Signal propagation in transmission lines with losses using fibonacci wave functions

In this paper, the general model for an infinite LC ladder network using Fibonacci wave functions that were applied to lossless transmission lines will be extended to transmission lines including losses. The general model that was derived from a first order system transfer function representing a simple RC or RL circuit will be used to model and analyze transmission lines presenting losses. The LC ladder network model can be applied to any order for each inductor current with its parasitic rc resistor and for each capacitor voltage with its parasitic rL  resistor. The extension of the proposed general model to transmission lines with losses is subject to Heaviside condition for both resistors rc  and r

Systematic approach furthering confirmation measures of safety critical automotive systems

Different system elements are developed independently from diverse suppliers and teams before being integrated together into safety critical automotive systems such as steering or braking systems by a manufacturer. It must be guaranteed that, despite this independent development, the achievement of the safety requirements for the overall system can be demonstrated. The necessary agreements and the integration of the necessary safety information for the overall system generate higher extra costs. In order to reduce development time and cost, systematic reuse can be a solution to engineering the required artifacts. Reassessment represents an additional source of cost. Even small modifications of a system or exchanging a component after it has been certified necessitates a reassessment. The effort required for reassessment, in many cases reaches the original effort of certification for the complete system or even exceeds it. To minimize the effort and cost of a reassessment, this paper introduces a theoretical foundation of a model-based engineering approach to reuse a safety case and change only the modified parts. This paper presents a reusability framework to support the distributed development environment together with the different composition scenarios with respect to ISO26262. A further benefit of this approach is that for development of variants in product-line, the Safety assessment process can now be easily expressed and managed

Management of Vesicouterine fistulae during fistulae surgical caravan in Cote d'Ivoire

Background: The urogenital fistula (UGF) which designate a solution of continuity between the urinary and genital tracts in women, are divided into several entities of variable gravity. The objective of this study was to describe the epidemiological, clinical and therapeutic characteristics of patients treated for vesicouterine fistula during ‘fistulas surgical caravans’.Methods: This was a prospective and descriptive study on a cohort of 34 patients treated for Vesico-uterine fistulae during ‘‘fistulas surgical caravans '' from 1st January 2012 to 31st December 2016.Results: Vesico uterine fistulae represented 2.1% of all urogenital fistulae treated. At the time of occurrence of fistulas, the average age of the patients stay was 33.3 years, and the majority was not educated (88.2%), lived in rural areas without occupations (73.5%). All the fistulae were secondary to childbirth, the majority of which took place on a scarred uterus (67.6%). And this childbirth responsible for the fistula was done by caesarean section in 97.7% of cases. Then the average duration of the fistula before management was 6 years. Finally, all the patients were operated by the same surgical technique, made by abdominal extra peritoneal transvesical way. The cure rate after this surgical technique was 97.1% (33 patients). The only case of failure required a second operation by another technique which permitted the healing of the patient.Conclusions: The vesicouterine fistulae were rare and the satisfactory results of their management invite us to sustain these surgical caravans and ensure their widespread

Review on the cost optimization of microgrids via particle swarm optimization

Economic analysis is an important tool in evaluating the performances of microgrid (MG) operations and sizing. Optimization techniques are required for operating and sizing an MG as economically as possible. Various optimization approaches are applied to MGs, which include classic and artificial intelligence techniques. Particle swarm optimization (PSO) is one of the most frequently used methods for cost optimization due to its high performance and flexibility. PSO has various versions and can be combined with other intelligent methods to realize improved performance optimization. This paper reviews the cost minimization performances of various economic models that are based on PSO with regard to MG operations and sizing. First, PSO is described, and its performance is analyzed. Second, various objective functions, constraints and cost functions that are used in MG optimizations are presented. Then, various applications of PSO for MG sizing and operations are reviewed. Additionally, optimal operation costs that are related to the energy management strategy, unit commitment, economic dispatch and optimal power flow are investigated. © 2019, The Author(s)

Dynamic stability of wind power flow and network frequency for a high penetration wind‐based energy storage system using fuzzy logic controller

Major changes in the technologies of power generation and distribution systems have been introduced in recent years due to concern over rapid climate change. Therefore, disturbances in the large‐scale generation, transmission, and distribution of energy are expected to occur in the near future. This is due to the difficulty in controlling the transmission and distribution of energy produced from renewable energy sources (RESs), caused by the instability of these sources and the intermittent nature of their energy. As a result, maintaining the dynamic stability of wind power flow and control of the network frequency is becoming more challenging due to the high penetration impacts of RESs. In this paper, a control algorithm using the power‐sharing method is proposed for a wind‐based energy storage system to maintain the dynamic stability of wind power flow and control of frequency in the power network. To maintain the network stability, a storage system (battery) was installed to store the excess wind power without throwing it into the Secondary/Dump Load (SL) and minimize losses in power generated by the wind turbine. The results show, the transient time of wind power flow and the fluctuation rate of frequency are reduced significantly using a Fuzzy Logic (FL) controller compared to the Proportional Integral Derivative (PID) controller. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Contamination du lait caillé et de l’oeuf consommé en Côte d’Ivoire par des pesticides organochlorés

La présente étude vise à évaluer l’aspect sanitaire de l’alimentation humaine à travers deux produits à forte consommation en Côte d’Ivoire : le lait caillé et l’oeuf. Ainsi, 30 échantillons de lait caillé ont été achetés et 30 échantillons d’oeufs de poulet ont été collectés dans trois fermes dans la ville d’Abidjan. Ces échantillons ont été traités dans le but de déterminer les résidus de 12 POC (Pesticides OrganoChlorés). Les analyses ont été réalisées au CG sur colonne capillaire avec un détecteur à capture d'électrons. Les résultats observés révèlent une contamination du lait caillé et de l’oeuf par 5 POC. Ainsi, des charges moyennes en μg/kg des isomères hexachlorocyclohexane (HCH) allant de 0,125 à 0,997 et de 1,870 à 35,907, de l’endosulfan allant de 0,045 à 0,563 et non détecté, de la dieldrine allant de 0,025 à 0,263 et de 5,727 à 69,710 et du Dichlorodiphenyltrichloroethane (DDT) et métabolites allant de 0,133 à 0,813 et de 21,105 à 75,22, ont été respectivement déterminées dans le lait caillé et dans l’oeuf. La teneur résiduelle moyenne des isomères HCH, des cyclodiènes (dieldrine, et endosulfane) et du DDT et ses métabolites constituent respectivement 40%, 40% et 20% de la moyenne du total des POC mesurés dans le lait caillé et respectivement 20%, 20% et 60% de celle mesurée dans l’oeuf.Mots-clés: pesticides organochlorés, lait caillé, oeuf, Côte d’Ivoire. Contamination of the curdled milk and the egg consumed in Ivory Coast by organochlorinated pesticides This study aims to determine the levels of organochlorinated pesticides (OCPs) in the curdled milk and egg. Thus, 30 samples of curdled milk were purchased and 30 egg samples were collected from three farms in the area of the lagoons. These samples were processed in order to determine the residues 12 OCPs. Analyses were performed by GC capillary column with electron capture detector. The observed results indicate contamination of curdled milk and egg by 5 OCPs. Thus, average loads in μg/kg of hexachlorocyclohexane (HCH) isomers ranging from 0.125 to 0.997 and 1.870 to 35.907, endosulfan ranging from 0.045 to 0.563 and undetected, dieldrin ranging from 0.025 to 0.263 and 5.727 to 69.710 and dichlorodiphenyltrichloroethane (DDT) and metabolites ranging from 0.133 to 0.813 and 21, 105 to 75.22, respectively, were determined in the curdled milk and egg. The average residual HCH isomers, cyclodiene (dieldrin and endosulfan) and DDT and its metabolites is respectively 40%, 40% and 20% of the average total OCPs measured in curdled milk and respectively 20%, 20 % and 60% of that measured in the bud.Keywords: organochlorinated pesticides, curdled milk, egg, Ivory Coast

Adaptive direct power control based on ANN-GWO for grid interactive renewable energy systems with an improved synchronization technique

This paper investigates the improvement of synchronization technique for single-phase inverter. Specifically, the paper proposes a modified structure of second-order generalized integrator with frequency-locked loop (SOGI-FLL) with FLL gain normalization. The proposed structure enhances the frequency detection, which makes it a powerful technique under distorted grid voltage. The validation of the proposed synchronization method includes simulations and experimental tests using Xilinx field programmable gate array (FPGA) as the target device. Moreover, time domain simulations using the direct power control (DPC) with the proposed structure are performed. The decoupled active and reactive powers are controlled using the artificial neural networks (ANNs) trained by the mean of a metaheuristic algorithm. In this paper, the grey wolf optimizer (GWO) is proposed to train the multilayer perceptron (MLP). The proposed approach shows better generation of synchronization signals and smooth power quality, making it suitable for grid-tied and microgrids (MGs) power systems control. © 2018 John Wiley & Sons, Ltd

Interconnection performance analysis of single phase neural network based NPC and CHB multilevel inverters for grid-connected PV systems

This paper presents the interconnection performance analysis of single-phase cascaded H-bridge and neutral point clamped multilevel inverters for grid-connected photovoltaic (PV) applications. Interconnection performance analysis of both inverters was investigated using fixed and variable bands hysteresis current control strategies to ensure a lower current's total harmonic distortion (THD). An intelligent control method based on neural networks was introduced to extract maximum power from the PV modules and to achieve optimal operation of the whole system when connected to the utility grid. Control algorithm was implemented in a microcontroller with interrupt routines priority. Both simulation and experimental results are presented to verify the performance of the proposed control methods. In addition, islanding detection capability of the two topologies was investigated. © 2019 International Journal of Renewable Energy Research

Artificial neural network photovoltaic generator maximum power point tracking method using synergetic control algorithm

In this paper, a new approach to find the maximum power point (MPP) of a PV generator based on a hybrid Artificial Neural Networks (ANN)-Synergetic Control Algorithm (SCA) has been proposed. In the first part, the optimal voltage and current of the PV generator are found by using ANN algorithm. The second part deals with the design of a Synergetic Controller Algorithm (SCA) which generates automatically the optimal duty cycle to control the boost converter. The complete PV system is implemented in MATLAB/Simulink software and the results are compared with those obtained using the conventional Perturbation and Observation (P&O) method. Simulation results reveal that the proposed ANN-SCA algorithm is more efficient than the P&O algorithm. © 2020, Research Trend. All rights reserved