<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>
This paper adapted the neural network for the estimating of the direction of arrival (DOA). It uses an unsupervised adaptive neural network with GHA algorithm to extract the principal components that in turn, are used by Capon method to estimate the DOA, where by the PCA neural network we take signal subspace only and use it in Capon (i.e. we will ignore the noise subspace, and take the signal subspace only).
Nanochemistry is a significant area which involves the synthesis, design, and manipulation of particle structures with dimensions ranging from 1 to 100 nanometres. It is now one of the major concerns of pharmaceutical and biological researchers. The current study discusses recent advances in the use of silver nanoparticles (AgNPs) as a selective sensor for qualitative and colorimetric quantitative detection of mercury ions. The synthesis of significant noble metal AgNPs is described as a novel, low-cost, quick, and simple method for detecting mercury ions. Due to the seriousness of mercury toxicity to our cells, AgNPs may be successfully employed for the detection of ecologically harmful mercury ions in a wide variety of aqueous
... Show MoreUltra-High Temperature Materials (UHTMs) are at the base of entire aerospace industry; these high stable materials at temperatures exceeding 1600 °C are used to manage the heat shielding to protect vehicles and probes during the hypersonic flight through reentry trajectory against aerodynamic heating and reducing plasma surface interaction. Those materials are also recognized as Thermal Protection System Materials (TPSMs). The structural materials used during the high-temperature oxidizing environment are mainly limited to SiC, oxide ceramics, and composites. In addition to that, silicon-based ceramic has a maximum-use at 1700 °C approximately; as it is an active oxidation process o
Self-repairing technology based on micro-capsules is an efficient solution for repairing cracked cementitious composites. Self-repairing based on microcapsules begins with the occurrence of cracks and develops by releasing self-repairing factors in the cracks located in concrete. Based on previous comprehensive studies, this paper provides an overview of various repairing factors and investigative methodologies. There has recently been a lack of consensus on the most efficient criteria for assessing self-repairing based on microcapsules and the smart solutions for improving capsule survival ratios during mixing. The most commonly utilized self-repairing efficiency assessment indicators are mechanical resistance and durab
... Show MoreThe research Aim is to provide support to small enterprises by providing tools that enable measurement and test their performance and identifying weaknesses and work on them is determined by the problem of searching using traditional assessment methods for small projects with only financial performance measurement standards that do not provide a complete picture of the performance of these projects so use the balanced scorecard the four pillars (financial, customer, learning and growth, and internal processes) and identify deviations and work on them through the use of the outputs of the programme (probe), PROmoting Business Excellence-PROBE), which It is a model of performance evaluation, with which you can deve
... Show MoreThis study seeks to clarify the adequacy of the current legal texts - procedural and objective - to respond to our situation under Corona and whether it needs to modify or develop treatment for this general exceptional circumstance or to avoid it, and the appropriateness of the idea of force majeure or emergency circumstance or (the idea of foreign reason) to face the consequences or effects of Corona on the rules of litigation and the formation of the court and its jurisdiction and procedural appointments and litigation procedures and appeal and judgment and its implementation in order to maintain and implement the public order that interferes with the mechanisms and measures taken It is intended and has legal and judicial implications
... Show MoreWireless sensor network (WSN) security is an important component for protecting data from an attacker. For improving security, cryptography technologies are divided into two kinds: symmetric and asymmetric. Therefore, the implementation of protocols for generating a secret key takes a long time in comparison to the sensor’s limitations, which decrease network throughput because they are based on an asymmetric method. The asymmetric algorithms are complex and decrease network throughput. In this paper, an encryption symmetric secret key in wireless sensor networks (WSN) is proposed. In this work, 24 experiments are proposed, which are encryption using the AES algorithm in the cases of 1 key, 10 keys, 25 keys, and 50 keys. I
... Show MoreBackground: The gold standard in assessing asthma control is the Global Initiative for Asthma (GINA) criteria. And because of the difficulties of access to pulmonary functions tests, The ACT has the added advantage that it does not require lung function assessment.
Objectives: The aim of this study is to assess asthma control through ACT score and GINA guideline, and to determine if the ACT can be as useful as the GINA-guidelines criteria in assessing asthma control in Iraq. Patient and method: Cross sectional study with comparing ACT vs. GINA guideline in control of asthma level. This study was conducted at Respiratory consultation unit of the Iraqi National center of early detection of Cancer, Baghdad-Ira
The kaizen is considered as one of the most important modern techniques which has been adopted by various economics entities especially manufacturing firms and its beginnings return to the middle of the earlier century that has been used by companies like Toshiba, Matsushita Electric, and Toyota. Which realized that these modern techniques would make a total change in the competitive environment and started qualifying and its staff in such away that enables them to go along with this unique environment. The continuous improvement (Kaizen) depends on the small continuous improvements in the product and the production operations during the production stage. Consequently, the research problem is represented in the improperly of the budg
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