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.
Review of multidrug sensitivity and resistance in enterococcus
All domains in this world built based on set of theories. Those theories have been responsible for interpretation of some phenomena and interlocking relationships around us. Commonly, theories are categorized by which aspect is believed. Also,can find a group of theories produced regardingto the leadership domain. This paper will be presented some of these theories like (Great Man Theory, Trait Theory, Behavioral Theories, Contingency Theories, Situational Theory, Transactional Theories, and Transformational Theories). where these theories considered the most popular and common in the field of leader and will be discussed by this work
We presented here a 25years old lady with a multiple hatdtid cysts in lung and liver and spleen in large number in each organ. Which regarded inoperable and difficult to treared.We use medical treatment with antihelimenthes drugs in new regime and follow-up over 1year clinically, laboratory investigations, U/s and CT.scan. There was good disappearance of liver and spleen cysts with very good response in lungs.
Background: Pregnancy is considered a major risk factor for development and progression of periodontal disease. There are hormonal changes in both estrogen and progesterone hormones in addition to bacterial effect and poor oral hygiene that will enhance development of periodontal disease in pregnant women. Materials and methods: Seventy subjects were enrolled in the study, the subjects with an age range (20-35) years old without any history of systemic disease. The subjects were divided into 20 non-pregnant women they represent the control group (G I), 30 pregnant women with gingivitis (GII) and 20 pregnant women with periodontitis (GIII).All periodontal parameters (plaque index, gingival index, bleeding on probing, probing pocket depth an
... Show MoreDiscourse markers are expressions used to connect sentences to what comes before or after and indicate a speaker's attitude to what he is saying.As linguistic items, they have important functions in discourses of various styles or registers. And being connective elements, discourse markers relate sentences, clauses and paragraphs to each other. "One of the most prominent function of discourse markers, however, is to signal the kinds of relations a speaker perceives between different parts of the discourse". (Lenk 1997: 2) Through political discourse, different types of discourse markers are used. This paper deals with the importance and functions of discourse markers and tries to shed light on the kinds of discourse markers used in polit
... Show MoreThrough the study of social work and social policy ( problems of marginalization and empowerment opportunities ) and taken a theoretically descriptive and analytical and highliyhed the role of social work in social policy its achieved only through community intraction and paamong all parties and according to social policies include of material resources and haman and integrated in to the planning and development framework with the aim of providing social services for allsegments of society and become the study in social work that include the introducation / and five chapters each chapter in cludes several detectives and each complements the other .
1 – The absence of social development projects on social policy .
2 – social pol
This study deals with the thems of "in-betweeness" in the modern Afro-American Drama, drawing upon the accumulated literature of the colonial and postcolonial studies. In-betweeness appears in these studies under the canopy of the terms mimicry, hybridity and liminality which refer to a transformative, in-between state of being. It also refers to themutual relations holdingbetween man and his cultural space.
This concept is fitting the Afro-American playwright Amiri Baraka's plays and his violent, revolutionary theatre. In his play Dutchman (1964), Clay, the protagonist, is a good example of the two-ness or in-betweeness. He finds difficulty choosing between the ethnocentric white culture and the black culture.He allows
... Show MoreThe most honorable of science was what was related to the book of God, the Almighty, the Constitution of this nation and the way of its guidance and method of advancement there is no life except for him and safety only by its application and it is no secret to the competent studies of the importance of the subjective studies in the Koranic studies to address issues of great importance enlighten the path of the nation and revive From here comes the importance of the topic covered by the research, which is "Intent in the Holy Quran meanings and semantics", and this topic features features that made it worthy of writing, including the importance of clarifying theories of Qur'anic character of a systematic nature, such as the theory of inten
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