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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
Mon Apr 08 2019
Journal Name
International Journal Of Building Pathology And Adaptation
A scientometric analysis of BIM studies in facilities management
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Purpose

The purpose of this paper is to statistically classify and categorize Building Information Modelling (BIM)-Facility Management (FM) publications in order to extract useful information related to the adoption and use of BIM in FM.

Design/methodology/approach

This study employs a quantitative approach using science mapping techniques to examine BIM-FM publications using Web of Science (WOS) database for the period between 2000 and April 2018.

Findings

The findi

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Publication Date
Tue Nov 01 2011
Journal Name
Journal Of The Saudi Society Of Dermatology & Dermatologic Surgery
“Acquired epidermodysplasia verruciformis” in kidney transplant patients
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KE Sharquie, SA Al-Mashhadani, AA Noaimi, MY Abbas, Journal of the Saudi Society of Dermatology & Dermatologic Surgery, 2011 - Cited by 5

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Publication Date
Sun Mar 19 2023
Journal Name
Journal Of Educational And Psychological Researches
The Psychological Security of Students in the Kindergarten Department
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Abstract

The current research aims to identify the psychological security of students in the kindergarten department and identify if there is a significant difference between stage one and stage four students. To do this, the researcher adopted the psychological research scale of (Al-mohamdawi, 2007) that consisted of (30) items. It was administered to (120) female students chosen randomly from the kindergarten department in the college of education for women for the academic year (2029-2021). The results revealed that students in the kindergarten department have psychological security. There is a significant difference between stage one and four students in favor of stage four students.

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Publication Date
Mon Dec 01 2008
Journal Name
Political Sciences Journal
The role of Japan in the reconstruction of Iraq
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The Role of Japan in the Reconstruction of Iraq 

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Publication Date
Wed Feb 29 2012
Journal Name
Al-khwarizmi Engineering Journal
Natural Convection in Trapezoidal Enclosure Heated Partially from Below
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Natural convection in a trapezoidal enclosure with partial heating from below and symmetrical cooling from the sides has been investigated numerically. The heating is simulated by a centrally located heat source on the bottom wall, and four different values of the dimensionless heat source length, 1/5, 2/5, 3/5, 4/5 are considered. The laminar flow field is analyzed numerically by solving the steady, two-dimensional incompressible Navier-Stokes and energy equations. The Cartesian velocity components and pressure on a collocated (non-staggered) grid are used as dependent variables in the momentum equations  discretized by finite volume method; body fitted coordinates are used to represent the trapezoidal enclosure, and grid generatio

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Publication Date
Mon May 21 2007
Journal Name
Journal Of Planner And Development
Role of functional relations in the identification of regions
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The region is defined by the spatial dimension, which consists of a set of stabilizers (towns and villages). The concept of the territory requires conditions on the nature of functional relations and the mutual influence of the regions within the region. Any territory must be based on the interdependence and interaction between the mother city and its surrounding countryside and cities, and when the interdependence is strong and the interaction is clear, it helps to define the territory. The regions are divided on different bases. There are geographically or national homogeneous regions, and there are cultural regions that want to preserve their culture in terms of language or religion. There are administrative regions to manage

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Publication Date
Sat Jan 01 2011
Journal Name
Journal Of Modern Physics
Direct Optical Energy Gap in Amorphous Silicon Quantum Dots
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Publication Date
Thu Aug 13 2020
Journal Name
Journal Of Physics: Conference Series
Chaos in Beddington–DeAngelis food chain model with fear
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Abstract<p>In the current paper, the effect of fear in three species Beddington–DeAngelis food chain model is investigated. A three species food chain model incorporating Beddington-DeAngelis functional response is proposed, where the growth rate in the first and second level decreases due to existence of predator in the upper level. The existence, uniqueness and boundedness of the solution of the model are studied. All the possible equilibrium points are determined. The local as well as global stability of the system are investigated. The persistence conditions of the system are established. The local bifurcation analysis of the system is carried out. Finally, numerical simulations are used t</p> ... Show More
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Publication Date
Wed Jan 01 2014
Journal Name
Journal Of The College Of Languages (jcl)
Learning English through Scaffolded Assistance in Iraqi EFL Classroom
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Learning a foreign language is a highly interactive process, and a belief that communicative activities foster a great amount of linguistic production provides language practice and opportunities for negotiation of meaning during communicative exchanges. Thus, this study examines what benefits learner-centered classroom setting offers compared with that of teacher–centered classroom, and how less proficient learners accomplish their tasks and activities with scaffolded help during interaction with the help of proficient classmates and under the guidance of a skilful person, i.e., the teacher. The subjects participating in this study are 30 Iraqi 4th year college students in the Department of English, College of Arts , Univer

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Publication Date
Fri Jan 01 2016
Journal Name
Wuhaib, K.m. , Hadi, B.h. , Hassan, W.a. Iraqi Journal Of Agricultural Sciences, 2016, 47(5), Pp. 1151–1165
Some genetic parameter in maize using full diallel crosses
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