The present study explores the effect of providing different types of written corrective feedback (WCF) on 79 Iranian EFL learners’ writings over time through a pre-test, immediate post-test and delayed post-test. In this way, the study first aims to investigate the extent to which different types of WCF result in improved accuracy in writing over a period of two months, and then maintain...

We give an upper bound to the finite block length capacity of discrete time nonstationary Gaussian channel with delayed feedback. With the aid of minimization of a quadratic form, it is proved that the L time delayed feedback capacity C n,FB(P ) and the nonfeedback capacity Cn(P ) satisfy Cn(P ) ≤ C n,FB(P ) ≤ Cn(P∗), where P∗ is concretely given. And we give a sufficient condition for C n,FB(P...

a new approach for pole placement of nonlinear systems using state feedback and fuzzy system is proposed. we use a new online fuzzy training method to identify and to obtain a fuzzy model for the unknown nonlinear system using only the system input and output. then, we linearized this identified model at each sampling time to have an approximate linear time varying system. in order to stabilize...

A delayed feedback control framework for stabilizing unstable periodic orbits of linear periodic time-varying systems is proposed. In this framework, act-and-wait approach is utilized for switching a delayed feedback controller on and off alternately at every integer multiples of the period of the system. By analyzing the monodromymatrix of the closed-loop system, we obtain conditions under whi...

Noise-induced dynamics of a prototypical bistable system with delayed feedback is studied theoretically and numerically. For small noise and magnitude of the feedback, the problem is reduced to the analysis of the two-state model with transition rates depending on the earlier state of the system. Analytical solutions for the autocorrelation function and the power spectrum have been found. The p...

This paper is the second in a series devoted to the study of Langevin systems subjected to a continuous time-delayed feedback control. The goal of our previous paper [Phys. Rev. E 91, 042114 (2015)PLEEE81539-375510.1103/PhysRevE.91.042114] was to derive second-law-like inequalities that provide bounds to the average extracted work. Here we study stochastic fluctuations of time-integrated observ...

The paper examines the stabilization and the H∞ norm performance analysis and control of state-delayed systems with a symmetric state-space realization. Such symmetric realizations appear in many engineering applications. By exploiting the state-space symmetry, we obtain an explicit solution for a bound on the H∞ norm of such symmetric time-delayed systems. Also, we derive an explicit parametri...

The problem of H∞ output feedback for uncertain linear discrete-time systems with state-delay and parameter uncertainties is considered. The objective is to design a linear output feedback controller such that, for the unknown state time-delay and all admissible norm-bounded parameter uncertainties, the feedback system remains robustly stable and the transfer function from the exogenous disturb...