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Theoretical investigation of the pressure broadening D1 and D2 lines of cesium atoms colliding with ground-state helium atoms

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Chinese Physics B 2019年第10期28卷 300-308页

作者： Moussaoui Abdelaziz alioua kamel Allouche Abdul-rahman Bouledroua Moncef Universite Cherif Messaidia B.P.1553Souk-Ahras 41000Algerie Laboratoire de Physique de la Matiere et du Rayonnement LPMR Universite Cherif MessaidiaB.P.1553Souk-Ahras 41000Algerie Universite Lyon 1 CNRSLASIM UMR5579bat.A.Kastler43 Bd du 11 novembre 1918F-69622 VilleurbanneFrance Laboratoire de Physique des Rayonnements LPR Universite Badji MokhtarB.P.12Annaba 23000Algerie

Full quantum mechanical calculations are performed to determine the broadening in the far wings of the cesium D1 and D2 line shapes arising from elastic collisions of Cs atom with inert helium atoms. The potential energy curves of the low-lying CsHe molecular states, as well as the related transition dipole moments, are carefully computed from ab initio methods based on state-averaged complete active space self-consistent field-multireference configuration interaction(SACASSCF-MRCI) calculations, involving the spin-orbit effect, and taking into account the Davidson and BSSE *** absorption and emission reduced coefficients are determined in the temperature and wavelength ranges of 323-3000 K and 800-1000 nm, respectively. Both profiles of the absorption and the emission are dominated by the free-free transitions,and exhibit a satellite peak in the blue wing near the wavelength 825 nm, attributed to B^2Σ1/2^+→ X^2Σ1/2^+/transitions. The results are in good agreement with previous experimental and theoretical works.

关键词： absorption coefficient emission coefficient pressure broadening potential curves

Actual TDoA-based augmentation system for enhancing cybersecurity in ADS-B

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Chinese Journal of Aeronautics 2021年第2期34卷 217-228页

作者： Ahmed AbdelWahab ELMARADY kamel RAHOUMA Faculty of Engineering Minia UniversityMinia 61519Egypt

Currently, cybersecurity and cyber resilience are emerging and urgent issues in nextgeneration air traffic surveillance systems, which depend primarily on Automatic Dependent Surveillance-Broadcast(ADS-B) owing to its low cost and high accuracy. Unfortunately, ADS-B is prone to cyber-attacks. To verify the ADS-B positioning data of aircraft, multilateration(MLAT)techniques that use Time Differences of Arrivals(TDoAs) have been proposed. MLAT exhibits low accuracy in determining aircraft positions. Recently, a novel technique using a theoretically calculated TDoA fingerprint map has been proposed. This technique is less dependent on the geometry of sensor deployment and achieves better accuracy than MLAT. However, the accuracy of the existing technique is not sufficiently precise for determining aircraft positions and requires a long computation time. In contrast, this paper presents a reliable surveillance framework using an Actual TDoA-Based Augmentation System(ATBAS). It uses historically recorded real-data from the OpenSky network to train our TDoA fingerprint grid network. Our results show that the accuracy of the proposed ATBAS framework in determining the aircraft positions is significantly better than those of the MLAT and expected TDoA techniques by 56.93% and 48.86%, respectively. Additionally, the proposed framework reduced the computation time by 77% compared with the expected TDoA technique.

关键词： ADS-B Cybersecurity Cyber resilience k-Nearest Neighbors(k-NN)classifier Machine learning Multilateration

Improved Local Projection for the Generalized Stokes Problem

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Advances in Applied Mathematics and Mechanics 2009年第6期1卷 862-873页

作者： kamel Nafa Department of Mathematics and Statistics Sultan Qaboos UniversityCollege of ScienceP.O.Box 36Al-Khoudh 123MuscatOMAN

We analyze pressure stabilized finite element methods for the solution of the generalized Stokes problem and investigate their stability and convergence *** important feature of the methods is that the pressure gradient unknowns can be eliminated locally thus leading to a decoupled system of *** the stability of the method has been established,for the homogeneous Stokes equations,the proof given here is based on the existence of a special interpolant with additional orthogonal property with respect to the projection *** makes it much simpler and more *** resulting stabilized method is shown to lead to optimal rates of convergence for both velocity and pressure approximations.

关键词： Generalized Stokes equations stabilized finite elements local projection convergence error estimates

A combined contour lines iteration algorithm and Delaunay triangulation for terrain modeling enhancement

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Geo-Spatial Information Science 2023年第3期26卷 558-576页

作者： Yehia Miky Abdullah kamel Ahmed Alshouny Department of Geomatics King Abdul aziz UniversityJeddahSaudi Arabia Faculty of Engineering Aswan UniversityAswanEgypt National Water Research Center Survey Research InstituteGizaEgypt

Digital Elevation Models(DEMs)play a crucial role in civil and environmental applications,such as hydrologic and geologic analyses,hazard monitoring,natural resources exploration,***,DEMs can be generated from various data sources,such as ground surveys,photogrammetric stereo methods,satellite images,laser scanning,and digitized contour *** with other data sources,contour lines are still the cheapest and more common data source becausethey cover all areas,at different scales,in most *** there are different algorithms and technologies for interpolation in between contour lines,DEMs extracted solely from contours still suffer from poor terrain quality representation,which in turn negatively affects the quality of analytical applications *** this paper,an approach for improving the digital terrain modeling based on contour line densification and Delaunay triangulation is presented to acquire a more suitable DEM for hydrographic modeling and its *** proposed methodology was tested using a variety of terrain patterns in terms of intensity:hilly,undulated,and plain(1:25,000 topographic map,5 m contour interval).The precision of the extracted GRID model increases as the number of added contours *** four contour lines,the Root Mean Square Error(RMSE)of examining points were 0.26 m,0.29 m,and 0.05 m for hilly,undulated,and plain samples,respectively,and the Mean Absolute Error(MAE)were 0.50 m,0.48 m,and 0.17 *** convergence probabilities between extracted and original flow lines for the same regions were 96.91%,94.93%,and 84.03%.Applying the methodology,experimental results indicate that the developed approach provides a significant advantage in terrain modeling enhancement,generates DEMs smoothly and effectively from contours,mitigates problems and reduces uncertainties.

关键词： Contours Digital Elevation Model(DEM) Triangulated Irregular Network(TIN) Delaunay triangulation

A comparative study between simplified and nonlinear dynamic methods for estimating liquefaction potential

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Journal of Rock Mechanics and Geotechnical Engineering 2017年第5期9卷 955-966页

作者： kamel Filali Badreddine Sbartai LMGHU Laboratory University of 20 August 1955-Skikda Skikda 21000 Algeria University of Badji Mokhtar Annaba 23000 Algeria

This paper estimated the liquefaction potential of a saturated soil deposit subjected to a horizontal seismic excitation at its base using the total stress approach.A comparative analysis between the simplified and the nonlinear dynamic methods was used to verify to what extent the simplified method could be *** order to generalise the reliability of the simplified method for any value of the maximum acceleration for the used earthquakes,a correction for the maximum acceleration less than 0.3 g was proposed based on the comparison of safety factor values determined by the dynamic method illustrated by the equivalent linear model with lumped masses and the simplified method for a given profile of soil subjected to 38 *** nonlinear behaviour of soil was represented by two hyperbolic models:Hardin and Drnevich,and *** determine the cyclic resistance ratio(CRR),the cone penetration test(CPT) based method,the standard penetration test(SPT) based method,and the shear wave velocity based method were *** safety factor was calculated as the ratio of CRR/CSR,where CSR represents the cyclic stress *** results of the proposed correction have given smaller values of the safety factor compared to the nonlinear dynamic methods for the maximum acceleration less than 0.3 *** other words,by considering this correction,the most unfavourable case is always given by the modified simplified method.

关键词： Liquefaction Soil Earthquake Simplified method Nonlinear dynamic method

New Results on PWARX Model Identification Based on Clustering Approach

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International Journal of Automation and computing 2014年第2期11卷 180-188页

作者： Zeineb Lassoued kamel Abderrahim Numerical Control of Industrial Processes National School of Engineers of GabesUniversity of GabesSt Omar Ibn-Khattab 6029 Gabes Tunisia

This paper deals with the problem of piecewise auto regressive systems with exogenous input(PWARX) model identification based on clustering solution. This problem involves both the estimation of the parameters of the affine sub-models and the hyper planes defining the partitions of the state-input regression. The existing identification methods present three main drawbacks which limit its effectiveness. First, most of them may converge to local minima in the case of poor initializations because they are based on the optimization using nonlinear criteria. Second, they use simple and ineffective techniques to remove outliers. Third, most of them assume that the number of sub-models is known a priori. To overcome these drawbacks, we suggest the use of the density-based spatial clustering of applications with noise(DBSCAN) algorithm. The results presented in this paper illustrate the performance of our methods in comparison with the existing approach. An application of the developed approach to an olive oil esterification reactor is also proposed in order to validate the simulation results.

关键词： Hybrid systems piecewise autoregressive systems with exogenous input(PWARX) model clustering identification density-based spatial clustering of applications with noise(DBSCAN) clustering technique experimental validation.

TWO DIMENSIONAL MELLIN TRANSFORM IN QUANTUM CALCULUS

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Acta Mathematica Scientia 2018年第2期38卷 546-560页

作者： kamel BRAHIM Latifa RIAHI Faculty of Sciences of Tunis. University of Tunis El Manar Tunisia

In this article, we introduce the two dimensional Mellin transform M4（f）（s,t）, give some properties, establish the Paley-Wiener theorem and Plancherel formula, present the Hausdorff-Young inequality, and find seve... 详细信息

关键词： Quantum calculus Two dimensional Mellin transform q-Double integral

GENERALIZED DISCRETE Q-HERMITE I POLYNOMIALS AND Q-DEFORMED OSCILLATOR

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Acta Mathematica Scientia 2018年第4期38卷 1411-1426页

作者： kamel MEZLINI Neji BETTAIBI High Institute of Applied Sciences and Technologies of Mateur University of Carthage Tunisia Department of Mathematics College of Science Qassim University KSA

In this paper, we present an explicit realization of q-deformed Calogero-Vasiliev algebra whose generators are first-order q-difference operators related to the generalized dis- crete q-Hermite I polynomials recently ... 详细信息

关键词： basic orthogonal polynomials quantum algebra coherent states

Effect of Titania Additive on Structural and Mechanical Properties of Alumina–Fluorapatite Composites

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Journal of Materials Science & Technology 2012年第12期28卷 1130-1136页

作者： Awatef Guidara kamel Chaari Jamel Bouaziz Laboratoire de chimie industrielle Ecole Nationale d'Ingnieurs de SfaxBP 1173 3038 Tunisie

Mechanical properties of alumina-fluorapatite composites with different titania additive amounts （0, 0.5, 1, 1.4, 2, 3, 4 and 5 wt%） have been investigated between 1200 and 1600℃. The optimum values of densification and mechanical properties of composites have been reached with 1.4 wt% of titania after the sintering process at 1500℃ for 1 h. Thus, the rupture strength of alumina-26.52 wt% Fap-1.4 wt% TiO2 reaches 75 MPa. At higher temperature and beyond 1.4 wt% TiO2 ,the densification and mechanical properties were hindered by the formation of both intergranular porosity and secondary phase. X-ray diffraction （XRD） analysis of alumina-Fap-TiO2 composites shows the formation of aluminium titanate （Al2O3-TiO2：Al2TiO5 ）. The 27Al magic angle scanning nuclear magnetic resonance analysis of Al2O3-Fap-TiO2 composites reveals the presence of octahedral and pentahedral aluminium and novel environment relative to tetrahedral aluminium sites.

关键词： Sintering Fluorapatite Alumina Titania Composites Biomedical applications