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.
Keys to four genera and twelve species of the subfamily Phlaeothripinae (Phlaeothripidae) were constructed, these are: Haplothrips; Karnyothrips; Phlaeothrips; and Dolicholepta ,and the species are: Haplothrips cerealis Priesner; Haplothrips tritici kurdjumov, Haplothrips hukkineni Priesner; Haplothrips subtilissimus (Haliday) ؛ Haplothrips reuteri Karny; Haplothrips jasonis Priesner; Haplothrips sallloumensis Priesner ; Haplothrips pharao Priesner ; Phlaeothrips sycomri Priesner ; Karnyothrips flavipus (Jones); Karnyothrips melaleucus (Bagnall) ; Dolicholepta micrurus (Bagnall). These were collected from Baghdad
... Show MoreThe Leishmania donovani parasite causes visceral leishmaniasis (VL), an acute and fatal form of leishmaniasis. Because traditional therapy alternatives, such as glucantime and other pentavalent medicines, are toxic and have side effects, new treatments with fewer negative effects are needed. Only a handful of drugs are clinically beneficial to treatments of the disease, but considerable limitations threaten their very usage. Novel, safe, and efficient drugs, including those against antimalaria and leishmaniasis co-infections, are so essential. Artemether (ATM) is an Artemisinin derivative that has been demonstrated to be useful in the treatment of malaria and, more recently, leishmaniasis. The current research was carried out to evaluate th
... Show Moreتحقق القراءةُ التَّناصيَّة قيمة موضوعيَّة للدرسِ النَّقديّ المعاصر؛ بمؤثراتها الثَّقافيَّة، والمعرفيَّة، لأنَّ الإبداعَ من سمات التُّراث الشِّعري في العصر الوسيط، وهو مسرحٌ لتداخلات نصِّيَّة مع مصادر متعددة دينيَّة، وأدبيَّة، وتاريخيَّة أداء ومضامين؛ يأتي اختيارُ (التَّناص مع الحديث النَّبوي في شعر صفيّ الدِّين الحلّي)؛ بوصفه امتدادًا شعريَّا أصيلًا لحضارة راقية معطاء
... Show MoreBackground: Ultrasound is a valuable tool for evaluating fetal problems throughout pregnancy. Amniotic fluid anomalies have been associated with unfavorable maternal, fetal, and obstetrical outcomes. Objective: To determine the effect of echogenic amniotic fluid during term pregnancy on the presence of meconium stain liquor and pregnancy outcome. Methods: A cross-sectional study was conducted on 1080 term pregnant women who visited Al-Elwiya Maternity Teaching Hospital from May 1st, 2021, to May 1st, 2023. Ultrasound was used to analyze echogenic amniotic fluid and turbid liquor. The liquor state was tested either after an artificial membrane rupture in the vaginal delivery trial or during a cesarean section. Results: Echogenic amni
... Show MoreThe Cassia glauca Lam. is the tree that belongs to the Fabaceae family and is native to India has many uses in indigenous systems of medicine, folk medicine, and traditional Brazilian medicine. Has many pharmacological activities such as anti-diabetic, antibacterial, antifungal, antioxidant, anti-hemolytic, anticancer, cardio-protective, and Hepato-protection. The aim of study is to Isolation, identification, and quantification of some compounds from aerial parts of Cassia glauca since no phytochemical investigation had previously been done in Iraq for this plant. The aerial parts were defatted in n. hexane for 48 hours. The defatted materials were extracted in 85% ethanol using the hot method (soxhlet), then the extract was fra
... Show MoreHeart sound is an electric signal affected by some factors during the signal's recording process, which adds unwanted information to the signal. Recently, many studies have been interested in noise removal and signal recovery problems. The first step in signal processing is noise removal; many filters are used and proposed for treating this problem. Here, the Hankel matrix is implemented from a given signal and tries to clean the signal by overcoming unwanted information from the Hankel matrix. The first step is detecting unwanted information by defining a binary operator. This operator is defined under some threshold. The unwanted information replaces by zero, and the wanted information keeping in the estimated matrix. The resulting matrix
... Show MoreIn data mining, classification is a form of data analysis that can be used to extract models describing important data classes. Two of the well known algorithms used in data mining classification are Backpropagation Neural Network (BNN) and Naïve Bayesian (NB). This paper investigates the performance of these two classification methods using the Car Evaluation dataset. Two models were built for both algorithms and the results were compared. Our experimental results indicated that the BNN classifier yield higher accuracy as compared to the NB classifier but it is less efficient because it is time-consuming and difficult to analyze due to its black-box implementation.
In the present work the clathrate hydrate dissociation enthalpies of refrigerant R134a+ water system, and R134a + water + salt system were determined. The heat of dissociation of three types of aqueous salts solutions of NaCl, KBr and NaF at three concentrations (0.09, 0.17and 0.26) mol·kg−1 for each salt type, were enthalpy measured. The Clapeyron equation was used tocalculate heat of dissociation of experimental data for binary and ternary system.In order to find the effect of compressibility factor on heat dissociation enthalpy, the study was conducted by using equation of state proposed by Peng and Robinson Stryjek-Vera (PRSV). The obtained results of dissociation enthalpy for binary system were (143.8) kJ.mol-1
... Show MoreThe study aims at identifying the sources of information and explaining their role in e-learning from the viewpoint of the Iraqi college students. The researchers relied on the descriptive method of the survey method to collect data and know the point of view of undergraduate students from the Department of Information in the College of Arts / Tikrit University and the Department of Quranic Studies at the College of Arts / University of Baghdad. The questionnaire was used as an instrument of the study, the research sample is (120) students; each section has (60) male and female students. The study concluded that there are many types and forms of information sources that students receive through electronic educational platforms from text con
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