Utilising wearable and environmental sensors to identify the context of gait performance in the home

In this paper we describe our work on the development of a multi-sensory deployment within the homes of elderly people prone to falling. The aim of our work is to provide both preventative guidance with regards to environmental hazards, as well as to create rich information context around gait performance, near-falls or falls that do happen so the cause can be diagnosed more thoroughly. We use a gait analysis platform developed at the TRIL Centre, coupled with a SenseCam wearable camera, to identify the activities and the location in the home during walking activities. In addition to this, and to add even more context, we use home energy- monitoring to enhance our understanding of activities and activity patterns in the home. This method could support older people in identifying a key problem and allow the participant to modify their behaviour or environment to limit or prevent future occurrences

A Chemical Kinetics Approach to The Duration-of-Load Problem in Wood

The theory of absolute rates of chemical processes is presented as an appropriate conceptual framework for understanding the creep-rupture phenomena of duration of load (DOL) and rate of loading (ROL). The theory predicts the following experimentally observed phenomena:(1) The logarithm of the time to failure under constant deadload stress increases linearly as the stress level is decreased.(2) The rupture strength in a linear-ramp ROL experiment increases with the logarithm of the rate of stressing.Moreover, the equations derived to describe these phenomena contain the same parameters. These parameters are denned physical quantities that describe the creep characteristics of the material. It is possible to predict how long a material will support a constant deadload stress (DOL behavior) from measurements of apparent rupture strength as a function of the rate of stressing in a linear-ramp loading experiment (ROL behavior).Rupture of Douglas-fir in bending is selected as an example, and the experimental results from ROL-behavior experiments are used to predict DOL behavior. The theory adequately describes the experimentally observed results

Structured input-output analysis of stably stratified plane Couette flow

We employ a recently introduced structured input-output analysis (SIOA) approach to analyze streamwise and spanwise wavelengths of flow structures in stably stratified plane Couette flow. In the low-Reynolds number ($Re$) low-bulk Richardson number ($Ri_b$) spatially intermittent regime, we demonstrate that SIOA predicts high amplification associated with wavelengths corresponding to the characteristic oblique turbulent bands in this regime. SIOA also identifies quasi-horizontal flow structures resembling the turbulent-laminar layers commonly observed in the high-$Re$ high-$Ri_b$ intermittent regime. An SIOA across a range of $Ri_b$ and $Re$ values suggests that the classical Miles-Howard stability criterion ($Ri_b\leq 1/4$) is associated with a change in the most amplified flow structures when Prandtl number is close to one ($Pr\approx 1$). However, for $Pr\ll 1$, the most amplified flow structures are determined by the product $PrRi_b$. For $Pr\gg 1$, SIOA identifies another quasi-horizontal flow structure that we show is principally associated with density perturbations. We further demonstrate the dominance of this density-associated flow structure in the high $Pr$ limit by constructing analytical scaling arguments for the amplification in terms of $Re$ and $Pr$ under the assumptions of unstratified flow (with $Ri_b=0$) and streamwise invariance.Comment: 27 pages, 12 figure

Facial trustworthiness judgments in children with ASD are modulated by happy and angry emotional cues

Appearance-based trustworthiness inferences may reflect the misinterpretation of emotional expression cues. Children and adults typically perceive faces that look happy to be relatively trustworthy and those that look angry to be relatively untrustworthy. Given reports of atypical expression perception in children with Autism Spectrum Disorder (ASD), the current study aimed to determine whether the modulation of trustworthiness judgments by emotional expression cues in children with ASD is also atypical. Cognitively-able children with and without ASD, aged 6–12 years, rated the trustworthiness of faces showing happy, angry and neutral expressions. Trust judgments in children with ASD were significantly modulated by overt happy and angry expressions, like those of typically-developing children. Furthermore, subtle emotion cues in neutral faces also influenced trust ratings of the children in both groups. These findings support a powerful influence of emotion cues on perceived trustworthiness, which even extends to children with social cognitive impairments

TennisSense: a multi-sensory approach to performance analysis in tennis

The TennisSense Project, that is run in collaboration with Tennis Ireland, aims to create the infrastructure required to digitally capture physical, tactical and physiological data from tennis players in order to assist in their coaching and improved performance. This study examined the potential for using Wireless Inertial Monitoring Units (WIMU) to model the biomechanical aspects of the tennis stroke and for developing coaching tools that utilise this information. There is significant evidence in the current literature that the ability to accurately capture and model the accelerations, angular velocities and orientations involved in the tennis stroke could facilitate a major step forward in the application of biomechanics to tennis coachin

Heat stress: A major contributor to poor animal welfare associated with long-haul live export voyages

Recent investigations by the Australian Department of Agriculture, Fisheries and Forestry into high mortalities on live export voyages from Australia to the Middle East during the Northern hemisphere summer suggest that animal welfare may be compromised by heat stress. The live export industry has generated a computer model that aims to assess the risk of heat stress and to contain mortality levels on live export ships below certain arbitrary limits. Although the model must be complied with under Australian law, it is not currently available for independent scientific scrutiny, and there is concern that model and the mandated space allowances are inadequate. This review appraises the relevant literature on heat stress in sheep and cattle, including laboratory studies aimed at mimicking the ambient temperatures and humidity levels likely to be encountered on live export voyages. Animal welfare is likely to be very poor as a result of heat stress in some shipments

A USB Interfaced Motion Capture Sensor, Using Tri-Axis Magnetic/Inertial Sensors For Use In Kinematic Studies

An unobtrusive tri-axis magnetic and gravitational field transducer for use in kinematic tracking is presented. Outlined is a novel approach for using such a sensor i.e. providing a Universal Serial Bus (USB) interface, allowing the direct utilization of the logical topology of the standard, making scalable deployment possible. Furthermore design considerations; construction and performance of the sensor are analysed and discussed in detail

A USB Interfaced Motion Capture Sensor, Using Tri-Axis Magnetic/Inertial Sensors For Use In Kinematic Studies

An unobtrusive tri-axis magnetic and gravitational field transducer for use in kinematic tracking is presented. Outlined is a novel approach for using such a sensor i.e. providing a Universal Serial Bus (USB) interface, allowing the direct utilization of the logical topology of the standard, making scalable deployment possible. Furthermore design considerations; construction and performance of the sensor are analysed and discussed in detail

Laboratory experiments on two coalescing axisymmetric turbulent plumes in a rotating fluid

Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of American Institute of Physics for personal use, not for redistribution. The definitive version was published in Physics of Fluids 23 (2011): 056601, doi:10.1063/1.3584134.We investigate the early-time coalescence of two co-flowing axisymmetric turbulent plumes and the later-time flow of the induced vortices in a rotating, homogeneous fluid using laboratory experiments. The experiments demonstrate the critical importance of the rotation period Tf = 2π/f, where f is the Coriolis parameter of the background rotation. We find that if the plumes’ sources are sufficiently “close” for the plumes to merge initially at an “early time” tm≲tr = 3Tf/4, the experimentally observed merging height zme agrees well with the non-rotating theoretical relationship of zmt ≈ (0.44/α)x0tr, however, the flow dynamics are substantially more complicated, as the flow becomes significantly affected by rotation. The propagation and entrainment of the plumes becomes strongly affected by the vortices induced by the entrainment flow in a rotating environment. Also, the plume fluid itself starts to interact with these vortices. If the plumes have already initially merged by the time t = tr, a single vortex (initially located at the midpoint of the line connecting the two plume sources) develops, which both advects and modifies the geometry of the merging plumes. Coupled with the various suppressing effects of rotation on the radial plume entrainment, the “apparent” observed height of merger can vary substantially from its initial value. Conversely, for more widely separated “distant” plumes, where x0>xc = (25α/2)F01/4f-3/4, the plumes do not merge before the critical time tr when rotation becomes significant in the flow dynamics and two vortices are observed, each located over a plume source. The combined effect of these vortices with the associated suppression of entrainment by rotation thus significantly further delays the merger of the two plumes, which apparently becomes possible only through the merger of the induced vortices.This work was supported by the Center for Planetary Science