Preferred Language
Articles
/
VoZ8soYBIXToZYAL47HT
Multi-Channel Distributed DSA Networks: Connectivity and Rendezvous Tradeoffs
...Show More Authors

In this paper, we investigate and characterize the effects of multi-channel and rendezvous protocols on the connectivity of dynamic spectrum access networks using percolation theory. 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-channel, 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 protocols, 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 represent the multiple channels as parallel edges in a graph and build a multi-layered graph (MLG) in R2. In order to study the connectivity, we show how percolation occurs in the MLG by coupling it with a typical discrete percolation. Using a Boolean model and the MLG, we study both cases of primaries' absence and presence. For both cases, we define and characterize connectivity of the secondary network in terms of the available number of channels, deployment densities, number of simultaneous transmissions per node, and communication range. When primary users are absent, we derive the critical number of channels which maintains supercriticality 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. For each region we show the requirement and the outcome of using either type of rendezvous techniques. Moreover, we find the tradeoff between deployment-density versus rendezvous probability which results in a connected network. Our results can be used to decide on the goodness of any channel rendezvous algorithm by computing the expected resultant connectivity. They also provide a guideline for achieving connectivity using minimal resources.

Scopus Clarivate Crossref
Publication Date
Fri Jul 01 2016
Journal Name
International Journal Of Modern Trends In Engineering And Research (ijmter)
An image processing oriented optical mark reader based on modify multi-connect architecture (MMCA)
...Show More Authors

Optical Mark Recognition (OMR) is the technology of electronically extracting intended data from marked fields, such as squareand bubbles fields, on printed forms. OMR technology is particularly useful for applications in which large numbers of hand-filled forms need to be processed quickly and with a great degree of accuracy. The technique is particularly popular with schools and universities for the reading in of multiple choice exam papers. This paper proposed OMRbased on Modify Multi-Connect Architecture (MMCA) associative memory, its work in two phases: training phase and recognition phase. The proposed method was also able to detect more than one or no selected choice. Among 800 test samples with 8 types of grid answer sheets and tota

... Show More
Preview PDF
Publication Date
Sat Jan 23 2021
Journal Name
Neural Computing And Applications
Multi-objectives TLBO hybrid method to select the related risk features with rheumatism disease
...Show More Authors

View Publication
Scopus (7)
Crossref (6)
Scopus Clarivate Crossref
Publication Date
Fri Apr 01 2022
Journal Name
International Journal Of Pharmacy Practice
Exploring job satisfaction among pharmacy professionals in the Arab world: a multi-country study
...Show More Authors
Abstract<sec> <title>Objectives

The study objectives were to (1) describe the characteristics of the pharmacy professionals and (2) explore the association between job satisfaction and factors, such as work control, work stress, workload and organization and professional commitments.

Methods

This study was a cross-sectional design. The survey items were mainly adapted from the US National Pharmacist Workforce Survey. An electronic (Qualtrics) questionnaire was posted on pharmacist social media in several A

... Show More
View Publication
Scopus (7)
Crossref (4)
Scopus Clarivate Crossref
Publication Date
Tue May 01 2018
Journal Name
Journal Of Physics: Conference Series
The Effect of Multi Wall Carbon Nanotubes on Some Physical Properties of Epoxy Matrix
...Show More Authors

View Publication
Scopus (6)
Crossref (4)
Scopus Clarivate Crossref
Publication Date
Thu Jul 01 2021
Journal Name
Journal Of Physics: Conference Series
Wireless Optimization Algorithm for Multi-floor AP deployment using binary particle swarm optimization (BPSO)
...Show More Authors
Abstract<p>Optimizing the Access Point (AP) deployment is of great importance in wireless applications owing the requirement to provide efficient and cost-effective communication. Highly targeted by many researchers and academic industries, Quality of Service (QOS) is an important primary parameter and objective in mind along with AP placement and overall publishing cost. This study proposes and investigates a multi-level optimization algorithm based on Binary Particle Swarm Optimization (BPSO). It aims to an optimal multi-floor AP placement with effective coverage that makes it more capable of supporting QOS and cost effectiveness. Five pairs (coverage, AP placement) of weights, signal threshol</p> ... Show More
View Publication
Scopus Crossref
Publication Date
Sun Oct 30 2022
Journal Name
Iraqi Journal Of Science
The Best Efficient Solutions for Multi-Criteria Travelling Salesman Problem Using Local Search Methods
...Show More Authors

     In this research, we propose to use two local search methods (LSM's); Particle Swarm Optimization (PSO) and the Bees Algorithm (BA) to solve Multi-Criteria Travelling Salesman Problem (MCTSP) to obtain the best efficient solutions. The generating process of the population of the proposed LSM's may be randomly obtained or by adding some initial solutions obtained from some efficient heuristic methods. The obtained solutions of the PSO and BA are compared with the solutions of the exact methods (complete enumeration and branch and bound methods) and some heuristic methods. The results proved the efficiency of PSO and BA methods for a large number of nodes ( ). The proposed LSM's give the best efficient solutions for the MCTSP for

... Show More
View Publication Preview PDF
Scopus (1)
Scopus Crossref
Publication Date
Fri Mar 05 2021
Journal Name
Materials
Optimum Placement of Heating Tubes in a Multi-Tube Latent Heat Thermal Energy Storage
...Show More Authors

Utilizing phase change materials in thermal energy storage systems is commonly considered as an alternative solution for the effective use of energy. This study presents numerical simulations of the charging process for a multitube latent heat thermal energy storage system. A thermal energy storage model, consisting of five tubes of heat transfer fluids, was investigated using Rubitherm phase change material (RT35) as the. The locations of the tubes were optimized by applying the Taguchi method. The thermal behavior of the unit was evaluated by considering the liquid fraction graphs, streamlines, and isotherm contours. The numerical model was first verified compared with existed experimental data from the literature. The outcomes re

... Show More
View Publication Preview PDF
Scopus (10)
Crossref (11)
Scopus Clarivate Crossref
Publication Date
Wed Apr 01 2015
Journal Name
Journal Of Economics And Administrative Sciences
Multi-level model of the factors that affect the escalation of dust in Iraq
...Show More Authors

In this research The study of Multi-level  model (partial pooling model) we consider The partial pooling model which is one Multi-level  models and one of  the Most important models and extensive use and application in the analysis of the data .This Model characterized by the fact that the treatments take hierarchical or structural Form, in this partial pooling models, Full Maximum likelihood FML was used to estimated parameters of partial pooling models (fixed and random ), comparison between the preference of these Models, The application was on the Suspended Dust data in Iraq, The data were for four and a half years .Eight stations were selected randomly  among the stations in Iraq. We use Akaik′s Informa

... Show More
View Publication Preview PDF
Crossref
Publication Date
Wed Jan 01 2020
Journal Name
International Conference Of Numerical Analysis And Applied Mathematics Icnaam 2019
Functionalized multi-walled carbon nanotubes network sensor for NO2 gas detection at room temperature
...Show More Authors

View Publication
Scopus (5)
Crossref (6)
Scopus Clarivate Crossref
Publication Date
Wed Dec 30 2020
Journal Name
Al-kindy College Medical Journal
Iraqi women Attitude towards Immediate Post-partum/ Post-abortion Contraception: a multi-institutional study
...Show More Authors

Background: Immediate postpartum contraceptive and post abortion contraception methods are effective safe methods and are becoming a standard practice in many countries, yet it is not widely used in Iraq.

Aims: this study: is designed to assess the attitude and willingness of women to immediate contraception after giving birth or abortion and their satisfaction to previous use.

Methods and Material: Four hundred thirty-four women were surveyed in the labor word immediately after giving birth/ abortion. Their knowledge, attitude and contraception use were assessed according to the response they reported to a given questionnaire.

Results: women were not sure abo

... Show More
View Publication Preview PDF
Crossref