Progress in Pattern Recognition, Image Analysis, Computer Vision, and Applications, 2019
This work presents a comparison between two methods for spatial feature extraction applied on a s... more This work presents a comparison between two methods for spatial feature extraction applied on a system to recognize shoulder flexion/extension motor imagery (SMI) tasks to convey on-line control commands towards a 4 degrees-of-freedom (DoF) upper-limb robotic exoskeleton. Riemannian geometry and Common Spatial Pattern (CSP) are applied on the filtered EEG for spatial feature extraction, which later are used by the Linear Discriminant Analysis (LDA) classifier for motor imagery (MI) recognition. Three bipolar EEG channels were used on six healthy subjects to acquire our database, composed of two classes: rest state and shoulder flexion/extension MI. Our system achieved a mean accuracy (ACC) of 75.12% applying Riemannian, with the highest performance for Subject S01 (ACC = 89.68%, Kappa = 79.37%, true positive rate (TPR) = 87.50%, and FPR < 8.13%). In contrast, for CSP, a mean ACC of 66.29% was achieved. These findings suggest that unsupervised methods for feature extraction, such as Riemannian geometry, can be suitable for shoulder flexion/extension MI to command an upper-limb robotic exoskeleton.
Is analyzed from a clinical and kinetic point of view the feasibility of using the transfemoral p... more Is analyzed from a clinical and kinetic point of view the feasibility of using the transfemoral prosthesis Otto Bock with 3R80 knee and articulate...
XXVI Brazilian Congress on Biomedical Engineering, 2019
This work presents a study of brain-computer interfaces (BCIs) to recognize motor imagery tasks, ... more This work presents a study of brain-computer interfaces (BCIs) to recognize motor imagery tasks, using the Riemannian covariance matrices to compute spatial features, and Linear Discriminant Analysis (LDA), Regularized Discriminant Analysis (RDA), and Support Vector Machine (SVM) as classifiers. These BCIs were evaluated through paired combination of four motor imagery tasks. The chosen BCI achieved promising results (accuracy (ACC) of 81.40%) using RDA, showing the best performance on Subject 1 (ACC = 94.45%). This study is a first stage to obtain a BCI based on motor imagery, in order to increase the effectiveness of a neuro-rehabilitation system using upper-limb robotic exoskeleton.
Journal of NeuroEngineering and Rehabilitation, 2020
Backgrounds Exoskeletons development arises with a leading role in neurorehabilitation technologi... more Backgrounds Exoskeletons development arises with a leading role in neurorehabilitation technologies; however, very few prototypes for upper limbs have been tested, contrasted and duly certified in terms of their effectiveness in clinical environments in order to incorporate into the health system. The purpose of this pilot study was to determine if robotic therapy of Hemiplegic Shoulder Pain (HSP) could lead to functional improvement in terms of diminishing of pain, spasticity, subluxation, the increasing of tone and muscle strength, and the satisfaction degree. Methods An experimental study was conducted in 16 patients with painful shoulder post- ischemic stroke in two experimental groups: conventional and robotic therapy. At different stages of its evolution, the robotic therapy effectiveness applied with anti-gravitational movements was evaluated. Clinical trial was developed at the Physical Medicine and Rehabilitation Department of the Surgical Clinical Hospital “Dr. Juan Bruno ...
The development of Brain–Computer Interfaces based on Motor Imagery (MI) tasks is a relevant rese... more The development of Brain–Computer Interfaces based on Motor Imagery (MI) tasks is a relevant research topic worldwide. The design of accurate and reliable BCI systems remains a challenge, mainly in terms of increasing performance and usability. Classifiers based on Bayesian Neural Networks are proposed in this work by using the variational inference, aiming to analyze the uncertainty during the MI prediction. An adaptive threshold scheme is proposed here for MI classification with a reject option, and its performance on both datasets 2a and 2b from BCI Competition IV is compared with other approaches based on thresholds. The results using subject-specific and non-subject-specific training strategies are encouraging. From the uncertainty analysis, considerations for reducing computational cost are proposed for future work.
All in-text references underlined in blue are linked to publications on ResearchGate, letting you... more All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.
Se realiza un estudio del desgaste erosivo en dos recubrimientos de carburos de tunsgteno (WC-10C... more Se realiza un estudio del desgaste erosivo en dos recubrimientos de carburos de tunsgteno (WC-10Co-4Cr y WC-12Co) y cromo (Cr3C2-25NiCr), depositados por proyeccion termica con llama a baja velocidad (Flame Spray, FS) e hipersonica, (High Velocity Oxygen Fuel, HVOF). En el metodo FS se emplearon para los depositos materiales en forma de cordon (Flexicords, FS/FC), a fin de caracterizar sus propiedades mecanicas y resistencia al desgaste erosivo, no reportados por la literatura. La evaluacion tribologica se realizo en un tribometro de recipiente de mezcla, empleandose en calidad de variables la velocidad y el angulo de impacto de las particulas erosivas. La morfologia superficial se examino utilizando imagenes de microscopia electronica de barrido (MEB) y permitio analizar el mecanismo de erosion presente. El recubrimiento de mejor resistencia por erosion fue el WC-Co-Cr (HVOF). Los recubrimientos FS/FC son una alternativa economica para aplicaciones de poca accesibilidad y mas bajo ...
Progress in Pattern Recognition, Image Analysis, Computer Vision, and Applications, 2019
This work presents a comparison between two methods for spatial feature extraction applied on a s... more This work presents a comparison between two methods for spatial feature extraction applied on a system to recognize shoulder flexion/extension motor imagery (SMI) tasks to convey on-line control commands towards a 4 degrees-of-freedom (DoF) upper-limb robotic exoskeleton. Riemannian geometry and Common Spatial Pattern (CSP) are applied on the filtered EEG for spatial feature extraction, which later are used by the Linear Discriminant Analysis (LDA) classifier for motor imagery (MI) recognition. Three bipolar EEG channels were used on six healthy subjects to acquire our database, composed of two classes: rest state and shoulder flexion/extension MI. Our system achieved a mean accuracy (ACC) of 75.12% applying Riemannian, with the highest performance for Subject S01 (ACC = 89.68%, Kappa = 79.37%, true positive rate (TPR) = 87.50%, and FPR < 8.13%). In contrast, for CSP, a mean ACC of 66.29% was achieved. These findings suggest that unsupervised methods for feature extraction, such as Riemannian geometry, can be suitable for shoulder flexion/extension MI to command an upper-limb robotic exoskeleton.
Is analyzed from a clinical and kinetic point of view the feasibility of using the transfemoral p... more Is analyzed from a clinical and kinetic point of view the feasibility of using the transfemoral prosthesis Otto Bock with 3R80 knee and articulate...
XXVI Brazilian Congress on Biomedical Engineering, 2019
This work presents a study of brain-computer interfaces (BCIs) to recognize motor imagery tasks, ... more This work presents a study of brain-computer interfaces (BCIs) to recognize motor imagery tasks, using the Riemannian covariance matrices to compute spatial features, and Linear Discriminant Analysis (LDA), Regularized Discriminant Analysis (RDA), and Support Vector Machine (SVM) as classifiers. These BCIs were evaluated through paired combination of four motor imagery tasks. The chosen BCI achieved promising results (accuracy (ACC) of 81.40%) using RDA, showing the best performance on Subject 1 (ACC = 94.45%). This study is a first stage to obtain a BCI based on motor imagery, in order to increase the effectiveness of a neuro-rehabilitation system using upper-limb robotic exoskeleton.
Journal of NeuroEngineering and Rehabilitation, 2020
Backgrounds Exoskeletons development arises with a leading role in neurorehabilitation technologi... more Backgrounds Exoskeletons development arises with a leading role in neurorehabilitation technologies; however, very few prototypes for upper limbs have been tested, contrasted and duly certified in terms of their effectiveness in clinical environments in order to incorporate into the health system. The purpose of this pilot study was to determine if robotic therapy of Hemiplegic Shoulder Pain (HSP) could lead to functional improvement in terms of diminishing of pain, spasticity, subluxation, the increasing of tone and muscle strength, and the satisfaction degree. Methods An experimental study was conducted in 16 patients with painful shoulder post- ischemic stroke in two experimental groups: conventional and robotic therapy. At different stages of its evolution, the robotic therapy effectiveness applied with anti-gravitational movements was evaluated. Clinical trial was developed at the Physical Medicine and Rehabilitation Department of the Surgical Clinical Hospital “Dr. Juan Bruno ...
The development of Brain–Computer Interfaces based on Motor Imagery (MI) tasks is a relevant rese... more The development of Brain–Computer Interfaces based on Motor Imagery (MI) tasks is a relevant research topic worldwide. The design of accurate and reliable BCI systems remains a challenge, mainly in terms of increasing performance and usability. Classifiers based on Bayesian Neural Networks are proposed in this work by using the variational inference, aiming to analyze the uncertainty during the MI prediction. An adaptive threshold scheme is proposed here for MI classification with a reject option, and its performance on both datasets 2a and 2b from BCI Competition IV is compared with other approaches based on thresholds. The results using subject-specific and non-subject-specific training strategies are encouraging. From the uncertainty analysis, considerations for reducing computational cost are proposed for future work.
All in-text references underlined in blue are linked to publications on ResearchGate, letting you... more All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.
Se realiza un estudio del desgaste erosivo en dos recubrimientos de carburos de tunsgteno (WC-10C... more Se realiza un estudio del desgaste erosivo en dos recubrimientos de carburos de tunsgteno (WC-10Co-4Cr y WC-12Co) y cromo (Cr3C2-25NiCr), depositados por proyeccion termica con llama a baja velocidad (Flame Spray, FS) e hipersonica, (High Velocity Oxygen Fuel, HVOF). En el metodo FS se emplearon para los depositos materiales en forma de cordon (Flexicords, FS/FC), a fin de caracterizar sus propiedades mecanicas y resistencia al desgaste erosivo, no reportados por la literatura. La evaluacion tribologica se realizo en un tribometro de recipiente de mezcla, empleandose en calidad de variables la velocidad y el angulo de impacto de las particulas erosivas. La morfologia superficial se examino utilizando imagenes de microscopia electronica de barrido (MEB) y permitio analizar el mecanismo de erosion presente. El recubrimiento de mejor resistencia por erosion fue el WC-Co-Cr (HVOF). Los recubrimientos FS/FC son una alternativa economica para aplicaciones de poca accesibilidad y mas bajo ...
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