more of a challenge for someone with a disability. We present a cost-effective virtual reality (VR) application that takes advantage of consumer level VR hardware. The system can be easily deployed in an assessment centre or for home use, and does not depend on a specialized high-end virtual environment such as a Powerwall or CAVE. This paper reviews previous work that has used virtual environments technology for training tasks, particularly wheelchair simulation. We then describe the implementation of our own system and the first validation study carried out using thirty three able bodied volunteers. The study results indicate that at a significance level of 5 percent then there is an improvement in driving skills from the use of our VR system. We thus have the potential to develop the competency of a wheelchair user whilst avoiding the risks inherent to training in the real world. However, the occurrence of cybersickness is a particular problem in this application that will need to be addressed.

A Cost-Effective Virtual Environment for Simulating and Training Powered Wheelchairs Manoeuvres

Control of a powered wheelchair is often not intuitive, making training of new users a challenging and sometimes hazardous task. Collisions, due to a lack of experience can result in injury for the user and other individuals. By conducting training activities in virtual reality (VR), we can potentially improve driving skills whilst avoiding the risks inherent to the real world. However, until recently VR technology has been expensive and limited the commercial feasibility of a general training solution. We describe Wheelchair-Rift, a cost effective prototype simulator that makes use of the Oculus Rift head mounted display and the Leap Motion hand tracking device. It has been assessed for face validity by a panel of experts from a local Posture and Mobility Service. Initial results augur well for our cost-effective training solution.

epSpread - Storyboarding for visual analytics

We present epSpread, an analysis and storyboarding tool for geolocated microblogging data. Individual time points and ranges are analysed through queries, heatmaps, word clouds and streamgraphs. The underlying narrative is shown on a storyboard-style timeline for discussion, refinement and presentation. The tool was used to analyse data from the VAST Challenge 2011 Mini-Challenge 1, tracking the spread of an epidemic using microblogging data. In this article we describe how the tool was used to identify the origin and track the spread of the epidemic.

Force-Directed Parallel Coordinates

Parallel coordinates are a well-known and valuable technique for the analysis and visualization of high dimensional data sets. However, while Inselberg emphasizes that the strength of parallel coordinates as a methodology is rooted in exploration and interactivity, the set of interaction techniques is currently limited. Axes can be re-ordered and brushing (simple, angular or multi-dimensional) can be performed. In this paper, we propose a force-directed algorithm and related interaction techniques to support the exploration of parallel coordinate plots through a physical metaphor. Our parallel-coordinates visualization offers novel user interaction beyond the standard techniques by allowing the user to rotate the axis according to forcedirected polylines. The new interaction provides the user with a more immersive experience for data exploration that results in greater intuition of the data, especially in cases where many polylines overlap. We demonstrate our approach, then present the results of a qualitative evaluation of the system.

The Use of Stereoscopy in a Neurosurgery Training Virtual Environment

We have previously investigated the effectiveness of a custom-built virtual environment in assisting training of a ventriculostomy procedure, which is a commonly performed procedure by a neurosurgeon and a core task for trainee surgeons. The training tool (called VCath) was initially developed as a low-fidelity app for a tablet platform to provide easy access and availability to trainees. Subsequently, we have developed a high-fidelity version of VCath that uses a stereoscopic display to immerse the trainee in the virtual environment. This article reports on two studies that have been carried out to compare the low- and high-fidelity versions of VCath, particularly to assess the value of stereoscopy. Study 1 was conducted at the second annual boot camp organized for all year-one trainees in neurosurgery in the UK. Study 2 was performed on lay people, with no surgical experience. Our hypothesis was that using stereoscopy in the training task would be beneficial. Results from Study 1 demonstrated that performance improved for both the control group and the group trained with the tablet version of VCath. The group trained on the high-fidelity version of VCath with a stereoscopic display showed no performance improvement. The indication is that our hypothesis is false. In Study 2, six different conditions were investigated that covered the use of training with VCath on a tablet, a mono display at two different sizes, a stereo display at two different sizes, and a control group who received no training. Results from this study with lay people show that stereoscopy can make a significant improvement to the accuracy of needle placement. The possible reasons for these results and the apparent contradiction between the two studies are discussed.

Double-diffusive natural convection in a differentially heated wavy cavity under thermophoresis effect

A numerical analysis is made for thermophoretic transport of small particles through the convection in a differentially heated square cavity with a wavy wall. The governing gas-particle partial dif...

Using Virtual Reality to Experience Different Powered Wheelchair Configurations

This paper presents recent additions to our Wheelchair-VR application, in particular the use of different drive configurations. We have previously shown that Wheelchair-VR can be used to improve driving skills. Here we consider the utility of the application in allowing users who are in the process of purchasing or upgrading a wheelchair to experience different configurations and options in a cost-effective virtual environment. A preliminary study is presented, which suggests that this approach can be effective.

VR Cardiovascular Blood Simulation as Decision Support for the Future Cyber Hospital

Planning treatment of acute cardiac events that limit the blood supply to major organs is particularly difficult for interventional cardiologists. The treatment of pathologies, such as vascular stenosis, can have numerous unforeseen consequences as the blood resumes its flow. Their decisions are largely based on 2D medical imagery and their own experience. This work in progress presents a virtual reality blood simulation tool that will augment and improve a clinicians decision-making arsenal, and an outline of the technologies required for this component of the cyber hospital of the future. The tool displays and provides interaction with vital information on how blood may continue to flow through the cardiovascular system after treatment. The blood flow will be simulated using a bespoke implementation of the increasingly effective smoothed particle hydrodynamics model.