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Block-Iterative Frequency-Domain Equalizations for SC-IDMA Systems
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In wireless broadband communications using single-carrier interleave division multiple access (SC-IDMA) systems, efficient multiuser detection (MUD) classes that make use of joint hybrid decision feedback equalization (HDFE)/ frequency decision-feedback equalization (FDFE) and interference cancellation (IC) techniques, are proposed in conjunction with channel coding to deal with several users accessing the multipath fading channels. In FDFE-IDMA, the feedforward (FF) and feedback (FB) filtering operations of FDFE, which use to remove intersymbol interference (ISI), are implemented by Fast Fourier Transforms (FFTs), while in HDFE-IDMA the only FF filter is implemented by FFTs. Further, the parameters involved in the FDFE/HDFE filtering are derived according to the minimum mean square error (MMSE) criteria, and the feedback symbol decisions are directly designed from soft detection of the decoded signals at the previous iteration. The simulation results including comparisons with those of frequency domain equalization (FDE), SC-FDE-IDMA and multi-carrier OFDM-IDMA schemes, with cyclic prefixing (CP) and zero padding (ZP) techniques, show that the combination of FDFE-IC/HDFE-IC provides an efficient solution with good performance for IDMA systems in ISI channels. Moreover, these iterative structures with block equalization yield a much lower complexity than equivalent existing structures, making them attractive for a wealth of applications.

 

 

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Publication Date
Tue Mar 12 2024
Journal Name
Semiconductor Physics, Quantum Electronics And Optoelectronics
Numerical study of single-layer and interlayer grating polarizers based on metasurface structures for quantum key distribution systems
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Polarization is an important property of light, which refers to the direction of electric field oscillations. Polarization modulation plays an essential role for polarization encoding quantum key distribution (QKD). Polarization is used to encode photons in the QKD systems. In this work, visible-range polarizers with optimal dimensions based on resonance grating waveguides have been numerically designed and investigated using the COMSOL Multiphysics Software. Two structures have been designed, namely a singlelayer metasurface grating (SLMG) polarizer and an interlayer metasurface grating (ILMG) polarizer. Both structures have demonstrated high extinction ratios, ~1.8·103 and 8.68·104 , and the bandwidths equal to 45 and 55 nm for th

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Publication Date
Wed Dec 01 2021
Journal Name
Baghdad Science Journal
Improvement of the Fault Tolerance in IoT Based Positioning Systems by Applying for Redundancy in the Controller Layer
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In recent years, the positioning applications of Internet-of-Things (IoT) based systems have grown increasingly popular, and are found to be useful in tracking the daily activities of children, the elderly and vehicle tracking. It can be argued that the data obtained from GPS based systems may contain error, hence taking these factors into account, the proposed method for this study is based on the application of IoT-based positioning and the replacement of using IoT instead of GPS.  This cannot, however, be a reason for not using the GPS, and in order to enhance the reliability, a parallel combination of the modern system and traditional methods simultaneously can be applied. Although GPS signals can only be accessed in open spaces, GP

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Publication Date
Wed Mar 01 2017
Journal Name
The Iraqi Postgraduate Medical Journal
The Frequency and Spectrum of K-ras Mutations among Iraqi Patients with Sporadic Colorectal Carcinoma (CRC)
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BACKGROUND: CRC is one of the most common cancers in the world. K-ras is proto-oncogene with GTPase activity that is lost when the gene is mutated. Analysis of K-ras mutational status is very important for CRC treatment, being the most important predictors of resistance to targeted therapy. OBJECTIVE: This study aims to determine the frequency and spectrum of K-ras mutation among Iraqi patients with sporadic CRC. PATIENTS, MATERIALS AND METHODS: This study enrolled 35 cases with sporadic CRC; their clinicopathological parameters were analyzed. The FFPE blocks were used for DNA extraction; PCR amplification of K-ras gene and hybridization of allele-specific oligoprobes were performed. The assay covers 29 mutations in the K-ras gene (codons 1

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Publication Date
Tue Nov 01 2016
Journal Name
Journal Of Cosmetics, Dermatological Sciences And Applications
Frequency of benign and malignant tumors in localized vitiligo in comparison to generalized and universal vitiligo
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KE Sharquie, AA Noaimi, SJ Murtada…, Journal of Cosmetics, Dermatological Sciences and Applications, 2016 - Cited by 4

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Publication Date
Fri Feb 08 2019
Journal Name
Iraqi Journal Of Laser
Frequency and Wavelength Dependences of the Electro-optic Coefficients r63 and r41 in Congruent KDP Crystals
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The electro-optic coefficient r63 and r41 are determined in congruent KDP crystals, using an experimental method based upon the direct measurement of material. Sénarmont system for electro-optic coefficient measurement and characterization of crystals was modified. This modification allowed us to obtain on the frequency dispersion dependence of the electro-optic coefficients within a frequency range up to 20 MHz and on a new version of modulation depth method. To the best of our knowledge, by using this system, the electro-optic coefficients r63 and r41 in different configurations (transverse and longitudinal) have been measured for the first time within a frequency range up to 20 MHz. The measurements have been investigated as a functi

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Publication Date
Sun Oct 01 2023
Journal Name
Medical Journal Of Babylon
Prevalence of coronary artery disease in patients with left bundle branch block and its association with risk factors hypertension and diabetes mellitus
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Abstract<sec> <title>Background:

Left bundle branch block (LBBB) is a common finding in electrocardiography, there are many causes of LBBB.

Objectives:

The aim of this study is to discuss the true prevalence of coronary artery disease (CAD) in patients with LBBB and associated risk factors in the form of hypertension and diabetes mellitus.

Materials and Methods:

Patients with LBBB were admitted to the Iraqi heart center for cardiac disea

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Publication Date
Mon Jan 01 2018
Journal Name
2018 Detroit, Michigan July 29 - August 1, 2018
Design and validation of an electronic data logging systems (CAN Bus) for monitoring machinery performance and management- Planting application
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Publication Date
Fri Feb 08 2019
Journal Name
Iraqi Journal Of Laser
Random Number Generation for Quantum Key Distribution Systems Based on Shot-Noise Fluctuations in a P-I-N Photodiode
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A simple setup of random number generator is proposed. The random number generation is based on the shot-noise fluctuations in a p-i-n photodiode. These fluctuations that are defined as shot noise are based on a stationary random process whose statistical properties reflect Poisson statistics associated with photon streams. It has its origin in the quantum nature of light and it is related to vacuum fluctuations. Two photodiodes were used and their shot noise fluctuations were subtracted. The difference was applied to a comparator to obtain the random sequence.

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Publication Date
Fri Nov 01 2013
Journal Name
Radioelectronics And Communications Systems
Erratum to: “BER Performance Enhancement for Secure Wireless Communication Systems Based on DCSK-MIMO Techniques under Rayleigh Fading Channel”
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There has been a growing interest in the use of chaotic techniques for enabling secure communication in recent years. This need has been motivated by the emergence of a number of wireless services which require the channel to provide low bit error rates (BER) along with information security. The aim of such activity is to steal or distort the information being conveyed. Optical Wireless Systems (basically Free Space Optic Systems, FSO) are no exception to this trend. Thus, there is an urgent necessity to design techniques that can secure privileged information against unauthorized eavesdroppers while simultaneously protecting information against channel-induced perturbations and errors. Conventional cryptographic techniques are not designed

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Publication Date
Wed Nov 01 2017
Journal Name
Journal Of Economics And Administrative Sciences
A Suggested Model for Using a Students Attendance Management Information Systems/ A Case Study In Lebanese French University/ Erbil
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This study aims to design unified  electronic information system to manage students attendance in Lebanese French university/Erbil, as a system that simplifies the process of entering and counting the students absence, and generate absence reports to expel students who passed  the acceptable limit of being absent, and by that we can replace the traditional way of  using papers to count absence,  with  a complete electronically system for managing students attendance, in a way that makes the results accurate and unchangeable by the students.

            In order to achieve the study's objectives, we designed an information syst

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