Communications Internationales

Permanent URI for this collectionhttps://dspace.univ-boumerdes.dz/handle/123456789/11

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Now showing 1 - 7 of 7
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    Optimization of circular antenna arrays using a differential search algorithm
    (Polish Academy of Sciences, 2015) Recioui, Abdelmadjid
    Circular and concentric circular antenna array patterns are synthesized to generate array factors with minimum side-lobe level and high directivity. The comprehensive learning differential search algorithm is used for synthesizing a one-and a three-ring circular and concentric circular antenna array with thirty elements. This synthesis is done by finding the optimum inter-element spacing of rings, phases and /or positions that give optimum side lobe level. The computational results show that side lobe level is reduced significantly in non-uniform case for concentric in comparison with a single ring
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    Genetic algorithm based objective functions comparative study for damage detection and localization in beam structures
    (Institute of Physics Publishing, 2015) Khatir, Samir; Belaidi, Idir; Serra, R.; Benaissa, Brahim; Ait Saada, Aicha
    The detection techniques based on non-destructive testing (NDT) defects are preferable because of their low cost and operational aspects related to the use of the analyzed structure. In this study, we used the genetic algorithm (GA) for detecting and locating damage. The finite element was used for diagnostic beams. Different structures considered may incur damage to be modelled by a loss of rigidity supposed to represent a defect in the structure element. Identification of damage is formulated as an optimization problem using three objective functions (change of natural frequencies, Modal Assurance Criterion MAC and MAC natural frequency). The results show that the best objective function is based on the natural frequency and MAC while the method of the genetic algorithm present its efficiencies in indicating and quantifying multiple damage with great accuracy. Three defects have been created to enhance damage depending on the elements 2, 5 and 8 with a percentage allocation of 50% in the beam structure which has been discretized into 10 elements. Finally the defect with noise was introduced to test the stability of the method against uncertainty
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    New algorithm for assessment of frequency duration of murmurs using Hilbert-Huang transform
    (Springer, 2015) Omari, Tahar; Bereksi-Reguig, Fethi
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    Experimentation of practical new technique for single and two simultaneous diodes open faults automatic detection and localization in six diodes three phase bridge rectifier
    (SAE International, 2008) Benslimane, T.
    The faulty performance of six diodes three phase rectifier is studied under one and two simultaneous open-diodes conditions. This rectifier is feeding a resistive load. The rectifier three phases currents zero harmonic components and their maximum and minimum values are used as diagnostic indices. A knowledge algorithm is based to get information on which diode is in open-switch fault condition. This algorithm testing shows that the system could not only detect the open-switch fault, but also identify the faulty switches. Presented simulation results confirm the effectiveness of the proposed methodology.
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    Currents mean and min/max values for diagnostic of one and two simultaneous open-switches faults in three phase voltage inverter fed permanent magnet brushless DC motor drives
    (SAE International, 2008) Benslimane, T.
    The faulty performance of permanent-magnet (PM) brushless dc motor drives is studied under one and two simultaneous open-switches faults conditions. This DC motor is supplied with three phase two level six IGBT (Insulated-Gate Bipolar Transistor) voltage source inverter. The three phases currents mean, min and max values of the DC motor are used as diagnostic indices. A knowledge algorithm is based to get information on which IGBT is in open-switch fault condition. This algorithm testing shows that the system could not only detect the open-switch fault, but also identify the faulty switch. Presented simulation results confirm the effectiveness of the proposed methodology
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    Fuzzy control motion design for mobile robots in unknown environments
    (2009) Hachour, O.
    we present an algorithm for path planning to a target for mobile robot in unknown environment. The proposed algorithm allows a mobile robot to navigate through static obstacles, and finding the path in order to reach the target without collision. This algorithm provides the robot the possibility to move from the initial position to the final position (target). The proposed path finding strategy is designed in a grid-map form of an unknown environment with static unknown obstacles. The robot moves within the unknown environment by sensing and avoiding the obstacles coming across its way towards the target. When the mission is executed, it is necessary to plan an optimal or feasible path for itself avoiding obstructions in its way and minimizing a cost such as time, energy, and distance. In order to get an intelligent component, the use of Fuzzy Logic In order to get an intelligent component, the use of Fuzzy Logic (FL), and Expert Systems (ES) is necessary to bring the behavior of Intelligent Autonomous Vehicles (IAV). To present a real intelligent task and to deal with autonomy requirements such as power and thermal, (FL), and Expert Systems (ES) is necessary to bring the behavior of Intelligent Autonomous Vehicles (IAV). The aim work must make the robot able to achieve these tasks: to avoid obstacles, and to make ones way toward its target by ES-FL system capturing the behavior of a human expert. The integration of ES and FL has proven to be a way to develop useful realworld applications, and hybrid systems involving robust adaptive control. The proposed approach has the advantage of being generic and can be changed at the user demand. The results are satisfactory to see the great number of environments treated. The results are satisfactory and promising