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Khatbi O.,Hassan 1er University | Mouhsen A.,Hassan 1er University | Hachkar Z.,Hassan 1er University
Advances in Intelligent Systems and Computing | Year: 2017

The surveys that have been done on the use spectrum shows that some frequency bands are less busy compared with others. Cognitive radio has come to give the possibility to use the free band of a primary user for a secondary user. Confirmation of the presence of the primary user is typically performed by a spectrum sensing. A function of cognitive radio based on the ability to find unoccupied spectrum without interference. The cognitive radio spectrum sensing method considered in this work is Energy detection method based on the central limit theorem and the sensing performance of this scheme is quantified by the receiver operating characteristic (ROC), such as between the probability of detection versus the probability of false alarm. A simulation is carried out in the Matlab environment to show the relation between Pd and Pf with various SNR values. © Springer International Publishing AG 2017.

El Fissaoui M.,Chouaïb Doukkali University | Beni-Hssane A.,Chouaïb Doukkali University | Saadi M.,Hassan 1er University
Advances in Intelligent Systems and Computing | Year: 2017

In this paper, we present an enhanced scheme to handle MAC layer misbehavior in wireless networks. It’s known that IEEE 802.11 wireless LAN medium access control (MAC) provides transmission fairness to nodes in a network. But some nodes can take advantage and modify its MAC to improve its own performance at the expense of other nodes. To handle these misbehaving nodes, we use a backslide strategy to react against the misbehaving nodes, which is based on the number of times the misbehaving nodes they misbehave. Extensive simulation results are presented to validate our proposed strategy by improving honest nodes throughput and then the performance of the network. © Springer International Publishing AG 2017.

El-Ansari A.,Chouab Doukkali University | Beni-Hssane A.,Chouab Doukkali University | Saadi M.,Hassan 1er University
Advances in Intelligent Systems and Computing | Year: 2017

Due to the massive growth of information on the Web, information retrieval systems come to play a more critical role. Most of these systems are based on content matching rather than the meaning, therefore the returned results are not always relevant to the user. To solve this problem, the next generation of information retrieval systems focus on the meaning of the user query and search data using ontologies that provide the vocabulary and structure associated with metadata. In this work we present a Question Answering system which combines multiple knowledge bases, with a Natural Language parser to transform questions into SPARQL queries or other query language. We demonstrate the feasibility to build such a semantic QA system and the accuracy and relevance of the returned results. © Springer International Publishing AG 2017.

Abdelmalki F.,University Sidi Mohammed Ben Abdellah | Ouaaline N.,Hassan 1er University
International Journal of Power Electronics and Drive Systems | Year: 2016

This paper aims to ensure a stability and observability of doubly fed induction generator DFIG of a wind turbine based on the approach of fuzzy control type T-S PDC (Parallel Distributed Compensation) which determines the control laws by return state and fuzzy observers. First, the fuzzy TS model is used to precisely represent a nonlinear model of DFIG proposed and adopted in this work. Then, the stability analysis is based on the quadratic Lyapunov function to determine the gains that ensure the stability conditions. The fuzzy observer of DFIG is built to estimate non-measurable state vectors and the estimated states converging to the actual statements. The gains of observatory and of stability are obtained by solving a set of linear matrix inequality (LMI). Finally, numerical simulations are performed to verify the theoretical results and demonstrate satisfactory performance. © 2016 Institute of Advanced Engineering and Science. All rights reserved.

Abboussi O.,Hassan 1er University | Paizanis E.,University of Caen Lower Normandy | El Ganouni S.,Hassan 1er University
Pharmacology Biochemistry and Behavior | Year: 2014

Several epidemiological studies show an increase in cannabis use among adolescents, especially in Morocco for being one of the major producers in the world. The neurobiological consequences of chronic cannabis use are still poorly understood. In addition, brain plasticity linked to ontogeny portrays adolescence as a period of vulnerability to the deleterious effects of drugs. The aim of this study was to investigate the behavioral neurogenic effects of chronic exposure to the cannabinoid agonist WIN55,212-2 during adolescence, by evaluating the emotional and cognitive performances, and the consequences on neurogenesis along the dorso-ventral axis of the hippocampus in adult rats. WIN55,212 was administered intraperitoneally (i.p.) once daily for 20 days to adolescent (27-30 PND) and adult Wistar rats (54-57 PND) at the dose of 1 mg/kg. Following a 20 day washout period, emotional and cognitive functions were assessed by the Morris water maze test and the two-way active avoidance test. Twelve hours after, brains were removed and hippocampal neurogenesis was assessed using the doublecortin (DCX) as a marker for cell proliferation. Our results showed that chronic WIN55,212-2 treatment significantly increased thigmotaxis early in the training process whatever the age of treatment, induced spatial learning and memory deficits in adolescent but not adult rats in the Morris water maze test, while it had no significant effect in the active avoidance test during multitrial training in the shuttle box. In addition, the cognitive deficits assessed in adolescent rats were positively correlated to a decrease in the number of newly generated neurons in dorsal hippocampus. These data suggest that long term exposure to cannabinoids may affect more potently spatial learning and memory in adolescent compared to adult rats via a negative action on hippocampal plasticity. © 2014 Elsevier Inc.

Barka N.,Hassan 1er University | Abdennouri M.,Hassan 1er University | El Makhfouk M.,British Petroleum | Qourzal S.,University Ibn Zohr
Journal of Environmental Chemical Engineering | Year: 2013

The biosorption of cadmium (II) and lead (II) ions onto a natural, plentiful and low-cost biosorbent developed from cactus cladodes was investigated in batch mode. Experiments were carried out as a function of average biosorbent particle size, pH, biosorbent mass, contact time, initial metal concentration and temperature. The experimental results indicate that, the percentage of biosorption increases with an increase in the biosorbent dosage and the decrease of particle size. The equilibrium uptake was increased with an increase in the initial metal concentration in solution. The maximum biosorption occurred at pH of 5.8 and 3.5, respectively for cadmium (II) and lead (II) ions. Biosorption kinetic data were properly fitted with the pseudo-second-order kinetic model. The equilibrium data fitted very well to the Langmuir model with a maximum monolayer biosorption capacity of 30.42 and 98.62 mg/g, respectively for cadmium (II) and lead (II) ions. The biosorption yield decreases with an increase in solution temperature. The FTIR analysis of unloaded and metal loaded biosorbent indicated the involvement of CO, OC and COC groups in metal binding. © 2013 Elsevier Ltd. All rights reserved.

Barka N.,Hassan 1er University | Abdennouri M.,Hassan 1er University | Makhfouk M.E.,British Petroleum
Journal of the Taiwan Institute of Chemical Engineers | Year: 2013

The biosorption of Methylene Blue (MB), Eriochrome Black T (EBT) and Alizarin S (AS) from aqueous solutions by dried prickly pear cactus cladodes as a low-cost, natural and eco-friendly biosorbent was investigated. The study was carried out under various parameters, such as average biosorbent particle size, pH, biosorbent dosage, contact time, initial dye concentration and temperature. The experimental results show that, the percentage of biosorption increases with an increase in the biosorbent dosage, and the decrease of particle size. The biosorption was pH dependent with a high biosorption of cationic dye (MB) in basic range and a high biosorption of anionic dyes (EBT and AS) in acidic range. The equilibrium uptake was increased with an increase in the initial dye concentration in solution. Biosorption kinetic data were properly fitted with the pseudo-second-order kinetic model. The experimental isotherm data were analyzed using Langmuir, Freundlich, Redlich-Peterson, Temkin and Toth isotherm equations. The best fit was obtained by the Redlich-Peterson model and the Langmuir model with a Langmuir maximum monolayer biosorption capacity of 189.83. mg/g for Methylene Blue, 200.22. mg/g for Eriochrome Black T and 118.35. mg/g for Alizarin S. The biosorption was exothermic in nature (ΔH° = -31.035 kJ/mol for MB, -10.25 kJ/mol for EBT and -11.69 kJ/mol for AS). The reaction was accompanied by a decrease in entropy (ΔS° = -94.76 J/K mol for MB, -38.44 J/K mol for EBT and -41.93 J/K mol for AS). The Gibbs energy (ΔG°) increased when the temperature was increased from 25 to 60. °C indicating a decrease in feasibility of biosorption at higher temperatures. © 2012 Taiwan Institute of Chemical Engineers.

Manoun B.,Hassan 1er University | Igartua J.M.,University of the Basque Country | Lazor P.,Uppsala University | Ezzahi A.,Hassan 1er University
Journal of Molecular Structure | Year: 2012

In this paper we report high-temperature (up to 550 °C) Raman spectroscopy of phase transitions in Sr2MWO6 (M = Zn, Co) double perovskite oxides. For Sr2ZnWO6 modes centered at 137 cm-1, 152 cm-1, merge around 80 °C. The same behavior was observed for the 436 cm-1 and 447 cm-1 modes. The mode centered at 854 cm-1 shows a change in the slope at the same temperature, thus indicating a first order phase transition from the monoclinic (P21/n) to tetragonal (I4/m) structure. With increasing temperature, a little change in the slope of the temperature dependence of mode centered at 855 cm-1 is observed around 480 °C which might be a sign of the second phase transition in Sr2ZnWO6 (tetragonal (I4/m) to cubic (Fm-3m)). The temperature dependence of the full width at half maximum (FWHM) of the most intense modes in Sr 2ZnWO6 spectra was studied. The width behaves linearly as a function of temperature with a break observed in the slope of the width of the modes at 80 °C; thus, showing the first phase transition occurrence. For Sr2CoWO6 the transition from tetragonal (I4/m) structure to cubic (Fm-3m) phase is accompanied by considerable changes in the temperature dependence of modes centered at 438 cm-1 and 845 cm-1. The transition was observed around 420 °C. © 2012 Elsevier B.V. All rights reserved.

Manoun B.,Hassan 1er University | Tamraoui Y.,Hassan 1er University | Lazor P.,Uppsala University | Yang W.,Carnegie Institution of Washington | Yang W.,HIGH-TECH
Applied Physics Letters | Year: 2013

Double-perovskite oxide Sr2MgTeO6 has been synthetized, and its crystal structure was probed by the technique of X-ray diffraction at room temperature. The structure is monoclinic, space group I2/m. Temperature-induced phase transitions in this compound were investigated by Raman spectroscopy up to 550 °C. Two low-wavenumber modes corresponding to external lattice vibrations merge at temperature of around 100 °C, indicating a phase transition from the monoclinic (I2/m) to the tetragonal (I4/m) structure. At 300 °C, changes in the slopes of temperature dependencies of external and O-Te-O bending modes are detected and interpreted as a second phase transition from the tetragonal (I4/m) to the cubic (Fm-3m) structure. © 2013 AIP Publishing LLC.

Jebbouj R.,Hassan 1er University | El Yousfi B.,French National Institute for Agricultural Research
European Journal of Plant Pathology | Year: 2010

Knowledge of pathotype diversity and virulence in local populations of Pyrenophora teres is a prerequisite to screening for durable resistance to net blotch. The current study aimed to quantify the virulence level of Moroccan isolates, identify and designate existing pathotypes, and select resistant genotypes. We developed a method for virulence quantification of P. teres isolates based on a conversion of infection responses into frequencies for use in correspondence analysis. Coordinates of the first axis of this analysis had a virulence spectrum and ranked isolates from virulent to avirulent. Mixed model analysis was also devised for virulence quantification. Coordinates of the first dimension of correspondence analysis were linearly correlated to BLUPs (Best Linear Unbiased Predictors) of the mixed model. A genotype by genotype by environment model (GGE) coupled with cluster analysis differentiated P. teres isolates into ten and nine pathotypes for net- and spot-forms respectively. Populations of these two forms were dissimilar in terms of classes of virulence. For P. teres f. maculata, avirulent, moderately virulent and highly virulent isolates represented one-third of the population, whereas 90% of P. teres f. teres population was composed of avirulent to moderately avirulent isolates. Barley differential sets were subsequently reduced to two new sets that simplified pathotyping through a key code based on resistant or susceptible reactions. Dendrograms of cluster analysis based on GGE analysis depicted the stability of a genotype's reactions across all isolates, and using only resistant cultivars as sources of resistance to control net blotch disease would, based on this analysis, fail to control all pathotypes. Therefore, we propose an alternative breeding strategy to control net blotch effectively. © 2010 KNPV.

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