International Journal of Progressive Sciences and Technologies, Jan 30, 2024
Free Space Optics (FSO) is a wireless optical communication system using light to establish high-... more Free Space Optics (FSO) is a wireless optical communication system using light to establish high-capacity links between points without the need for physical cables. However, its susceptibility to atmospheric conditions such as fog, rain, and turbulence presents challenges to signal quality maintenance. To address this, Dense Wavelength Division Multiplexing (DWDM), traditionally employed in fiber optics, is leveraged to optimize bandwidth utilization and scalability in high-capacity communications. The integration of DWDM into FSO systems offers redundancy and resilience against signal degradation induced by atmospheric conditions. To the best of our knowledge, this is the first time a paper explores the performance of the Subcarrier Index Modulation Orthogonal Frequency Division Multiplexing (SIM-OFDM) technique within a DWDM-FSO system. The objective is to reinforce FSO link robustness and improve transmission rates. Through a comparative analysis with conventional OFDM in an Additive White Gaussian Noise (AWGN) channel, the study reveals a notable Signal-to-Noise Ratio (SNR) gain of at least 3dB with enhanced SIM-OFDM (ESIM-OFDM). Simulations, conducted with realistic parameters within the DWDM-FSO architecture, demonstrate that ESIM-OFDM modulation enables a transmission range of 2 km with an aggregated rate of 10.1 Gb/s. These results underscore the potential of SIM-OFDM in enhancing FSO system performance through the integration of DWDM technology. The proposed ESIM-OFDM DWDM-FSO scenario could represent a highly interesting solution for establishing 5G Backhaul links.
International journal of multimedia and image processing, Jun 29, 2023
Individuals' recognition has been the major concern of many computer science scholars. This paper... more Individuals' recognition has been the major concern of many computer science scholars. This paper highlights the development of a biometric fingerprint recognition system using an artificial intelligence method. The methodology used is structured into three main steps: fingerprint image acquisition, feature extraction and comparison or matching. Firstly, we use non-contact fingerprint images for training the recognition model to allow the developed system to work without contact. Secondly, we used a database of nineteen individuals each having fifteen fingerprint images acquired without contact. To perform the transfer learning, we have exploited the MobileNets model while adapting its architecture to the new task of contactless fingerprint classification. After training the new model obtained, we performed it evaluation through a confusion matrix. This evaluation reveals that the developed method confuses one individual out of 19, i.e. a confusion rate of 5.26%. This rate testifies to the efficiency of the method used for non-contact fingerprint recognition.
Robotics & automation engineering journal, Dec 8, 2023
In hospitals, there is a lot of medical equipment's that is sensitive to monitor patients' status... more In hospitals, there is a lot of medical equipment's that is sensitive to monitor patients' status. In this condition, it is prohibited of using Wi-Fi especially in the case of intensive care unit due to probable interference between Wi-Fi radio waves and hospital operation equipment's. To overcome such restrictions, this work proposes to design a low-cost LiFi prototype for data transmission between two medical equipment's in hospital. LiFi is based on LED light bulbs through which data can be transmitted. Meanwhile, it doesn't interfere with medical equipment's, since LiFi uses illumination for data transmission. In this paper, we built a prototype using accessible tools and platforms such as Arduino with hardware and software. The designed prototype allows text and image transmission between two equipment's using an LED and a photodiode. After many experimental tests, we showed the possibility to transmit data rate of 115,200 bits/s throughput over 2,5cm using the LiFi prototype designed. To the best of our knowledge, this is the first Benin LiFi transmission that opens the way for huge possibilities of projects.
Transient Film Condensation on a Vertical Plate in an Anisotropic Permeability Porous Medium With Oblique Principal Axes
Journal of Heat Transfer
This work deals with the flow of a liquid film condensation on a vertical wall in contact with an... more This work deals with the flow of a liquid film condensation on a vertical wall in contact with an anisotropic porous medium, with main axes of permeability noncoincident with the gravitational field. Generalized Darcy's law is used to describe the fluid flow in the porous medium, and boundary layer equations are formulated. The time variable is involved only in the energy equation. The studies concerning isotropic porous medium have been extended to take into account the anisotropic properties of the porous medium, using the flow permeability tensor. Thus, on the basis of Kärman-Pholhausen integral method, the analytical solution of the governing equations of the problem by the similarity method allows the inference of the expressions of the dimensionless thickness of the liquid film, the Nusselt number, and the characteristic limit time of the transition from transient to steady-state.
Study of a centrifugal pump, asynchronous motor and inverter, using hardware in the loop simulation concept
Journal de la Recherche Scientifique de l'Universite de Lome, 2014
ABSTRACT RESUME Ce travail traite d'une forme à faible coût de l'applicat... more ABSTRACT RESUME Ce travail traite d'une forme à faible coût de l'application du concept de la simulation Hardware in the Loop (SHIL) à l'étude d'un onduleur triphasé, un moteur asynchrone et une pompe centrifuge. Il présente la réalisation d'une commande rectangulaire grâce à un micro contrôleur (ATMEGA 168). Les signaux générés par le micro contrôleur ont été utilisé pour programmer le port parallèle d'un ordinateur. En lisant l'état des bits programmés sur le port parallèle, dans l'environnement de programmation LabVIEW, les signaux provenant du micro contrôleur ont été restaurés et mis à disposition du modèle de simulation du groupe formé par l'onduleur triphasé, le moteur asynchrone et la pompe centrifuge. Ce modèle avait déjà été réalisé dans le logiciel de simulation LabVIEW. Ce modèle qui lui est dans l'ordinateur est alors contrôlé par des signaux externes provenant du micro contrôleur. La difficulté était de pouvoir transférer les signaux externes du microcontrôleur vers le modèle logé dans l'ordinateur et réaliser une simulation comme dans le cas classique où tout le système étudié est simulé entièrement dans l'ordinateur. Nous avons comparé les résultats de notre simulation et ceux d'une simulation classique et avons constaté qu'ils correspondaient l'un à l'autre. ABSTRACT This work is about a low coast application of Hardware In the Loop simulation (HILS) concept to the study of a three-phase inverter, asynchronous motor and centrifugal pump. It presents the realization of the rectangular control using a micro controller (ATMEGA 168). The signals generated by the micro controller have been used to program the parallel port of a computer. By reading the recorded bits of the parallel port in LabVIEW software, the signals from the micro controller have been restored and made available to the simulation model of the three-phase inverter, asynchronous motor and centrifugal pump, made in advance in LabVIEW. These models realized in the computer are then controlled by external signals coming from the micro controller. The challenge was to be able to transfer signals from the micro controller to the model lodged on the computer and perform a simulation like in classical case, where all the system under study is simulated. We compare the results of our simulation with those of classical simulation. We notice that both results match.
Codage de canal pour les transmissions optiques sans fil de type « indoor »
This dissertation deals with the performance of channel coding for indoor wireless optical transm... more This dissertation deals with the performance of channel coding for indoor wireless optical transmissions. The targeted application concerns the remote monitoring of physiological data of mobile patients in the hospital. Thus, we proposed an implementation of LDPC coding in indoor optical wireless links with two modulation schemes: NRZ - OOK modulation and QAM modulation. The study allows showing that in the AWGN channel, the LDPC coding performance increases with the decrease of the code rate and that the use of LDPC coding allows not only, to improve the Bit Error Rate (BER) but also the efficiency in electric power of the transmitted signal. In the case of a realistic wireless optical link, we show that it is possible to improve the BER of 05 decades with the LDPC ¼ in NRZ – OOK modulation for a useful rate of 2.2 𝐺𝑏/𝑠 and 3 𝑚 range. With the same range and a transposition in the frequency of 2 GHz, we show that the implementation of a 16 - QAM + LDPC ¼ allows a gain in useful throughput of nearly three times that in NRZ - OOK. This demonstrates the interest of the LDPC channel coding for the broadband of indoor wireless optical links.
Performance analysis of known unipolar optical OFDM techniques in PON IM/DD fiber link
2013 High Capacity Optical Networks and Emerging/Enabling Technologies, 2013
ABSTRACT We show taking into account realistic component parameters, the performance analysis of ... more ABSTRACT We show taking into account realistic component parameters, the performance analysis of known power efficient unipolar optical OFDM techniques in a 10Gbps intensity modulated, direct detected (IM/DD) fiber link for passive optical network (PON) application. The Diversity-Combined ACO-OFDM is shown to give better BER performance in overall studied case and to be suitable to efficiently compensate frequency selective distortion of optical fiber link channel. We also show that data rate of 10Gpbs with split ratio of 128 and 4-QAM modulation format can be sent through 60km of SSMF fiber using Noise cancellation ACO-OFDM and 109km using Diversity-Combined ACO-OFDM. The BER performance value is fixed to 10-3 (limit value when Forward Error Codes are used).
Journal of Optical Communications and Networking, 2015
In the context of access networks, orthogonal frequency division multiplexing (OFDM) has been ext... more In the context of access networks, orthogonal frequency division multiplexing (OFDM) has been extensively studied for fiber-based optical communications. A DC-biased optical OFDM (DCO-OFDM) scheme (where no real constellation or Hermitian symmetry constraint is used), is proposed and explored for the first time, to the best of our knowledge, in an intensity modulated and direct detected (IM/DD) passive optical network (PON). In this paper, an analysis of the peak-to-average-power ratio and a discussion of the algorithm complexity are investigated. By means of numerical simulation in 12 Gb∕s next-generation (NG)-PON1 OFDM with a split ratio of 1∶64 users and 35 km reach, the new DCO-OFDM method is shown to achieve the same performance as the wellknown conventional DCO-OFDM but with less computational complexity (gain of almost 54.3% on the required operations per bit). As a result, the new DCO-OFDM seems very interesting and a good candidate for NG-PON costsensitive applications, considering the implementation of real-time demonstrators including digital modulators and demodulators based on digital signal processing or a field-programmable gate array (FPGA).
L’évolution rapide des services et applications multimédias (Internet haut débit, 3G, LTE) a entr... more L’évolution rapide des services et applications multimédias (Internet haut débit, 3G, LTE) a entrainé un besoin chez les clients qui contraint les opérateurs à augmenter le débit de tous les segments du réseau, y compris le réseau d’accès. Les solutions utilisant la fibre optique tendent à remplacer progressivement les liaisons câblées (cuivre ou coaxial) afin de garantir des capacités de transfert plus importantes. La fibre optique est un medium très attractif car son atténuation linéique est très faible et sa bande passante importante. Cependant la dispersion chromatique de la fibre associée au chirp des sources optiques limite la montée en débit dans les futurs réseaux d’accès optiques (débits au-delà de 10 Gb/s) NG-PON (Next Generation Passive Optical Network). Dans ce contexte, des formats de modulation à efficacité spectrale meilleure que le NRZ pourraient être retenus. L’OFDM est une solution pour accroître l’efficacité spectrale, tout en garantissant une meilleure performanc...
An IFFT/FFT size efficient improved ACO-OFDM scheme for next-generation passive optical network
2016 21st European Conference on Networks and Optical Communications (NOC), 2016
In this paper, we propose for the first time, to the best of our knowledge, a novel Improved Asym... more In this paper, we propose for the first time, to the best of our knowledge, a novel Improved Asymmetrically Clipped Optical OFDM scheme namely, Eff-IACO-OFDM. This technique employs a novel approach to get real OFDM signals suitable for PON IM/DD systems with no use of Hermitian symmetry. It has relative low computational complexity. The system was analyzed over both an AWGN channel and realistic PON fiber link. Over an AWGN channel, it achieves up to 3 dB gain in optical power in comparison with conventional ACO-OFDM and similar performance as Noise Cancellation ACO-OFDM (NC-ACO) and Diversity-Combined ACO-OFDM (DC-ACO). It offers improvement of 20 km distance transmission with computational complexity savings of 8% compared to ACO-OFDM and similar performance as DC-ACO with very low complexity. We showed by numerical simulation that 11.3 Gb/s transmission with 32 users is possible through 50 km SSMF link by using the proposed Eff-IACO-OFDM technique. As a result, it seems to be an...
Déploiement de réseaux optiques d'accès NGPON dans des métropoles de pays en développement : proposition de nouvelles techniques d'implémentation de l'OFDM
L’evolution rapide des services et applications multimedias (Internet haut debit, 3G, LTE) a entr... more L’evolution rapide des services et applications multimedias (Internet haut debit, 3G, LTE) a entraine un besoin chez les clients qui contraint les operateurs a augmenter le debit de tous les segments du reseau, y compris le reseau d’acces. Les solutions utilisant la fibre optique tendent a remplacer progressivement les liaisons câblees (cuivre ou coaxial) afin de garantir des capacites de transfert plus importantes. La fibre optique est un medium tres attractif car son attenuation lineique est tres faible et sa bande passante importante. Cependant la dispersion chromatique de la fibre associee au chirp des sources optiques limite la montee en debit dans les futurs reseaux d’acces optiques (debits au-dela de 10 Gb/s) NG-PON (Next Generation Passive Optical Network). Dans ce contexte, des formats de modulation a efficacite spectrale meilleure que le NRZ pourraient etre retenus. L’OFDM est une solution pour accroitre l’efficacite spectrale, tout en garantissant une meilleure performanc...
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