Time-Frequency Analysis of GPR Signal Using a Modified Hilbert Huang Approach

In this paper, we will discuss the efficiency of a modified Hilbert Huang transform (HHT) approach [1, 2], which is largely applied to fault diagnosis for rolling bearing and vibration analysis, for the time-frequency analysis of the GPR signals. The aim of this approach is to improve the readability of the HHT spectrum and hence improving the visibility of all the events and reducing the effects of interference terms. An improved Hilbert-Huang transform (HHT) combined with wavelet packet transform (WPT) is proposed for recognizing reflected echoes in A-scans profiles. The HHT consists of Empirical Mode Decomposition (EMD) and Hilbert-Huang spectrum. Firstly, the Wavelet Packet Transform (WPT) decomposes the signal into a set of narrow band signals, then a series of Intrinsic Mode Functions (IMFs) can be obtained after application of the EMD. Where after, a screening processes is conducted on the IMFs of each narrow band signal to remove unrelated IMFs. Hilbert Transform is then employed to calculate the Hilbert amplitude spectrum. The results show that the proposed method has better discriminability than the traditional HHT and the Continuous Wavelet Transform (CWT) among different states. The proposed algorithm has the potentiality to trace the different changes, which paves a way for a better interpretation of radar profiles

Optimisation des Performances de Rayonnement d'une Nouvelle Structure d'Antenne Patch de Forme Carrée pour un Lecteur RFID

L’objectif principal de ce travail est d’optimiser les performances de rayonnement d’une nouvelle structure d'antenne patch de forme carrée. Cette antenne est excitée par une ligne microruban ayant un port d’alimentation adapté

MPPT Fuzzy Logic Control of a Variable Speed Wind Turbine

This work is focused on the control of a wind turbine system based on (PMSG). In order to enhance the efficiency of the wind turbine system, the maximum power point tracking (MPPT) control is applied to exploit the maximum power from the wind. The Fuzzy Logic controller (FLC) has been proposed and developed for the speed control. The simulation results show good performances of this control

Real-Time Vehicle Detection Using Cross-Correlation and 2D-DWT for Feature Extraction

Nowadays, real-time vehicle detection is one of the biggest challenges in driver-assistance systems due to the complex environment and the diverse types of vehicles. Vehicle detection can be exploited to accomplish several tasks such as computing the distances to other vehicles, which can help the driver by warning to slow down the vehicle to avoid collisions. In this paper, we propose an efficient real-time vehicle detection method following two steps: hypothesis generation and hypothesis verification. In the first step, potential vehicles locations are detected based on template matching technique using cross-correlation which is one of the fast algorithms. In the second step, two-dimensional discrete wavelet transform (2D-DWT) is used to extract features from the hypotheses generated in the first step and then to classify them as vehicles and nonvehicles. The choice of the classifier is very important due to the pivotal role that plays in the quality of the final results. Therefore, SVMs and AdaBoost are two classifiers chosen to be used in this paper and their results are compared thereafter. The results of the experiments are compared with some existing system, and it showed that our proposed system has good performance in terms of robustness and accuracy and that our system can meet the requirements in real time

Ultra Wideband Planar Microstrip Array Antennas for C-Band Aircraft Weather Radar Applications

A miniaturized ultra wideband (UWB) planar array antennas for C-band aircraft weather RADAR applications is presented. Firstly, the effect of the ground plane is studied. Later, the realization and experimental validation of the geometry that has an UWB characteristic are discussed. This array antennas is composed of a twenty-four radiating element that is etched onto FR-4 substrate with an overall size of 162×100×1.58 mm3 and a dielectric constant of εr=4.4. The results show that this miniaturized array antennas gives us a bandwidth which is about 115% and a gain greater than 13 dB which are required in aircraft weather radar applications

Gain and bandwidth enhancement of New Planar microstrip array antennas geometry for C band weather radar applications

International audienceA 4–8 GHz ultra wide band microstrip array antennas with improved gain for weather Radar applications was designed and fabricated. The microstrip radiating elements of the proposed array antennas are powered using a T-junction power divider with quarter wave-transformer impedance for a best matching. The design of this array antennas is based on the geometry of a linear array antennas well studied [ref (8)], which is based on minimizing of the electromagnetic (EM) coupling between the radiating elements and as decreasing the number of side lobes. The array antennas with dimension of (110 × 214 × 1.58 mm3) is fabricated on FR-4 epoxy dielectric with relative permittivity of 4.4 and thickness h = 1.58 mm, it is performed in the full-wave EM solver High Frequency Structure Simulator, CST and verified by measurement. The proposed broadband array antennas show a better performance than the references antennas in deferent parameter which cited after

Study of Physicochemical and Bacteriological Quality of Treated Wastewater by the New Aourir Plant (Southwestern of Morocco) Using Activated Sludge Technology in a Semi-Arid Region

In order to use the purified wastewater for the irrigation of a golf course in the Taghazout area (Southwestern of Morocco), this study was conducted to evaluate the physicochemical and bacteriological quality of the treated wastewater in the new Aourir plant (Activated Sludge technology). In order to achieve these objectives, three types of water were analyzed: raw water (RW), biologically treated water (BTW) and water treated by ultraviolet radiation (UV-TW). The physicochemical parameters analyzed were Temperature, pH, Electrical Conductivity (EC), Dissolved Oxygen (DO), Chemical Oxygen Demand (COD), five-day Biological Oxygen Demand (BOD5), Total Suspended Solids (SS), Nitrate (NO3), and Orthophosphates (PO4). Otherwise, the analyzed biological parameters are Total Coliforms (TC), Fecal Coliforms (FC), Escherichia coli (E. coli), and Fecal Streptococci (FS). The physicochemical parameters showed that temperature is always lower than 30°C, the pH is close to neutrality and a strong fluctuation of the high electrical conductivity (2700 μS/cm) occurs in UV-TW. At all stages of wastewater treatment, COD, BOD5, SS, NO3 and PO4 were below the limit values recommended by Moroccan standards. The bacteriological results showed a high level of bacterial contamination in RW and BTW, but in UV-TW the loads did not exceed 3 log10. The average loads of TC, FC, E. coli and FC in UV-TW were 2.13, 1.67, 1.77, and 2 (log10 CFU/100ml) respectively. Activated sludge treatment combined with UV has demonstrated sufficient quality to reuse treated water in irrigation; however, the UV treatment requires control to avoid any effect on the microbiological and physicochemical quality of green spaces and groundwater

Comparative Analysis of Different Excitation Techniques for Cylindrical Dielectric Resonator Antenna

International audienceDirect Microstrip line, Microstrip slot-coupled feed and hybrid coupler techniques are investigated for Cylindrical Dielectric Resonator Antenna (CDRA). The Dielectric resonator has a dielectric constant of 30, and etched on Arlan dielectric substrate having a relative permittivity of 3.58 and dimensions of 150 x 150 mm2. The structures are numerically analyzed using the numerical software HFSS. Radiation characteristics including return loss, gain, directivity and VSWR versus frequency characteristic are presented and compared based on the excitation method employed for the studied CDRA. The simulation results proved that the 90° hybrid coupler provides good performances particularly: a wider impedance bandwidth of 1.15 GHz and a maximum coupling of -45 dB