Preferred Language
Articles
/
XYZ-soYBIXToZYAL3LHN
Connectivity and rendezvous in distributed DSA networks
...Show More Authors

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.

Scopus Crossref
Publication Date
Thu Dec 01 2016
Journal Name
Journal Of Economics And Administrative Sciences
Assessment of Human Investment Efficiency in the Private University Teaching according to the strategy of Higher Education in Iraq and chosen Colleges))
...Show More Authors

Abstract:

the current research aims at analyzing the efficiency of the private university teaching  that recently expanded after 2003 ,;besides , the commitment of the private colleges ,definitely Al-Maamun and Al-Mansour colleges with strategy  of the ministry of higher  education and scientific  research.  This could be done through many indications that measure the efficiency of the  private university teaching , including ( the indication of  the efficiency of   using human resources and efficiency  in using  the materialistic indications.  But the human efficiency in these colleges , including the sample  of the research ( Maamun 

... Show More
View Publication Preview PDF
Crossref
Publication Date
Wed Mar 01 2023
Journal Name
Iraqi Journal Of Physics
Design and Construction of a Dust Detection System using Infrared Laser: The Case of Dust Storms in Baghdad in the Summer 2022
...Show More Authors

Iraq suffers from serious pollution with harmful particles that have important direct and indirect effects on human activities and human health. In this research, a system for detecting pollutants in the air was designed and manufactured using infrared laser technology. This system was used to detect the presence of pollutants in the dust storms that swept the city of Baghdad which could have a negative impact on human health and living organisms.

The designed detection system based on the use of infrared laser (IR) with a wavelength of 1064 nm was used for the purposes of detecting pollutants based on the scattering of the laser beam from these pollutants. The system was aligned to obtain the best signal for the scattered rays, w

... Show More
View Publication Preview PDF
Crossref
Publication Date
Mon Mar 07 2022
Journal Name
Journal Of Educational And Psychological Researches
Math Word Problems in Mathematics Books for the First Three Grads of the Basic Stage in Palestine (An analytical and Evaluative Study)
...Show More Authors

This study aimed at revealing the degree of availability of standards of word problems in mathematics books for the first three grades of the basic stage in Palestine. For this purpose, the researcher prepared an analysis tool and a list of criteria consisting of two areas: linguistic formulation and mathematical content. Every area had seven items. The results of the study showed that the third-grade mathematics book has the highest degree of availability of the standards with 85.75%, and then came the second-grade mathematics book with 83.12%. Finally, the first-grade mathematics book came with 80.13%. In the light of the previous results, the researcher recommended to develop the language of word problems, to take into account their i

... Show More
View Publication Preview PDF
Publication Date
Thu Mar 30 2017
Journal Name
Iraqi Journal Of Pharmaceutical Sciences ( P-issn 1683 - 3597 E-issn 2521 - 3512)
Effect of Chronic Exposure of Cadmium Chloride in Drinking Water on Structural and Functional Aspects of Thyroid Gland in Mature Male Rabbits
...Show More Authors

The effect of chronic exposure to two different levels of cadmium chloride (CdCl2) 30 ppb and 40 ppb in drinking water for 12 weeks on thyroid function of mature male rabbits was studied. Eighteen mature male rabbits  were randomly divided into three groups (each of six ) , control group (group I ): were offered ordinary tap water , and treated groups (II and III ) were offered tap water containing 30ppb and 40 ppb respectively for 12 weeks .Serum concentration of  thyroxin (T4 ) and triiodothyronine (T3) were measured every six weeks ,as an index  of  thyroid function , further more ,  section of thyroid gland were prepared for histological studies. The results showed that  chronic exposure of male rabbits

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sun Jun 22 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Enamel defect of primary and permanent teeth in relation to nutrients daily intake among Down's syndrome children in comparison to normal children
...Show More Authors

Background: Any child with Down's syndrome does not develop in the same manner as normal child. Therefore, the child should not be viewed as being like everyone else. Developmental enamel defects in primary teeth have been found at least twice as frequently in disabled children as in control children. Down's syndrome consumed protein more than the recommended daily allowance compared to other disabled groups. Therefore, the aim of this study was to investigate developmental defects of enamel and their relations to nutrient intake among Down's syndrome children in comparison to normal children. Materials and Methods: A sample consisted of fifty institutionalized Down's syndrome children (study group) and 50 normal children (control group)

... Show More
View Publication Preview PDF
Publication Date
Mon May 20 2019
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Investigation in the Effect of Applied Voltage and Working Pressure on Some Plasma Parameters in the Positive Column of Dc Glow Discharge
...Show More Authors

     Comsol multiphysics software is established to make a simulation that is comparable with experimental device. by utilizing comsol, the positive column domain of direct-current glow discharge with argon is considered for both of different applied voltage and working gas pressure. The calculations are exhibited by using a precise collision cross sections and Townsend coefficients for the argon. The impacts of voltage and pressure on the Debye length, number of particles in Debye sphere and plasma frequency are calculated and graphically delineated. With this regard to the dependence of plasma parameters on the applied voltage and pressure, some of them are found to be compatible with the experimental

... Show More
View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Sun Jul 30 2023
Journal Name
Iraqi Journal Of Science
Integration of Sunflower and Sorghum Water Extracts Applied Alone or in Combination With Reduced Doses of Chevalier for Weed Control in Wheat
...Show More Authors

      Field trial was conducted with the aim of utilizing extract of allelopathic crop to reduce the use of synthetic herbicides in wheat fields. Sorghum extract at 12 L /ha, sunflower extract at 12 L /ha, combination of sorghum and sunflower extracts at 12 L /ha and chevalier at 25, 50 and 100% of recommended dose were applied alone or in combination with each other. Weed free and weedy check treatments were included for comparison. The experiment was conducted in a randomized complete block design with three replications. The results showed that the recommended  dose of chevalier  treatment recorded lowest means of weed density 15.7, 23.7, 25.3 and 27.9 weeds m-2and weeds dry weight 13.4, 16.4, 23.3 and 29.2 g m-2 and gave

... Show More
View Publication
Scopus (4)
Crossref (1)
Scopus Crossref
Publication Date
Tue Jun 30 2020
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
MUNICIPAL SOLID WASTE IN IRAQ BETWEEN THE HAMMER OF POPULATION GROWTH AND THE ANVIL OF THE ADMINISTRATION, FACTS, TREATMENTS AND VISION OF THE FUTURE: MUNICIPAL SOLID WASTE IN IRAQ BETWEEN THE HAMMER OF POPULATION GROWTH AND THE ANVIL OF THE ADMINISTRATION, FACTS, TREATMENTS AND VISION OF THE FUTURE
...Show More Authors

   Municipal solid waste is one of the most important environmental problems in the world and is an important source of environmental pollution and contributes significantly to the pollution of the basic environmental elements of soil, water and air. The management of municipal waste in general is a process of monitoring, collection, treatment or recycling if possible or disposal of waste. This term is used for waste produced by some human activities. States provide this process to mitigate the negative effects of waste on the environment, health and appearance of the city. It is possible to find solutions to the problem of solid waste and make it an important source of income and contribute to securing employment oppor

... Show More
View Publication Preview PDF
Publication Date
Tue Apr 18 2023
Journal Name
Al–bahith Al–a'alami
The uses of social networking applications and websites in promoting the gulf stock markets
...Show More Authors

The study aims to identify the uses and the impact of social networking applications and websites on stock markets and their role in defining the details of dealing with stock movement and trading. The study also aims to highlight the role of these networks by increasing confidence in stock markets and companies as well as encouraging and inciting young people to invest in these markets, the study belongs to the descriptive analytical approach, the study population consisted of all current and potential investors in the stock and financial markets in the United Arab Emirates. The study used a questionnaire that was distributed to a number of followers of social networking pages and websites that deal with trading

... Show More
View Publication Preview PDF
Crossref
Publication Date
Fri Jul 01 2016
Journal Name
Journal Of Economics And Administrative Sciences
biofuels industry and impact on the development of the agricultural sector in developing countries
...Show More Authors

Abstract

       Although the subject of biofuels industry is linked directly to the energy sector, but has links and numerous indirect effects, in particular effects on the environment and agriculture, this study (opportunities and challenges of biofuels industry and impact on the development of the agricultural sector in developing countries) a modest step to identify the industry in detail and identify the types of products and raw materials entering, then define or limit the positive and negative impacts of this industry in General and for specific products In particular, detailed, and then flip all those effects on the agricultural sector in developing countries can benef

... Show More
View Publication Preview PDF
Crossref