Search results for "feedback"

A limited feedback scheme based on spatially correlated channels for coordinated multipoint systems

2012

High spectral efficiency can be achieved in the downlink of multi-antenna coordinated multi-point systems provided that the multiuser interference is appropriately managed at the transmitter side. For this sake, downlink channel information needs to be sent back by the users, thus reducing the rate available at the uplink channel. The amount and type of feedback information required has been extensively studied and many limited feedback schemes have been proposed lately. A common pattern to all of them is that achieving low rates of feedback information is possible at the cost of increasing complexity at the user side and, sometimes, assuming that some statistics of the channel are known. I…

Robust l2-gain control for 2D nonlinear stochastic systems with time-varying delays and actuator saturation

2013

Abstract This paper is concerned with the problems of stability analysis and l2-gain control for a class of two-dimensional (2D) nonlinear stochastic systems with time-varying delays and actuator saturation. Firstly, a convex hull representation is used to describe the saturation behavior, and a sufficient condition for the existence of mean-square exponential stability of the considered system is derived. Then, a state feedback controller which guarantees the resulting closed-loop system to be mean-square exponentially stable with l2-gain performance is proposed, and an optimization procedure to maximize the estimation of domain of attraction is also given. All the obtained results are for…

GH responses to two consecutive bouts of neuromuscular electrical stimulation in healthy adults.

2008

BackgroundIt is well established that repeated GHRH administration or repeated voluntary exercise bouts are associated with a complete blunting of GH responsiveness when the administration of the second stimulus follows the first one after a 2-h interval.AimTo evaluate GH responses to neuromuscular electrical stimulation (NMES) in healthy adults.MethodsSix volunteers (mean age±s.d. 31.7±5.5 years) were studied before and after two consecutive bouts of NMES exercise (a series of 20 contractions at the maximum of individual tolerance, frequency: 75 Hz, pulse duration: 400 μs, on–off ratio: 6.25–20 s) administered at a 2-h interval.ResultsBaseline GH levels (mean: 0.3±0.2 ng/ml) significantly …

Passive-damping design for vibration control of large structures

2013

In this work, a systematic strategy to design passive damping systems for structural vibration control is presented. The proposed design methodology is based on the equivalence between decentralized static velocity-feedback controllers and passive damping systems. By using recent developments in static output-feedback control, the design of passivedamping systems can be formulated as a single optimization problem with Linear Matrix Inequality constraints. Moreover, this optimization problem can be efficiently solved with standard numerical tools, even for large dimension systems. Due to its computational effectiveness, the proposed methodology can be applied to the design of passive damping…

A Human-Humanoid Interaction Through the Use of BCI for Locked-In ALS Patients Using Neuro-Biological Feedback Fusion.

2018

This paper illustrates a new architecture for a human–humanoid interaction based on EEG-brain computer interface (EEG-BCI) for patients affected by locked-in syndrome caused by Amyotrophic Lateral Sclerosis (ALS). The proposed architecture is able to recognise users’ mental state accordingly to the biofeedback factor $\text {B}_{\text f}$ , based on users’ attention, intention, and focus, that is used to elicit a robot to perform customised behaviours. Experiments have been conducted with a population of eight subjects: four ALS patients in a near locked-in status with normal ocular movement and four healthy control subjects enrolled for age, education, and computer expertise. The results s…

Effects of assisted training with neurofeedback on EEG measures, executive function and mood in a healthy sample

2015

The training in neurofeedback (NF) consists of teaching individuals to modify, adjust and enhance their brain activity pattern. The aim of our research was to evaluate the effect of training on cognitive processes, specifically executive function, and mood in a non-clinical sample. A sample of 30 female college students were assigned to three groups: RH: right hemisphere (n = 10), LH: left hemisphere (n = 10) and control (n = 10). The dominance pattern of beta and the inhibition of the theta pattern were trained in a single session. Measures of executive function (Iowa Gambling Test) and questionnaires of mood were taken pre and post training. We found that NF training produced significant …

Valutazione tra pari all’università: due approcci didattici a confronto

2020

Nell’ambito della didattica universitaria occorre rinnovare e diversificare gli strumenti di valutazione includendo sempre più anche tecnologie progettate per la valutazione. Il presente contributo mira a contribuire alla riflessione sulle pratiche didattiche che risultano più efficaci per l’integrazione delle nuove tecnologie per la valutazione formativa e la valutazione tra pari in università. In particolare si vuole verificare se l’utilizzo di tali forme valutative tramite la piattaforma Peergrade sia più efficace in un approccio didattico basato sull’interazione face-to-face o su interazioni a distanza tra una lezione e la successiva. La ricerca, condotta su un campione di 203 studenti …

Online detection and removal of eye blink artifacts from electroencephalogram

2021

Abstract The most prominent type of artifact contaminating electroencephalogram (EEG) signals are the eye blink (EB) artifacts, which could potentially lead to misinterpretation of the EEG signal. Online identification and elimination of eye blink artifacts are crucial in applications such a Brain-Computer Interfaces (BCI), neurofeedback, and epilepsy diagnosis. In this paper, algorithms that combine unsupervised eye blink artifact detection (eADA) with modified Empirical Mode Decomposition (FastEMD) and Canonical Correlation Analysis (CCA) are proposed, i.e., FastEMD-CCA2 and FastCCA, to automatically identify eye blink artifacts and remove them in an online setting. The average accuracy, …

Out‐of‐Equilibrium (Supra)molecular Systems and Materials: An Introduction

2021

Internal model-based feedback control design for inversion-free feedforward rate-dependent hysteresis compensation of piezoelectric cantilever actuat…

2018

Abstract This study proposes a new rate-dependent feedforward compensator for compensation of hysteresis nonlinearities in smart materials-based actuators without considering the analytical inverse model. The proposed rate-dependent compensator is constructed with the inverse multiplicative structure of the rate-dependent Prandtl–Ishlinskii (RDPI) model. The study also presents an investigation for the compensation error when the proposed compensator is applied in an open-loop feedforward manner. Then, an internal model-based feedback control design is applied with the proposed feedforward compensator to a piezoelectric cantilever actuator. The experimental results illustrate that the propo…