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Downlink Training Sequence Design Based on Waterfilling Solution for Low-Latency FDD Massive MIMO Communications Systems
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Future generations of wireless communications systems are expected to evolve toward allowing massive ubiquitous connectivity and achieving ultra-reliable and low-latency communications (URLLC) with extremely high data rates. Massive multiple-input multiple-output (m-MIMO) is a crucial transmission technique to fulfill the demands of high data rates in the upcoming wireless systems. However, obtaining a downlink (DL) training sequence (TS) that is feasible for fast channel estimation, i.e., meeting the low-latency communications required by future generations of wireless systems, in m-MIMO with frequency-division-duplex (FDD) when users have different channel correlations is very challenging. Therefore, a low-complexity solution for designing the DL training sequences to maximize the achievable sum rate of FDD systems with limited channel coherence time (CCT) is proposed using a waterfilling power allocation method. This achievable sum rate maximization is achieved using sequences produced from a summation of the user’s covariance matrices and then applying a waterfilling power allocation method to the obtained low-complexity training sequence. The results show that the proposed TS outperforms the existing methods in the medium and high SNR regimes while reducing computational complexity. The obtained results signify the proposed TS’s feasibility for practical consideration compared with the existing DL training sequence designs.

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Publication Date
Mon May 27 2019
Journal Name
Al-academy
A Hypothesis of Architectural Environment Exercise for Actor Training (Continuous exercise space workshop – A model): هيثم عبد الرزاق علي
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The peculiarity of the theater does not lie in its dramatic content because many literary genres and other artistic styles share with it in this content. The peculiarity of the theater lies in contemplating the drama through what is architectural, and this architectural axis is what distinguishes its character. It is a spatial poetry which is composed by the laws of physics and chemistry, (Weight, height, distance, rhythm, gravity, impulses and chemical excretions). i.e., what cannot be expressed in words. This is a game of space to exchange and organize energy and communicate in space by the living body, which contains the possibilities of the living drawing in space: in the time and place. This research deals with the importance of the

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Publication Date
Mon Mar 08 2021
Journal Name
Baghdad Science Journal
A stuy Some physical properties for play (vunyl alcohol) in aquecous solution at four temperatures
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The densities and visconsities of solutions of poly(vinyl alcohol)(PVA) molccuar weight (14)kg.mol-1in water up to 0.035%mol.kg-1

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Publication Date
Sun Jan 01 2023
Journal Name
Alexandria Engineering Journal
Calcium/iron-layered double hydroxides-sodium alginate for removal of tetracycline antibiotic from aqueous solution
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Publication Date
Wed Aug 01 2018
Journal Name
Journal Of Economics And Administrative Sciences
Proposed Measure for Effect Size in Mediation Analysis with Solution to Some Mediation Process Problems
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In this paper, the effect size measures was discussed, which are useful in many estimation processes for direct effect and its relation with indirect and total effects. In addition, an algorithm to calculate the suggested measure of effect size was suggested that represent the ratio of direct effect to the effect of the estimated parameter using the Regression equation of the dependent variable on the mediator variable without using the independent variable in the model. Where this an algorithm clear the possibility to use this regression equation in Mediation Analysis, where usually used the Mediator and independent variable together when the dependent variable regresses on them. Also this an algorithm to show how effect of the

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Publication Date
Mon Oct 01 2012
Journal Name
Computers & Mathematics With Applications
Boundary element formulations for the numerical solution of two-dimensional diffusion problems with variable coefficients
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Publication Date
Sun Jul 01 2012
Journal Name
Journal Of Endodontics
Synthesis and Preliminary Evaluation of a Polyolefin-based Core for Carrier-based Root Canal Obturation
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Introduction: Carrier-based gutta-percha is an effective method of root canal obturation creating a 3-dimensional filling; however, retrieval of the plastic carrier is relatively difficult, particularly with smaller sizes. The purpose of this study was to develop composite carriers consisting of polyethylene (PE), hydroxyapatite (HA), and strontium oxide (SrO) for carrier-based root canal obturation. Methods: Composite fibers of HA, PE, and SrO were fabricated in the shape of a carrier for delivering gutta-percha (GP) using a melt-extrusion process. The fibers were characterized using infrared spectroscopy and the thermal properties determined using differential scanning calorimetry. The elastic modulus and tensile strength tests were dete

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Publication Date
Thu Oct 01 2009
Journal Name
Iraqi Journal Of Physics
PMMA/ Anthracene Film as a Low Doses Dosimeter
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A prepared PMMA/Anthracene film of thickness 70μm was irradiated under reduced pressure ~10-3 to 60Coγ-ray dose of (0.1mrad-10krad) range. The optical properties of the irradiated films were evaluated spectrophotometrically. The absorption spectrum showed induced absorption changes in the 200-400nm range. At 359nm, where there is a decrease in radiation-induced absorption, the optical density as a function of absorbed dose is linear from 10mrad-10Krad.It can therefore, be used as radiation dosimeter for gamma ray in the range 10mrd-10krad

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Publication Date
Sun Sep 07 2008
Journal Name
Baghdad Science Journal
Proparyation of Low frequency microwave in dusty Plasma
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The numerical simulation for the low frequency waves in dusty plasma has been studied. The studying was done by taking two special cases depending on the direction of the propagation of the wave:First, when the propagation is parallel to the magnetic field K//B,this mode is called acoustic mode.Second,when K B this mode is called cyclotron mode.In addition, every one of the two modes divided into two modes depending on the range of the frequency.The Coulomb coupling parameter was studied, with temperature T,density of the dust particles Nd ,and the charge of the particle Qd.The low frequency electrostatic waves in dusty grains were studied. Also, the properties of ion-acoustic waves and ion-cyclotron waves are shown to modify even through

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Publication Date
Sat Mar 01 2008
Journal Name
Al-khwarizmi Engineering Journal
Impact Energy of 100Cr6 under low different velocities
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This study has been undertaken to postulate the mechanism of impact test at low velocities. Thin-walled tubes of 100Cr6 were deformed under axial compression. In the present work there are seven velocities (4.429,4.652,5.240,5.600,5.942,6.264, 6.569) m\sec were applied to show how they effect the load, change in length, also the kinetic energy. However, the comparison between the obtained results and the other studies (Alexandar[3] , Abramowicz[4], Ayad[5]) was made the present work and Ayad data show good agreement. Load, change in length, kinetic energy were determined to understand the impact test.

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Publication Date
Sun Jan 01 2023
Journal Name
Proceedings Of International Conference On Data Science And Applications
Very Low Illumination Image Enhancement via Lightness Mapping
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