2016
Authors
Martin, OA; Correia, CM; Gendron, E; Rousset, G; Gratadour, D; Vidal, F; Morris, TJ; Basden, AG; Myers, RM; Neichel, B; Fusco, T;
Publication
ADAPTIVE OPTICS SYSTEMS V
Abstract
CANARY is an open-loop tomographic adaptive optics (AO) demonstrator that was designed for use at the 4.2m William Herschel Telescope (WHT) in La Palma. Gearing up to extensive statistical studies of high redshifted galaxies surveyed with Multi-Object Spectrographs (MOS), the demonstrator CANARY has been designed to tackle technical challenges related to open-loop Adaptive-Optics (AO) control with mixed Natural Guide Star (NGS) and Laser Guide Star (LGS) tomography. We have developed a Point Spread Function (PSF)-Reconstruction algorithm dedicated to MOAO systems using system telemetry to estimate the PSF potentially anywhere in the observed field, a prerequisite to deconvolve AO-corrected science observations in Integral Field Spectroscopy (IFS). Additionally the ability to accurately reconstruct the PSF is the materialization of the broad and fine-detailed understanding of the residual error contributors, both atmospheric and opto-mechanical. In this paper we compare the classical PSF-r approach from Véran (1) that we take as reference on-Axis using the truth-sensor telemetry to one tailored to atmospheric tomography by handling the off-Axis data only. We've post-processed over 450 on-sky CANARY data sets with which we observe 92% and 88% of correlation on respectively the reconstructed Strehl Ratio (SR)/Full Width at Half Maximum (FWHM) compared to the sky values. The reference method achieves 95% and 92.5% exploiting directly the measurements of the residual phase from the Canary Truth Sensor (TS).
2016
Authors
Figueiredo, J; Ferreira, C; Santos, CP; Moreno, JC; Reis, LP;
Publication
2016 IEEE INTERNATIONAL CONFERENCE ON AUTONOMOUS ROBOT SYSTEMS AND COMPETITIONS (ICARSC 2016)
Abstract
Temporal abnormalities in events and gait phases of human walking can be potentially applied in the gait performance analysis. In this study is presented a novel real-time gait events detector that continuously considers the previous gait motions in order to improve this gait analysis. The detection of heel-strike and toe-off events is performed by a finite state machine (FSM), through decision rules and adaptive thresholds. The proposed algorithm stands out of the state-of-the-art by using adaptive thresholds in the FSM's decision rules, making the proposed gait event detector robust to sporadic perturbations, and adaptive to locomotion mode changes. For such, three stages were considered: thresholds' calibration, real-time detection of gait events and thresholds' update. Anatomical differences between lower limbs demanded independent FSMs for each limb. The algorithm was validated in a simulated biped model, and on a real DARwIn-OP robot, what shows up the generality of the proposed approach. Results highlight that the proposed algorithm correctly detects the gait events (accuracy of 100% and 84.348% in simulated and real conditions, respectively), with average time delays from 15.5 to 34ms. Thus, the proposed detector is an adaptive, accurate and versatile tool for real-time analysis of the feet movements along gait cycle.
2016
Authors
Alvarez, MM; Kruschwitz, U; Kazai, G; Hopfgartner, F; Corney, DPA; Campos, R; Albakour, D;
Publication
SIGIR Forum
Abstract
2016
Authors
Guesalaga, A; Neichel, B; Correia, C; Butterley, T; Osborn, J; Masciadri, E; Fusco, T; Sauvage, JF;
Publication
ADAPTIVE OPTICS SYSTEMS V
Abstract
Estimating the outer scale profile, L0(h) in the context of current very large and future extremely large telescopes is crucial, as it impacts the on-line estimation of turbulence parameters (Cn2(h), r0, ?0 and t0) and the performance of Wide Field Adaptive Optics (WFAO) systems. We describe an on-line technique that estimates L0(h) using AO loop data available at the facility instruments. It constructs the cross-correlation functions of the slopes of two or more wavefront sensors, which are fitted to linear combinations of theoretical responses for individual layers with different altitudes and outer scale values. We analyze some restrictions found in the estimation process, which are general to any measurement technique. The insensitivity of the instrument to large values of outer scale is one of them, as the telescope becomes blind to outer scales larger than its diameter. Another problem is the contradiction between the length of data and the stationarity assumption of the turbulence (turbulence parameters may change during the data acquisition time). Our method effectively deals with problems such as noise estimation, asymmetric correlation functions and wavefront propagation effects. It is shown that the latter cannot be neglected in high resolution AO systems or strong turbulence at high altitudes. The method is applied to the Gemini South MCAO system (GeMS) that comprises five wavefront sensors and two DMs. Statistical values of L0(h) at Cerro Pachón from data acquired with GeMS during three years are shown, where some interesting resemblance to other independent results in the literature are shown.
2016
Authors
Vaz de Carvalho, C; Escudeiro, P; Coelho, A;
Publication
Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering, LNICST
Abstract
Welcome to SGAMES 2015, the 5th International Conference on Serious Games, Interaction and Simulation. This conference is a multidisciplinary approach to the presentation of research, theory, application, practice and validation in the fields of Serious Games, Interaction and Simulation. As such it covers areas like cognition, psychology, technology-enhanced education, evaluation and assessment, multimedia and information technology. It is the place to show and to see new scientific approaches and results from experiments and real-life applications. © ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering 2016.
2016
Authors
Serrenho A.; Mourão Z.; Norman J.; Cullen J.; Allwood J.;
Publication
Resources, Conservation and Recycling
Abstract
The steel industry is the world's largest industrial source of CO2 emissions. Recent UK economic policies have led to reduced domestic steel production giving an apparent reduction in national emissions. However, demand for goods made from steel has not reduced. Emissions have thus been transferred not reduced and implementation of UK climate policies may in future expand this 'carbon leakage.' This paper explores how future UK demand for goods made from steel might be supplied while satisfying national climate policies, and how this will influence global CO2 emissions. Current flows and stocks of steel are estimated from existing databases. Evidence from other developed economies suggests that per capita stocks are tending towards a saturation level so future demand is forecast from population growth and the expected rate of replacement of a stable stock. The carbon intensities of five different steel-making routes are used to predict the allowed scale of future domestic steel production within the industrial emissions allowances set in four energy pathways defined by the UK Government. The remaining requirement for steel must be sourced offshore and the associated emissions are predicted, to give an estimate of the global emissions arising from final demand in the UK. The results show that current UK climate strategy may have a limited effect in reducing the CO2 emissions of the global steel industry, unless the UK shifts towards producing more of its own steel products with domestic secondary steel-making. This option would also increase the security of UK supply and support an expansion of UK manufacturing.
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