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Improving the Direction of Arrival Estimation Using the Parasitic Subspace Generated by Active-Parasitic Antenna (APA) Arrays
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The improvement in Direction of Arrival (DOA) estimation when the received signals impinge on Active-Parasitic Antenna (APA) arrays will be studied in this work. An APA array consists of several active antennas; others are parasitic antennas. The responses to the received signals are measured at the loaded terminals of the active element. The terminals of the parasitic element are shorted. The effect of the received signals on the parasites, i.e., the induced short-circuit current, is mutually coupled to the active elements. Eigen decomposition of the covariance matrix of the measurements of the APA array generates a third subspace in addition to the traditional signal and noise subspaces generated by the all-active antenna receiving array. This additional subspace, the parasitic subspace, is accompanied by very small eigenvalues (approaching zero). Hence, a complete orthogonality between this subspace and the column space of the steering matrix of the array can be obtained. As a result, better resolution in estimating the DOA can be achieved. Several simulations in conjunction with the MUSIC algorithm, which have been conducted in this work, depict that the APA array outperforms the all-active antenna array as a direction finder, regardless of the size of the array, the number of active elements, or the number of measurement snapshots. Furthermore, super-resolution DOA estimation can be achieved when a subset of the parasitic subspace is used as if the measurement were noiseless. Also, the APA array contributes to very small RMSE values over a wide range of S/N of the received signals.

 

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Publication Date
Mon Aug 02 2021
Journal Name
International Journal Of Dental Hygiene
Efficacy of erythritol powder air‐polishing in active and supportive periodontal therapy: A systematic review and meta‐analysis
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Abstract<sec><title>Objective

This systematic review aimed to analyse available evidence to answer two focused questions about the efficacy of erythritol powder air‐polishing (EPAP) (i) as an adjunctive during active periodontal therapy (APT) and (ii) as an alternative to hand/ultrasonic instrumentation during supportive periodontal therapy (SPT). Additionally, microbiological outcomes and patient's comfort/perceptions were assessed as secondary outcomes.

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PubMed, Cochrane and Medline were searched for relevant articles published before February 2021 following PRISMA guidelines. The search was conducted by three indep

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Publication Date
Fri Jul 01 2022
Journal Name
Advanced Powder Technology
Modification of FAU zeolite as an active heterogeneous catalyst for biodiesel production and theoretical considerations for kinetic modeling
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Publication Date
Mon Nov 03 2025
Journal Name
Lecture Notes In Networks And Systems
The Role of Social Media Sites Supported by Artificial Intelligence Tools in Spreading and Promoting the Civilizations Dialogues
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Mixing this strategy with a qualitative research design and an idea known as AI-supported journalism, the paper is going to approach the requirements of how AI technologies may transform journalism content and culture in a way beyond what one anticipates; therefore, enabling more of it to reach an audience. The current research used descriptive research design to investigate the potential applications of the AI tools that mediate civilizational conversation and a structured questionnaire to media professionals. AI-driven journalism can promote peaceful cohabitation and mutual respect and thus act as a bridge between cultures, the research said. The piece even goes on to mention the need for media establishments and civil soc

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Publication Date
Thu Dec 01 2016
Journal Name
Journal Of Al-nahrain University-scienc
Synthesis and Characterization of Some Anti-bacterial Active Transition Metal Complexes of N'-[2-(2-Phenyl hydrazinyl) Phenyl] Benzothiohydrazide
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Publication Date
Wed Aug 10 2016
Journal Name
Al-nahrain
Synthesis and characterization of some Anti-bactrial Active Transition Metal Complexes of N-12-(2-phenyl hydrazinyl) phenyl [ benzothiohydrazide
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Publication Date
Thu Jun 30 2016
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Determination of the Optimum Conditions for the Production of Gamma Alumina (ɤ-Al2O3) By the Precipitation Method of the Sodium Aluminate Solution
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Design of experiments (DOE) was made by Minitab software for the study of three factors used in the precipitation process of the Sodium Aluminate solution prepared from digestion of α-Al2O3  to determine the optimum conditions to a produce Boehmite which is used in production of ɤ-Al2O3 during drying and calcination processes, the factors are; the temperature of the sodium aluminate solution, concentration of HCl acid added for the precipitation and the pH of the solution at which the precipitation was ended. The design of the experiments leads to 18 experiments.

   The results show that the optimum conditions for the precipitation of the sodium aluminate solution which

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Publication Date
Wed Mar 01 2023
Journal Name
Journal Of Engineering
Directive and Steerable Radiation Pattern using SASPA Array
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This work examines the ability of a special type of smart antenna array known as Switched Active Switched Parasitic Antenna (SASPA) to produce a directive and electronically steerable radiation pattern. The SASPA array consists of antenna elements that are switchable between active and parasitic states by using P-Intrinsic-N (PIN) diodes. The active element is the element that is supplied by the radio frequency while short-circuiting the terminals of an element in the array results in a parasitic element. Due to the strong mutual coupling between the elements, a directional radiation pattern with high gain and a small beamwidth can be produced with only one active element operating at a time. By changing the parasitic state to the active

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Publication Date
Sat Dec 28 2024
Journal Name
Journal Of Physical Education
The effect of using special intense exercise accompanied by intermittent electrical stimulation to get rid of lower neck pain among professors of the College of Science - University of Baghdad for ages (40-60) years
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Lower neck pain is one of the problems facing all ages, especially the elderly, as it revolves around the causes of this pain from many diverse factors. The aim of the research is to use special intense exercise accompanied by intermittent electrical stimulation to get rid of lower neck pain among professors of the College of Science - University of Baghdad for ages. (40-60) years and to identify the extent of the effect. The research assumed the presence of statistically significant differences. The research sample represented professors at the University of Baghdad - College of Science who suffer from continuous pain for the period between (10/15/2023) and (1/15/) 2024) and their number is (5), The researchers used the experimenta

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Publication Date
Mon Aug 15 2022
Journal Name
American Journal Of Research In Humanities And Social Sciences
THE IMAGE OF THATCHERISM IN TOP GIRLS BY CARYL CHURCHILL
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Caryl Churchill's Top Girls (1982) reveals how women have achieved a point of strength and independence in their battle to face men's oppression throughout history. Churchill has replicated recent transitions in the 1980s and 1990s in works that depict these movements' central concerns and contradictions as they change. Similarly, her theater is a result of many problems and shifts in hegemonic modes of production during this time. This paper traces the achievements of the major character of Top Girls, Marlene, in her way of life and her handling of the struggles of other women around her. Because of this strength, Marlene is compared to the British Prime Minister, Thatcher. Therefore, this paper will shed light on the term of T

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Publication Date
Sun Jul 01 2018
Journal Name
Journal Of Educational And Psychological Researches
The Use of Discourse Markers by Iraqi Secondary Schools Pupils
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This research aims at investigating pupils’ ability in using discourse markers which are identified in the English textbooks of secondary schools. Four texts are chosen from third intermediate class. The four texts are short stories of different topics.                                                  

        This research hypothesizes that there are no statistical significant differences among Iraqi intermediate pupils’ ability in using textual

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