A Hybrid PAPR Reduction Scheme for Optical Wireless OFDM Communication Systems

( Ayad A. Abdulkafi ),( Mohamad Yusoff Alias ),( Yaseein Soubhi Hussein ),( Nazaruddin Omar ),( Mohd Kamarulzamin Bin Salleh ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.3

This paper proposes a new hybrid scheme to decrease the high peak to average power ratio (PAPR) of optical orthogonal frequency division multiplexing (OFDM) signals in visible light communication (VLC) systems. The PAPR causes nonlinear signal distortions and high power requirements for the VLC transmitter (light emitting diode, LED). The proposed method is applicable for both direct current-biased optical OFDM (DCO-OFDM) and asymmetrically clipped optical OFDM (ACO-OFDM). In the proposed scheme, the PTS method is firstly modified to fit both optical OFDM approaches transmission and then combined with signal clipping method for further PAPR reduction and bit error rate (BER) improvement of the VLC system. The performance of hybrid scheme has been evaluated and compared with the original OFDM based VLC system, conventional PTS and clipping methods. The results show that the hybrid scheme outperforms other methods in terms of both the PAPR reduction and BER performance.

ROBUST PATTERN RECOGNITION BASED FAULT DETECTION AND ISOLATION METHOD FOR ABS SPEED SENSOR

Ayad Qays Abdulkareem,Abdulrahim Thiab Humod,Oday Ali Ahmed 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.6

Anti-lock braking system (ABS) is considered an essential safety system in electric vehicles that works to grant a reliable vehicle driving experience, and it is very important to ensure the security of such an onboard safety system. This work presents a detailed analysis associated with a comparison that includes several techniques based on pattern recognition for biasing fault detection in wheel and vehicle speed sensors. These techniques are K-nearest neighbor (KNN), support vector machine (SVM) and decision tree (DT), which were selected among other pattern recognition techniques that have been studied. The MATLAB Simulink model for the ABS system was implemented, and data was extracted from healthy and unhealthy operating conditions in order to be used to train each technique individually. An offline test was applied to these trained FDI models using the same implemented ABS Simulink model to express the performance of each one. Specifically speaking, accuracy and sensitivity were used in the algorithm’s efficiency comparison, with 99.9 % accuracy in the Fine KNN, 75 % accuracy in the Coarse Gaussian SVM, and 61.5 % accuracy in the Coarse Tree. From the result, and considering the ABS issues mentioned above, it can be concluded that the KNN classifier is superior to both the SVM and TREE classifiers.

Multifractal Classification of the Disturbed Areas of the Sidi Chennane Phosphate Deposit, Morocco

Ayad, Abderrahim,Bakkali, Saad The Korean Society of Economic and Environmental G 2022 자원환경지질 Vol.55 No.3

The irregular shape of the disturbances is a fundamental issue for mining engineers at the Sidi Chennane phosphate deposit in Morocco. A precise classification of disturbed areas is therefore necessary to understand their part in the overall volume of phosphate. In this paper, we investigate the theoretical and practical aspects of studying and measuring multifractal spectrums as a defining and representative parameter for distinguishing between the phosphate deposit of a low rate of disturbances and the deposit of a high rate. An empirical multifractal approach was used by analyzing the disturbed areas through the geoelectric images of an area located in the Sidi Chennane phosphate deposit. The Generalized fractal dimension, D(q), the Singularities of strength, α(q), the local dimension, f(α) and their conjugate parameter the mass exponent, τ(q) as well as f(α)-α spectrum were the common multifractal parameters used. The results reported show wide variations of the analyzed images, indicating that the multifractal analysis is an indicator for evaluate and characterize the disturbed areas within the phosphates deposits through the studied geoelectric images. This could be the starting point for future work aimed at improving phosphate exploration planning.

A Survey of Energy Efficiency Optimization in Heterogeneous Cellular Networks

( Ayad A. Abdulkafi ),( Tiong S. Kiong ),( Ibrahim K. Sileh ),( David Chieng ),( Abdulaziz Ghaleb ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.2

The research on optimization of cellular network`s energy efficiency (EE) towards environmental and economic sustainability has attracted increasing attention recently. In this survey, we discuss the opportunities, trends and challenges of this challenging topic. Two major contributions are presented namely 1) survey of proposed energy efficiency metrics; 2) survey of proposed energy efficient solutions. We provide a broad overview of the state of-the-art energy efficient methods covering base station (BS) hardware design, network planning and deployment, and network management and operation stages. In order to further understand how EE is assessed and improved through the heterogeneous network (HetNet), BS`s energy-awareness and several typical HetNet deployment scenarios such as macrocell-microcell and macrocell-picocell are presented. The analysis of different HetNet deployment scenarios gives insights towards a successful deployment of energy efficient cellular networks.

Optimal Stabilizer PID Parameters Tuned by Chaotic Particle Swarm Optimization for Damping Low Frequency Oscillations (LFO) for Single Machine Infnite Bus system (SMIB)

Ayad Fadhil Mijbas,Bahaa Aldin Abas Hasan,Hussein Ali Salah 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.4

In this paper, the Power system stabilizer (PSS) and (PID) are enhanced with a Chaotic Particle Swarm Optimization (CPSO) Damping Controller in order to suppression the Low-Frequency Oscillations (LFO) in a Single Machine Infnite Bus (SMIB) power system. Chaotic particle swarm optimization (CPSO) is used to tune the parameters of the PSS-PID. The design damping controller is an optimized lead-lag controller, which extracts the speed deviation of the generator rotor and generates the output feedback signal, which aims to modulate the reference values of the PSS-PID controller to achieve the best damping of LFO. In order to search the better damping option, the damping controller is applied to a series of the PSS-PID and the results are compared in two cases (PSS without PID and PSS with PID). The efectiveness of the proposed controller is achieved by time-domain simulation results in MATLAB environment, using three diferent operational conditions (Nominal, Light, and heavy). In addition, the results obtained from the PSS-PID were robust and more efcient compared to the PID only in terms of oscillations damping, overshoot minimizing and settling time reducing.

Preparation, structure and adsorption properties of synthesized multiwall carbon nanotubes for highly effective removal of maxilon blue dye

Ayad Fadhil Alkaim,Zainab Sadik,Dunia Kamil Mahdi,Saif Mohammed Alshrefi,Abdulkareem Mohammed Al-Sammarraie,Faisal Muhammad Alamgir,Preet Mohinder Singh,Aseel Mushtaq Aljeboree 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.12

Multiwall carbon nanotubes (MWCNTs) have been hydrothermally prepared using polyethylene glycol as the carbon source. Herein, new MWCNTs composites with high adsorption capacity were prepared and applied as efficient adsorbents for adsorption of maxilon blue dye (GRL) from aqueous solution. The morphologies of the MWCNTs were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform-infrared (FT-IR) spectroscopy. The adsorption property of maxilon blue (GRL) from aqueous solution onto MWCNTs was studied as a function of mass dosage, pH of solution, initial dye concentration and temperature. The adsorption of GRL depends on the initial pH of the solution with maximum uptake occurring at about pH 10. The maximum adsorption capacity of prepared MWCNTs was 260.7mg/g. Langmuir, Freundlich and Temkin isotherms were applied to fit the experimental data. The Freundlich equilibrium isotherm fitted well the experimental data indicating the homogeneity of the adsorbent surface sites. Thermodynamics parameters were studied the changes in free energy (ΔG0), enthalpy (ΔH0) and entropy (ΔS0) during adsorption. It is noticeable that the adsorption of GRL dye onto MWCNTs was a spontaneous and endothermic process and indicates that the adsorption is favored at high temperature.

Effect of slag and bentonite on shear strength parameters of sandy soil

Sabbar, Ayad Salih,Chegenizadeh, Amin,Nikraz, Hamid Techno-Press 2018 Geomechanics & engineering Vol.15 No.1

A series of direct shear tests were implemented on three different types of specimens (i.e., clean Perth sand, sand containing 10, 20 and 30% bentonite, sand containing 1, 3 and 5% slag, and sand containing 10, 20 and 30% bentonite with increasing percentages of added slag (1%, 3% and 5%). This paper focuses on the shear stress characteristics of clean sand and sand mixtures. The samples were tested under different three normal stresses (100, 150 and 200 kPa) and three curing periods of no curing time, 7 and 14 days. It was observed that the shear stresses of clean sand and mixtures were increased with increasing normal stresses. In addition, the use of slag has improved the shear strength of the sand-slag mixtures; the shear stresses rose from 128.642 kPa in the clean sand at normal stress of 200 kPa to 146.89 kPa, 154 kPa and 161.14 kPa when sand was mixed with 1%, 3% and 5% slag respectively and tested at the same normal stress. Internal friction angle increased from $32.74^{\circ}$ in the clean sand to $34.87^{\circ}$, $37.12^{\circ}$ and $39.4^{\circ}$ when sand was mixed with 1%, 3% and 5% slag respectively and tested at 100, 150, and 200 kPa normal stresses. The cohesion of sand-bentonite mixtures increased from 3.34 kPa in 10% bentonite to 22.9 kPa, 70.6 kPa when sand was mixed with 20% and 30% bentonite respectively. All the mixtures of clean sand, different bentonite and slag contents showed different behaviour; some mixtures exhibited shear stress more than clean sand whereas others showed less than clean sand. The internal friction angle increased, and cohesion decreased with increasing curing time.

Advanced Control Techniques of Impedance Source Inverters for Distributed Generation Applications

Ayman Ayad 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

Evaluation of hair growth properties of Topical Kombucha tea extracts

Alboreadi Mohammed Ayad,Al-Najdawi Manal Mamdouh,Jarrar Qais Bashir,Moshawih Said 경희대학교 융합한의과학연구소 2022 Oriental Pharmacy and Experimental Medicine Vol.22 No.1

Consuming functional foods and drinks such as kombucha tea is believed to give many beneficial effects for promoting immunity and preventing cancer. The fermented tea with sugar and symbiotic culture of yeast and bacteria is also useful in the topical application for hair re-growth. This study aims to investigate hair re-growth properties of kombucha black tea and chamomile with and without methylsulfonylmethane. Treatments were applied topically to denuded Balb/c mice and observed for hair growth initiation time, density and length in 15 and 30 days in addition to microbiological identification of the main yeast and bacteria. Results showed significantly better hair density and length in groups treated with kombucha black tea with and without MSM, followed by kombucha chamomile tea with and without MSM respectively. In addition, it has been found that MSM promotes hair growth significantly when combined with kombucha ferments. Microbiological analysis indicated the presence of Zygosaccharomyces bailii and Acetobacter genus in the tea broth. Black tea kombucha with MSM can be used as a natural alternative therapy for hair fall and a cost-effective treatment with fewer side effects compared to the synthetic drugs.

Kinetics and isotherm studies of methylene blue adsorption onto polyaniline nanotubes base/silica composite

Mohamad M. Ayad,Ahmed Abu El-Nasr,Jaroslav Stejskal 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.6

A cationic dye, such as methylene blue (MB), was adsorbed from water by using polyaniline nanotubes (PANI NTs) base/silica composite as adsorbent. Experiments were conducted by using the UV–visible spectroscopy and by varying parameters namely: initial concentration of MB and contact time. The percentage of color removal decreased with increase of initial dye concentration. Equilibrium data were fit to Langmuir isotherm. The Langmuir isotherm fits best the MB adsorption data on PANI NTs base/silica composite. The kinetic models: pseudo first order, pseudo-second order and the intraparticle diffusion models were applied to the experimental data. It was observed that pseudo-second order kinetic model described the adsorption process better than any other kinetic models. Results obtained indicate that PANI NTs base/silica composite could be employed as an efficient adsorbent much more than the conventional PANI base/silica composite powder for dye uptake.