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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
Sat Jan 01 2022
Journal Name
Journal Of Engineering
Developing Crisis Management System for Construction Projects in Iraq
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Construction is a complicated process that takes place in an almost uncontrollable environment. Although projects can be carefully planned in advance in principle, there is a chance that unforeseen events and crises can disrupt these plans, affecting project development. Because the initial investment expenditures in construction projects are so large, they may be quickly influenced by crises, resulting in significant financial losses. The 2014 financial crisis was one of the most prominent crises that Iraq faced, which significantly impacted various activities in general and the construction industry in particular. Despite the importance of crisis management systems, the researchers found a great lack of local studies l

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Publication Date
Wed Jul 31 2024
Journal Name
International Journal Of Health & Medical Research
Review Article: Cupping Therapy in Treatment of Certain Diseases
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The research undertaken has provided a comprehensive insight into the practice of cupping therapy, a traditional treatment modality that has seen resurgence in. modern complementary medicine. This exploration, focusing on a spectrum of. Conditions such as migraines, lower back pain, neck pain, knee osteoarthritis, and chronic urticaria, highlights the potential benefits and the necessity for a deeper. Scientific understanding of cupping therapy. Cupping therapy, with its roots deeply embedded in ancient medical practices, offers a unique approach to treatment by promoting healing through increased blood flow and the release of toxins from the body. The application of this therapy in treating migraines has shown promising results, su

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Publication Date
Sat May 16 2009
Journal Name
Journal Of Planner And Development
Planning Schemes for Human Settlements in the Desert Areas
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Despite the vast areas occupied by deserts in the world, it is still far from the civilized development and development of the other regions, so they became semi-neglected areas that extend to the hand of urbanization only in specific places and for special purposes, due to the harsh natural conditions surrounding it and to the accuracy The ecological balance in it became the greatest enemy of human beings in the desert areas is the same person who paved the way for increased intervention in the exploitation of natural resources and increase the demand for them to drain seriously affect the impact and still on the environmental and climatic conditions and thus living for the inhabitants of these Areas. The main potential for deve

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Publication Date
Fri Feb 08 2019
Journal Name
Iraqi Journal Of Laser
Refractive Index Scaling in Hollow Core Photonic Crystal Fiber
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In this paper, simulation study of the frequency shift of photonic bandgaps due to refractive index scaling using liquids filled hollow-core photonic crystal fibers is presented. Different liquids (distilled water, n-hexane, methanol, ethanol and acetone) are used to fill the cladding of 2 types of hollow core photonic crystal fibers (HC19-1060, HC7-1060). These liquids are used to change the effective index scaling and index contrast of the cladding. The effect of increasing temperature of the liquid (20-100 0C for water and 20-70 0C for other liquids ) infiltrated hollow core fiber on the bandgap width and transmission properties has been computed. The maximum photonic bandgap width at 0.0243 has appeared with filling HC7-1060 PCF with

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Publication Date
Mon Jul 01 2019
Journal Name
Iop Conference Series: Materials Science And Engineering
Approximations of Minimum Approach Distance in Electron Mirroring Phenomena
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Abstract<p>The minimum approaches distance of probing electrons in scanning electron microscope has investigated in accordance to mirror effect phenomenon. The analytical expression for such distance is decomposed using the binomial expansion. With aid of resulted expansion, the distribution of trapped electrons within the sample surface has explored. Results have shown that trapped electron distributes with various forms rather an individual one. The domination of any shape is mainly depend on the minimum approaches distance of probing electrons</p>
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Publication Date
Wed May 17 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
On Pairwise Semi-p-separation Axioms in Bitopological Spaces
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In this paper, we define a new type of pairwise separation axioms called pairwise semi-p- separation axioms in bitopological spaces, also we study some properties of these spaces and relationships of each one with the ordinary separation axioms in the bitopological spaces.

 

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Publication Date
Sun Apr 30 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
etermination of Some Phenols in Tigris River by HPLC
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   This study describes the determination of some phenols in four different zones of Tigris river in Iraq including, AL-Krieat, AL-Kadhimiya, AL-Jadiriyah, and AL-Adhamiyah. The  phenolic compounds analyzed were (2,3-dimethylphenol, 4-chlorophenol, 3-nitrophenol and 2,4-dinitrophenol) using reverse phase high performance liquid chromatography (RPHPLC) with a UV detector on ODS-C18 column(150×4.6 mm I.D) and a mobile phase consisted of methanol-water(30:70)%(v/v) at pH 5.0, and a column temperature at 30C° with 20 µL injection. UV detection helps to identify different phenols at wave length at 280 nm  with a flow rate at 0.5 ml/min. The separation time was (< 6) min.The results indicated that the AL-Adhami

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Publication Date
Wed May 29 2019
Journal Name
Journal Of Planner And Development
Elements of Public Transportation Systems Operating in City Center
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The traffic congestion caused by the increase in the number of vehicles in the cities as a result of the increase in the population and the density of construction requires the provision of appropriate infrastructure and the provision of transport systems and logistics services that meet the needs of the population to meet the many challenges now and in the future by introducing various modes of transport , In accordance with integrated plans such as the use of (pedestrian friendly environments, bicycles and their own paths, light rail, metro, express bus, as well as public transport buses and others), through the development of Projects High-level roads, such as the annual and major roads, etc., and integrated with the urban planning of

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Publication Date
Mon Aug 28 2023
Journal Name
Journal Of Planner And Development
Using GIS to identify hazardous earthquake locations in Iran
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The objective of all planning research is to plan for human comfort and safety, and one of the most significant natural dangers to which humans are exposed is earthquake risk; therefore, earthquake risks must be anticipated, and with the advancement of global technology, it is possible to obtain information on earthquake hazards. GIS has been utilized extensively in the field of environmental assessment research due to its high potential, and GIS is a crucial application in seismic risk assessment. This paper examines the methodologies used in recent GIS-based seismic risk studies, their primary environmental impacts on urban areas, and the complexity of the relationship between the applied methodological approaches and the resulting env

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Publication Date
Sun Jun 01 2025
Journal Name
Archives Of Medical Research
Galectins: A New Frontier in Gastroesophageal Reflux Disease Research
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