Blind Channel Estimation and Equalization

Said Elkassimi,Said Safi,B. Manaut 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.12

This paper presents the problem of blind channel estimation of a non-minimum phase system using three algorithms. These algorithms play an important role for blindly estimate the parameters of radio mobile channel. Thus studying the problem of blind channel equalization based on, the proposed algorithm, CMA and SKMAA algorithms. The simulation results in noisy environment and for different SNR values demonstrate that the proposed algorithm is more performing than other algorithms. In addition the Sign Kurtosis Maximization Adaptive Algorithm (SKMAA) is more powerful in comparison to constant modulus algorithm (CMA) at the blind channel equalization, that is to say gives the right equalization.

Highly Efficient Control of the Doubly Fed Induction Motor

Said Drid,Abdesslam Makouf,Mohamed-Said Nait-Said,Mohamed Tadjine 대한전기학회 2007 Journal of Electrical Engineering & Technology Vol.2 No.4

This paper deals with the high efficient vector control for the reduction of copper losses of the doubly fed motor. Firstly, the feedback linearization control based on Lyapunov approach is employed to design the underlying controller achieving the double fluxes orientation. The fluxes' controllers are designed independently of the speed. The speed controller is designed using the Lyapunov method especially employed to the unknown load torques. The global asymptotic stability of the overall system is theoretically proven. Secondly, a new Torque Copper Losses Factor is proposed to deal with the problem of the machine copper losses. Its main function is to optimize the torque in keeping the machine saturation at an acceptable level. This leads to a reduction in machine currents and therefore their accompanied copper losses guaranteeing improved machine efficiency. The simulation and experimental results in comparative presentation confirm largely the effectiveness of the proposed DFIM control with a very interesting energy saving contribution.

Highly Efficient Control of the Doubly Fed Induction Motor

Drid, Said,Makouf, Abdesslam,Nait-Said, Mohamed-Said,Tadjine, Mohamed The Korean Institute of Electrical Engineers 2007 Journal of Electrical Engineering & Technology Vol.2 No.4

This paper deals with the high efficient vector control for the reduction of copper losses of the doubly fed motor. Firstly, the feedback linearization control based on Lyapunov approach is employed to design the underlying controller achieving the double fluxes orientation. The fluxes# controllers are designed independently of the speed. The speed controller is designed using the Lyapunov method especially employed to the unknown load torques. The global asymptotic stability of the overall system is theoretically proven. Secondly, a new Torque Copper Losses Factor is proposed to deal with the problem of the machine copper losses. Its main function is to optimize the torque in keeping the machine saturation at an acceptable level. This leads to a reduction in machine currents and therefore their accompanied copper losses guaranteeing improved machine efficiency. The simulation and experimental results in comparative presentation confirm largely the effectiveness of the proposed DFIM control with a very interesting energy saving contribution.

Development of a non-standard finite difference method for solving a fractional decay model

Said Al Kathiri,Eihab B.M. Bashier,Nur Nadiah Abd Hamid,Norshafira Ramli 한국전산응용수학회 2024 Journal of applied mathematics & informatics Vol.42 No.3

In this paper we present a non-standard finite difference method for solving a fractional decay model. The proposed NSFDM is constructed by incorporating a non-standard denominator function, resulting in an explicit numerical scheme as easy as the conventional Euler method, but it provides very accurate solutions and has unconditional stability. Two examples from the literature are presented to demonstrate the performance of the proposed numerical scheme, which is compared to three methods from the literature. It is found that the method's estimated errors are extremely minimal, such as within the machine precision.

Oscillation of Higher Order Strongly Superlinear and Strongly Sublinear Difference Equations

Said R. Grace,Zhenlai Han,Xinhui Li 한국전산응용수학회 2014 Journal of applied mathematics & informatics Vol.32 No.3

We establish some new criteria for the oscillation of mth order nonlinear difference equations. We study the case of strongly superlinear and the case of strongly sublinear equations subject to various conditions. We also present a sufficient condition for every solution to be asymptotic at ∞ to a factorial expression (t)(m-1).

New Open Channel with Elliptic Sides and Horizontal Bottom

Said M. Easa,Ali R. Vatankhah 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.4

This paper presents a new general open channel section with elliptic sides and horizontal bottom. The proposed section producesspecial channel forms, such as a circular section with a horizontal bottom, a circular section, and a rectangular section. Exact andapproximate formulas for the area and perimeter of the channel are derived. These formulas are then used to develop an optimizationmodel for determining the optimal section design that minimizes the total construction cost for excavation and composite linings. Inaddition, the most hydraulically efficient elliptic section was derived. The constraints of the optimization model include channeldischarge and physical requirements, such as flow depth, top width, and side slope with fixed or depth-dependent freeboard. The costperformance of the proposed section was compared with another general open channel section (power-law) and the trapezoidalsection using different design scenarios. The results show that the new section is substantially more economical and more flexiblethan the existing power-law section, and is generally superior to the trapezoidal section.

Evaluation of Nonlinear Muskingum Model with Continuous and Discontinuous Exponent Parameters

Said M. Easa 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.7

The nonlinear Muskingum model is traditionally calibrated using a constant exponent parameter. A recent study has proposed a discontinuous function of the exponent parameter that has substantially improved model performance. This paper evaluates model performance using continuous and discontinuous parameters, expressed as a function of dimensionless inflow variable. The parameters were represented by discontinuous (two-step) function and continuous (three-coefficient) function, resulting in a fiveparameter nonlinear Muskingum model (5P-NLMM) for each scheme. Two continuous functions (logarithmic and exponential) were evaluated using two flood routing procedures: the Modified Euler’s (ME) routing procedure and the Fourth-Order Runge-Kutta (FORK) routing procedure. The continuous functions and routing procedures were integrated into the Muskingum model. The five parameters of the model were determined using optimization based on minimizing the deviations from observed outflows. The model was applied to three examples with different hydrograph types. The continuous parameter (with ME or FORK) substantially outperformed the discontinuous parameter for smooth and non-smooth hydrographs, and vice versa for multi-peak hydrograph. Guidelines for model selection for different types of hydrographs are presented.

Electric Conduction Mechanisms Study within Zr Doped Mn₃O₄ Hausmannite Thin Films through an Oxidation Process in Air

Said, L. Ben,Boughalmi, R.,Inoubli, A.,Amlouk, M. Korean Society of Microscopy 2017 Applied microscopy Vol.47 No.3

In this work further optical and electrical investigations of pure and Zr doped $Mn_3O_4$ (from 0 up to 20 at.%) thin films as a function of frequency. First, the refractive index, the extinction coefficient and the dielectric constants in terms of Zr content are reached from transmittance and reflectance data. The dispersion of the refractive index is discussed by means of Cauchy model and Wemple and DiDomenico single oscillator models. By exploiting these results, it was possible to estimate the plasma pulse ${\omega}_p$, the relaxation time ${\tau}$ and the dielectric constant ${\varepsilon}_{\infty}$. Second, we have performed original ac and dc conductivity studies inspired from Jonscher model and Arrhenius law. These studies helped establishing significant correlation between temperature, activation energy and Zr content. From the spectroscopy impedance analysis, we investigated the frequency relaxation phenomenon and hopping mechanisms of such thin films. Moreover, a special emphasis has been putted on the effect of the oxidation in air of hausmannite thin films to form $Mn_2O_3$ ones at $350^{\circ}C$. This intrigue phenomenon which occurred at such temperature is discussed along with this electrical study. Finally, all results have been discussed in terms of the thermal activation energies which were determined with two methods for both undoped and Zr doped $Mn_3O_4$ thin films in two temperature ranges.

Finite element analysis of elastic property of concrete composites with ITZ

Said Abdelmoumen,Brandon Lynge,Michele Queneudec-t'Kint,Emmanuel Bellenger 사단법인 한국계산역학회 2010 Computers and Concrete, An International Journal Vol.7 No.6

For better estimation of elastic property of concrete composites, the effect of Interfacial Transition Zone (ITZ) has been found to be significant. Numerical concrete composites models have been introduced using Finite Element Method (FEM), where ITZ is modeled as a thin shell surrounding aggregate. Therefore, difficulties arise from the mesh generation. In this study, a numerical concrete composites model in 3D based on FEM and random unit cell method is proposed to calculate elastic modulus of concrete composites with ITZ. The validity of the model has been verified by comparing the calculated elastic modulus with those obtained from other analytical and numerical models.

Asymptotic Behavior of Solutions of Certain Nonlinear Differential and Integro-differential Equations

Said R. Grace,Sandra Pinelas 장전수학회 2010 Proceedings of the Jangjeon mathematical society Vol.13 No.2

We establish several growth theorems for second order nonlinear differential and integro-differential equations. We also give necessary and suffcient conditions for solutions of second order non-linear differential equations to be bounded together with their frst derivatives and investigate its asymptotic behavior.