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.
1.Chapter I (systematic framework) which includes: the research problem and the importance of the research, the need for it, the goals of the research, the temporal &spatial boundaries, determine the terms and defined procedurally.2.Chapter II - the theoretical framework: It consists of three sections are:•The first topic:- the concept of references and experimentation in the theater. •The second topic:- the director of academic and experimentation in Iraq. Two paragraphs in this section came after the introduction, in first paragraph to talk about the Iraqi theater academic and experimentation, and in the second paragraph the researcher spoke about the academic director of the Iraqi and experimentation. 3.Chapter III - Actions -
... Show More• Commercial papers are one of the most important tools of the contemporary monetary market, and many of those who deal with them are ignorant of the Shariah rulings related to them, hence the urgent need to know the most prominent Sharia rulings related to commercial papers, including the discount. It is an agreement between the bank and its customer requesting the discount (the holder of the commercial paper) under which the bank is required By accelerating the value of the paper to the customer, in exchange for the latter’s obligation to transfer the ownership of the fixed right in the paper to the bank by endorsing it to him as a transfer of ownership.
• The noble Islamic Sharia does not prohibit dealing in commercial papers
In recent decades, breeding deer populations in Iraq have expanded significantly in size and distribution. Owing to their role in pathogen transmission, these deer populations pose a risk to the livestock industry. However, little is known about the parasitic infection status of the breeding deer and the surrounding environment in Iraq. Atotal of 150 deer faecal samples were collected from male and female deer of various ages from four regions of Iraq and examined microscopically for intestinal parasites. Microscopic analysis revealed the presence of seven intestinal parasite species: Entamoeba spp. (48%), Giardia duodenalis (17%), Toxocara spp. (12%), Balantidium coli(9%), Taenia spp. (9%), Strongyloides spp. (3%) and Trichostrongy
... Show MoreThe Mythical Reference in the Poetry of Nabil Yassin
A simple, accurate and rapid method for separation and determination of most commonly usedinsecticides in Iraq [thiamethoxam (Thi), imidacloprid (Imi), indoxacarb (Ind), and abamectin (Aba)] ispresented. The separation was performed by gradient reversed-phase high performance liquidchromatography on a C18 stationary phase column. The method was developed and validated. The-1mobile phase was a mixture of acetonitrile and water using gradient flow. The flow rate was 1.0 mL min .The optimum temperature of separation was 25 ºC. The detection was performed at multiple wavelengths.The analysis time was up to 10.5 minutes with retention times of 3.221, 3.854, 6.385, and 9.452 min for-1the studied insecticides. The linearity was in the range of 0.
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