Daily rainfall-runoff modelling by neural networks in semi-arid zone: case of Wadi Ouahrane’s basin

This research work will allow checking efficiency of formal neural networks for flows’ modelling of wadi Ouahrane’s basin from rainfall-runoff relation which is non-linear. Two models of neural networks were optimized through supervised learning and compared in order to achieve this goal, the first model with input rain, and the second one with rain and input ETP. These neuronal models were compared with another overall model, the GR4j model. Then, it has been optimized and compared with the three first models, a third model of neural network with rain, ETP and soil moisture (calculated by the model GR4j) input.The neuronal models were optimized with algorithm of Levenberg Marquarld (LM), while the GR4j model was optimized with SCE-UA method. The Nash criterion (%) and the correlation coefficient of Pearson (R) allowed appreciating performances of these models.Keywords: modeling; neural network; supervised learning; algorithm of Levenberg Marquarld; GR4

Preliminary control variates to improve empirical regression methods

International audienceWe design a variance reduction method to reduce the estimation error in regression problems. It is based on an appropriate use of other known regression functions. Theoretical estimates are supporting this improvement and numerical experiments are illustrating the efficiency of the method

Analysis of the adhesive damage for different shapes and types patch’s in Aircraft Structures corroded with an inclined crack

In this study, the finite element method is used to analyze the effect of corrosion and the behavior of inclined cracks of an aluminum plate Al 2024 -T3 under thermomechanical loading.  The effects of the inclination of the crack and the effect of temperature for and different types and shapes of adhesives are highlighted.  The results obtained show the increase of the crack inclination leads to a decrease of the damaged area and the damaged area ratio of the adhesive.  In addition, the ratio DR increases with increasing temperature variation ΔT.  The best performing patch shape that gave interesting results during this analysis is the circular and for type the Boron/epoxy is the best

Commande par modes glissants d'ordre supérieur et observateur grand gain de la génératrice asynchrone double alimentation d'une éolienne

International audienceLe rendement d'une éolienne dépendant essentiellement de la puissance du vent, de la courbe de puissance de la turbine et de l'habilité de la génératrice à répondre aux fluctuations du vent, cet article propose alors une stratégie de commande robuste de la génératrice asynchrone double alimentation d'une éolienne qui permet d'optimiser sa production énergétique (rendement). Pour ce faire, il est mit en œuvre un observateur grand gain pour estimer le couple aérodynamique et des commandes par mode glissant d'ordre supérieur. La stratégie globale ainsi proposée a été validée sur une éolienne tripale de 1.5 MW en utilisant le simulateur FAST

Hybrid sliding mode control of DFIG with MPPT using three multicellular converters

International audienceThis paper deals with hybrid sliding mode control of Doubly Fed Induction Generator DFIG with Maximum Power Point Tracking MPPT connected by rotor side to three bridges of Multicellular Converters MCCs. The hybrid aspect of the converters is taken into consideration which includes the continuous and discrete states of the converters. The vector control is used to command the DFIG speed and reactive stator power. The currents in Park d-q reference are controlled using hybrid sliding mode. The sliding surfaces are developed using Lyapunov stability method. The developed controller allows decoupled control of the stator active and reactive power. The final results are illustrated at the end of this paper to present the advantages of the control method developed in this paper

A PI/Backstepping Approach for Induction Motor Drives Robust Control

International audienceThis paper presents a robust control design procedure for induction motor drives in case of modeling errors and unknown load torque. The control law is based on the combination of nonlinear PI controllers and a backstepping methodology. More precisely, the controllers are determined by imposing flux-speed tracking in two steps and by using appropriate PI gains that are nonlinear functions of the system state. A comparative study between the proposed PI/Backstepping approach and the feedback linearizing control is made by realistic simulations including load torque changes, parameter variations and measurement noises. Flux-speed tracking results show the proposed method effectiveness in presence of strong disturbances

Multicell Converters Hybrid Sliding Mode Control

International audienceThis paper deals with hybrid sliding mode control of multicell power converter. It takes into account the hybrid aspect of the conversion structure which includes the converter continuous and discrete states. The basic idea used in this paper is to consider the interconnected systems that represent the hybrid model and to generate commutation surfaces based on a Lyapunov function that satisfies asymptotic stability. Simulations are carried-out on a two-cells converter to assess the performances and the robustness of the synthesized controller

Supplementation of olive mill wastes in broiler chicken feeding

This work was conducted in order to study the value of olive mill wastes as diet on the growth performance, abdominal and muscle fat deposition, adipose and muscle tissues fatty acid composition in broilers. 200 male chickens that were 2 weeks old, 50 for each diet, were assigned to one of the three diets containing 5, 10 or 15% olive mill wastes (OMW) compared to control diet (CD). There were no significant differences in body and weight gain, final body carcass, thighs and pectoral muscle weight between birds. The same observation was seen for abdominal tissue fat (% of body weight) of which no differences were detected in birds fed OMW diet compared to those fed on the control diet. Linoleic acid proportion increases significantly in the pectoral muscle (p < 0.0001) with the three diets containing OMW, but its level decreases in tight muscle with 5 and 10% OMW diets (p < 0.0001) and remainunchanged in abdominal fat. Oleic acid proportion increases in thigh muscle (p < 0.006) and remain unchanged in pectoral muscle and in abdominal adipose tissue. Palmitic acid proportion decreasessignificantly in pectoral muscle (p < 0.0001) and in abdominal adipose tissue (p < 0.002), but increases significantly in thigh muscle (p < 0.05). In conclusion, OMW diet gives attractive results. It bringsidentical growth performances and affect abdominal and muscle fat deposition and fatty acid composition

Protein kinase C in heart failure: a therapeutic target?

Heart failure (HF) afflicts about 5 million people and causes 300 000 deaths a year in the United States alone. An integral part of the pathogenesis of HF is cardiac remodelling, and the signalling events that regulate it are a subject of intense research. Cardiac remodelling is the sum of responses of the heart to causes of HF, such as ischaemia, myocardial infarction, volume and pressure overload, infection, inflammation, and mechanical injury. These responses, including cardiomyocyte hypertrophy, myocardial fibrosis, and inflammation, involve numerous cellular and structural changes and ultimately result in a progressive decline in cardiac performance. Pharmacological and genetic manipulation of cultured heart cells and animal models of HF and the analysis of cardiac samples from patients with HF are all used to identify the molecular and cellular mechanisms leading to the disease. Protein kinase C (PKC) isozymes, a family of serine–threonine protein kinase enzymes, were found to regulate a number of cardiac responses, including those associated with HF. In this review, we describe the PKC isozymes that play critical roles in specific aspects of cardiac remodelling and dysfunction in HF

Biomarkers of Extracellular Matrix Metabolism (MMP-9 and TIMP-1) and Risk of Stroke, Myocardial Infarction, and Cause-Specific Mortality: Cohort Study

Objective: Turnover of the extracellular matrix in all solid organs is governed mainly by a balance between the degrading matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs). An altered extracellular matrix metabolism has been implicated in a variety of diseases. We investigated relations of serum levels of MMP-9 and TIMP-1 to mortality risk from an etiological perspective. Design: The prospective Uppsala Longitudinal Study of Adult Men (ULSAM) cohort, followed from 1991–1995 for up to 18.1 years. A random population-based sample of 1,082 71-year-old men, no loss to follow-up. Endpoints were all-cause (n = 628), cardiovascular (n = 230), non-cardiovascular (n = 398) and cancer mortality (n = 178), and fatal or non-fatal myocardial infarction (n = 138) or stroke (n = 163). Results: Serum MMP-9 and TIMP-1 levels were associated with risk of all-cause mortality (Cox proportional hazard ratio [HR] per standard deviation 1.10, 95% confidence interval [CI] 1.03–1.19; and 1.11, 1.02–1.20; respectively). TIMP-1 levels were mainly related to risks of cardiovascular mortality and stroke (HR per standard deviation 1.22, 95% CI 1.09–1.37; and 1.18, 1.04–1.35; respectively). All relations except those of TIMP-1 to stroke risk were attenuated by adjustment for cardiovascular disease risk factors. Relations in a subsample without cardiovascular disease or cancer were similar to those in the total sample. Conclusion: In this community-based cohort of elderly men, serum MMP-9 and TIMP-1 levels were related to mortality risk. An altered extracellular matrix metabolism may be involved in several detrimental pathways, and circulating MMP-9 or TIMP-1 levels may be relevant markers thereof