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Connectivity and rendezvous in distributed DSA networks
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In this paper, we use concepts and results from percolation theory to investigate and characterize the effects of multi-channels on the connectivity of Dynamic Spectrum Access networks. In particular, we focus on the scenario where the secondary nodes have plenty of vacant channels to choose from-a phenomenon which we define as channel abundance. To cope with the existence of multi-channels, we use two types of rendezvous protocols: naive ones which do not guarantee a common channel and advanced ones which do. We show that, with more channel abundance, even with the use of either type of rendezvous protocol, it becomes difficult for two nodes to agree on a common channel, thereby potentially remaining invisible to each other. We model this invisibility as a Poisson thinning process and show that invisibility is even more pronounced with channel abundance. Following the disk graph model, we define and characterize connectivity of the secondary network in terms of the available number of channels, deployment densities, number of transceivers per node, and communication range. When primary users are absent, we derive the critical number of channels which maintains super-criticality of the secondary network. When primary users are present, we characterize and analyze the connectivity for all the regions: channel abundance, optimal, and channel deprivation. Our results can be used to decide on the goodness of any channel rendezvous algorithm by computing the expected resultant connectivity.

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Publication Date
Sun Oct 01 2023
Journal Name
Baghdad Science Journal
Numerical Investigation, Error Analysis and Application of Joint Quadrature Scheme in Physical Sciences
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In this work, a joint quadrature for numerical solution of the double integral is presented. This method is based on combining two rules of the same precision level to form a higher level of precision. Numerical results of the present method with a lower level of precision are presented and compared with those performed by the existing high-precision Gauss-Legendre five-point rule in two variables, which has the same functional evaluation. The efficiency of the proposed method is justified with numerical examples. From an application point of view, the determination of the center of gravity is a special consideration for the present scheme. Convergence analysis is demonstrated to validate the current method.

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Publication Date
Thu Sep 26 2013
Journal Name
Astronomy & Astrophysics
High-resolution observations of SDSS J080800.99+483807.7 in the optical and radio domains
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Publication Date
Thu Jun 16 2022
Journal Name
Al-khwarizmi Engineering Journal
Comparative study of vibration analysis in rotary shafts between Rayleigh's and Dunkerley's methods
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The importance of vibrations in rotating rotors in engineering applications has been examined, as has the best approach to interpreting vibration data. The most extensively used analytical approaches for rotating shaft vibration analysis have been investigated. In this research, a detailed study was made of the Rayleigh and Dunkerley methods due to their importance in the special calculations to find the amplitude of vibrations in the rotation system. The multi-node method was used to calculate both Dunkerley's and Rayleigh's methods. An experimental platform was built to study the vibrations that occur in the rotating shafts, and the results were compared with theoretical calculations and with different distances of the bearings. It pro

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Publication Date
Fri Jul 28 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Morphological and Growth Properties of Albino Rat Bone Marrow Stromal Cells In Vitro
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   The potential use of bone marrow stromal cells as a cellular therapy for chronic diseases relies on the ability of the cell to replicate extensively in vitro.For this reason the present study investigated the replication lifespan and examined the growth properties of albino rats mesenchymal stem cells(MSCS)in vitro. To establish an in vitro system for isolating and culturing the  MSCs of albino rats and to provide research data for its further application,the bone marrow (BM)was collected from young male rats and separated by gradient centrifugation.Then, the mononuclear cells(MNCs) were retrieved from the buffy layer and cultured in Modified Eagle,s Medium (MEM) supplemented with 10%Fetal Calf Serum (FCS)and incubation

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Publication Date
Thu Nov 02 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Determination of Magnesium, Zinc, and Reduced Glutathione Levels in Serum of Asthmatic Patients
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Asthma  is a disease  characterized by hyper reactivity  of the trachea and   bronchi   to  reversible   either   spontaneously  or  as  a  result   of treatment.

In this study serum magnesium,  Zinc, and reduced glutathione  levels

were  meas ured  in  order  to  determine   their  levels  in  the  asthmatic patients and comparing  these levels with healthy controls.

Fifty-  four  asthmatic   patients  were  enrolled  in  the  study  and  had their pulmonary  function test, and the levels of Mg,Zn

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Publication Date
Sun Jan 01 2006
Journal Name
Journal Of The College Of Languages (jcl)
The Play as Intellectual Ping-Pong: Art and Politics in Tom Stoppard's Travesties
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Throughout history, artists have played many important roles in society.

Generally speaking, the role of the artist is defined by the society he is part of.

Indeed, there are as many ideas as to the role of the artist and, ultimately the purpose

of art in society, as there are types of art. This is, as a matter of fact, neither a new

question- the dialogue has been present within art for centuries- nor probably one

that will ever fully be answered.

Tom Stoppard came to prominence in the mid-sixties, when art and politics

were closely linked, and theatre sought to change the world. Stoppard would have

none of that: his work has no overt message, no political program. In fact,

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Publication Date
Mon Feb 04 2019
Journal Name
Journal Of The College Of Education For Women
Popular naming for goods and materials in the Iraqi slang "A Semantic Study"
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The current research is concerned with the prices of Goods and materials in the Iraqi slang a descriptive, lexicographic , and semantic study expressing the meanings of these names and their positions , as well as expressing the imaginations of Human mind , the popular mind in describing these goods with evaluating them besides the semantic of each word accordingly
The current research is divided into two parts , the first part is consisted of Vocalizations" words" That are arisen through cognitive naming that concentrate on the mental imaginations for the most important and sensitive such as colors , taste , shapes and forms impacts of Goods and materials according to users' ' taste for those words , on other hand, the second part of

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Publication Date
Mon Dec 02 2013
Journal Name
Iraqi Medical Journal
Etiology and Antibiotic Sensitivity for Otitis Media in A Central Pediatric Teaching Hospital.
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Publication Date
Fri Jan 20 2023
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Quasi Semi and Pseudo Semi (p,E)-Convexity in Non-Linear Optimization Programming
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The class of quasi semi -convex functions and pseudo semi -convex functions are presented in this paper by combining the class of -convex functions with the class of quasi semi -convex functions and pseudo semi -convex functions, respectively. Various non-trivial examples are introduced to illustrate the new functions and show their relationships with -convex functions recently introduced in the literature. Different general properties and characteristics of this class of functions are established. In addition, some optimality properties of generalized non-linear optimization problems are discussed. In this generalized optimization problems, we used, as the objective function, quasi semi -convex (respectively, strictly quasi semi -convex

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Publication Date
Fri Dec 29 2023
Journal Name
Iraqi Journal Of Pharmaceutical Sciences ( P-issn 1683 - 3597 E-issn 2521 - 3512)
Consequences of Anabolic Androgenic Steroids Abuse in Males, Sexual Hepatic and Metabolic Perspective
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Abstract

Background: anabolic androgenic steroids (AASs) are becoming increasingly popular between bodybuilders and people who want to enhance their physiques. However, according to the rise of the Internet and laws prohibiting sales of these substances without prescription, the route of obtaining and administration practices have become more and more dangerous.

Objective: Anabolic-androgenic steroids represents a group of synthetic testosterone derivatives its play an important role in clinical treatment. These group of drugs are widely abused among the general public to increase lean body weight and improve athletic performance. It has been reported that AAS use can cause many adverse e

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