Substitutional Reality System: A Novel Experimental Platform for Experiencing Alternative Reality

We have developed a novel experimental platform, referred to as a substitutional reality (SR) system, for studying the conviction of the perception of live reality and related metacognitive functions. The SR system was designed to manipulate people's reality by allowing them to experience live scenes (in which they were physically present) and recorded scenes (which were recorded and edited in advance) in an alternating manner without noticing a reality gap. All of the naïve participants (n = 21) successfully believed that they had experienced live scenes when recorded scenes had been presented. Additional psychophysical experiments suggest the depth of visual objects does not affect the perceptual discriminability between scenes, and the scene switch during head movement enhance substitutional performance. The SR system, with its reality manipulation, is a novel and affordable method for studying metacognitive functions and psychiatric disorders

Phase II randomised trial of chemoradiotherapy with FOLFOX4 or cisplatin plus fluorouracil in oesophageal cancer

International audienceBackground: Concurrent chemoradiotherapy is a valuable treatment option for localised oesophageal cancer (EC), but improvement is still needed. A randomised phase II trial was initiated to assess the feasibility and efficacy in terms of the endoscopic complete response rate (ECRR) of radiotherapy with oxaliplatin, leucovorin and fluorouracil (FOLFOX4) or cisplatin/fluorouracil. Methods: Patients with unresectable EC (any T, any N, M0 or M1a), or medically unfit for surgery, were randomly assigned to receive either six cycles (three concomitant and three post-radiotherapy) of FOLFOX4 (arm A) or four cycles (two concomitant and two post-radiotherapy) of cisplatin/fluorouracil (arm B) along with radiotherapy 50 Gy in both arms. Responses were reviewed by independent experts. Results: A total of 97 patients were randomised (arm A/B, 53/44) and 95 were assessable. The majority had squamous cell carcinoma (82%; arm A/B, 42/38). Chemoradiotherapy was completed in 74 and 66%. The ECRR was 45 and 29% in arms A and B, respectively. Median times to progression were 15.2 and 9.2 months and the median overall survival was 22.7 and 15.1 months in arms A and B, respectively. Conclusion: Chemoradiotherapy with FOLFOX4, a well-tolerated and convenient combination with promising efficacy, is now being tested in a phase III trial

Perception of image motion during head movement

We examined human perception of head-referenced image motion during concurrent head movement. The visual stimulus was a checkerboard image in a head mounted display that moved from side-to-side. Observers rated the magnitude of the checkerboard motion while either rotating their head about a vertical axis (yaw), about a horizontal axis (pitch), or holding it still. In Experiment 1, we tested four image oscillation frequencies (0.25, 0.5, 1, and 2 Hz) while holding the head motion frequency constant at 0.5 Hz. In Experiment 2, we tested three head motion frequencies (0.25, 0.5, and 1 Hz) while holding the image oscillation frequency constant at 1 Hz. Across all image and head motion frequencies, perceptual sensitivity to image motion was reduced by about 45% during horizontal head movement. During vertical head movement, perceptual sensitivity was reduced by about 25% when head and image motion were of the same frequency. Compared with when the head was still, horizontal and vertical head movements produced a downward shift of about 10% in overall motion magnitude estimation response. Findings from this study provide virtual environment developers with a quantitative description of the influence of concurrent head movement on the perception of frontoparallel image motion. © 2009 ACM.link_to_subscribed_fulltex

Interacting With Virtual Reality

Interacting with virtual reality is fundamentally different from interacing with traditional desktop graphics. The three features that characterize virtual reality interaction are immersion, rich interaction and presence; I define these features. To achieve them, virtual reality system designers need to address many different issues. I discuss some of these issues, in particular multiple inputs, multiple outputs, multiple participants, dynamic virtual worlds, user interface paradigms and performance. Keywords Virtual reality, interaction, user interface, performance 1 INTRODUCTION Even though virtual reality (VR) originates in traditional, interactive 3D graphics, it now is its own area of research: VR has its own specific problems and specialized solutions that are often different from those in interactive 3D computer graphics. Therefore, the applicability of even basic concepts of interactive 3D graphics is questioned. For example, 3D graphics architectures have used essentially t..

Performance measures for haptic interfaces

A haptic interface is distinct from other display devices because it is bi-directional � it is capable of both reading and writing input to and from a human user. Due to both the direct human interaction and bi-directionality there has been much ambiguity in describing and evaluating these devices, making evaluation and comparison di-cult. The goal of this paper is to set out requirements and guidelines for the performance measures of haptic devices and to hopefully lead towards resolving the current equivocal situation. In particular, performance measures are introduced whichhaveso far not been pertinent in traditional robotics � these include, peak force, peak acceleration and frequency dependent measurements. Performance measures often quoted in traditional robotics are also discussed, however, the focus and relevance of these measures are different in haptic devices. Each of the suggested performance measures in this paper is discussed with respect to its importance, its measurabilty and the condition under which it should be measured.