The access part of all cellular networks generation suffers from common issues related to dead spots (parts that are not covered by the network) and hot spots (parts where the active cellular clients exceed the network resources). During the last eighteen years, lots of research proposals have tried to overcome cellular problems through MCN (Multi-hop Cellular Networks) architectures or what is newly called D2D multi-hop communications which is a new paradigm allowing the extension of cellular access part via ad-hoc networks. In this paper, we identify the key D2D architecture classification factors, we present some proposed D2D architectures, and then we build our experimental platform in real indoor environment, with android smartphones to compare uplin/downlink throughputs and latency between single hop and multi-hop communication trough D2D architecture inside a 4G cellular network.
The current paper gives an overview on the technologies used in word spotting especially for handwritten documents. We present recent interesting published researches in this domain. We firstly give a general overview on the steps of the word spotting system, and then we describe a framework of techniques and methods used in each step, at the end we present a summary of these research in a table.
A conventional sliding mode (SMC) and second-order sliding mode (SOSMC) control schemes based on pulse width modulation (PWM) for the rotor side converter (RSC) and grid side converter (GSC) feeding a doubly fed induction generator (DFIG) are presented in this paper. The proportional integral (PI) controllers for wind turbine system (WTS) driven-DFIG have shown many limitations such as parameter adjustment difficulties, sensibility to DFIG parameter variations and poor robustness. Therefore, nonlinear controllers based on SMC and SOSMC are proposed to improve the wind energy conversion efficiency and the system robustness by controlling the RSC and GSC at a constant switching frequency. The proposed controllers turn-out to be more robust against parameter variations of the DFIG and external disturbances. In addition, the SMC and SOSMC approaches can optimize the WTS production, i.e. improve quality of energy produced and energy efficiency. Detailed simulation studies of WTS under various conditions are carried out in MATLAB/Simulink software, and the results confirm the robustness of the proposed control techniques.
In this work, we propose an inverted L-shaped monopole printed antenna operating at 2.45GHz / 5.8GHz for RFID applications. The proposed antenna consists of an inverted L- monopole fed by a meandered microstrip line and two complementary split ring resonators (CSRR) cells etched in the ground plane located on the back side of the substrate. Initially, the antenna resonates at 2.45 GHz by properly choosing the position of CSRRs in the ground plane we could generate a new resonant frequency in the vicinity of 5.8 GHz. A wide impedance bandwidth in both frequency bands is achieved (400MHz at 2.45 GHz and 1.6 GHz at 5.8 GHz) and an acceptable gain is also obtained. The proposed antenna can be considered an excellent candidate for RFID reader applications. The simulation results are obtained by using CST MWS and HFSS solvers.
Traffic congestion at intersections is one of the most problems encountered by the population in large cities. Shutdowns and delays in traffic light consume fuel and increase the vehicle's travel time and greenhouse gas emissions. Therefore, an effective traffic control system can minimize shutdowns and delays at traffic lights. In this paper, an image processing system in real time has been proposed to measure the density of traffic to adjust the timing of the traffic light. The method proposed here is based on applying the combination of background updating and edge detection to separate the edges of vehicles from the edges of the objects of the background (e.g., marks on the road or shadows of trees or building). The algorithm is applied to videos obtained by stationary cameras.
Recently Vehicular Cloud Computing (VCC) has become an attractive solution that support vehicle's computing and storing service requests. This computing paradigm insures a reduced energy consumption and low traffic congestion. Additionally, VCC has emerged as a promising technology that provides a virtual platform for processing data using vehicles as infrastructures or centralized data servers. However, vehicles are deployed in open environments where they are vulnerable to various types of attacks. Furthermore, traditional cryptographic algorithms failed in insuring security once their keys compromised. In order to insure a secure vehicular platform, we introduce in this paper a new decoy technology DT and user behavior profiling (UBP) as an alternative solution to overcome data security, privacy and trust in vehicular cloud servers using a fog computing architecture. In the case of a malicious behavior, our mechanism shows a high efficiency by delivering decoy files in such a way making the intruder unable to differentiate between the original and decoy file.
We present a new analog design of an operational amplifier (OP-AMP), operating in the temperature range from - 55 °C to 225 °C due to the used technology process and its ability to support the temperature changes. The 0.064us settling time amplifier is developed in the standard process of 1um (Fully Depleted Silicon On Insulator) FDSOI CMOS and can be used in designing high-speed applications such as aerospace and automotive embedded applications. The proposed OP-AMP achieved 41.12 dB CMRR, the phase margin is more than 100 degrees for the DC gain of 13.97dB, which is a reasonable margin when temperature range increases. The OP-AMP biasing current of 70uA while consuming only 0.62 mW in a sub-threshold region with 3.75 V supply voltage including the cascode bias circuitry
Integrating new plants of renewable energies for electrical production in a distribution network presents challenges for the grid operators. However, the power systems are not designed to receive these intermittent renewable energy sources. The distributed generation (DG) integration causes several problems such as overvoltage, lines overload, transformers overload, protection issues, and exceeding network limits. The hosting capacity approach (HCA) defined the hosting capacity (HC) as the maximum power that will be injected into the gird without causing any problem in the electrical system. In this paper, we propose a new method to calculate the HC of distributed generation (DG) facilities. Therefore, the variety of distribution line configurations and cross admittance are considered in the calculation and the overvoltage as a limit of HC. The proposed method is applied to an underground medium voltage grid.The simulation is carried out using Matlab and Etap.
Organizations around the world are drowning in data. Although their information is everywhere, it is more difficult than ever to find reliable answers between data accumulation and data management, strategic decision-making in an organization requires the use of multiple sources of information that affect all departments. These data are generally subject to many data transformations; scattered in departments unrelated to each other; Heterogeneous in their technical formats and their structural organizations, even their semantics, and organization aspects, volatile, as their updating may lead to the forgetting of obsolete information. However, these challenges of connecting the government information system to the public administrations need instant access to relevant data in a properly interoperable form. The emergence of E-Government has been one of the most important developments that represent a collaborative process of government functionality that allows the sharing of information and services for external and internal government agencies, and for citizens and companies they serve. Creating a BI environment for e-Gov systems, using open source technologies, can affect the scalability and stability of reports. Therefore, in this article, we will propose an evolved architecture to a more hybrid BI solution for E-Government based on large-scale data, by using Data Warehouse, to ensure interoperability in any E-Government system. The importance of this approach of E-Government interoperability is to enable the government to address a number of challenges related to their information system on the one hand, and to contribute to Morocco's-government project on the other hand. E-Government is currently in developing, using BI technology, which helps decision-makers to draw key conclusions from data, essential elements of any e-governance initiative to lead to more efficient and reliable solutions for integrity E-Government data.
The major challenges facing Intelligent Transportation Systems (ITS) are how to decrease traffic congestion and increase safety. Recent efforts are focusing on using new technologies such as sensors and vehicular communication to enhance road traffic flaw. However, novel systems based on cooperative driving aim to reduce congestion by decreasing travel delay and avoiding vehicle stopping as much as possible without taking into account other road users such as bicycles. Cyclists are one of the three most vulnerable road users that are usually injured or even killed when they are involved in a collision with a vehicle. To fill this gap, we propose Distant Bicycle Detection and Avoidance (DBDA) protocol for autonomous vehicles that enables distant detection of bicycle using V2V communication for up to 1 km and guarantees a safe avoidance of a bycicle in non-signalized roads.
This This paper presents a low noise amplifier (LNA) for WLAN applications. The target frequency band 802.11b/g@ 2.4GHz. The amplifier is characterized by input and output reflection coefficients less than -15dB, a forward gain (S21) of 15.112dB, a noise figure of 0.37dB and the third input intercept point of 14.8dB.
An implementation of an analogue-to-digital converter (ADC) with a dynamically adjustable resolution. This new architecture is well adapted for applications in which the noise level varies with the amplitude of the useful signal such as CMOS Image Sensors (CIS). The converter is designed in CMOS 65 nm technology (1Poly and 3Metals) and the low power constraints have been respected. A simulation environment with post-layout accuracy is incorporated to demonstrate the advantage of the proposed converter. Simulation results indicate that the Successive Approximation Register (SAR) ADC consumes $142.8\ \boldsymbol{\mu W}$ , achieves a bit rate of 8.33MS/s and has an SNR of 71.5dB, an ENOB of 11,3bits and a FOM of 3,399 fJ/conv.
This paper presents a comparative study of solar hydrogen production via water electrolysis between Morocco and Southern Europe. To achieve that goal, we gathered the meteorological data of Benguerir, Morocco and Almeria, Spain from high accurate local stations for a period of 3 years starting from 2014. For the sake of accuracy, we used the 3 years average to simulate a hydrogen production from a system composed of 100 MW p PV plant coupled with a PEM electrolyzer. The results show that the annual hydrogen production is 3342 Tons for Benguerir and 3230 Tons for Almeria. As for the cost of hydrogen production it was found to be 5.78 $/Kg and 5.96 $/Kg for Benguerir and Almeria respectively. The findings of this study highlights the solar energy potential for hydrogen production in Morocco, and provides the policy makers as well as investors with important informations to encourage them to invest more in this sector which can help the country to diverse its energy mix, expand its industry and move toward a more sustainable economy.
In this paper we present nonlinear control of the DFIG used in a wind energy conversion system (WECS). The DFIG is directly connected to the grid, moreover the the rotor is connected to the back-to-back converters. the DFIG's active and reactive powers are regulated by controlling the converters. In this work we used 2 methods based on sliding mode to control the rotor side converter. The first one is a normal sliding mode control using with reliable grid, the second one is a modified sliding mode used during the voltage dip. The machine is tested in association with a wind turbine. Simulations results are presented and discussed for the whole system.
In this paper we describe our experience to implement a proposed algorithm of routing protocol based on Neural Networks (NNs), our approach focus on improving the clustering performances. The energy consumption is an important factor for the Wireless Sensors Networks (WSNs). In our solution based on the Neural Networks tool and the routing protocol LEACH (Low-Energy Adaptive Clustering Hierarchy) we introduce the criterion of the consumed energy for the process of the election of the Cluster-Head (CH). The sensor node with the highest level of the energy is selected to be the Cluster-Head. The results of the simulation show that our proposed solution performs better than classical LEACH.
In this paper, a new 16-elements, Corporate-series Feed Rectangular Patch Antenna Array operated at 28GHz, for 5G mobile wireless applications have been designed and simulated. The proposed array contains 16-elements excited by one port, through a Y-Junction power divider. The array has a wide bandwidth from 26.42 to 28.94GHz and a high gain of 17.1dB with a radiation efficiency of 92%. The simulations are based using both HFSS (High-Frequency Structure Simulator) and CST Microwave Studio Software.
In this article, we focus on boat real time detection in high resolution aerial images taken by UAVs, using convolutional neural networks. This problem is similar to object detection in images taken from the terrestrial surface at ground level or on elevations, but present certain specificities regarding: the smaller size of objects to be detected and camera orientations that are different. As a result, the methods designed for the general detection purpose are not adapted to our problem. Some of these convolutional network-based methods have been adapted for locating objects on remote sensing images by making changes and enhancements on the networks' models and parameters. In this article, we will take a look at some of these techniques and architectures. We will also draw up a comparison table between the various improvements used in these methods. We will also present the strategy and techniques we will adopt in order to provide practical advantages and a reliable solution to our problem. And finally, we will expose the results obtained using our approach.
In this paper, a new method for optimizing the parameters of a composite right/left -handed transmission lines antennas (CRLH TL) is presented, starting from a periodic structure formed of a multitude of elementary cells, giving cascade structure permitting to evaluate the parameters ABCD and consequently scattering parameters.
In the current paper, we present a comparative analysis of the wireless standards IEEE 802.15.4 and IEEE 802.15.6 over a WBAN healthcare monitoring system based on the MAC sub-layer. The main consideration of this work is to look for determined factors to decide about the norm providing the optimal quality of service (QoS) for such system in normal traffic conditions. For this purpose, a comprehensive set of simulations has been conducted using Castalia Simulator to evaluate the average latency, throughput and reliability of the two standards under the same conditions.
In this paper, we introduce a modified database for English spoken digits under all types of noise conditions (SDDN). This database was designed for use in scientific research, especially in the field of speech enhancement, nois robustness, background noise, speech recognition, noise reduction, signal processing. It was synthesized by a set of open source spoken numbers of the public on the network, in particular from Speech Commands Dataset v0.02 released by Google's TensorFlow and AIYteams. Various types of real and artificial noise were added for a SNR from 10 dB to −10 dB to make them more suitable for reality. The AURORA, CHiME3 and NOISEX-92 databases were used to select noise types.
