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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 Jan 13 2023
Journal Name
Atmosphere
Impact of North African Sand and Dust Storms on the Middle East Using Iraq as an Example: Causes, Sources, and Mitigation
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This study aims to determine the reasons for the increase in the frequency of sand and dust storms in the Middle East and to identify their sources and mitigate them. A set of climatic data from 60 years (1960–2022) was analyzed. Sand storms in Iraq are a silty sand mature arkose composed of 72.7% sand, 25.1% silt, and 2.19% clay; the clay fraction in dust storms constitutes 70%, with a small amount of silt (20.6%) and sand (9.4%). Dust and sand storms (%) are composed of quartz (49.2, 67.1), feldspar (4.9, 20.9), calcite (38, 5), gypsum (4.8, 0.4), dolomite (0.8, 1.0), and heavy minerals (3.2, 6.6). Increasing temperatures in Iraq, by an average of 2 °C for sixty years, have contributed to an increase in the number of dust storm

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Publication Date
Fri Apr 26 2024
Journal Name
Mathematical Modelling Of Engineering Problems
Solving Tri-criteria: Total Completion Time, Total Earliness, and Maximum Tardiness Using Exact and Heuristic Methods on Single-Machine Scheduling Problems
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Publication Date
Sat Dec 26 2020
Journal Name
International Journal Of Pharmaceutical Research
Complexes of Co(II), Cu(II), Ni(II), Pt(II) And Pd(II) with N 3 O-Chelating Ligand Incorporating Azo and Schiff Base Moieties: Synthesis, Spectroscopic, Thermal Decomposition, Theoretical Studies, and thermodynamic parameters
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Publication Date
Sat Sep 23 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Synthesis and Charact'erizatio.n of new Schiff base ligand [(2-{1-[(2 hydraxy­ benzylidene)-hydrazono]-ethyl} benzene-I, 3, 5--triol.] and it's CQmp.lexes. with Co en\ Ni . (U),, c·u(U)' and · zn(II).
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The eaction  of 2 4 .6-trihydroxyactophenonemonohydra1e  with

l hydr.azine monohydrate was realized ti·nder reflu.(( in methanol and i:l.

Jew drops of glacial acetic acid we.re added to give lhe'(int rmediate)

2-(1hydr pno-ctbyt)-benzcne-·1.3.5-r:Qql,       which      reacted     wittl

saEcy.laldehyde. jn methm)ql to gjy;e 'a new :tyRe CNzOi) Ligand  (H:flL]

f(2-{1-[(2-=bydroxy-bertzylide·ne)-bydrazqoo,J-e·thy.1}bcnze·neJ ;3·,5

of

 

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Publication Date
Wed Mar 30 2022
Journal Name
Journal Of Economics And Administrative Sciences
The Extent of the Practice of Iraqi Banks to Manage Profits Using the (LLp it) Model and Its Reflection on the Tax Base, A Case Study of A Sample of Iraqi Private Banks Listed in The Iraqi Stock Exchange
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The research aims to identify the extent to which Iraqi private banks practice profit management motivated by reducing the taxable base by increasing the provision for loan losses by relying on the LLP it model, which consists of a main independent variable (net profit before tax) and independent sub-variables (bank size, total debts to total equity, loans granted to total obligations) under the name of the variables governing the banking business. (Colmgrove-Smirnov) was used to test the normal distribution of data for all banks during the period 2017-2020, and then find the correlation between the main independent variable sub and the dependent variable by means of the correlation coefficient person, and then using the multiple

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Publication Date
Fri May 01 2020
Journal Name
مجلة بحوث الشرق الأوسط
دراسة مقارنة لمستوى التمکین الإداری بین مشرفی التربیة الریاضیة (الاختصاص والفنی) لمدیریات التربیة فی محافظة بغداد A Comparative Study of the Level of Administrative Empowerment between the Physical Education Supervisors (Specialization and Technical) of Education Directorate in Baghdad Governorate
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Publication Date
Sun Jul 13 2025
Journal Name
Al–bahith Al–a'alami
Frameworks for international press coverage of external interference in the formation of the Iraqi government Analytical study for the Saudi Al-Sharq Al-Awsat and Kayhan Al-Arabi-Iranian newspapers for the period (1/1/2018 - 31/12/2018)
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This research deals with the frameworks and mechanisms of international press coverage of the issue of foreign interference in the formation of the Iraqi government in the Saudi newspapers Asharq Al-Awsat and Kayhan Al-Arabi Iran and how this topic was addressed in the two newspapers. The frameworks for international press coverage of external interference in the formation of the Iraqi government. ”This research is one of the descriptive research that adopted the survey method، which made it possible to use the content analysis tool to analyze
the content of the two newspapers، whose numbers are (624) from the
newspapers (Al-Sharq Al-Awsat Al-Saudi Arabia and Kayhan Al-Arabi Iran) from (1/1/2018 to 31/12/2018)، and the researc

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Publication Date
Fri Dec 31 2021
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
TO WHAT EXTENT THE APPLICATION OF MALCOLM BALDRIGE OF THE COMPREHENSIVE QUALITY STANDARDS IN THE AFTER- SALES SERVICES/ APPLIED RESEARCH IN ONE OF THE PRIVATE SECTOR COMPANIES: TO WHAT EXTENT THE APPLICATION OF MALCOLM BALDRIGE OF THE COMPREHENSIVE QUALITY STANDARDS IN THE AFTER- SALES SERVICES/ APPLIED RESEARCH IN ONE OF THE PRIVATE SECTOR COMPANIES
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The aim of the research is to identify to what extent to which Malcolm Baldrige standards of total quality are applied in the after-sales services of a private sector company for electrical appliances, from the point of view of administrative leaders, in it. To achieve this aim a questionnaire has been used to measure the degree of application of Malcolm’s seven criteria for total quality, namely: (leadership, strategic planning, focus on the customer, measurement and analysis and knowledge management, focus in human resource and operation management and results of the company’s management), the research found that the company achieved a good level of the standard from the de

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Publication Date
Wed Dec 09 2015
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
Effect of Sodium sulfite treatment on the trypsin inhibitors activity, protein isolate and protein solubility of complete and dehulling white bean seeds Phaseolus vulgaris.: Effect of Sodium sulfite treatment on the trypsin inhibitors activity, protein isolate and protein solubility of complete and dehulling white bean seeds Phaseolus vulgaris.
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The study aimed to increase the biological value of white bean. The effect of different concentrations 0.01 ,0.02,0.03,and 0.04 M of sodium sulfite solutions for 1hr at 70 ºC on the trypsin inhibitors activity, protein isolate and protein solubility of complete and dehulling white bean flour were studied.Trypsin inhibitors activity were reduced by 42.97, 58.69, 68.59 and 69.58% in complete white bean flour at 0.01 ,0.02, 0.03, 0.04 M respectively, while the corresponding values were 50.43, 61.00, 75.61 and 85.66% respectively in dehulling white bean flour .Protein isolate value was 13.41% and protein solubility was 2.2% in control sample, Furthermore, the using of chemical treatment showed that protein isolate was reduced gradually and

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Publication Date
Fri May 01 2020
Journal Name
Journal Of Engineering
Building 1D Mechanical Earth Model for Zubair Oilfield in Iraq
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Many problems were encountered during the drilling operations in Zubair oilfield. Stuckpipe, wellbore instability, breakouts and washouts, which increased the critical limits problems, were observed in many wells in this field, therefore an extra non-productive time added to the total drilling time, which will lead to an extra cost spent. A 1D Mechanical Earth Model (1D MEM) was built to suggest many solutions to such types of problems. An overpressured zone is noticed and an alternative mud weigh window is predicted depending on the results of the 1D MEM. Results of this study are diagnosed and wellbore instability problems are predicted in an efficient way using the 1D MEM. Suitable alternative solutions are presented

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