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.
Most cities in the world are suffering from the problem of solid waste and the resting adverse impact on the environment and public health, in particular the spread of diseases, insects and rodents, As well as the proliferation of nuisance odors result of provided by the responsible parties, As wall as weak environmental awareness among those who dwell in dealing in environmentally sound disposal of solid waste, this study was bembgesan first intake of solid waste and the kinds of concept and components by land use, As wall as the effects of solid waste on the environment spatial, factors affecting the quality and quantity of solid waste, the second topic was included as a study field presented the historical city of Baghdad
... Show MoreObjective:To measure the acceptance level of the Personal Digital Assistance (PDA)’suse among nursing students as a tool of education in the Kingdom of Saudi Arabia. Methodology: Eighty-nine nursing students participated in this cross-sectional descriptive study by completing a questionnaire based on the Technology Acceptance Model (TAM) by Davis. Two dimensions were explored and evaluated; (1) the applicability of the TAM model in assessing this technology; and (2) the overall percentage of students’ agreement on the different TAM variables. Results: This study presented significant positive influence bet
The Almighty Allah has addressed His followers by advising them to follow the example of the prophet (PBUH). Allah says: (INDEED IN THE MESSENGER OF ALLAH YOU HAVE A GOOD EXAMPLE TO FOLLOW). So, He was a true and everlasting example for the people to follow and imitate in all aspects of life. Knowledge and learning, especially Qura'nic knowledge, are among the priorities.
The present study is concerned with how to follow the Prophet example (PBUH) in the field of Qur'an reciting. It aims at showing His instructions on Qur'an reciting, and how He was followed by His Companions. The present study falls into an introduction and four sections. Section One deals with the commands given by Allah to follow His prophet. Second Two
... Show MoreAbstract Leishmania species are intracellular protozoan parasites that spend a portion of their life cycle in the midgut of sand flies and the remainder in the tissues of mammals. These parasites, which cause a class of human disorders known as leishmaniasis, live mostly in macrophages, where they multiply and survive by employing a variety of defense mechanisms against the oxidative stress and acidity generated by these immune cells. To help control their reaction to heat stress, they also produce heat shock proteins. Furthermore, the promastigote form has a glycocalyx that is necessary for colonizing the gut wall of the sand fly and completing its life cycle. Consequently, a variety of virulence factors contribute to the parasite's pathog
... Show MoreThe region is defined by the spatial dimension, which consists of a set of stabilizers (towns and villages). The concept of the territory requires conditions on the nature of functional relations and the mutual influence of the regions within the region. Any territory must be based on the interdependence and interaction between the mother city and its surrounding countryside and cities, and when the interdependence is strong and the interaction is clear, it helps to define the territory. The regions are divided on different bases. There are geographically or national homogeneous regions, and there are cultural regions that want to preserve their culture in terms of language or religion. There are administrative regions to manage
... Show MoreContext has occupied a distinguished place as far as the understanding of the texts and deducting the rules from them or analyzing them. The context was considered as one of the important presumptions as far arriving at the desired meanings is concerned. The word is worthless and the meaning is not known unless we know the context in which it came. The context in its two types the lingual and non-lingual types. It is the best for knowing the intended meaning of the Quranic verses to know the real meaning.
It is estimated that over the next few decades, EOR will be used for the more than 50% of oil production in the US and worldwide. From these, in reservoir with viscositites ranging between 10 – 150 mPa.s, polymer flooding is suggsted as the EOR method. Therefore, there is an upper limit to the recommended range of reservoir oil viscosities for polymer flooding. To address the issue of this limitation of polymer injectivity and pumping efficiency, we propose a novel method. The method involves the use of Supramolecular Systems, which are composed of long-chain aminoacids and maleic acids post complexation. Their unique feature of resersible viscosities allows the operator to overcome
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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