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Multi-Channel Distributed DSA Networks: Connectivity and Rendezvous Tradeoffs
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In this paper, we investigate and characterize the effects of multi-channel and rendezvous protocols on the connectivity of dynamic spectrum access networks using percolation theory. 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-channel, 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 protocols, 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 represent the multiple channels as parallel edges in a graph and build a multi-layered graph (MLG) in R2. In order to study the connectivity, we show how percolation occurs in the MLG by coupling it with a typical discrete percolation. Using a Boolean model and the MLG, we study both cases of primaries' absence and presence. For both cases, we define and characterize connectivity of the secondary network in terms of the available number of channels, deployment densities, number of simultaneous transmissions per node, and communication range. When primary users are absent, we derive the critical number of channels which maintains supercriticality 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. For each region we show the requirement and the outcome of using either type of rendezvous techniques. Moreover, we find the tradeoff between deployment-density versus rendezvous probability which results in a connected network. Our results can be used to decide on the goodness of any channel rendezvous algorithm by computing the expected resultant connectivity. They also provide a guideline for achieving connectivity using minimal resources.

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The city is often discussed in barren, eviscerated terms and in technical jargon by urban professionals as if it were a lifeless, detached being. In fact, it is a sensory, emotional, lived experience. How often do strategic urban plans start with the words ‘beauty’, ‘love’, ‘happiness’ or ‘excitement’, as opposed to ‘bypass’, ‘spatial outcome’ or ‘planning framework, So the research problem was formed by the weakness of the sensory perception of cities and the weakness of the sense of different spaces, which in turn leads to weakness of belonging, identity and clarity, Therefor we focus here on the sensory perception. The hypothesis Recognize Senses as helpful tool in increasing people's understanding of differe

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Wed May 24 2023
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Rwandan branches and objectives
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This is a search for Al-Rwandiyah and its heretical deviant sects, and its destructive goals that targeted the Arab nation, and its true Islamic religion in order to exhale poisons of demolition and sabotage, leading to its racist, populist goals ( ) that the Magi aspire to to restore the so-called ancient Persian glories, and undermine the Abbasid caliphate.
Al-Biruni said: (And that a person will emerge who will restore the Magian state and seize all the land, and remove the king of the Arabs) (), and among the indications of Ibn Al-Nadim is that a populist man called Muhammad bin Al-Hussein who was turned into Zaidan () was (claiming... the transition of the Islamic state to a state Persia ..... and their religion, which is the rel

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Mon Feb 23 2026
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Television and Agenda Building
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Most media studies on the development of the agenda have focused on the relationship between the content of the media and the audience of these media, and the extent of its impact on the agenda of the media, in addition to comparing it to the extent of interest in the agenda of those means. While in the construction of the agenda, we focus on the relationship between news sources and the media and the role of these sources in the process Building the agenda.These sources are institutions, parties, pressure groups, interest groups, the head of state and other media. The impact of these sources on the process of building the agenda are shown through the process of the selection of resources by the channel and communicators, and the technic

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Tue Jun 01 2010
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Racism and blacks struggle
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    Traditionally, women playwrights in general, and black women playwrights in particular have been excluded from the American theater       because of racial and gender oppression. However, early twentieth-century African-American women playwrights, such as Angelina Weld Grimke (1880-1958), Alice Dunbar-Nelson (1875-1935), Marry Burrill (1879-1946), and Myrtle Smith Livingston (1901-1973), whose works have been overshadowed for decades, were able to express their awareness of the racial discrimination facing African-Americans. They also paved the way for the next generation of black women playwrights, such as Alice Childress (1920-1994), Lorraine Hansberry (1930-1965) and many others.

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Publication Date
Fri Feb 08 2019
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The problem of informal settlements in Iraqi is one of the most serious problems due
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those areas. Requirements of each decision are also discussed.
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needed. The study revealed important findings that would help take appropriate measures that
deal with the informal settlements in Iraqi. The study also proposes effective mechanisms to
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Mon Sep 30 2019
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In recent times, many of those who practice the professions of Koranic treatment away from the legal controls, which dragged Muslims a lot of sedition and inflicted many in heresies and irregularities, and even spoiled the doctrines of many people making them relate to the causes and forget the Lord of the causes.
    For this reason it was incumbent upon the scholars to show the right from falsehood in this section, and because of the importance of the subject of jetting in Ruqyah and others, and how it is related, I chose the subject (jets and its jurisprudence), for all this I called on God to help me to show the right from wrong with regard to jetting And its provisions.

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Publication Date
Fri Jun 29 2018
Journal Name
Journal Of The College Of Education For Women
Spinsterhood Reasons and treatments
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The research includes an introduction on Unmarried as one of the most dangerous phenomena's in Arab society in general and Iraqi society in specific especially after last decades wars that ruined the country and enlarged the number of unmarried women. First chapter dealt with the research problem that was increasing day after another while the percentage of unmarried women became 85% due to embargo and wars made by ex-regime that led to kill many Iraqis and decreasing marriage chances.

The research aims to recognize the reasons behind that and tries to find solutions by using quest ways and tools to get rid of old habits that represent obstacle marriage. The research dealt with unmarried in Arab countries where National Instituti

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