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Performance evaluation of frequency division duplex (FDD) massive multiple input multiple output (MIMO) under different correlation models
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Massive multiple-input multiple-output (massive-MIMO) is considered as the key technology to meet the huge demands of data rates in the future wireless communications networks. However, for massive-MIMO systems to realize their maximum potential gain, sufficiently accurate downlink (DL) channel state information (CSI) with low overhead to meet the short coherence time (CT) is required. Therefore, this article aims to overcome the technical challenge of DL CSI estimation in a frequency-division-duplex (FDD) massive-MIMO with short CT considering five different physical correlation models. To this end, the statistical structure of the massive-MIMO channel, which is captured by the physical correlation is exploited to find sufficiently accurate DL CSI estimation. Specifically, to reduce the DL CSI estimation overhead, the training sequence is designed based on the eigenvectors of the transmit correlation matrix. To this end, the achievable sum rate (ASR) maximization and the mean square error (MSE) of CSI estimation with short CT are investigated using the proposed training sequence design. Furthermore, this article examines the effect of channel hardening in an FDD massive-MIMO system. The results demonstrate that in high correlation scenarios, a large loss in channel hardening is obtained. The results reveal that increasing the correlation level reduces the MSE but does not increase the ASR. However, exploiting the spatial correction structure is still very essential for the FDD massive-MIMO systems under limited CT. This finding holds for all the physical correlation models considered.

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Publication Date
Thu Dec 15 2022
Journal Name
Journal Of Baghdad College Of Dentistry
Clinicopathological assessment of chronic hyperplastic candidasis
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Background: Chronic hyperplastic candidiasis is the least common type of oral candidiasis. The diagnosis, long-term treatment, and prognosis of this potentially malignant oral condition are still currently unclear. Objective: the aim of this study is to analyze the demographic features and clinical characteristics of oral chronic hyperplastic candidiasis. Materials and Methods: A retrospective analysis was performed on blocks and case sheets of patients who were diagnosed with chronic hyperplastic candidiasis in the archives of Oral and Maxillofacial Pathology at the College of Dentistry/University of Baghdad. Demographic and clinical characteristics were analyzed. Results: twenty-one cases with chronic hyperplastic candidiasis were coll

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Publication Date
Wed Aug 01 2018
Journal Name
2018 International Conference On Computer And Applications (icca)
Evolutionary Perspective of Mobile Communication Technologies
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Publication Date
Wed Oct 11 2023
Journal Name
Journal Of Educational And Psychological Researches
Agentic Thinking of the University Students
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The research aims to identify the level of Agentic thinking among a sample of male and female undergraduate students for both disciplines (scientific, and humanities). The researcher targeted the third and fourth stages for the academic year

(2021-2022). The study sample is (382) male and female students who were selected randomly from the University of Baghdad. To achieve the above-mentioned study aims. The researcher has developed a scale of Agentic thinking consisting of (25) items distributed over three domains. The results showed that the study sample has a high level of Agentic thinking. There are significant differences in agentive thinking in terms of gender in favor of females. There are no statistically significant diff

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Publication Date
Sun Oct 02 2005
Journal Name
Journal Of The Faculty Of Medicine Baghdad
distribution of mercury in biological fluids
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Background:

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Publication Date
Wed Jun 30 2021
Journal Name
College Of Islamic Sciences
Methodological fundations for narrators of Sunan
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بحث لمعرفة رواة السنن والمسانيد للحافظ ابن نقطة

 

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Publication Date
Sun Dec 07 2008
Journal Name
Baghdad Science Journal
ON CERTAIN SUB-SPACE OF X
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The study of properties of space of entire functions of several complex variables was initiated by Kamthan [4] using the topological properties of the space. We have introduced in this paper the sub-space of space of entire functions of several complex variables which is studied by Kamthan.

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Publication Date
Wed May 17 2023
Journal Name
College Of Islamic Sciences
Dignity in the books of faith
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The issue of dignity is one of the topics that do not pass as long as the earths and the heavens remain; Because the earth is not devoid of the righteous, the believers, the saints, and the pious, and these do not cease from them aid, dignity, insight, or good vision, and from here the authorship in this section was continuous; Because the people’s need for it is confirmed as time progresses, and in that, Ibn Taymiyyah says in the sum of his fatwas, “And from what it should be known is that dignities may be according to the man’s need, so if the weak needs them Faith or the needy, he is given from it what strengthens his faith and fulfills his needs, and he who is more complete is the guardianship of God than him. He is independent

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Publication Date
Thu Mar 01 2018
Journal Name
Journal Of Engineering
Analysis of Double Skin Composite Slabs
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This paper deals with finite element modeling of the ultimate load behavior of double skin composite (DSC) slabs. In a DSC slab, shear connectors in the form of nut bolt technique studs are used to transfer shear between the outer skin made of steel plates and the concrete core. The current study is based on finite element analysis using ANSYS Version 11 APDL release computer program. Experimental programmes were carried out by the others, two simply supported DSC beams were tested until failure under a concentrated load applied at the center. These test specimens were analyzed by the finite element method and the analyses have shown that these slabs displayed a high degree of flexural characteristics, ultimate strength,

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Publication Date
Wed Dec 30 2009
Journal Name
Iraqi Journal Of Physics
Electrical Properties of ZnS Thin Films
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The effect of annealing temperature (Ta) on the electrical properties like ,D.C electrical conductivity (σ DC), activation energy (Ea),A.C conductivity σa.c ,real and imaginary (ε1,ε2) of dielectric constants ,relaxation time (τ) has been measured of ZnS thin films (350 nm) in thickness which were prepared at room temperature (R.T) using thermal evaporation under vacuum . The results showed that σD.C increases while the activation energy values(Ea) decreases with increasing of annealing temperature.(Ta) from 303- 423 K .
The density of charge carriers (nH) and Hall mobility (μH) increases also with increasing of annealing temperature Hall effect measurements showed that ZnS films were n-type converted to p-type at high annealin

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Publication Date
Tue Sep 18 2018
Journal Name
Kant
SOME METHODOLOGICAL OF LEARNING TENNIS STUDENTS
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This study is due to insufficient development of the issues of initial training in tennis at youthful (student) age. Objective: development of a methodological and scientific-methodological base of students' tennis with current trends in tennis. Summing up the best practices of modern tennis, we came to the conclusion that the formation of the art of reflection backhands in teaching beginner students of sports specialization to achieve future success. In modern conditions in the development of Russian tennis student opens the possibility of using new technologies and programs. Using these approaches, we have developed a training program and tested students' tennis in the pedagogical experiment, which resulted in its effectiveness.