Preferred Language
Articles
/
VoZ8soYBIXToZYAL47HT
Multi-Channel Distributed DSA Networks: Connectivity and Rendezvous Tradeoffs
...Show More Authors

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.

Scopus Clarivate Crossref
Publication Date
Wed Mar 01 2023
Journal Name
Baghdad Science Journal
Fractional Hartley Transform and its Inverse
...Show More Authors

The Hartley transform generalizes to the fractional Hartley transform (FRHT) which gives various uses in different fields of image encryption. Unfortunately, the available literature of fractional Hartley transform is unable to provide its inversion theorem. So accordingly original function cannot retrieve directly, which restrict its applications. The intension of this paper is to propose inversion theorem of fractional Hartley transform to overcome this drawback. Moreover, some properties of fractional Hartley transform are discussed in this paper.

View Publication Preview PDF
Scopus (1)
Scopus Clarivate Crossref
Publication Date
Thu Sep 01 2022
Journal Name
Beiruit:kans Publishing House
Sufi Commentary: Formative and Later Periods
...Show More Authors

Publication Date
Sat Dec 06 2008
Journal Name
Al-nahrain Journal Of Science
Study of Comets Composition and Structure
...Show More Authors

The present paper focuses on the nature of the different interactions between cometary nucleus and tail with solar wind. The dynamics of the comet will impose many features that provide unique behavior of the comet when entering the solar system. These features are reviewed in this paper and few investigations are made. The calculations made in this work represent the analysis and interpretation of the different features of the comet, such as perihelion and eccentricity dependence on the gas production rate, and the dependence of the latter on the composition of the comet nucleus. The dependences of the heliocentric, bow shock, contact surface, and stand-off distances with gas production rate for many types of comets that cover linear and n

... Show More
Publication Date
Wed Jul 02 2025
Journal Name
Dijlah Journal
Grammar between logic and linguistic usage
...Show More Authors

View Publication
Publication Date
Thu Oct 14 2021
Journal Name
Kufa Medical Journal
Total Superficial Parotidectomy: Pros and Cons
...Show More Authors

Background: Total superficial parotidectomy is the most commonly used approach in excising the tumors that affect the superficial lobe of the parotid gland, whether they're benign or malignant. The aim of the study is to evaluate the benefits and drawbacks of total superficial parotidectomy for parotid gland tumors within five years of follow-up. Patients and methods: Nineteen patients with lateral facial swelling affecting the parotid region were included in this study. All of them operated under general anesthesia with oral endotracheal intubation, where Modified Blair Incision (lazy S incision) was utilized in all cases. Anterograde dissection with facial nerve identification was accomplished with total superficial parotidectomy.

... Show More
View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Sun Feb 03 2019
Journal Name
Journal Of The College Of Education For Women
WISDOM AND ITS CAUSE BY FUNDEMENTALISTS
...Show More Authors

Allah's wisdom has necessitated concentrating un human nature the ability of
mediation and forethought .among the aspect of this ability is the recognition of the
relationship between causes and effects issues and reasons behind them and the
sensing of similarities and differences and distinguish the connection between the
subjects and characteristics and the innate perception of material and immaterial good
and bad.
Allah's wisdom has willed not to make his law away from the nature of people of
discovering the relationship between things and their causes, or similarity between
things and their counterparts to use the Quranic text to convince reason and to enable
reason to realize the wisdom quranic text within

... Show More
View Publication Preview PDF
Publication Date
Sun Jun 01 2014
Journal Name
Baghdad Science Journal
Liquid crystalline dendrimer: Sythesis and Chracterization
...Show More Authors

A new family of nematic liquid crystal dendrimers derived from 3,5-dihydroxybenzoic acid were synthesized. The synthesis of the dendrimers compounds shows the influence of the dendritic core on the mesomorphic properties. The liquid crystalline properties were studied by polarizing optical microscopy (POM) equipped with a hot stage, the structures of the synthesized compounds characterized using FTIR and 1HNMR spectroscopy.

View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Tue Jan 02 2024
Journal Name
Journal Of The College Of Languages
Ironic Metonymy in Russian and Arabic
...Show More Authors

This article is devoted to the cognitive study of ironic metonymy in Russian and Arabic. Metonymy and irony have traditionally been seen as parallel linguistic phenomena. But their formation and interpretation are based on different cognitive mechanisms. At the formal and functional level, metonymy and irony have a number of significant differences. Metonymy is an artistic technique, the mechanism of which is based on obvious, easily traced connections between objects and phenomena of the surrounding world. Irony is a satirical technique or a rhetorical figure that is used to create a certain artistic image, aimed at forming the hidden meaning of the statement. A native speaker intuitively feels the difference between metonymy and i

... Show More
View Publication Preview PDF
Crossref
Publication Date
Wed Jul 02 2025
Journal Name
Magazine Aldhakwat Albedh
Imam Hussain and the Great Conspiracy
...Show More Authors

View Publication
Publication Date
Tue Jun 07 2022
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Financial Fraud and Corruption with Examples
...Show More Authors

He mentioned in this article the main types of corruption, which are political, moral, financial and administrative. Others may add other types of corruption, such as religious, scientific, media, informational and statistical corruption. At the global level, the focus is largely on financial corruption, although other types of corruption are no less bad than it. Financial corruption can be defined as all financial deviations in violation of general laws or the provisions of regulations, legislation, and procedures regulating the work of the state, private institutions and individuals and applied in state institutions and the private sector in general and inconsistent with the controls and instructions of financial control.

In th

... Show More
View Publication Preview PDF