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.
Hedging is a linguistic phenomenon used to convey interpersonal messages in spoken interaction. It is a communicative strategy which enables speakers to soften the force of utterances or moderate the assertive force of utterances. It is resulted from different features such as uncertainty, doubt, tentativeness, ambiguity, neutrality, mitigation, and subjectivity. Hedging is used widely in TV debates to make utterances more acceptable to the interlocutors. Hedges are expressions used to communicate the speaker's weak commitment to information conveyed. The utterances in debates are often hedged because in an unhedged form might sound threatening to the addressees, and, therefore, be likely to be rejected.
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... Show MoreAbstract Rationality and freedom are fundamental elements of Western modernity. Although modern and contemporary Islamic thought has established its intellectual foundations on the fundamentals of intellectual thought that are at the core of its Islamic intellectual system, at the same time many of its intellectual products have been a response In spite of the fact that this Islamic intellectual response stands out from Western modernity as a negation or a positive attitude. The Islamic intellectual response differed in determining its position on Western modernity, depending on the nature of the historical stage that was The Islamic nation, as well as the nature of the challenge posed by Western civilization to other nations and other c
... Show MoreMelatonin, a hormone synthesized mainly by the pineal gland, has been found in extra-pineal organs as well. It’s known as an organizer of circadian rhythms and more recently as an anti-oxidant. In addition to its role in maintaining immunity, pathophysiology of cardiovascular and neurological diseases, and as an anti-cancer agent, evidence has demonstrated that melatonin exerts a positive impact on male and female fertility primarily through oxygen scavenging effects. In In Vitro Fertilization (IVF) programs, supplementation of melatonin may be associated with better outcomes in terms of sperm quality, oocyte quality, embryo quality and pregnancy rates. This review summarizes various actions of melatonin on the body focusing on ma
... Show MoreThe research aims to focus on the human rights guarantees as they are subjected to continuous violations due to changes, wars and conflicts between nations and people, especially in the Arab world and the third world due to political, social, economic and environmental conditions and the failure of democratic tracks under the current reality.
Keyword: Human rights, Reality, Ambition.
There is a natural problem raised by the issue of media performance. As a separate activity and express its own capabilities. This problem can be framed in the form of a question: Is media performance merely a reflection of the activity of other sectors of society, especially political and economic, and what links them to other societal sectors of interrelated relations? Is the media limited to mere transfer, or is it an industry with its own mechanisms and rules? The answer may seem somewhat complicated if we handle media with research and study in general, but the issue may be less complicated when it comes to Arab media, because its data may add another setback to the overall Arab setbacks.
Despite the history of Baghdad city extends into a long history, most of the contemporary buildings of Baghdad have been shaped in the era of modernity. Furthermore, most of the buildings of modernity in Baghdad are types of modernity buildings in Iraq as a whole, and due to all the joints of change and development are taking place in Iraq starts from Baghdad. Accordingly, all selected buildings, which would be presented as case studies of modernity will be exclusively in Baghdad. Although the importance of this significant modernist product, which represents the identity of Baghdad, which should be preserved by the renewal and preservation policies, the problem of research was emerged as follow: new fin
... Show MoreThe person who wants to learn. The history of Bab’is will notice a very
starnge phenomenon that they (Babis and Baha’is) resort to visions to prove their
delusion.
The believers usually reach to each other by their visions. This phenomenon
are shared among them from Al- Ahsa’ai time till the last phase of their propaganda
which is the Baha’is propaganda, and this is due to their ignorance and under
development in doctrine of islam which was widespread in Iran and the Islamic world.
The whole secrets of Babis and Baha’is movement were restricted among
particular group, most of them were Al- Rashti’s students and knew the basic
principles of their movement which deperding or (the principles) declarati