EVALUATION OF THE ACCURACY OF GAIT EVENTS DETECTED USING THREE DIFFERENT METHODS DURING RUNNING

Different methods have been proposed for determining initial contact and toe off with inertial measurement unit (IMU) attached to different anatomical positions. However, the accuracy has not yet been compared. This study aimed to evaluate the accuracy of three commonly used methods (S-, M-, and L-method) in detecting gait events at two running speed conditions (slow and fast). Obvious differences of detected initial contact and toe off and estimated stance duration among the three detection methods using IMU were found at the two running speed conditions. It was shown that initial contact detected using the S-method and toe off detected by the M-method were the best estimates of the gait events. Combined use of both methods is recommended for determining stance duration during overground running

The effect of school bag design and load on spinal posture during stair use by children

This is an Accepted Manuscript of an article published by Taylor & Francis in Ergonomics on 22/11/2011, available online: http://dx.doi.org/10.1080/00140139.2011.615415.Thirteen male children ascending and descending stairs with loads that equalled 0%, 10%, 15% and 20% of their body weight were the subject of our research: the boys were wearing an asymmetrical single-strap athletic bag or a symmetrical double-strap backpack during our experiments with them. The maximum spinal tilt to the loading side and to the support side, and the range of spinal motions, were obtained by using a motion analysis system. Our results showed that symmetry of spinal posture was observed both when they ascended staircase with all loads and descended in a backpack. When carrying an athletic bag with 15% and 20% of their body weight while ascending the staircase, the lateral spinal tilt to the supporting side was significantly increased. We concluded that a symmetrical backpack with a load not exceeding 20% or an asymmetrical single-strap athletic bag with a load not exceeding 10% should be recommended for school children in order to promote safer staircase use. Statement of Relevance: Children carrying heavy school bags may develop spinal problems. This study suggested that when they are using stairs, a symmetrical backpack with a load within 20% body weight is acceptable for them. When they are carrying an asymmetrical single-strap athletic bag, the bag's weight should not exceed 10% of the body weight in order to avoid excessive spinal tilt

Multi-dimensional modeling and simulation of semiconductor nanophotonic devices

Self-consistent modeling and multi-dimensional simulation of semiconductor nanophotonic devices is an important tool in the development of future integrated light sources and quantum devices. Simulations can guide important technological decisions by revealing performance bottlenecks in new device concepts, contribute to their understanding and help to theoretically explore their optimization potential. The efficient implementation of multi-dimensional numerical simulations for computer-aided design tasks requires sophisticated numerical methods and modeling techniques. We review recent advances in device-scale modeling of quantum dot based single-photon sources and laser diodes by self-consistently coupling the optical Maxwell equations with semiclassical carrier transport models using semi-classical and fully quantum mechanical descriptions of the optically active region, respectively. For the simulation of realistic devices with complex, multi-dimensional geometries, we have developed a novel hp-adaptive finite element approach for the optical Maxwell equations, using mixed meshes adapted to the multi-scale properties of the photonic structures. For electrically driven devices, we introduced novel discretization and parameter-embedding techniques to solve the drift-diffusion system for strongly degenerate semiconductors at cryogenic temperature. Our methodical advances are demonstrated on various applications, including vertical-cavity surface-emitting lasers, grating couplers and single-photon sources

Effect of Cyber-Golfing on Balance Amongst the Elderly in Hong Kong: A Pilot Randomised Trial

Background/Objective: Recent evidence showed that golf can develop balance amongst the elderly. This study aimed at evaluating if exergaming, in particular cyber-golfing, can be a feasible and inexpensive alternative to this valuable exercise. Methods: Twenty healthy community-dwelling elderly were recruited, and they were randomly assigned to either the experimental group (n = 10) or the control group (n = 10). Daily cyber-golfing training for 2 weeks was assigned to the participants of the experimental group, where regular table games with equal lengths and durations were arranged for the control group. Results: The results revealed that the participants in the experimental group showed significantly better post-training performances in the functional-reach test, F(2,17) = 5.16, p = .04, and single-leg-stance test, F(2,17) = 5.32, p = .03, than those in the control group. Conclusion: The results of this study suggest that cyber-golfing might be an alternative to golfing, which is capable of enhancing balance ability amongst community-dwelling elderly. The potential of exergaming as a clinical tool for geriatric rehabilitation was discussed