Solving Harmonics Elimination Problem in Three-Phase Voltage controlled Inverter using Artificial Neural Networks

A novel concept of application of Artificial Neural Networks (ANN) for generating the optimum switching functions for the voltage and harmonic control of DC-to-AC bridge inverters is presented. In many research, the neural network is trained off line using the desired switching angles given by the classic harmonic elimination strategy to any value of the modulation index. This limits the utilisability and the precision in other modulation index values. In order to avoid this problem, a new training algorithm is developed without using the desired switching angles but it uses the desired solution of the elimination harmonic equation, i.e. first harmonics are equal to zero. Theoretical analysis of the proposed solving algorithm with neural networks is provided, and simulation results are given to show the high performance and technical advantages of the developed modulator

Devenir du peuplier blanc dans le Nord-Ouest algérien Diagnostic sanitaire de quelques peuplements sur la région de Tlemcen.

Cet article descriptif fait état du dépérissement du peuplier blanc dans la région de Tlemcen en Algérie. Les différentes observations suggèrent le rôle fragilisant du déficit hydrique récurrent. Dans le cadre du réchauffement planétaire actuel, il est plus que jamais indispensable de favoriser l'observation, la surveillance et la mise en place d'actions préventives sur ces peuplements

Fuzzy control turns 50: 10 years later

In 2015, we celebrate the 50th anniversary of Fuzzy Sets, ten years after the main milestones regarding its applications in fuzzy control in their 40th birthday were reviewed in FSS, see [1]. Ten years is at the same time a long period and short time thinking to the inner dynamics of research. This paper, presented for these 50 years of Fuzzy Sets is taking into account both thoughts. A first part presents a quick recap of the history of fuzzy control: from model-free design, based on human reasoning to quasi-LPV (Linear Parameter Varying) model-based control design via some milestones, and key applications. The second part shows where we arrived and what the improvements are since the milestone of the first 40 years. A last part is devoted to discussion and possible future research topics.Guerra, T.; Sala, A.; Tanaka, K. (2015). Fuzzy control turns 50: 10 years later. Fuzzy Sets and Systems. 281:162-182. doi:10.1016/j.fss.2015.05.005S16218228

Adaptive observer-based fault estimation for a class of Lipschitz nonlinear systems

Fault input channels represent a major challenge for observer design for fault estimation. Most works in this field assume that faults enter in such a way that the transfer functions between these faults and a number of measured outputs are strictly positive real (SPR), that is, the observer matching condition is satisfied. This paper presents a systematic approach to adaptive observer design for joint estimation of the state and faults when the SPR requirement is not verified. The proposed method deals with a class of Lipschitz nonlinear systems subjected to piecewise constant multiplicative faults. The novelty of the proposed approach is that it uses a rank condition similar to the observer matching condition to construct the adaptation law used to obtain fault estimates. The problem of finding the adaptive observer matrices is formulated as a Linear Matrix Inequality (LMI) optimization problem. The proposed scheme is tested on the nonlinear model of a single link flexible joint robot system

Fuzzy control for Electric Power Steering System with assist motor current input constraints

Friction and disturbances of the road are the main sources of nonlinearity in the Electric Power Steering (EPS) System. Consequently, conventional linear controllers design based on a simplified linear model of the EPS system will result in poor dynamic performance or system instability. On the other hand, a brush-type DC motor is more used in EPS control with an input current that is limited in practice. The control laws designed without taking into account the saturation effect may have undesirable consequences on the system stability. In this paper, a Takagi-Sugeno (T-S) fuzzy is used to represent the nonlinear behavior of an EPS system, and stabilization conditions for nonlinear EPS system with both constrained and saturated control input cases are proposed in terms of linear matrix inequalities (LMI). Simulation results show that both the saturated and constrained controls can stabilize the resulting closed-loop EPS system and provide a stable driving in the presence of nonlinear friction, disturbance of the road and actuator saturation

Fuzzy Control of DC-DC Converters with Input Constraint

This paper proposes a method for designing fuzzy control of DC-DC converters under actuator saturation. Because linear control design methods do not take into account the nonlinearity of the system, a T-S fuzzy model and a controller design approach is used. The designed control not only handles the external disturbance but also the saturation of duty cycle. The input constraint is first transformed into a symmetric saturation which is represented by a polytopic model. Stabilization conditions for the state feedback system of DC-DC converters under actuator saturation are established using the Lyapunov approach. The proposed method has been compared and verified with a simulation example

Devenir du peuplier blanc dans le Nord-Ouest algérien

National audienc

Evaluation des performances de SLOPS : technique d'estimation de la bande passante dans les réseaux sans fil IEEE 802.11b

Extrait de documentOver the past few years, to actively measure the end-to-end available bandwidth of a network path several algorithms have been created (TOPP, SLoPS, Spurce, VPS ldots). These algorithms are dedicated to wired Ethernet network; however the bandwidth estimation in wireless network field remains a challenge. In the present work we evaluate the performance of Self-Loading Periodic Stream (SLoPS) method to estimate the available bandwidth in the IEEE 802.11b wireless network. By using different probe packet sizes and different Cross-Traffics, we show that the available bandwidth measurements are affected by the varying Cross-Traffic in both Ethernet and wireless IEEE 802.11b network. The variation of probe packet size affects only the available bandwidth measurements in the wireless network and not in Ethernet network case. Also SLoPS technique provides less accurate measurements in the IEEE 802.11b wireless network. The simulation is built in NS-2. The results are analyzed by MatLab softwar

Enhanced adaptive cross-layer scheme for low latency HEVC streaming over Vehicular Ad-hoc Networks (VANETs)

JIF=4.706International audienceVehicular communication has become a reality guided by various applications. Among those, high video quality delivery with low latency constraints required by real-time applications constitutes a very challenging task. By dint of its never-before-achieved compression level, the new High-Efficiency Video Coding (HEVC) is very promising for real-time video streaming through Vehicular Ad-hoc Networks (VANET). However, these networks have variable channel quality and limited bandwidth. Therefore, ensuring satisfactory video quality on such networks is a major challenge. In this work, a low complexity cross-layer mechanism is proposed to improve end-to-end performances of HEVC video streaming in VANET under low delay constraints. The idea is to assign to each packet of the transmitted video the most appropriate Access Category (AC) queue on the Medium Access Control (MAC) layer, considering the temporal prediction structure of the video encoding process, the importance of the frame and the state of the network traffic load. Simulation results demonstrate that for different targeted low-delay video communication scenarios, the proposed mechanism offers significant improvements regarding video quality at the reception and end-to-end delay compared to the Enhanced Distributed Channel Access (EDCA) adopted in the 802.11p. Both Quality of Service (QoS) and Quality of Experience (QoE) evaluations have been also carried out to validate the proposed approach. (C) 2018 Elsevier Inc. All rights reserved

Open architecture to raise awareness of energy consumption on the home environment

The climate changes as well as the sustainability of our energy supplies present multiple challenges and require a worldwide coordinated response. Europe 2020 is a jigsaw of policies and measures binding targets for 2020 to reduce greenhouse gas emissions by 20%, ensure 20% of renewable energy sources in the EU energy mix, and the reduction of EU global primary energy use by 20%. In the longer term, new generations of technologies have to be developed via breakthroughs in research if we are to meet the greater ambition of reducing our greenhouse gas emissions by 60-80% by 2050. The reduction of the primary energy use can be accomplished with mentality awareness of the home users. By educating ourselves and those around us, our negative behaviors can be changed, creating a culture of sustainability. In order to achieve this goal, we are suggesting an open architecture with a friendly visualization interface that can be used to raise the households inhabitants awareness o f their power consumption. With the proposed architecture, energy consumption data can be stored in a remote server and can be further processed in order to extract the power consumption for each electrical appliance, opening the door to the development of service extensions to provide user- and context-aware advice on how to save energy