Preferred Language
Articles
/
7xa0CYoBVTCNdQwChI-0
Deployment of multiservice code in FSO-based hybrid subcarrier system
...Show More Authors
Abstract<p>This research aims to investigate and improve multi-user free space optic systems (FSO) based on a hybrid subcarrier multiplexing spectral amplitude coding-optical code division multiple access (SCM-SAC-OCDMA) technique using MS code with a direct decoding technique. The performance is observed under different weather conditions including clear, rain, and haze conditions. The investigation includes analyzing the proposed system mathematically using MATLAB and OptiSystem software. The simulation is carried out using a laser diode. Furthermore, the performances of the MS code in terms of angles of bit rate, beam divergence and noise are evaluated based on bit error rate (BER), received power, and transmission distance. The performance of the MS code-based system was subsequently compared with Khazani Syed code (KS), multi-diagonal (MD), and modified quadratic congruence code (MQC) codes under different weather conditions at a bit rate of 1 Gb/s and BER threshold of 10<sup>−9</sup>. Heavy rain indicates the worst performance in terms of transmission distance of 0.9 km. Nevertheless, the system designed using the MS code outperformed the KS, MD and MQC systems as it is capable of supporting up to 6.3, 0.8, 0.9, and 1.5 km, respectively, under clear weather. In conclusion, this study provides a means of improving FSO communications that suits tropical and Malaysia weather conditions.</p>
Scopus Crossref
View Publication
Publication Date
Fri Feb 09 2001
Journal Name
Molecular Crystals And Liquid Crysta
Synthesis and characterization of symmetrical liquid crystalline compounds based on oxazole and thaizole rings
...Show More Authors

Twelve compounds containing a sulphur- or oxygen-based heterocyclic core, 1,3- oxazole or 1,3-thiazole ring with hydroxy, methoxy and methyl terminal substituent, were synthesized and characterized. The molecular structures of these compounds were performed by elemental analysis and different spectroscopic tequniques. The liquid crystalline behaviors were studied by using hot-stage optical polarizing microscopy and differential scanning calorimetry. All compounds of 1,4- disubstituted benzene core with oxazole ring display liquid crystalline smectic A (SmA) mesophase. The compounds of 1,3- and 1,4-disubstituted benzene core with thiazole ring exhibit exclusively enantiotropic nematic liquid crystal phases.

Scopus (8)
Scopus
Publication Date
Wed Nov 16 2016
Journal Name
Eurasip Journal On Wireless Communications And Networking
Evaluation of efficient vehicular ad hoc networks based on a maximum distance routing algorithm
...Show More Authors

Traffic management at road intersections is a complex requirement that has been an important topic of research and discussion. Solutions have been primarily focused on using vehicular ad hoc networks (VANETs). Key issues in VANETs are high mobility, restriction of road setup, frequent topology variations, failed network links, and timely communication of data, which make the routing of packets to a particular destination problematic. To address these issues, a new dependable routing algorithm is proposed, which utilizes a wireless communication system between vehicles in urban vehicular networks. This routing is position-based, known as the maximum distance on-demand routing algorithm (MDORA). It aims to find an optimal route on a hop-by-ho

... Show More
View Publication Preview PDF
Scopus (27)
Crossref (19)
Scopus Clarivate Crossref
Publication Date
Mon Sep 25 2017
Journal Name
Bn Al-haitham Jour. For Pure & Appl. Sci.
Synthesis of Some New Heterocyclic Fused Rings Compounds Based on 5-Aryl-1,3,4-Oxadiazole
...Show More Authors

The work includes synthesis and characterization of some new heterocyclic compounds, as flow: The compound (3) (5-(4-chlorophenyl) -2-hydrazinyl-1,3,4-oxadiazole was synthesized by using two methods; the first method includes the direct reaction between hydrazine hydrate 80% and 5-(4-chlorophenyl)-2- (ethylthio) 1,3,4-oxadiazole (1), the second method involves converting 5-(4-chlorophenyl)-1,3,4-oxadiazol-2-amine (2) to diazonium salt then reducing this salt to compound (3) by stannous chloride. Compound (3) was used as starting material for synthesizing several fused heterocyclic compounds. The compound 6-(4-chlorophenyl)[1,2.4] triazolo [3,4,b][1,3,4] oxadiazole-3-(2H) thione (compound 4) was synthesized from the reaction of compound (3)

... Show More
Publication Date
Sat Dec 01 2012
Journal Name
Journal Of Engineering
Effect Of Technology Based Learning As A Supplement To Traditional Technology On Student's Achievement
...Show More Authors

This paper describes a practical study on the impact of learning's partners, Bluetooth Broadcasting system, interactive board, Real – time response system, notepad, free internet access, computer based examination, and interaction classroom, etc, had on undergraduate student performance, achievement and involving with lectures. The goal of this study is to test the hypothesis that the use of such learning techniques, tools, and strategies to improve student learning especially among the poorest performing students. Also, it gives some kind of practical comparison between the traditional way and interactive way of learning in terms of lectures time, number of tests, types of tests, student's scores, and student's involving with lectures

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sun Oct 01 2017
Journal Name
Ieee Transactions On Neural Systems And Rehabilitation Engineering
A Framework of Temporal-Spatial Descriptors-Based Feature Extraction for Improved Myoelectric Pattern Recognition
...Show More Authors

View Publication
Scopus (129)
Crossref (129)
Scopus Clarivate Crossref
Publication Date
Tue Sep 01 2020
Journal Name
Al-khwarizmi Engineering Journal
Pre-Processing and Surface Reconstruction of Points Cloud Based on Chord Angle Algorithm Technique
...Show More Authors

Abstract

Although the rapid development in reverse engineering techniques, 3D laser scanners can be considered the modern technology used to digitize the 3D objects, but some troubles may be associate this process due to the environmental noises and limitation of the used scanners. So, in the present paper a data pre-processing algorithm has been proposed to obtain the necessary geometric features and mathematical representation of scanned object from its point cloud which obtained using 3D laser scanner (Matter and Form) through isolating the noised points. The proposed algorithm based on continuous calculations of chord angle between each adjacent pair of points in point cloud. A MATLAB program has been built t

... Show More
View Publication Preview PDF
Crossref (3)
Crossref
Publication Date
Sun Sep 01 2013
Journal Name
Baghdad Science Journal
Synthesis And Characterization Of Some New Acetylenic Mannich Bases Based On Biphenyl – 4,4 - Dithiol
...Show More Authors

One of the most important , compound which have active hydrogen is the compound possessing (thiol group) Biphenyl-4,4-dithiol is agood example utilized in a wide field for preparation mannich bases , avariety of new acetylenic mannich bases have been Synthesized and all proposed structure were Supported by FTIR , 1H – NMR, 13C-NMR , Elemental analysis and microbial study .

View Publication Preview PDF
Crossref
Publication Date
Sun Feb 03 2019
Journal Name
Journal Of The College Of Education For Women
Solution of the electromechanical machining problem using the collocation method based on Bernstein polynomials
...Show More Authors

0

View Publication Preview PDF
Publication Date
Thu Jun 18 2020
Journal Name
Biochem. Cell. Arch.
NEW DERIVATIVE OF CHITOSAN BASED ON EPICHLOROHYDRNE, SYNTHESIS, CHARACTERIZATION, ANTIBACTERIAL ACTIVITY AND SWELLING STUDY
...Show More Authors

A novel series of chitosan derivatives were synthesized via reaction of chitosan with carbonyl compounds and grafted it’s by with different amine compounds substituted hydrogen. The produced polymers were characterized by different analyses FTIR, 1HCNMR, XRD, DSC and TGA. Solubility in water as well as many solvent was investigated, antibacterial activity of chitosan and its derivatives against two types of bacteria E. coli and S. aureus was also investigated. The results showed that derivatives sort of have antibacterial activities against Esherichia coli (Gram negative) better than chitosan whilst compound IX has better antibacterial against Staphylococcus aureus (Gram positive). SEM analysis showed that increase of surface roughness wi

... Show More
Publication Date
Thu Jul 01 2021
Journal Name
Applied Thermal Engineering
Consecutive charging and discharging of a PCM-based plate heat exchanger with zigzag configuration
...Show More Authors

View Publication
Scopus (70)
Crossref (62)
Scopus Clarivate Crossref