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.

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.

The Use of New Emerging Technology in Echocardiography-Glass View

Said Alsidawi,Faysal Alhasan,Reza Arsanjani 대한심장학회 2022 Korean Circulation Journal Vol.52 No.1

The burden and management strategies of hypertensive crisis in adult patients presenting to emergency departments of district and regional hospitals in Sub-Saharan Africa

Said S. Kilindimo,Abdulkarim Ahmed,Alphonce N. Simbila,Raynald Harrison,Lucy Shirima,Farida Abdallah,Aliasghar G. Mukhtar,Juma Mfinanga,Joseph Saika,Kisanga Emanuel,Hendry R. Sawe 대한고혈압학회 2023 Clinical Hypertension Vol.29 No.-

Background Hypertensive crisis is among the causes of morbidity and mortality in adult patients with hypertension in Sub-Saharan Africa. We aimed to determine the burden, risk factors and describe the management strategies of hypertensive crisis among adult patients seen at emergency departments of district and regional hospitals in Tanzania. Methods This was a prospective multicenter longitudinal study which included all 162 district and regional hospitals in Tanzania. It was part of the Tanzania Emergency Care Capacity Survey (TECCS), a large assessment of burden of acute illness and emergency care capacity in Tanzania. Adult patients who presented to emergency departments with blood pressure ≥ 180/110mmHg were enrolled. Demographics, clinical presentation, management, and 24-hours outcomes were recorded using a structured case report form. Descriptive statistics were summarized in frequency and median, while logistic regression was used to evaluate the association between risk factors and presence of hypertensive crisis. Results We screened 2700 patients and enrolled 169 adults, henceforth proportion of adult patients with hypertensive crisis was 63 per 1000. Median age was 62 years (IQR 50–70 years) and predominantly females, 112 (66.3%). Majority 151(89.3%) were self-referred with two-wheel motorcycle being the commonest 46 (27.2%) mode of arrival to the hospital. Hypertensive emergency was found in over half 96 (56.8%) of the patients with hypertensive crisis, with oral medications administered in more than half of them, 71 (74%) as means to control the high blood pressure, and one-third 33 (34.4%) were discharged home. On multivariate analysis increasing age (AOR 4.53, p < 0.001), use of illicit drug (AOR 4.14, p-0.04) and pre-existing hypertension (AOR 8.1, p < 0.001) were independent risk factors for hypertensive crisis occurrence. Conclusion Hypertensive crisis among adult patients attending district and regional hospitals is common (63 patients per every 1000 patients). Increasing age, use of illicit drug and pre-existing hypertension are independent associated factors for developing hypertensive crisis.

DNA barcodes in Egyptian olive cultivars (Olea europaea L.) using the rbcL and matK coding sequences

Said Eglal M.,Hassan M. E. 한국작물학회 2023 Journal of crop science and biotechnology Vol.26 No.4

Olives (Olea europaea L.) are the most well-known trees of the Mediterranean basin. The genetic heritage of olive trees is very rich and characterized by an abundance of varieties, eventually leading to significant genotype mixing. Therefore, the classification and analysis of the genetic diversity of olive cultivars are challenges of high priority. It helps make more efficient use of the olive resources distributed globally and benefits the genetic improvement and breeding of olive varieties. DNA barcoding is a method for evaluating and classifying species that uses short, variable, and uniform DNA regions. This study used DNA sequencing data for the first time for DNA barcoding of Egyptian olive cultivars and assessed the genetic relationship between four local cultivars grown in Egypt and their relation to sequences within the database. PCR amplification and sequence characterization were used to assess the effectiveness of the two barcoding sites, rbcL and matK. Based on multiple alignments of all the sequences obtained from the analyzed regions, matK had the longest sequence (816 bp) and rbcL the shortest (411 bp) of the two barcoding loci. The matK gene region was the least varied, with a variability level of 77%, while the rbcL gene region had the highest amount of variability (98.7%). Because of the presence of unique variable sites, both barcoding loci rbcL and matK efficiencies discriminate the selective Egyptian olive cultivars. The DNA sequences from the individual and combined barcode loci were used in a maximum likelihood tree-based phylogenetic analysis to successfully distinguish the selected olive cultivars.

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.

Critical Analysis of Density-based Spatial Clustering of Applications with Noise (DBSCAN) Techniques

Said Akbar,M.N.A. Khan 보안공학연구지원센터 2014 International Journal of Database Theory and Appli Vol.7 No.5

Clustering is the most used technique in data mining. Clustering maximize the intra-cluster similarity and minimize the inter clusters similarity. DBSCAN is the basic density based clustering algorithm. Cluster is defined as regions of high density are separated from regions that are less dense. DBSCAN algorithm can discover clusters of arbitrary shapes and size in large spatial databases. Beside its popularity, DBSCAN has drawbacks that its worst time complexity reaches to O (n2). Similarly, it cannot deal with varied densities. It is hard to know the initial value of input parameters. In this study, we have studied and discussed some significant enhancement of DBSCAN algorithm to tackle with these problems. We analysed all the enhancements to computational time and output to the original DBSCAN. Majority of variations adopted hybrid techniques and use partitioning to overcome the limitations of DBSCAN algorithm. Some of which performs better and some have their own usefulness and characteristics.

Implementation of Multilateral Environmental Agreements in Kazakhstan

Said Tulibayev 이준국제법연구원 2022 Journal of East Asia and International Law Vol.15 No.2