Subject-specific computer simulation model for determining elbow loading in one-handed tennis backhand groundstrokes

This article was published in the journal Sports Biomechanics [© Taylor and Francis] and the definitive version is available from; http://www.tandfonline.com/doi/abs/10.1080/14763141.2011.629306.A subject-specific angle-driven computer model of a tennis player, combined with a forward dynamics, equipment-specific computer model of tennis ball–racket impacts, was developed to determine the effect of ball–racket impacts on loading at the elbow for one-handed backhand groundstrokes. Matching subject-specific computer simulations of a typical topspin/slice one-handed backhand groundstroke performed by an elite tennis player were done with root mean square differences between performance and matching simulations of < 0.5°over a 50 ms period starting from ball impact. Simulation results suggest that for similar ball–racket impact conditions, the difference in elbow loading for a topspin and slice one-handed backhand groundstroke is relatively small. In this study, the relatively small differences in elbow loading may be due to comparable angle–time histories at the wrist and elbow joints with the major kinematic differences occurring at the shoulder. Using a subject-specific angle-driven computer model combined with a forward dynamics, equipment-specific computer model of tennis ball–racket impacts allows peak internal loading, net impulse, and shock due to ball–racket impact to be calculated which would not otherwise be possible without impractical invasive techniques. This study provides a basis for further investigation of the factors that may increase elbow loading during tennis strokes

Generation of Virtual Display Surfaces for In-vehicle Contextual Augmented Reality

In-vehicle contextual augmented reality (I-CAR) has the potential to provide novel visual feedback to drivers for an enhanced driving experience. To enable I-CAR, we present a parametrized road trench model (RTM) for dynamically extracting display surfaces from a driver's point of view that is adaptable to constantly changing road curvature and intersections. We use computer vision algorithms to analyze and extract road features that are used to estimate the parameters of the RTM. GPS coordinates are used to quickly compute lighting parameters for shading and shadows. Novel driver-based applications that use the RTM are presented

User-centered perspectives for automotive augmented reality

Augmented reality (AR) in automobiles has the potential to signif-icantly alter the driver’s user experience. Prototypes developed in academia and industry demonstrate a range of applications from advanced driver assist systems to location-based information ser-vices. A user-centered process for creating and evaluating designs for AR displays in automobiles helps to explore what collaborative role AR should serve between the technologies of the automobile and the driver. In particular, we consider the nature of this role along three important perspectives: understanding human percep-tion, understanding distraction and understanding human behav-ior. We argue that AR applications should focus solely on tasks that involve the immediate local driving environment and not sec-ondary task spaces to minimize driver distraction. Consistent depth cues should be supported by the technology to aid proper distance judgement. Driving aids supporting situation awareness should be designed with knowledge of current and future states of road users, while focusing on specific problems. Designs must also take into account behavioral phenomena such as risk compensation, inatten-tional blindness and an over-reliance on augmented technology in driving decisions