Browsing by Author "Messaoudi, Noureddine"

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Ability of spatial filters to distinguish between two MUAPs generated from MUs with different locations, sizes and fibers pennation
(IOP Publishing, 2023) Messaoudi, Noureddine; Belkacem, Samia; Bekka, Raïs El’hadi
In this study, we investigated the effects of the motor unit (MU) location and size and the fibres pennation on the ability of anisotropic and almost isotropic spatial filters used to detect surface electromyographic (EMG) signals to make a distinction between motor unit action potentials (MUAPs) generated from two MUs. The study was based on simulated MUAPs. The fibres orientation was performed by varying the fibres pennation angle (FPA). The root mean square error (RMSE) between MUAPs generated from two MUs was used as a criterion to evaluate the ability of the investigated filters to distinguish between two generated MUAPs. The location of a MU was fixed and the second MU moved away from the first MU in the transversal direction for the first case and in the depth direction in the second case to take five different locations in every case. We showed that the capability of the studied filters to more separate two MUAPs strongly depended on MU location, MU size and FPA. This capability of separation was best with large distances between the two MUs and with large sizes of them. Furthermore, the main survey of this work was that the BiTDD filter has the best ability of separation of two MUAPs than the other filters in a given FPA interval. The number of pennation angles in this interval is related to the location and size of the moved MU
Antennes et lignes de transmission
(Université M'hamed bougara de boumerdes Faculté de Technologie / Département Ingénierie des Systèmes Electriques, 2023) Messaoudi, Noureddine
L'émetteur qui produit l’énergie radiofréquence (RF) pour l'antenne d’émission est habituellement situé à une certaine distance des bornes d'antenne. Le lien de connexion entre l’antenne et l’émetteur est la ligne de transmission radiofréquence (RF). Son rôle est de transporter l’énergie RF d'un endroit à l'autre et de le faire aussi efficacement que possible. Du côté du récepteur, l'antenne est responsable d’attraper tous les signaux de radio dans l’air et de les passer au récepteur avec un minimum de distorsion de sorte que la radio puisse décoder le signal convenablement. C’est pour ces raisons que le câble RF a un rôle très important dans les systèmes radios: il doit maintenir l'intégrité des signaux dans les deux directions. Il y a deux catégories principales de lignes de transmission: les câbles et les guides d’ondes. Les deux sont très efficaces pour transporter de l’énergie RF sur sa fréquence........
Classification of the systems used in surface electromyographic signal detection according to the degree of isotropy
(J-STAGE, 2018) Messaoudi, Noureddine; Bekk, Raïs El’hadi; Belkacem, Samia
Surface electromyographic (EMG) signals are known to be strongly influenced by anatomical, physiological and detection system parameters. Among the detection system parameters, we are interested in the effect of muscle fiber inclination on the electrode arrangement. The purpose of this study was to determine the best and the worst orientation of the electrodes arranged in nine detection systems relative to the muscle fiber direction and also to classify the investigated systems according to their degree of isotropy. The study was based on simulated surface EMG (sEMG) signals generated in a cylindrical multilayer volume conductor. The orientation of electrodes with respect to the fiber direction was defined by the fiber inclination angle (FIA). For each detection system, the mean power (MP) of the simulated signals was computed at different FIAs and used as a basis for evaluating the effect of muscle fiber inclination. We showed that for the FIA range of 0–180°, approximately isotropic systems had three positions to record sEMG signals under good conditions (MP was maximum). However, longitudinal and transversal highly anisotropic systems had two and one positions, respectively, at which sEMG signals were detected under good conditions. We showed also that the degree of isotropy of the nine detection systems investigated was less affected by the increase in muscle and fat thicknesses. However, with an increase in inter-electrode distance (IED), the degree of isotropy of approximately isotropic systems decreased while the degree of isotropy of highly anisotropic systems increased
Comparative study between EMD, EEMD, and CEEMDAN based on De-Noising Bioelectric Signals
(Institute of Electrical and Electronics Engineers, 2024) Bennia, Fatima; Moussaoui, Siham; Boutalbi, Mohammed Chaker; Messaoudi, Noureddine
In synch with the artificial intelligence era and particularly in the biomedical field, biomedical signals like electrocardiographic (ECG), electromyographic (EMG), and Electroencephalogram (EEG) are being used in various applications, such as artificial hand and arterial pressure. However, identifying a patient's ailment is still a challenge. In this paper, we have utilized three empirical mode decomposition techniques to minimize the impact of additive noises on noninvasive biomedical signals. These methods are the classical empirical mode decomposition (EMD), ensemble empirical mode decomposition (EEMD), and the complete ensemble empirical mode decomposition with additive noise (CEEMDAN). Using the correlation coefficient, we conducted an extensive simulation and detailed comparative study between the noisy and reconstructed signals. The results show that the CEEMDAN method is the most effective in reducing noise compared to the other two methods.
Cross-correlation coefficient as a means for estimating the effect of MVC level according to the fibres inclination
(IEEE, 2017) Messaoudi, Noureddine; Bekka, Raïs El’hadi; Belkacem, Samia
The cross-correlation coefficient (CC) was used to estimate the effects of muscular voluntary contraction (MVC) and fibres inclination. The study was based on simulated surface electromyographic (sEMG) signals generated in a cylindrical multi-layer volume conductor (bone, muscle, fat and skin) and detected by longitudinal single differential (LSD), inverse binomial of order two (IB2) and maximum kurtosis (MKF) systems. We calculated correlation coefficients of sEMG signal generated from parallel fibres and sEMG signals detected when the fibres inclination angle (FIA) varied from 0° to 360° by a step of 5°. The results showed that the CC decreases as the FIA increases. Moreover, for each pair of sEMG signals, the effect of the fat layer thickness on CC was negligible. The signals detected by LSD system were more correlated at low MVC level than the high MVC level. However, the signals detected by IB2 and MKF systems have an inverse effect
Detection system parameters' effects on amplitude and spectral features of SFAP generated from a cylindrical multilayer volume conductor
(Nova Science Publishers, Inc, 2023) Messaoudi, Noureddine; Belkacem, Samia
The electromyographic (EMG) signal represents the electrical variations of muscles activities. It can be detected on the skin surface above the aimed muscle. The assessment of the effects of anatomical, physiological and detection system parameters on the shape of the detected surface EMG signal is more evident by using the signal generated by a single fibre action potential (SFAP). Amplitude and spectral characteristics of the detected signal are good estimators of the effects of the anatomical, physiological and detection system parameters on the shape of generated signal. In this work, we interpret the effects of the detection system parameters (the fibres inclination angle and the inter-electrode distance) on the average rectified value (ARV) and on the median frequency (MDF) of the surface SFAP signal generated in a multilayer cylindrical volume conductor contains the limb muscle. The potential is detected on the skin surface with a detection system which is constituted by eight 1D and 2D spatial filters and a grid of nine point electrodes. We show that the increase of the fibres inclination angle decreases the ARV and the MDF of the simulated signal and that the increase of the inter-electrode distance increases them.
ECG beats classification with interpretability
(IEEE, 2022) Hammachi, Radhouane; Messaoudi, Noureddine; Belkacem, Samia
Recently, a lot of emphasis has been placed on Artificial Intelligence (AI) and Machine Learning (ML) algorithms in medicine and the healthcare industry. Cardiovascular disease (CVD), is one of the most common causes of death globally, and Electrocardiogram (ECG) is the most widely used diagnostic tool to investigate this disease. However, the analysis of ECG signals is a very difficult process. Therefore, in this work, automated classification of ECG data into five different arrhythmia classes is proposed, based on MIT-BIH dataset. Convolutional Neural Network (CNN) and Long Short-Term Memory (LSTM) Deep Learning (DL) models were used. The black-box nature of these complex models imposes the need to explain their outcomes. Hence, both Permutation Feature Importance (PFI) with Gradient-Weighted Class Activation Maps (Grad-CAM) interpretability techniques were investigated. Using the K-Fold cross-validation method, the models achieved an accuracy of 97.1% and 98.5% for CNN and LSTM, respectively
Effects of detection system parameters on cross-correlations between MUAPs generated from parallel and inclined muscle fibres(Article)
(Sciendo, 2021) Messaoudi, Noureddine; Bekka, R.E.; Belkacem, S.A
The aim of this study was to investigate the effects of inter-electrode distance (IED), electrode radius (ER) and electrodes configurations on cross-correlation coefficient (CC) between motor unit action potentials (MUAPs) generated in a motor unit (MU) of parallel fibres and in a MU of inclined fibres with respect to the detection system. The fibres inclination angle (FIA) varied from 0° to 180° by a step of 5°. Six spatial filters (the longitudinal single differential (LSD), longitudinal double differential (LDD), bi-transversal double differential (BiTDD), normal double differential (NDD), an inverse binomial filter of order two (IB2) and maximum kurtosis filter (MKF)), three values of IED and three values of ER were considered. A cylindrical multilayer volume conductor constituted by bone, muscle, fat and skin layers was used to simulate the MUAPs. The cross-correlation coefficient analysis showed that with the increase of the FIA, the pairs of MUAPs detected by the IB2 system were more correlated than those detected by the five other systems. For each FIA, the findings also showed that the MUAPs pairs detected by BiTDD, NDD, IB2 and MKF systems were more correlated with smaller IEDs than with larger ones, while inverse results were found with the LSD and LDD systems. In addition, the pairs of MUAPs detected by the LDD, BiTDD, IB2 and MKF systems were more correlated with large ERs than with smaller ones. However, inverse results were found with the LSD and NDD systems.
Efficient image encryption scheme using a nonlinear shift register and chaos
(TARU PUBLICATIONS, 2024) Bourekouche, Hadjer; Belkacem, Samia; Messaoudi, Noureddine
Powerful cryptographic systems require a qualified random number generator. This research purposes to provide a comprehensive comparative analysis done on several of the well-known pseudo-random number generators (PRNGs) regarding their efficiency and resilience against crypto-analytical threats. These generators consist of the basic 8-bit Non- Linear Feedback Shift Register (NLFSR), the logistic map (LM), and our proposed hybrid random number generator named NLFSR-LM, which combines through XOR operation the sequences of the NLFSR with the LM to achieve a high quality of randomness. The performance of the created generator is examined and subsequently compared according to statistical tests of randomness alongside cryptographic features in terms of key space, key sensitivity and resistance to numerous attacks. The proposed generator produced good results and exhibited several interesting properties, such as a high degree of security, a sufficiently large key space, and it provided better randomness than other frequently used PRNGs.
Efficient invisible color image watermarking based on chaos
(Institute of Advanced Engineering and Science (IAES), 2024) Belkacem, Samia; Messaoudi, Noureddine
Several difficulties are faced in developing a robust and transparent color image watermarking system, which requires the blending of the human visual system (HVS) during its design. Therefore, employing masks that take into account the features of HVSs has become a very effective tool for boosting robustness requirements without significant alterations in image imperceptibility. The present article offers watermarking strategy for colored images employing a reverse self-reference image in conjunction with the HVS constraint. A color image first undergoes conversion through the Red, Green, and Blue (RGB) format to the National Television Systems Committee (NTSC) space. The reference image is derived from the luminance channel through the discrete wavelet transform (DWT) domain. However, the chaotic map serves to generate the watermark, and a 2D torus automorphism is subsequently used to scramble the watermark. Therefore, the watermark is scrambled and placed in the reference image. Moreover, the detecting phase involves the host image, where the reference image is extracted from both the host and the image with a watermark, and the correlation is subsequently used to assess the similarity between the retrieved and the introduced watermark. The proposed watermarking scheme can retain the watermarked image's perceptibility justified by the PSNR. In addition, it achieves high robustness to withstand a wide array of attacks.
From single fiber action potential to surface electromyographic signal : a simulation study
(Springer, 2015) Messaoudi, Noureddine; Bekka, Raïs El’hadi
Influence of Fibres Inclination on the Degree of Gaussianity of Simulated Surface EMG Signals
(ACM DIGITAL LIBRARAY, 2020) Messaoudi, Noureddine; Bekka, Raïs El’hadi; Belkacem, Samia
The main purpose of this simulation study was to estimate the effect of muscle fibres inclination on the degree of Gaussianity of the surface electromyographic (sEMG) signals generated in a cylindrical multilayer volume conductor constituted by bone, muscle, fat and skin layers and detected by the longitudinal single differential (LSD), inverse binomial of order two (IB2), maximum kurtosis filter (MKF) and three rings (3RGs) systems. This estimation was based on the computation of the Kurtosis of simulated sEMG signals when the fibres inclination angle (FIA) varied from 0° to 180° in a step of 2.5°. For each FIA, the effects of the motor units (MUs) recruitment range (RR) and the level of muscular voluntary contraction (MVC) were also assessed. The results showed that with the same detection system, the degree of Gaussianity of the EMG signal is highly influenced by the fibres inclination with respect to the electrodes arrangement. Indeed, the classification of the studied detection systems according to the degree of Gaussianity of sEMG signals detected by them is different from a FIA interval to another i.e. a surface EMG signal detected by any detection system may be the most Gaussian with an FIA interval as it may be the least Gaussian in another FIA interval.
Randomness evaluation of coupled chaotic maps via NIST tests: A comparative study
(IEEE, 2020) Bourekouche, Hadjer; Belkacem, Samia; Messaoudi, Noureddine
A vital requirement for any random number generator based on chaos is to ensure that the generated sequence always benefits of a significant level of randomness. It is critical to examine such sequences by means of Lyapunov exponents, bifur-cation diagrams, or other tests in order to accurately select the parameters of the dynamic system. However, the sequence’s randomness quality varies depending on the generator's design and must be examined in different ways. Therefore, we argue to use the National Institute of Standards and Technology (NIST) suite tests to evaluate and compare the randomness properties of two coupled systems found in existing literature: the logistic-sine system (LSS) and the logistic-tent system (LTS). The results reveal that the LSS has much superior statistical features in terms of randomness than the LTS in the range [3.1–4]. This conclusion will substantially affect the selection of the perfect chaotic map to create sequences of keys that match the requirements of cryptography applications.
Simulated surface electromyographic (semg) signal generation and detection model
(Sciendo, 2023) Messaoudi, Noureddine; Belkacem, Samia; Bekka, Rais El’hadi
For didactic purposes, the aim of this work was to improve a simulation model of surface electromyographic (sEMG) signal by taking into consideration the shortcomings of previously developed models. This model started with the simulation of the single fibre action potential (SFAP), then the model of the single motor unit action potential (MUAP), afterwards the imitation of the train of MUAP and finally the modellig of the resultant sEMG signal which is the sum of the MUAPs trains. SFAP simulation was based on: i) the description of the volume conductor model which is composed of four layers (bone, muscle, fat and skin), ii) the description of the electrodes shapes and sizes as well as spatial filters, iii) and the transmebrane current. The proposed model shows its effectiveness in the possibility of carrying out practical work by simulation on the modelling of SFAP, MUAP, MUAPT and the sEMG signal. The most important result of this model is that signal processing tools can be applied to analyze and interpret real-world phenomena such as the effects of physiological , non physiological and sensing system parameters on the shape of the simulated sEMG signal.
Smart embedded system for sleep apnea monitoring from ECG signals
(American Institute of Physics, 2023) Ammar, Mohammed; Messaoudi, Noureddine; Faked, Djouher; Noui, Rima; Mahmoudi, Said
In this paper, an intelligent monitoring system was proposed to follow vital parameters such as the electrocardiogram (ECG), oxygen saturation (SPO2), the temperature of the patient, and also heart rate. The system is built around a Raspberry 3B+ and an Arduino Uno. The prototype is equipped with an intelligent system that can currently detect sleep apnea from ECG signals. These parameters are detected by the following sensors: AD8232, and MAX 30102. We have implemented and compared three algorithms: Perceproron multi-layer, Support Vector Machine, and a Random Forest Classifier.