We investigate a cognitive radio network in which a primary user (PU) may cooperate with a cognitive radio user (i.e., a secondary user (SU)) for transmissions of its data packets. The PU is assumed to be a buffered node operating in a time-slotted fashion where the time is partitioned into equal-length slots. We develop two schemes which involve cooperation between primary and secondary users. To

We consider a class of wireless powered devices employing hybrid automatic repeat request to ensure reliable end-to-end communications over a two-state time-varying channel. A receiver, with no power source, relies on the energy transferred by a simultaneous wireless information and power transfer enabled transmitter to receive and decode information. Under the two-state channel model, information

In this paper, an access scheme for cognitive radio networks is proposed in which secondary users (SUs) make use of the primary user(s) (PUs) channel quality feedback information. SUs decide their transmission strategy based on the PUs' channel quality indicator (CQI) feedback available in the PU network and the SUs' sensing of PUs' activity. We consider two energy sensing approaches, namely, hard

In this paper, a new combined fuzzy observer-based fault-tolerant tracking control scheme is proposed for a doubly fed induction generator (DFIG) based wind turbine (WT) subject to actuator faults. The main contribution consists of the proposal of a novel fault-tolerant fuzzy tracking controller combined with a nominal control law. The control objective is to ensure good state references tracking

This chapter is intended to design and analyze several sliding mode techniques for the stabilization and synchronization of fractional order complex chaotic and hyperchaotic systems. Considering that chaos is a hot topic nowadays due to the vast number of real physical systems such as mechanical, electrical, and chemical systems in which this phenomenon is found; this book chapter will provide

A novel 4-D chaotic hyperjerk system with four quadratic nonlinearities is presented in this work. It is interesting that the hyperjerk system has no equilibrium. A chaotic attractor is said to be a hidden attractor when its basin of attraction has no intersection with small neighborhoods of equilibrium points of the system. Thus, our new non-equilibrium hyperjerk system possesses a hidden

This article proposes a new simple scheme for direct power control of a PWM rectifier without a switch table and voltage sensor. The selection of the switching state of the converter is based on the transition of a Petri net, using the instantaneous active and reactive power tracking errors and the angular position of the network line voltage estimated as variables of Controller input based on

The need for portable and low-cost bio-impedance analyzers that can be deployed in field studies has significantly increased. Due to size and power constraints, reducing the hardware in these devices is crucial and most importantly is removing the need for direct phase measurement. In this paper a new magnitude-only technique based on modified Kramers–Kronig transforms is proposed and tested

The dynamic stress–strain behavior and the damping characteristics of carbon black (CB)/polymer composites at high strain rates are measured using the split Hopkinson pressure bar. These characteristics are determined for polyurethane impregnated with 20% CB nanoparticles and compared with those of pristine polyurethane at strain rates ranging between 2,400 and 7,000 s−1. The obtained results

Recently, numerous research works in retinal-structure analysis have been performed to analyze retinal images for diagnosing and preventing ocular diseases such as diabetic retinopathy, which is the first most common causes of vision loss in the world. In this paper, an algorithm for vessel detection in fundus images is employed. First, a denoising process using the noise-estimation-based