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Connectivity and rendezvous in distributed DSA networks
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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.

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Publication Date
Fri Mar 26 2021
Journal Name
Oral Diseases
Association between maternal periodontitis, acute‐phase reactants and preterm birth
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Publication Date
Sat Oct 13 2018
Journal Name
International Research Journal Of Pharmacy
INTENTIONS AND PERCEPTIONS OF IRAQI PHARMACY STUDENTS TOWARD POSTGRADUATE EDUCATION
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Publication Date
Sun May 01 2016
Journal Name
Journal Of Engineering
Numerical Investigation Using Harmonic and Transient Analysis To Rotor Dynamics
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The rotor dynamics generally deals with vibration of rotating structures. For designing rotors of a high speeds, basically its important to take into account the rotor dynamics characteristics. The modeling features for rotor and bearings support flexibility are described in this paper, by taking these characteristics of rotor dynamics features into standard Finite Element Approach (FEA) model. Transient and harmonic analysis procedures have been found by ANSYS, the idea has been presented to deal with critical speed calculation. This papers shows how elements BEAM188 and COMBI214 are used to represent the shaft and bearings, the dynamic stiffness and damping coefficients of journal bearings as a matrices have been found

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Publication Date
Fri Jul 23 2021
Journal Name
International Journal Of Dentistry
Predicting Canine and Premolar Mesiodistal Crown Diameters Using Regression Equations
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Objectives. The current study aimed to predict the combined mesiodistal crown widths of maxillary and mandibular canines and premolars from the combined mesiodistal crown widths of maxillary and mandibular incisors and first molars. Materials and Methods. This retrospective study utilized 120 dental models from Iraqi Arab young adult subjects with normal dental relationships. The mesiodistal crown widths of all teeth (except the second molars) were measured at the level of contact points using digital electronic calipers. The relation between the sum mesiodistal crown widths of the maxillary and mandibular incisors and first molars and the combined mesiodistal crown widths of the maxillary and mandibular canines and premolars was as

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Publication Date
Sat Dec 15 2018
Journal Name
Journal Of The College Of Education For Women
Social responsibility of kindergarten teachers Eligibility and Government (Comparative Study)
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      The present research aims to identify the social responsibility of the kindergarten teachers of the civil and governmental schools (comparative study)? For the purpose of achieving the objectives of the research, the following formulas were formulated:

- Are there statistically significant differences at the level of (0.05) among the kindergarten teachers in the social responsibility scale?

 The current research was limited to kindergarten teachers (governmental and non-governmental) in the Directorate General of Education Baghdad Rusafa / Second.

The main research sample consisted of (100) teachers, (50) teachers from government kindergartens and (50) female kindergarten teache

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Publication Date
Sat Jun 30 2018
Journal Name
College Of Islamic Sciences
Violators of the law of God   (Between platforms and intimates)
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Al-Manas and Al-Muhais are two words in a close sense of the strange words of the Holy Quran. The word Al-Manas was mentioned once in the Holy Qur'an in Surat (PBUH). ) / 36 .. What we will see in the folds of the search, God willing.

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Publication Date
Wed Oct 12 2022
Journal Name
College Of Islamic Sciences
The Concept of the Text, its Divisions, Connotations, and Methodology
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The text has many connotations in the Arabic language, such as vowel points, designation, completion, etc., and the original meaning of the text is to show. The Western text has its owen independent semantic unit .The biblical texts are a mixture of what was reported by the Prophet Moses (peace be upon him) and what the authors described in terms of texts over many centuries.The meaning of the text is guidance and payment, and it is a natural connotation. The religious text for Muslims is divided into peremptory texts that are national proof. The evidence for the meaning of the text is proven by language, and it is not required that the researcher be a jurist. The approach is a factual questionnaire by the researcher according to a speci

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Publication Date
Mon Apr 09 2018
Journal Name
Al-khwarizmi Engineering Journal
Construction and Evaluation of a Uniaxial Mechanical Actuated Vibration Shaker
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In the present paper a low cost mechanical vibration shaker of rotating unbalanced type with uniaxial shaking table was designed and constructed in an attempt to provide opportunities for experimental testing and application of vibration in experimental modal analysis, stress relief of weldments, effect of vibration on heat transfer and seismic testing of civil engineering structures. Also, it provides unexpressive solution to enhance the knowledge and technical skills of students in mechanical vibration laboratory. The shaker consists of a five main parts shaker frame, shaker table, flexible support, drive motor, and eccentricity mechanism. The experimental results show that the amplitude of the shaker is increased with increasing the f

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Publication Date
Mon Jan 01 2024
Journal Name
Journal Of Law And Political Sciences
CONDITIONS OF COMPULSORY SALE AND THE RIGHT TO BE COLLECTING
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Publication Date
Sun Aug 09 2015
Journal Name
No
Stability and Instability of Some Types of Delay Differential Equations
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