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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
Thu Jul 01 1999
Journal Name
Bulletin Of The Iraq Natural History Museum (p-issn: 1017-8678 , E-issn: 2311-9799)
New Records And Some Notes On The Broad Bean Root Aphids and Their Natural Enemies in Hammam Al-Alil
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In May 20th. 1985 two species of aphids were found on the roots of Vicia faba L. in Hammam region 30 Kilometer south of Mosul. Samples of these aphids were sent to the Commonwealth Institute of Entomology, London. ( No. 17002/9804 Asia ) and identified as being Smynthurodes betas westwood and Dysaphis crataegi (Kaltenbach) (APhididae : Homoptera). The first species was dominant. The latter species was also noticed on the roots of the common bishop's weed (Ammi majus L.) and on the wide carrot (Daucus carrota L.) of the family Umbelliferae (Bodenheimer & Swirski, 1957).

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Publication Date
Fri Nov 01 2019
Journal Name
Journal Of Engineering
Prediction of Heat Transfer Coefficient and Pressure Drop in Wire Heat Exchanger Working with R-134a and R-600a
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An experimental and theoretical works were carried out to model the wire condenser in the domestic refrigerator by calculating the heat transfer coefficient and pressure drop and finding the optimum performance. The two methods were used for calculation, zone method, and an integral method. The work was conducted by using two wire condensers with equal length but different in tube diameters, two refrigerants, R-134a and R-600a, and two different compressors matching the refrigerant type. In the experimental work, the optimum charge was found for the refrigerator according to ASHRAE recommendation. Then, the tests were done at 32˚C ambient temperature in a closed room with dimension (2m*2m*3m). The results showed that th

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Publication Date
Fri Jul 07 2023
Journal Name
Journal Of Obstetrics, Gynecology And Cancer Research
Evaluation of Maternal and Fetal Complications in Pregnant Women with Polycystic Ovary Syndrome (PCOS) with Severe and Mild Phenotype
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An essential issue in obstetrics is the prevalence of maternal and fetal complications in pregnant women with polycystic ovary syndrome (PCOS). The purpose of the present study was to investigate the prevalence of pregnancy complications among various phenotypes of pregnant women with PCOS.

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Publication Date
Sun Jan 08 2023
Journal Name
Journal Of Planner And Development
Statistical Evaluation of the Planning Process and Scheduling Management for Irrigation and Drainage Projects in the Republic of Iraq
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The Research aims to investigate into reality in terms of planning and scheduling management process for sake the implementation and maintenance of irrigation and drainage projects in the Republic of Iraq, with an indication of the most important obstacles that impede the planning and scheduling management process for these projects and ways of addressing them and minimizing their effects.                                                  For the purpose of achieving the goal of the research, a sci

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Publication Date
Tue Aug 01 2023
Journal Name
Iop Conference Series: Earth And Environmental Science
Diagnosis the Pseudoperonospora cubensis Causes Downy Mildew in Cucumbers and its Resistance to Potassium Silicate and Extract Eggplant Wild
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Abstract<p>A field experiment was carried out to test the efficiency of potassium silicate and wild eggplant <italic>Solanum eleaegnifolium</italic> normal and nano for the management of downy mildew disease on cucumber caused by <italic>Pseudoperonospora cubensis</italic> under greenhouse conditions by reducing the incidence and severity of the disease and its reflection on the efficiency of the control and the area under the disease progress curve AUDPC compared to the fungicide Energy Previcur (Hcl - Propamocarb and Fosetyl-aluminum). The results of phenotypic and molecular diagnosis using polymerase chain reaction (PCR) technology for the two tested isolates showed that t</p> ... Show More
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Publication Date
Fri Dec 01 2017
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The relationship between the external environment analysis and banking facilities: An Applied Research in the Rafidain and Rasheed Bank
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Is the subject of environmental analysis of the important issues that should occupy the attention of the departments of banks in general and banks in particular, the research sample, regardless of their size and the nature of its activity, So if the current era and witnessing rapid developments and changes, making the banking environment is more complex and interconnected than ever, And it became not possible for banks to be aware and understand the external environment variables without an analysis of the various constituent elements and influential heavily in its financial and administrative,Therefore research aims to find out the relationship between the external environment and banking facilities analysis application on the Rafidain

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Publication Date
Sun Feb 03 2019
Journal Name
Journal Of The College Of Education For Women
The evolution of demographic variables and their relationship to the demographic opportunity in Iraq and the possibility of investing
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The variables of quantitative and qualitative Population role in the economic development process and it was said the human center of development and population is the goal of development and its tool , and Iraq suffers from problems in the economic growth and the standard of living and development in general, and if I want him evolution and development sectors must pay for these demographic changes especially , to study and that invest Pmaasb in the interest of the man
The study of the demographic situation in Iraq and at the provincial level to track paths demographic change and its impact on the entry of Iraq to the demographic window due to the change in the age structure of the population and how to use them and invested well in

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Publication Date
Thu Dec 01 2022
Journal Name
Baghdad Science Journal
Investigation of the association of AGTR1 A1166C rs5186 and FTO rs9939609 polymorphisms with the obesity in children and adolescents
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Obesity is a risk factor for a number of chronic conditions. Obesity is clinically defined using the body mass index (BMI) as weight in kg divided by (height)2 in m2 correlated with obesity. Currently, genetic markers of obesity are being studied. This study focused on the association between the angiotensin II receptor AGTR1 gene (A1166C) and fat mass and obesity-associated protein also known as alpha-ketoglutarate-dependent dioxygenase (FTO) (rs9939609) in obese children and adolescents patients in Rostov region, Russia.  Five-hundreds of Russian nationality child and adolescent were recruited for the obesity-control studies. The relationship between the A1166C polymorphism of the AGTR1 gene in

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Publication Date
Wed Mar 10 2021
Journal Name
Baghdad Science Journal
EFFECT OF SALINE WATER AND POTASH FERTILIZER ON PROLINE CONTENT AND WATER POTENTAL IN PISUM SATIVUM L. (VAR.SENADOR CAMBADOS)
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Filed experiment was conducted to test the effect of saline water and potassium fertilizers rate on proline and water potential of Pisum sativum L. (Var.Senador Cambados ) leaves . Treatments of the experiment included two levels of water salinity( 2, 7 dSm-1) as a main plot and fertilizer rates as a sub plot. Results indicated that irrigation of plant with saline water 7 dSm-1 and fertilization 150 kg/donum increased proline accumulation and water potential 0.31 mmol/g,-17.00 bar at 9 AM morning and 0.62 mmol/g , -21.00 bar at 3 PM afternoon ,Irrigating plant with a 2 dSm-1 and fertilization 300 kg/donum decreased proline accumulation and water potential of leaves 0.22 mmol/g, -16.00 bar at 9 A

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Publication Date
Sun Dec 01 2013
Journal Name
Journal Of Economics And Administrative Sciences
The relationship between human investment and economic growth in Iraq(1985-2010) and measuring return of investment of human
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Abstract:

Investment in human capital of renewable energy can be relied upon to get to achieve the goals of development is important for Iraq through the intellectual community cards creative able to innovate and develop what is so is study the effect of human investment on economic growth through the adoption of the index of national income as a function of variables independent ( human capital, physical capital) and this is built on the premise that the relationship direct correlation between economic growth and human investment, and it can measure the return on human investment, which is an incentive to increase human capital through education and the development of the economy in general have shown th

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