Nowadays, a global interest for renewable energy sources has been growing intensely. In particular, a wind energy has become the most popular. In case of autonomous systems, wind energy conversion system (WECS) based on a double fed induction generator (DFIG) is widely used. In this paper, in order to control the stand-alone system outputs under wind speed and load variations, three kinds of nonlinear control strategies have been proposed, applied and compared, such as: Classical PI controller, Back-Stepping and Sliding Mode controllers. A series of experiments have been conducted to evaluate and to compare the developed controllers’ dynamic performances under load demand and speed variations. The design and the implementation of different control strategies to a 1.5kW doubly fed induction machine is carried out using a dSpace DS1104 card based on MATLAB/Simulink environment …

Mobility has always represented a complicated phenomenon in the network routing process. This complexity is mainly facilitated in the way that ensures reliable connections for efficient orientation of data. Many years ago, different studies were initiated basing on routing protocols dedicated to static environments in order to adapt them to the mobile environment. In the present work, we have a different vision of mobility that has many advantages due to its ’mobile’ principle. Indeed, instead of searching to prevent mobility and testing for example to immobilize momentarily a mobile environment to provide routing task, we will exploit this mobility to improve routing. Based on that, we carried out a set of works to achieve this objective. For our first contribution, we found that the best way to make use of this mobility is to follow a mobility model. Many models have been proposed in the literature and employed as a data source in most studies. After a careful study, we focused on the Random Waypoint mobility model (RWP) in order to ensure routing in wireless networks. Our contribution involves a Random Waypoint model (in its basic version) that was achieved on the TOSSIM simulator, and it was considered as a platform for our second (and main) contribution, in which we suggested an approach based RWP where network nodes can collaborate and work together basing on our recommended algorithm. Such an approach offers many advantages to ensure routing in a dynamic environment. Finally, our contributions comprise innovative ideas for suggesting other solutions that will improve them.

In the last few years, an accelerated trend toward the miniaturization of nanoscale circuits has been recorded. In fact, this has been reflected by numerous enhancements at different levels of multi-gate structures such as the channel body or the gate material. Our aim in this work is to investigate the reliability performance of junctionless DG MOSFET including graded channel aspect. The behavior of the considered device is analyzed numerically using ATLAS-2D simulator, where degradation phenomena are accounted for in the model. The variation of some analog/RF criteria namely the transconductance and cut-off frequency are established in terms of the channel length and traps density. The obtained responses indicate the superior immunity of the graded channel device against traps-induced degradation in comparison to the conventional structure. Thus, this work can offer more insights regarding the benefit of adopting the channel doping engineering for future nanoscale electronic applications.

In this paper, new multilayer design based on ZnO/Ag/ZnO structure is proposed as a new way to achieve UV-based photodetector (PD) with superior optical behavior. Our purpose resides on reducing the refracting light and achieving an effective absorption in the Ag metallic sub-layers. New numerical model based on accurate solutions of Maxwell’s equations is developed in order to elucidate the impact of the metallic sub-layers on the UV-PD optical performance. An overall analysis regarding the optical parameters such as the integral absorption and the total reflection is conducted. It is found that the metallic sub-layers have profound implications on modulating the electric field in the structure and facilitating photon forward scattering in the ZnO sub-layers which led to better optical behavior. Moreover, Particle Swarm Optimization (PSO) approach is proposed as a metaheuristic technique to reach effectiveness absorption through carefully adjusting the Ag and ZnO sub-layers thickness. It is confirmed that the optimized design can provide superior optical performance as compared to the conventional counterpart, where the optimized multilayer design exhibits an enhancement of 60% in the integral absorption over ZnO-based PD. The obtained results make the proposed multilayer design efficient for providing high performance PDs for communication applications.