Low-Cost Virtual Reality System (PS2-driven)

A low cost virtual reality system that generates corner projection using three PlayStation2 is presented. Two display stations each connected to one projector is used to provide panoramic view of the VR scene. A control station receives user input and broadcasts the instruction to the two display stations in order to update their respective camera positions and orientations. A demo application which immerses the user inside a glider flying through a night city has also been implemented. We report the performance of our system using random primitives. The benchmark revealed a gradual decline in frame rate in response to polygon counts in the scene. Polygon rate in our system remained near constant and does not vary with the polygon count on the screen. The results indicated for our system, a polygon count of 3540 on the screen with a refresh rate of 24fps is optimum in an interactive environment. Investigation on the relationship between roundtrip time and scene complexity revealed a significant positive correlation of (0.966). This suggests system response to user command can be delayed in a complex virtual environment

Low-Cost Virtual Reality System - PC Driven System

The concept of Virtual Reality has been around since early 1960s, but the availability and development of Virtual Reality systems were largely limited due to its nature of high cost and difficulty in maintenance. Until recently, thanks to the fast development of the modern technology, the idea of building Virtual Reality system using commodity-off-the-shelf hardware became feasible. By using Personal Computers, we have in this project developed a Low-Cost Distributed Virtual Reality system that is much cheaper, easier to maintain and mobile. In this project, the design of stereo vision, corner projection and distributed architecture had been discussed and applied in the implementation of the Virtual Reality system. User experiment had been conducted. The aim of the user experiment is to test the system for presence level, Slater, Usoh and Steed (SUS) questionnaire was used as an indication to the level of presence. Furthermore, network performance related to scene complexities were also evaluated. From these experiment, we have found that the Virtual Reality system developed creates a good level of presence to the participants and scene complexity would influence the roundtrip time of the network. Lastly, this paper concludes by discussing why the Low-Cost Virtual Reality system developed to be an effective Virtual Reality system

The interferon gamma gene polymorphism +874 A/T is associated with severe acute respiratory syndrome

BACKGROUND: Cytokines play important roles in antiviral action. We examined whether polymorphisms of IFN-γ,TNF-α and IL-10 affect the susceptibility to and outcome of severe acute respiratory syndrome (SARS). METHODS: A case-control study was carried out in 476 Chinese SARS patients and 449 healthy controls. We tested the polymorphisms of IFN-γ,TNF-α and IL-10 for their associations with SARS. RESULTS: IFN-γ +874A allele was associated with susceptibility to SARS in a dose-dependent manner (P < 0.001). Individuals with IFN-γ +874 AA and AT genotype had a 5.19-fold (95% Confidence Interval [CI], 2.78-9.68) and 2.57-fold (95% CI, 1.35-4.88) increased risk of developing SARS respectively. The polymorphisms of IL-10 and TNF-α were not associated with SARS susceptibility. CONCLUSION: IFN-γ +874A allele was shown to be a risk factor in SARS susceptibility

ICAR: endoscopic skull‐base surgery

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