Search results for "feedback"

Using Brain Technologies in Practice

2020

Brain Biophysics: Perception, Consciousness, Creativity. Brain Computer Interface (BCI)

2018

The paper presents connections between perception, awareness, and creativity from the biophysical point of view. Attention was drawn to human senses’ limitations and their influence on cognition. The role of interfaces connecting brain with computer and particular role of Brain Computer Interface (BCI) are indicated which the authors believe will be the next stage of human brain supporting technology evolution. It will enable the growth of perception, awareness, and creativity, and consequently lead to social development.

New media and perennial problems in foreign language learning and teaching

2015

The book concerns the ways in which the new media shape communication along with educational expectations and practices in foreign language classrooms. Although foreign language learners have cheap and easy access to information and ways of communication, they also wrestle with problems that have always accompanied language learning. The focus of the book is two-fold. On the one hand, the authors demonstrate how using social networks, videoconferencing, mobile phones, wikis, and computer-mediated interaction contributes to the development of language skills, negotiated interaction, autonomy, and intercultural competence. On the other, they discuss “old” issues pertaining to the role of voca…

Aggregation and sedimentation of active Brownian particles at constant affinity.

2019

We study the motility-induced phase separation of active particles driven through the interconversion of two chemical species controlled by ideal reservoirs (chemiostats). As a consequence, the propulsion speed is non-constant and depends on the actual inter-particle forces, enhancing the positive feedback between increased density and reduced motility that is responsible for the observed inhomogeneous density. For hard discs, we find that this effect is negligible and that the phase separation is controlled by the average propulsion speed. For soft particles and large propulsion speeds, however, we predict an observable impact on the collective behavior. We briefly comment on the reentrant…

Stability and -gain controller design for positive switched systems with mixed time-varying delays

2013

This paper investigates the problems of stability and L"1-gain controller design for positive switched systems with mixed time-varying delays. The mixed time-varying delays are presented in the forms of discrete delay and distributed delay. The purpose of this paper is to design a class of switching signals and a state feedback controller for the considered system such that the resulting closed-loop system is exponentially stable with L"1-gain performance. By constructing an appropriate co-positive type Lyapunov-Krasovskii functional and using the average dwell time approach, we propose a sufficient condition to ensure the exponential stability with weighted L"1-gain performance for the sys…

On the Coincidence of the Feedback Nash and Stackelberg Equilibria in Economic Applications of Differential Games

2002

In this paper the scope of the applicability of the Stackelberg equilibrium concept in differential games is investigated. Firstly, conditions for obtaining the coincidence between the Stackelberg and Nash equilibria are defined in terms of the instantaneous pay-off function and the state equation of the game. Secondly, it is showed that for a class of differential games with state-interdependence both equilibria are identical independently of the player being the leader of the game. A survey of different economic models shows that this coincidence is going to occur for a good number of economic applications of differential games. This result appears because of the continuous-time setting i…

Feedback linearization control of wind turbine equipped with doubly fed induction generator

2017

This paper focuses on several control techniques of a wind turbine of rated power of about 1 MW. In particular, a wind generator equipped with an asynchronous doubly-fed induction machine has been considered and its dynamic model in MATLAB/SIMULINK environment has been implemented. Starting from this model the feedback linearization control has been derived, and several simulations have been carried out, with the aim of compare its dynamic performances with the classical field oriented control, and with the V/f control. The results allow us to conclude that a DFIG controlled by a feedback linearization technique ensures better dynamic performance.

Are nonlinear model-free conditional entropy approaches for the assessment of cardiac control complexity superior to the linear model-based one?

2016

Objective : We test the hypothesis that the linear model-based (MB) approach for the estimation of conditional entropy (CE) can be utilized to assess the complexity of the cardiac control in healthy individuals. Methods : An MB estimate of CE was tested in an experimental protocol (i.e., the graded head-up tilt) known to produce a gradual decrease of cardiac control complexity as a result of the progressive vagal withdrawal and concomitant sympathetic activation. The MB approach was compared with traditionally exploited nonlinear model-free (MF) techniques such as corrected approximate entropy, sample entropy, corrected CE, two k -nearest-neighbor CE procedures and permutation CE. Electroca…

Active Disturbance Rejection Control of Synchronous Reluctance Motors

2020

This paper describes how the ADRC (Active Disturbance Rejection Control) strategy can be successfully applied to SynRM (Synchronous Reluctance Motor) drives. The ADRC is an adaptive robust extension of the input-output Feedback Linearization Control (FLC). Its main feature is that the nonlinear transformation of the state is computed on-line and not by using the model. As a consequence, any unmodelled dynamics or uncertainty of the parameters can be addressed. The control strategy has been verified successfully with experimental tests confirming the high dynamic response of the drive.

Developing hand-worn input and haptic support for real-world target finding

2019

Locating places in cities is typically facilitated by handheld mobile devices, which draw the visual attention of the user on the screen of the device instead of the surroundings. In this research, we aim at strengthening the connection between people and their surroundings through enabling mid-air gestural interaction with real-world landmarks and delivering information through audio to retain users' visual attention on the scene. Recent research on gesture-based and haptic techniques for such purposes has mainly considered handheld devices that eventually direct users' attention back to the devices. We contribute a hand-worn, mid-air gestural interaction design with directional vibrotacti…