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Publications

Publications by CTM

2018

On the Use of Natural User Interfaces in Physical Rehabilitation: A Web-based Application for Patients with Hip Prosthesis

Authors
Rybarczyk, Y; Cointe, C; Goncalves, T; Minhoto, V; Deters, JK; Villarreal, S; Gonzalo, AA; Baldeon, J; Esparza, D;

Publication
JOURNAL OF SCIENCE AND TECHNOLOGY OF THE ARTS

Abstract
This study aims to develop a telemedicine platform for self-motor rehabilitation and remote monitoring by health professionals, in order to enhance recovery in patients after hip replacement. The implementation of such a technology is justified by medical (improvement of the recovery process by the possibility to perform rehabilitation exercises more frequently), economic (reduction of the number of medical appointments and the time patients spend at the hospital), mobility (diminution of the transportation to and from the hospital) and ethics (healthcare democratization and increased empowerment of the patient) purposes. The Kinect camera is used as a Natural User Interface to capture the physical exercises performed at home by the patients. The quality of the movement is evaluated in real-time by an assessment module implemented according to a Hidden-Markov Model approach. The results show a high accuracy in the evaluation of the movements (92% of correct classification). Finally, the usability of the platform is tested through the System Usability Scale (SUS). The overall SUS score is 81 out of 100, which suggests a good usability of the Web application. Further work will focus on the development of additional functionalities and an evaluation of the impact of the platform on the recovery process.

2018

Supervised learning methods for pathological arterial pulse wave differentiation: A SVM and neural networks approach

Authors
Paiva, JS; Cardoso, J; Pereira, T;

Publication
INTERNATIONAL JOURNAL OF MEDICAL INFORMATICS

Abstract
Objective: The main goal of this study was to develop an automatic method based on supervised learning methods, able to distinguish healthy from pathologic arterial pulse wave (APW), and those two from noisy waveforms (non-relevant segments of the signal), from the data acquired during a clinical examination with a novel optical system. Materials and methods: The APW dataset analysed was composed by signals acquired in a clinical environment from a total of 213 subjects, including healthy volunteers and non-healthy patients. The signals were parameterised by means of 39 pulse features: morphologic, time domain statistics, cross-correlation features, wavelet features. Multiclass Support Vector Machine Recursive Feature Elimination (SVM RFE) method was used to select the most relevant features. A comparative study was performed in order to evaluate the performance of the two classifiers: Support Vector Machine (SVM) and Artificial Neural Network (ANN). Results and discussion: SVM achieved a statistically significant better performance for this problem with an average accuracy of 0.9917 +/- 0.0024 and a F-Measure of 0.9925 +/- 0.0019, in comparison with ANN, which reached the values of 0.9847 +/- 0.0032 and 0.9852 +/- 0.0031 for Accuracy and F-Measure, respectively. A significant difference was observed between the performances obtained with SVM classifier using a different number of features from the original set available. Conclusion: The comparison between SVM and NN allowed reassert the higher performance of SVM. The results obtained in this study showed the potential of the proposed method to differentiate those three important signal outcomes (healthy, pathologic and noise) and to reduce bias associated with clinical diagnosis of cardiovascular disease using APW.

2018

Automatic Methods for Carotid Contrast-Enhanced Ultrasound Imaging Quantification of Adventitial Vasa Vasorum

Authors
Pereira, T; Muguruza, J; Mária, V; Vilaprinyo, E; Sorribas, A; Fernandez, E; Fernandez-Armenteros, JM; Baena, JA; Rius, F; Betriu, A; Solsona, F; Alves, R;

Publication
Ultrasound in Medicine & Biology

Abstract

2018

Quantitative Operating Principles of Yeast Metabolism during Adaptation to Heat Stress

Authors
Pereira, T; Vilaprinyo, E; Belli, G; Herrero, E; Salvado, B; Sorribas, A; Altés, G; Alves, R;

Publication
Cell Reports

Abstract

2018

Focal-plane C<sub>n2</sub>(<i>h</i>) profiling based on single-conjugate adaptive optics compensated images

Authors
Beltramo Martin, O; Correia, CM; Neichel, B; Fusco, T;

Publication
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

Abstract
Knowledge of the atmospheric turbulence in the telescope line-of-sight is crucial for widefield observations assisted by adaptive optics (AO), particularly tomodel how the point spread function (PSF) elongates across the field of view(FOV) owing to the anisoplanatism effect. The extraction of key astronomical parameters accounts on an accurate representation of the PSF, which call for an accurate anisoplanatism characterisation . This one is, however, a function of the Cn2(h) profile, which is not directly accessible from single-conjugate AO telemetry. It is possible to rely on external profilers, but recent studies have highlighted discrepancies of more than 10 per cent with AO internal measurements, while we aim at better than 1 per cent accuracy for PSF modelling. In order to tackle this limitation, we present focal-plane profiling (FPP) as a Cn2(h) profiling method that relies on post-AO focal-plane images.We demonstrate that such an approach complies with a 1 per cent level of accuracy on the Cn2(h) estimation and establish how this accuracy varies regarding the calibration star magnitudes and their positions in the field. We highlight the fact that photometry and astrometry errors caused by PSF mis-modelling reach respectively 1 per cent and 50 µas using FPP on a Keck baseline, with a preliminary calibration using a star of magnitude H = 14 at 20 arcsec. We validate this concept using Canada's NRC-Herzberg HeNOS testbed images by comparing FPP retrieval with alternative Cn2 (h) measurements on HeNOS. The FPP approach allows the Cn2(h) to be profiled using the SCAO systems and significantly improves the PSF characterization. Such a methodology is also ELT-size-compliant and will be extrapolated to tomographic systems in the near future.

2018

William Herschel telescope site characterization using the MOAO pathfinder CANARY on-sky data

Authors
Martin O.A.; Correia C.M.; Gendron E.; Rousset G.; Vidal F.; Morris T.J.; Basden A.G.; Myers R.M.; Ono Y.; Neichel B.; Fusco T.;

Publication
Proceedings of SPIE - The International Society for Optical Engineering

Abstract

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