449 research outputs found

    A New Methodology for Tuning PID‐Type Fuzzy Logic Controllers Scaling Factors Using Genetic Algorithm of a Discrete‐Time System

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    In this chapter, a proportional‐integral derivative (PID)‐type fuzzy logic controller (FLC) is proposed for a discrete‐time system in order to track a desired trajectory generated using the flatness property. In order to improve the performance of the proposed controller, genetic algorithm (GA) based on minimizing the integral of the squared error (ISE) is used for tuning the input and output PID‐type FLC scaling factors online. The considered controller is applied to an electronic throttle valve (ETV). GA tuning shows a better and robust performance compared to Simulink design optimization (SDO) algorithm in terms of tracking a desired trajectory with disturbances rejection

    Predicting cognitive scores with graph neural networks through sample selection learning

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    Analyzing the relation between intelligence and neural activity is of the utmost importance in understanding the working principles of the human brain in health and disease. In existing literature, functional brain connectomes have been used successfully to predict cognitive measures such as intelligence quotient (IQ) scores in both healthy and disordered cohorts using machine learning models. However, existing methods resort to flattening the brain connectome (i.e., graph) through vectorization which overlooks its topological properties. To address this limitation and inspired from the emerging graph neural networks (GNNs), we design a novel regression GNN model (namely RegGNN) for predicting IQ scores from brain connectivity. On top of that, we introduce a novel, fully modular sample selection method to select the best samples to learn from for our target prediction task. However, since such deep learning architectures are computationally expensive to train, we further propose a \emph{learning-based sample selection} method that learns how to choose the training samples with the highest expected predictive power on unseen samples. For this, we capitalize on the fact that connectomes (i.e., their adjacency matrices) lie in the symmetric positive definite (SPD) matrix cone. Our results on full-scale and verbal IQ prediction outperforms comparison methods in autism spectrum disorder cohorts and achieves a competitive performance for neurotypical subjects using 3-fold cross-validation. Furthermore, we show that our sample selection approach generalizes to other learning-based methods, which shows its usefulness beyond our GNN architecture

    Repellency and insecticidal activities of Thapsia garganica crude extract against some important pests

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    Repellency and insecticidal activities of Thapsia garganica leaf methanolic extract were investigated against Tribolium castaneum, Myzus persicae, Phthorimaea operculella, and Spodoptera littoralis. Repellency and toxic activities (by ingestion and topical application) were evaluated on T. castaneum nymphs and adults. Topical application treatment caused total larval growth inhibition at 10%, until mortality after 7 days. The highest mortality was recorded with 94% at the same concentration. Methanolic extracts incorporation into T. castaneum larvae artificial diet at 10% caused 100% mortality after 3 days. The extract at 1% cause high repellent effect on T. castaneum after 60 min of exposure, while M. persicae was less sensitive. P. operculella female’s showed sensitivity by a repellent effect at oviposition. Egg’s number laid on treated tubers at 1% and 2% decreased significantly to 32% and 72%, respectively. In addition, methanolic extracts had a preventive effect on P. operculella larval penetration. In fact, the number of larvae was reduced by 30.46% and 76.12% in the treated tubers at 1% and 2%, respectively. For S. littoralis, a low antifeeding effect was recorded. However, the relative growth rate (RGR), conversion of ingested and digested food to biomass, were decreased. The approximate digestibility increased. Moreover, a delay in larval development was observed. This study suggests that the leaf extract of T. garganica could be applied as bio-insecticide

    Assessment of Enterococcus durans F21 Isolated from Lben, a Moroccan Fermented Milk as a Biopreservative Agent

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    Abstract  Background and Objective: Lactic acid bacteria used in food processing for a long time are known for their benefits to consumers and their ability to produce natural antimicrobial compounds used as bio-preservatives in foods. The aim of the present study was the characterization and assessment of F21 strain, isolated from Lben (a traditional Moroccan fermented milk), as food biopreservative. Material and Methods: Isolate F21 was isolated from Lben, subjected to screening of inhibitory activity production, and identified based on morphological, biochemical and molecular identification. Then, the production and physicochemical characterization of the antagonistic substance were determined. Also, the safety profiling and biotechnological properties of isolate were evaluated. Finally, a biopreservative powder with antimicrobial activity was produced and assessed in various food systems (milk, ground beef and fresh cheese). Results and Conclusion: Of the isolated lactic acid bacteria, Enterococcus durans F21, isolated from Lben (a traditional Moroccan fermented milk), was remarkably endowed with interesting enterocin-like substance (heat stable and pH resistant) active against potentially pathogens and food spoilages (Listeria monocytogenes, Listeria innocua, Enterococcus faecalis, Brochothrix thermosphacta, and Mycobacterium smegmatis). Concerning the safety properties, Enterococcus durans F21 was not hemolytic, sensible to antibiotics tested, unable to produce biogenic amines and other virulence enzymes (gelatinase, DNase and urease). In addition, Enterococcus durans F21 showed satisfactory biotechnological characteristics such as acidification power, exopoly-saccharides production and antioxidant activity. The biopreservative powder containing enterocin-like substance F21 that was achieved via freeze-drying showed a minimum inhibition concentration of 60 AU ml-1 against Listeria monocytogenes in culture media. In addition, this biopreservative powder (at 665 AU ml-1) was able to improve safety and shelf-life of numerous foods (milk, Jben and ground beef). Thus, these results provided foundations for further uses of Enterococcus durans F21 as producer of potential food biopreservative agent. Conflict of interest: The authors declare no conflict of interest

    Quality and Trace Element Profile of Tunisian Olive Oils Obtained from Plants Irrigated with Treated Wastewater

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    In the present work the use of treated wastewater (TWW) to irrigate olive plants was monitored. This type of water is characterized by high salinity and retains a substantial amount of trace elements, organic and metallic compounds that can be transferred into the soil and into the plants and fruits. In order to evaluate the impact of TWW on the overall quality of the oils, the time of contact of the olives with the soil has been taken into account. Multi-element data were obtained using ICP-MS. Nineteen elements (Li, B, Na, Mg, Al, K, Ca, Sc, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Mo, Ba and La) were submitted for statistical analysis. Using analysis of variance, linear discriminant analysis and principal component analysis it was possible to differentiate between oils produced from different batches of olives whose plants received different types of water. Also, the results showed that there was correlation between the elemental and mineral composition of the water used to irrigate the olive plots and the elemental and mineral composition of the oils

    Electronic Throttle Valve Takagi-Sugeno Fuzzy Control Based on Nonlinear Unknown Input Observers

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    This paper deals with the synthesis of a new fuzzy controller applied to Electronic Throttle Valve (ETV) affected by an unknown input in order to enhance the rapidity and accuracy of trajectory tracking performance. Firstly, the Takagi-Sugeno (T-S) fuzzy model is employed to approximate this nonlinear system. Secondly, a novel Nonlinear Unknown Input Observer (NUIO)-based controller is designed by the use of the concept of Parallel Distributed Compensation (PDC). Then, based on Lyapunov method, asymptotic stability conditions of the error dynamics are given by solving Linear Matrix Inequalities (LMIs). Finally, the effectiveness of the proposed control strategy in terms of tracking trajectory and in the presence of perturbations is verified in comparison with a control strategy based on Unknown Input Observers (UIO) of the ETV described by a switched system for Pulse-Width-Modulated (PWM) reference signal

    Flatness-based Control and Conventional RST Polynomial Control of a Thermal Process

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    In this paper, a comparison between conventional RST polynomial control by poles placement and RST flatness-based control is proposed. These approaches were developed, in discrete-time formalism by carrying out a generation of a reference starting from a flat output and by then analyzing the tracking error in closedloop. The case of the thermal system, that we applied an output disturbance, was considered by simulation to study the effectiveness of given flatness-based robust controller with the integration of an anti-windup device, in terms of tracking trajectory and disturbance rejection

    A new way of valorizing biomaterials: the use of sunflower protein for 1 a-tocopherol microencapsulation

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    Biopolymer based microparticles were efficiently prepared from sunflower protein (SP) wall material and a-tocopherol (T) active core using a spray-drying technique. Protein enzymatic hydrolysis and/or N-acylation were carried out to make some structural modifications to the vegetable protein. Native and hydrolyzed SP were characterized by Asymmetrical Flow Field-Flow Fractionation (AsFlFFF). Results of AsFlFFF confirmed that size of proteinic macromolecules was influenced by degree of hydrolysis. The effect of protein modifications and the influence of wall/core ratio on both emulsions and microparticle properties were evaluated. Concerning emulsion properties, enzymatic hydrolysis involved a decrease in viscosity, whereas acylation did not significantly affect emulsion droplet size and viscosity. Microparticles obtained with hydrolyzed SP wall material showed lower retention efficiency (RE) than native SP microparticles (62-80% and 93% respectively). Conversely, acylation of both hydrolyzed SP and native SP allowed a higher RE to be reached (up to 100%). Increasing T concentration increased emulsion viscosity, emulsion droplet size, microparticle size, and enhanced RE. These results demonstrated the feasibility of high loaded (up to 79.2% T) microparticles

    Microencapsulation of rice bran oil using pea protein and maltodextrin mixtures as wall material

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    In this work, the encapsulation of rice bran oil extracted using supercritical CO2 has been studied. In the first stage, the emulsification process by high pressure homogenization was studied and optimized. The effect of the working pressure (60–150 MPa), the composition of the carrier (mixtures of pea protein isolate (PPI) and maltodextrin (MD), from 50 to 90% of PPI) and the carrier to oil ratio (2–4) on the emulsion droplet size (EDS) was studied. To minimize the EDS, moderate pressures (114 MPa), a carrier composed mainly by PPI (64%) and carrier to oil ratios around 3.2 were required. The emulsion obtained in the optimal conditions (EDS ¼ 189 3nm) was dried using different technologies (spray-drying, PGSS-drying and freeze drying). The supercritical CO2 based drying process (PGSS) provided spherical particles that resulted in the smallest average size (but broader distribution) and lower encapsulation efficiency (53 2%).Junta de Castilla y Leon and ERDF Project BU301P18)
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