Micro-doppler-based in-home aided and unaided walking recognition with multiple radar and sonar systems

Published in IET Radar, Sonar and Navigation. Online first 21/06/2016.The potential for using micro-Doppler signatures as a basis for distinguishing between aided and unaided gaits is considered in this study for the purpose of characterising normal elderly gait and assessment of patient recovery. In particular, five different classes of mobility are considered: normal unaided walking, walking with a limp, walking using a cane or tripod, walking with a walker, and using a wheelchair. This presents a challenging classification problem as the differences in micro-Doppler for these activities can be quite slight. Within this context, the performance of four different radar and sonar systems – a 40 kHz sonar, a 5.8 GHz wireless pulsed Doppler radar mote, a 10 GHz X-band continuous wave (CW) radar, and a 24 GHz CW radar – is evaluated using a broad range of features. Performance improvements using feature selection is addressed as well as the impact on performance of sensor placement and potential occlusion due to household objects. Results show that nearly 80% correct classification can be achieved with 10 s observations from the 24 GHz CW radar, whereas 86% performance can be achieved with 5 s observations of sonar

Ultrasonic distance sensor improvement using a two-level neural network

This paper discusses the performance improvement that a neural network can provide to a contactless distance sensor based on the measurement of the time of flight (TOF) of an ultrasonic (US) pulse. The sensor, which embeds a correction system for the temperature effect, achieves a distance uncertainty (rms) of less than 0.5 mm over 0.5 m by using a two-level neural network to process the US echo and determine the TOF in the presence of environmental acoustic noise. The network embeds a "guard" neuron that guards against gross measurement errors, which would be possible in the presence of high environmental noise

Algorithms for Longest Common Abelian Factors

In this paper we consider the problem of computing the longest common abelian factor (LCAF) between two given strings. We present a simple $O(\sigma~ n^2)$ time algorithm, where $n$ is the length of the strings and $\sigma$ is the alphabet size, and a sub-quadratic running time solution for the binary string case, both having linear space requirement. Furthermore, we present a modified algorithm applying some interesting tricks and experimentally show that the resulting algorithm runs faster.Comment: 13 pages, 4 figure

Quantile contours and allometric modelling for risk classification of abnormal ratios with an application to asymmetric growth-restriction in preterm infants

We develop an approach to risk classification based on quantile contours and allometric modelling of multivariate anthropometric measurements. We propose the definition of allometric direction tangent to the directional quantile envelope, which divides ratios of measurements into half-spaces. This in turn provides an operational definition of directional quantile that can be used as cutoff for risk assessment. We show the application of the proposed approach using a large dataset from the Vermont Oxford Network containing observations of birthweight (BW) and head circumference (HC) for more than 150,000 preterm infants. Our analysis suggests that disproportionately growth-restricted infants with a larger HC-to-BW ratio are at increased mortality risk as compared to proportionately growth-restricted infants. The role of maternal hypertension is also investigated.Comment: 31 pages, 3 figures, 8 table

Ensemble dependence of Critical Casimir Forces in Films with Dirichlet Boundary Conditions

In a recent study [Phys. Rev. E \textbf{94}, 022103 (2016)] it has been shown that, for a fluid film subject to critical adsorption, the resulting critical Casimir force (CCF) may significantly depend on the thermodynamic ensemble. Here, we extend that study by considering fluid films within the so-called ordinary surface universality class. We focus on mean-field theory, within which the OP profile satisfies Dirichlet boundary conditions and produces a nontrivial CCF in the presence of external bulk fields or, respectively, a nonzero total order parameter within the film. Our analytical results are supported by Monte Carlo simulations of the three-dimensional Ising model. We show that, in the canonical ensemble, i.e., when fixing the so-called total mass within the film, the CCF is typically repulsive instead of attractive as in the grand canonical ensemble. Based on the Landau-Ginzburg free energy, we furthermore obtain analytic expressions for the order parameter profiles and analyze the relation between the total mass in the film and the external bulk field.Comment: 22 pages, 15 figures. Version 2: minor corrections; added Journal referenc

Light curves and spectra from off-axis gamma-ray bursts

If gamma-ray burst prompt emission originates at a typical radius, and if material producing the emission moves at relativistic speed, then the variability of the resulting light curve depends on the viewing angle. This is due to the fact that the pulse evolution time scale is Doppler contracted, while the pulse separation is not. For off-axis viewing angles $\theta_{\rm view} \gtrsim \theta_{\rm jet} + \Gamma^{-1}$, the pulse broadening significantly smears out the light curve variability. This is largely independent of geometry and emission processes. To explore a specific case, we set up a simple model of a single pulse under the assumption that the pulse rise and decay are dominated by the shell curvature effect. We show that such a pulse observed off-axis is (i) broader, (ii) softer and (iii) displays a different hardness-intensity correlation with respect to the same pulse seen on-axis. For each of these effects, we provide an intuitive physical explanation. We then show how a synthetic light curve made by a superposition of pulses changes with increasing viewing angle. We find that a highly variable light curve, (as seen on-axis) becomes smooth and apparently single-pulsed (when seen off-axis) because of pulse overlap. To test the relevance of this fact, we estimate the fraction of off-axis gamma-ray bursts detectable by \textit{Swift} as a function of redshift, finding that a sizable fraction (between 10\% and 80\%) of nearby ($z<0.1$) bursts are observed with $\theta_{\rm view} \gtrsim \theta_{\rm jet} + \Gamma^{-1}$. Based on these results, we argue that low luminosity gamma-ray bursts are consistent with being ordinary bursts seen off-axis.Comment: 13 pages, 17 figures, submitted to MNRAS main journal; updated estimate of the fraction of off-axis grbs seen by Swif

Mothers and fathers with Binge Eating Disorder and their 18-36 months old children: a longitudinal study on parent-infant interactions and offspring\u2019s emotional-behavioral profiles

Maternal Binge Eating Disorder (BED) has been suggested to be associated with poor parent\u2013infant interactions during feeding and with children\u2019s emotional and behavioral problems during infancy (Blissett and Haycraft, 2011). The role of fathers has received increasing consideration in recent years, yet the research has not focused on interactional patterns between fathers with BED and their children. The present study aimed to longitudinally investigate the in\ufb02uence of BED diagnosis, in one or both parents, on parent\u2013infant feeding interactions and on children\u2019s emotional\u2013behavioral functioning. 612 subjects (408 parents; 204 children), recruited in mental health services and pre-schools in Central Italy, were divided into four groups: Group 1 included families with both parents diagnosed with BED, Group 2 and 3 included families with one parent diagnosed with BED, Group 0 was a healthy control. The assessment took place at T1 (18 months of age of children) and T2 (36 months of age of children): feeding interactions were assessed through the Scale for the Assessment of Feeding Interactions (SVIA) while child emotional\u2013behavioral functioning was evaluated with the Child Behavior Check-List (CBCL). When compared to healthy controls, the groups with one or both parents diagnosed with BED showed higher scores on the SVIA and on the CBCL internalizing and externalizing scales, indicating poorer adult\u2013child feeding interactions and higher emotional\u2013behavioral dif\ufb01culties. A direct in\ufb02uence of parental psychiatric diagnosis on the quality of mother\u2013infant and father\u2013infant interactions was also found, both at T1 and T2. Moreover, dyadic feeding interactions mediated the in\ufb02uence of parental diagnosis on children\u2019s psychological functioning. The presence of BED diagnosis in one or both parents seems to in\ufb02uence the severity of maladaptive parent\u2013infant exchanges during feeding and offspring\u2019s emotional\u2013behavioral problems over time, consequently affecting different areas of children\u2019s psychological functioning. This is the \ufb01rst study to demonstrate the speci\ufb01c effects of maternal and paternal BED on infant development. These results could inform prevention and intervention programs in families with one or both parents diagnosed with BED

Gender and Mutation in Irish: a Preliminary Account for Further Investigation

Standard Irish is the outcome of language planning and as such it significantly diverges from the three main spoken dialects of the language (or traditional Gaeltacht varieties) that provided the basis for its creation. It is also expected to differ, in its codified form, from the way it is actually employed within the small, usually urban communities of bilinguals who employ standard Irish and not some form of Gaeltacht Irish as a second language. The reason why such difference is expected is that the language planners codified as part of the standard many complex structures that had already been abandoned in the spoken dialects, basing their reconstruction on historicity rather than actual usage (especially as the actual usages were far from uniform). In this article, which presents part of the work involved in my currently ongoing research, some such complexities are presented which pertain to grammatical gender