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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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Publication Date
Wed Jun 03 2020
Journal Name
Political Sciences Journal
The Muslim Arab Self and the image of the other, religiously and culturally different: a critical analytical study of the causes and forms of political and social intolerance in Iraq
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This research aims to analyze the intellectual and civilizational regression that afflicted Iraqi and Arab society due to political and religious tyranny and internal conflicts, which was reflected in the deterioration of human rights values and the absence of equality and justice in dealing with the other religiously, which affected the reluctance of members of religious groups to interact with their national societies and then migrate to Outside, which contributed to a double loss, in terms of the loss of these societies by productive and effective national competencies, and in terms of distorting the image of Islam. The research stressed that the first treatments of this phenomenon are the consolidation of the values of citize

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Publication Date
Sat Sep 03 2022
Journal Name
International Journal Of Health Sciences
Using Elisa and nested PCR for detection of the toxoplasmosis in milk and the influence of infection and some factors on milk composition in the Iraqi local and Shami goats
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This study concluded detection of Toxoplasma gondii in milk, immunologically by using Elisa and nested PCR)nPCR (based on B1 gene, also to investigate the effect of toxoplasmosis, parity, breed and flock on some milk composition in the Iraqi local and Shami goats in the middle of Iraq. A total of 80 milk samples of the lactating goats were collected. Results of this study showed the prevalence of Toxoplasmosis was 21.25% and 28.75% by Elisa and nPCR respectively without significant differences. The sensitivity of Elisa was a low (30.43%) whereas the specificity was a high (82.45%). The degree of agreement estimated by Kappa coefficient revealed a slight agreement (0.14) between two methods. The results indicated that goats infected

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Publication Date
Wed Jun 21 2017
Journal Name
Research Journal Of Pharmaceutical, Biological And Chemical Sciences
Synthesis and characterization of Mixed-Ligand Complexes of Oxalic Acid and Trimethoprim with Mn(II), Co(II), Ni(II), Cu(II),Zn(II), and Cr (III) Ions: and antimicrobial Activities
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Publication Date
Sun Jul 01 2018
Journal Name
Journal Of Educational And Psychological Researches
Item Difficulty and Item Discrimination Coefficient for School and College Ability Tests (SCAT) Advanced Form in Classical Test Theory (CTT) and Item Response Theory (IRT) and the Correlation among Them
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Item Difficulty and Item Discrimination Coefficient for School and College Ability Tests (SCAT) Advanced Form in Classical Test Theory (CTT) and Item Response Theory (IRT) and the Correlation among Them Mohammad moqasqas Haifa T. Albokai Assistant Professor of Measurement and Evaluation Associate Professor of Measurement and Evaluation College of Education, Taibah University The aim of this study was to study the item difficulty and item discrimination of the SCAT (advance form) with CTT, and IRT, and to study the correlation among them. To do this, the researchers used the data of their previous study, which conducted in (2011). It consisted of (3943) subject. Then, they used two-statistical programs (TAP, Bilog-MG-3) to obtain the item

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Publication Date
Mon Jun 01 2020
Journal Name
Journal Of Planner And Development
Senses and urban Landscape
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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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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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Publication Date
Mon Oct 01 2012
Journal Name
Al–bahith Al–a'alami
Internet and Press Blogging
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The emergence of the Internet and its transformation in the early nineties of the last century led to a means of mass communication that brought about significant structural changes in the media map.

Over the course of historical development, the public did not engage the media in its behavior in the implementation and dissemination of an idea, generalization or theory put forward by media experts or practitioners through these means to do it. Blogs represent the most important service provided by the Internet in recent years which has gained special importance in the media field. Where the word “Blogs” has several names: (alternative media), (blogging press), (popular press) and other names.

The medi

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Publication Date
Tue Jun 01 2010
Journal Name
Journal Of The College Of Languages (jcl)
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 Jun 20 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Photodynamic Therapy and Periodontology
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This review highlights the importance of photodynamic therapy in periodontology. It can be confirmed that the photodynamic therapy as adjunct to classical scaling and root planing can be recommended as treatment option, which can by no means replace the classical therapy concepts. But even over an observation period of six months a slightly higher improvement of the clinical parameters was achieved than with SRP alone.

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Crossref (3)
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Publication Date
Sat Feb 02 2019
Journal Name
Journal Of The College Of Education For Women
Smoking and Social Behavior
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