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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 Feb 01 2023
Journal Name
Baghdad Science Journal
Synthesis, Theoretical Study, and Biological Evaluation of Some Metal Ions with Ligand "Methyl -6-[2-(4-Hydroxyphenyl) -2-((1-Phenylethylidene) Amino) Acetamido] -2,2-Dimethyl-5—Oxo-1-Thia-4-Azabicyclo [3.2.0] Heptane-3-Carboxyylate
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Schiff base (methyl 6-(2- (4-hydroxyphenyl) -2- (1-phenyl ethyl ideneamino) acetamido) -3, 3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0] heptane-2-carboxylate)Co(II), Ni(II), Cu (II), Zn (II), and Hg(II)] ions were employed to make certain complexes. Metal analysis M percent, elemental chemical analysis (C.H.N.S), and other standard physico-chemical methods were used. Magnetic susceptibility, conductometric measurements, FT-IR and UV-visible Spectra were used to identified. Theoretical treatment of the generated complexes in the gas phase was performed using the (hyperchem-8.07) program for molecular mechanics and semi-empirical computations. The (PM3) approach was used to determine the heat of formation (ΔH˚f), binding energy (ΔEb), an

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Scopus (15)
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Publication Date
Mon Feb 28 2022
Journal Name
Journal Of Educational And Psychological Researches
The Effectiveness of a Proposed Unite in Voluntary Work in Enhancing Critical Thinking Skills and The Attitudes towards Responsible Citizenship among Eighth Grade Female Students in the Governorate in Sultanate of Oman North Batinah
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The aim of the present study is to examine the effectiveness of a proposed unite in voluntary work in enhancing critical thinking skills and the attitudes towards responsible citizenship among eighth grade female students in the Sultanate of Oman. In order to collect the study data, the researchers employed a quasi-experimental research design with twenty female students from Al-Sideeqah bint Al-Sideeq for basic education school. The research data were collected via a critical thinking test that consisted of twenty-five items and a scale of twenty items under three different dimensions, which aimed to measure students' attitudes towards responsible citizenship. The researchers implemented these two instruments as pre- and post the experi

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Publication Date
Mon Jun 28 2021
Journal Name
Journal Of The College Of Education For Women
The Sources of Organizational Power Prevailing among Academic Leaders at University of Tabuk and its Relationship to Institutional Creativity from the Viewpoint of Faculty Members: شروق بنت عبد الخالق الأسمري , علي بن حسن القرني
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This study aims to examine the sources of organizational power prevailing among the academic leaders at the University of Tabuk from the faculty members’ viewpoint. The purposes behind such an aim are: to reveal the level of administrative and technical institutional creativity, the nature of the relationship between the reality of organizational power and the level of institutional creativity, and to disclose statistically the significant differences between the averages of faculty members’ responses attributed to the demographic variables (gender,  years of experience, academic degree). The study used the descriptive approach, both survey and correlational. A questionnaire was used to collect data from a simple random sample o

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Publication Date
Mon Mar 07 2022
Journal Name
Journal Of Educational And Psychological Researches
Awareness of Students at Imam Muhammad bin Saud Islamic University of the Requirements of Married Life in the Light of Social Changes and Methods of Deepening It in Accordance with an Islamic Educational Vision
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This study aims to identify the level of students’ awareness at Imam Muhammad bin Saud University of the requirements of married life in the light of social changes and suggested methods to deepen this awareness (according to the Islamic educational vision) from their own perspective. In this study, the researcher used the descriptive approach with a survey research method, depending on questionnaires to collect data, which he applied to students of College of Sharia in Imam Muhammad bin Saud Islamic University, as well as, students in the fields of Sociology, Social Work, and Psychology in the College of Social Sciences. The findings of the study revealed that students are aware of the requirements of married life concerning mutual ri

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Publication Date
Mon May 17 2021
Journal Name
Indian Journal Of Forensic Medicine & Toxicology
The Effect of Exercises with a Proposed Device to Improving Some Bio-Kinematic Variables and the Performance of the Arab Round off Skill on Floor Movement Mat Device of the Artistic Gymnastics for Women
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The importance of the research lies in preparing exercises using a proposed device to learn the skill of thehuman wheel on a machine rug of ground movements of the artistic gymnastics. As for the research problem:Through the presence of the two researchers as teachers and observers of this sport in the gymnastics hall,they noticed that there is difficulty in the students’ performance of the skill of the round off on the machineof the mat of ground movements, according to the researchers’ opinion, the reason for this is that skillsare taught with the limited availability of assistive devices, as well as the lack of use of these devices inexercises according to biomechanical variables, although they facilitate the learning process

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Publication Date
Fri Jul 01 2022
Journal Name
Eurasian Chemical Communications
Assessment of hypoxemia status by measuring serum level of hypoxia inducible factor 1 alpha in relation to tumor suppression protein p53, estradiol and tumor proliferation markers of breast cancer in Thi-Qar province/Iraq
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Publication Date
Thu Jan 02 2020
Journal Name
Journal Of The College Of Languages (jcl)
Iranian Jews’ Customs and Traditions in The Works of Dorrit Rabinyan (A Study in The Alley of Almond Bushes in Omerijan ): מסורת ומנהגים יהודי אירן ביצירותה של דורית רביניאן " עיון ברומן סמטת השקדות בעומריג'אן "
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The orient culture and heritage has directly influenced ,in a way or another , the literary works which recently have been noted by the oriental  Jews inside and outside of Israel. Several Jewish writers, who came from the orient  (especially from Iran ), have written their works while influenced by traditions and customs of the Iranian society, in which they were born , lived , and raised, and by the writers who were born in that society and then moved to Israel and lived there as a result of the Zionism and its notorious promises to gather Jewish people from all over the world to establish their national home at the expense of the Palestinian   land and people.

       That final

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Publication Date
Sat Dec 01 2012
Journal Name
Journal Of Economics And Administrative Sciences
Developing strategic leadership practices in the light of transparency and organizational citizenship behavior - A field study of a sample of the staff of the Office of the Inspector General at the Iraqi Ministry of Culture
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Diversity the terms and practice the organizational filed with different concepts and environment, which Iraqi environment part from them. Some organizational in Iraqi environment leave its basic oriented to agreement with the leader desire, their fore this research focus tow basic variable (organizational citizenship behavior & transparence), we supposition which is dependent to explanation the response variable (strategic leadership). The results justification in part and not justification in another part. For example the organizational citizenship behavior effect on some parte of the strategic leadership. The transparence have faraway to fly from the relation with organizational citizenship behavior and strategic leadershi

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Publication Date
Tue Jan 02 2018
Journal Name
Journal Of Educational And Psychological Researches
The effectiveness of educational design design according to the theory of Ozbal in the acquisition of geographical concepts among the pupils of the fourth primary in the geography and development of their habits of mind
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Summary The objective of the research is to learn the design of a learning educational learning according to the theory of Ausubel in the acquisition of geographical concepts among the students of the fourth primary in the field of geography and the development of their habits of mind. To achieve this, the researcher relied on the two hypotheses the researcher used the design of equal groups the first experimental group was studied according to the design educational educational learning according to the theory and the other is an officer according to the traditional method. The research community consists of fourth grade pupils in primary school day for girls in the Directorate of Education Baghdad, Al-Rusafa, the third academic year 20

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Publication Date
Wed Apr 01 2015
Journal Name
Al–bahith Al–a'alami
University Youth Attitudes towards Electronic Advertisements and their Relationship to the Behavior of the Consumer A Field Study of a Sample of Students of the College of Mass-Communication / University of Baghdad as a Model
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This research aims at identifying the communicative habits and content reflections on the communication process, especially the young audience which is one of the main group for whom the announcements are made. Because young people face life with passion and aspiration making them respond to each effect used by the media in the design of the advertising using all the effective techniques, attractive methods for young children like depending on drama, technical tricks, music and logos easily to be remembered and responded to the desires of the young in their entertainment. This research also aims at identifying the impact of the internet as a channel of commercial advertising on the purchasing behavior of young people at the universities

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