<p><span>Medium access control (MAC) protocol design plays a crucial role to increase the performance of wireless communications and networks. The channel access mechanism is provided by MAC layer to share the medium by multiple stations. Different types of wireless networks have different design requirements such as throughput, delay, power consumption, fairness, reliability, and network density, therefore, MAC protocol for these networks must satisfy their requirements. In this work, we proposed two multiplexing methods for modern wireless networks: Massive multiple-input-multiple-output (MIMO) and power domain non-orthogonal multiple access (PD-NOMA). The first research method namely Massive MIMO uses a massive number of antenna elements to improve both spectral efficiency and energy efficiency. On the other hand, the second research method (PD-NOMA) allows multiple non-orthogonal signals to share the same orthogonal resources by allocating different power level for each station. PD-NOMA has a better spectral efficiency over the orthogonal multiple access methods. A review of previous works regarding the MAC design for different wireless networks is classified based on different categories. The main contribution of this research work is to show the importance of the MAC design with added optimal functionalities to improve the spectral and energy efficiencies of the wireless networks.</span></p>
Abstract :
The aim of the study is to diagnose the level and nature of the relationship between cognitive interactions, cognitive ignorance and the achievement of strategic excellence). The aim of this is to explore theoretical philosophy and intellectual implications of these variables, and, then test the correlation and impact relationships and their feasibility in the application environment, which was formed from the seven directorates in the Ministry of Education. The sample of the study was determined by the directors, their assistants, and the department directors. The sample number is (130). The importance of the study is to come out with a philosophical basis for the nature of the variables, based on an app
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Our research was launched in the study of the sustainable conflict of globalization and the rebalancing of the great powers that have made life on the earth unstable and insecure over the past and present eras, the purpose of which is to pay attention to the waste and instability that human societies are exposed to in different proportions between abstract right and continuous deviation.
The purpose of the study is to show the loss, waste and backwardness in managing and governing societies towards private interests, away from the standards of good institutional governance.
The study’s design was based on two demands, the first on the nature and eternity of
... Show MoreThe oil exports play a vital role in supporting economic development and raise the economic growth. The oil exports can increase the economic growth via three main channels which are supporting the productive, distributive and service sectors; increasing the investment and capital formation; and increasing the employment rate.
However, the oil exports did not have an important role in increasing the economic growth in Iraq. Therefore, it also did not provide the required support to other economic sectors, neither participated in increase the employees’ skills nor increase the investment rate. It may slightly contribute in enhancement the infrastructure that can attract the public and private investments
... Show Moreأستهدفت الدراسة اختبار أثر التوجه السوقي والتزام العاملين على أداء المنظمة المسوقة لخدمات النقل الجوي. حيث تم اختيار شركة الخطوط الجوية الملكية الأردنية كمجال تطبيقي.وقد اعتمدت الدراسة في قياس المتغيرات على مقاييس مختبرة وقد تأكد صحتها وثباتها لقياس المتغيرات في البيئة الحالية. وقد بينت نتائج التحليل الإحصائي الذي استخدمت فيه أساليب إحصائية مختلفة بالاستعانة ببرنامج SPSS))
Atorvastatin (ATR) is a poorly water-soluble anti-hyperlipidemic drug. The drug belongs to the class II group according to the biopharmaceutical classification system (BCS) with low bioavailability due to its low solubility. Solid dispersion is an effective technique for enhancing the solubility and dissolution of drugs. Phospholipid solid dispersion (PSD) using phosphatidylcholine (PC) as a carrier with or without adsorbent (magnesium aluminum silicate, silicon dioxide 15nm, silicon dioxide 30nm, calcium silicate) was used to prepare ATR PSD using different drug: PC: adsorbent ratios by solvent evaporation method. The resulted PSD was evaluated for its percentage yield, drug content, solubility, dissolution rate, Fourier transforma
... Show MoreKetoprofen is a non-steroidal anti-inflammatory (NSAID) drug with analgesic, anti-inflammatory, and antipyretic effects. It is widely used in the treatment of inflammation and pain associated with rheumatic disorders such as rheumatoid arthritis, osteoarthritis, and in soft tissue injury. The purpose of this study was to prepare an oral disintegrating tablets of ketoprofen by simple method. The tablets were prepared by direct compression method and different ratios of various subliming agents or superdisintegrants were incorporated. Then these tablets were evaluated for hardness, friability, weight variation, water absorption ratio, disintegrating time and dissolution time. The results showed that Formula F11 batch had short disint
... Show MoreEverybody is connected with social media like (Facebook, Twitter, LinkedIn, Instagram…etc.) that generate a large quantity of data and which traditional applications are inadequate to process. Social media are regarded as an important platform for sharing information, opinion, and knowledge of many subscribers. These basic media attribute Big data also to many issues, such as data collection, storage, moving, updating, reviewing, posting, scanning, visualization, Data protection, etc. To deal with all these problems, this is a need for an adequate system that not just prepares the details, but also provides meaningful analysis to take advantage of the difficult situations, relevant to business, proper decision, Health, social media, sc
... Show MorePortulacaria afra is a small succulent tree, previously belonging to the Portulacaceae family, but with further studies, the plant transferred to the Didieracea family. P. afra was used as an ornamental, vegetable, and ethnomedicinal plant. Uses of the plant by rural South Africans to treat chronic skin conditions and rashes, alleviate exhaustion, and aid in treating TB and diarrhea have been documented in folklore. According to pharmaceutical research, plant extracts off er a wide range of remedial outcomes, such as antidiabetic, antifungal, antibacterial, anticancer, antioxidant, and anti-infl ammatory. The study aims to determine some bioactive constituents responsible for pharmacological activities and traditional usefulness. Th
... Show MoreThe Capparis spinosa L. is a species has a great interest in the field of traditional medicine for its pharmacological properties with many bioactive compounds. Our study is aiming at the recovery of this species through a phytochemical analysis and an evaluation of antibacterial and antioxidant activities of leaves of Capparis spinosa L. collected from natural habitats within the region of Al-Jadriya, Baghdad, Iraq. Phytochemical investigation demonstrated the presence of flavonoids, phenols, alkaloids, tannins, and glycosides in the methanolic extract of leaves. The quantitative analysis of total phenolic contents is being performed by Folin-Ciocalteau method and expressed in terms of gallic acid equivalents. C. spinosa exhibited progress
... Show MoreThe growing use of tele
This paper presents a new secret diffusion scheme called Round Key Permutation (RKP) based on the nonlinear, dynamic and pseudorandom permutation for encrypting images by block, since images are considered particular data because of their size and their information, which are two-dimensional nature and characterized by high redundancy and strong correlation. Firstly, the permutation table is calculated according to the master key and sub-keys. Secondly, scrambling pixels for each block to be encrypted will be done according the permutation table. Thereafter the AES encryption algorithm is used in the proposed cryptosystem by replacing the linear permutation of ShiftRows step with the nonlinear and secret pe
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