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.
The interpretation is one of the means used to by the designer to construct his perceptions of the world in which he lives, either to better understand or rediscover or reproduce the new thing and the creative thing which is characterized by novelty and originality. The design innovations in the political posters, achieved by the designer, result from his perceptions for the response towards a certain subject through what he has of practical experience to interpret his ideas and his desire to achieve harmony with the reality and compatibility with his aims in visible visual effects that will be established in the recipient's memory and stimulate his senses in the realization of the content of the media message. The political poster has a
... Show MoreLeishmaniasis is a widespread parasitic disease caused by Leishmania parasite, this disease considers a major health problem among worldwide. Treatments available are expensive or with cytotoxic side effect. This study was aimed to investigate the effect of an herbal new compound, called artemisinin, derived from a Chinese plant called Artemisia annua. Various concentrations were studied in vitro against L. tropica amastigotes by chamber counting to investigate its effect on the proliferation of promastigotes. Three incubation periods were adopted (24, 48, 72) hours. The results showed a significant decrease in surviving promastigotes, in parallel with the normal parasite count of untreated promastigotes, along the periods studied. Th
... Show MoreBackground: Determination of sex and estimation of stature from the skeleton is vital to medicolegal investigations. Skull is composed of hard tissue and is the best preserved part of skeleton after death, hence, in many cases it is the only available part for forensic examination. Lateral cephalogram is ideal for the skull examination as it gives details of various anatomical points in a single radiograph. This study was undertaken to evaluate the accuracy of digital cephalometric system as quick, easy and reproducible supplement tool in sex determination in Iraqi samples in different age range using certain linear and angular craniofacial measurements in predicting sex. Materials and Method The sample consisted of 113of true lateral cepha
... Show MoreSilymarin is derived from the milk thistle plant, and possesses numerous pharmacological actions, including hepatoprotective, anti-inflammatory, antioxidant, and anticancer properties. The aim of the study was to the determination of influence different concentrations of Silymarin on the rumen performance in 30 local lambs (divided into three groups of 10 lambs each). In the first and second groups, 420 and 210 mg kg-1 of silymarin were administered for 8 weeks, and the third group was the control, which received normal saline solution. The parameters evaluated included the level of volatile fatty acids (VFAs), ammonia and pH in the rumen. Furthermore, the in vitro digestibility of ash, protein, fat and dry matter was investigated.
... Show MoreBackground: There are various secreted proteins affecting the prognosis of oral squamous cell carcinoma (OSCC) and one of them is Angiopoietin-2(Ang-2) which is thought to have an essential role in the development and progression of the tumor. Aim of the study: This study was conducted to determine the expression of (Ang-2) in (OSCC) to assess its correlations with clinicopathological parameters of the tumor. Material and Methods: 36 formalin- fixed, paraffin- embedded tissue blocks histologically diagnosed as OSCC were examined for Ang-2 immunohistochemical expression semi quantitively. Results: The expression of Ang-2 was significantly associated with histopathological grade (P value=0.023), while there is no significant association wi
... Show MoreAcquires this research importance of addressing the subject (environmental problems) with
age group task, a category that children pre-school, and also reflected the importance of
research, because the (environmental problems) constitute a major threat to the continuation
of human life, particularly the children, so the environment is Bmchkladtha within
kindergarten programs represent the basis of a hub of learning where the axis, where the
kindergarten took into account included in the programs in order to help the development of
environmental awareness among children and get them used to the sound practices and
behaviors since childhood .
The research also detected problem-solving skills creative with kids Riyad
Objective: This study aims to analyze the role of the People's Republic of China in the 1955 Bandung Conference and assess its contributions to international cooperation and peace. It specifically examines how China's participation aligns with the United Nations Sustainable Development Goals (SDGs), particularly Goal 16. Theoretical Framework: The research is grounded in a structuralist approach to international relations, focusing on the agency of developing nations in shaping a post-colonial global order. It considers concepts such as peaceful coexistence, national sovereignty, and South-South cooperation. Method: A historical-analytical method is employed, tracing China’s diplomatic trajectory from the 1954 Colombo and Bo
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