Ultra-Dense Networks in 5G and Beyond: Challenges and Promising Solutions

Ultra-Dense Network (UDN) is one of the promising and leading directions in Fifth Generation and beyond (5GB) networks. In UDNs, Small Cells (SCs) or Small Base Stations (SBSs) such as microcells, picocells, or femtocells are deployed in high densities where inter-site distances are within the range of few or tens of meters. UDNs also require that SCs are typically deployed in relatively large densities compared to the Human-Type Communication Users (HTCUs) such as smartphones, tablets, and/or laptops. Such SCs are characterized by their low transmission powers, small coverage areas, and low cost. Hence, the deployment of the SCs can be done either by the cellular network operators or by the customers themselves within their premises to maintain certain levels of Quality of Service (QoS). However, the randomness of the deployment of the SCs along with the small inter-site distances may degrade the achievable performance due to the uncontrolled Inter-Cell Interference (ICI). Therefore, idle mode capability is an inevitable feature in the high-density regime of SCs. In idle mode, a SC is switched off to prevent ICI when no user is associated to it. In doing so, we can imagine the UDN as a mobile network that keeps following the users to remain as close as possible to them. In 5G, different use cases are required to be supported such as enhanced Mobile Broad-Band (eMBB), Ultra-Reliable and Low-Latency Communication (URLLC), and massive Machine-Type Communication (mMTC). On one hand, the inevitable upcoming era of smart living requires unprecedented advances in enabling technologies to support the main building blocks of this era which are Internet of Things (IoT) devices. Machine-Type Communication (MTC), the cellular version of Machine-to-Machine (M2M) communication, constitutes the main enabling technology to support communications among such devices with minimal or even without human intervention. The massive number of these devices, Machine-Type Communication Devices (MTCDs), and the immense amount of traffic generated by them require a paramount shift in cellular and non-cellular wireless technologies to achieve the required connectivity. On the other hand, the sky-rocketing number of data hungry applications installed on human-held devices, or HTCUs, such as video conferencing and virtual reality applications require their own advances in the wireless infrastructure in terms of high capacity, enhanced reliability, and reduced latency. Throughout this thesis, we exploit the UDN infrastructure integrated with other 5G resources and enabling technologies to explore the possible opportunities in supporting both HTC and MTC, either solely or simultaneously. Given the shorter distances between transmitters and receivers encountered in UDNs, more realistic models of the path loss must be adopted such as the Stretched Exponential Path Loss (SEPL) model. We use tools from stochastic geometry to formulate novel mathematical frameworks that can be used to investigate the achievable performance without having to rely on extensive time-consuming Monte-Carlo simulations. Besides, the derived analytical expressions can be used to tune some system parameters or to propose some approaches/techniques that can be followed to optimize the performance of the system under certain circumstances. Tackling practical scenarios, the complexity, or sometimes in-feasibility, of providing unlimited backhaul capacity for the massive number of SCs must be considered. In this regard, we adopt multiple-association where each HTCU is allowed to associate with multiple SCs. By doing so, we carefully split the targeted traffic among several backhaul links to mitigate the bottleneck forced by limited backhaul capacities. It is noteworthy that for coexisting MTCDs with the HTCUs, activating more SCs would allow more MTCDs to be supported without introducing additional ICI towards the HTCUs. Targeting different application, multiple-association can be also adopted to tackle computation-intensive applications of HTCUs. In particular, for applications such as augmented reality and environment recognition that require heavy computations, a task is split and partially offloaded to multiple SCs with integrated Edge Computing Servers (ECSs). Then, the task partitions are processed in parallel to reduce the end-to-end processing delay. Based on relative densities between HTCUs and SCs, we use tools from stochastic geometry to develop an offline adaptive task division technique that further reduces the average end-to-end processing delay per user. With the frequent serious data breaches experienced in recent years, securing data has become more of a business risk rather than an information technology (IT) issue. Hence, we exploit the dense number of SCs found in UDN along with Physical Layer Security (PLS) protocols to secure data transfer. In particular, we again adopt multiple-association and split the data of HTCUs into multiple streams originating from different SCs to prevent illegitimate receivers from eavesdropping. To support massive number of MTCDs, we deploy the Non-Orthogonal Multiple-Access (NOMA) technique. Using power NOMA, more than one device can be supported over the same frequency/time resource and their signals are distinguished at the receiver using Successive Interference Cancellation (SIC). In the same scope, exploiting the available resources in 5G and beyond networks, we investigate a mMTC scenario in an UDN operating in the Millimeter Wave (mmWave) band and supported by wireless backhauling. In doing so, we shed lights on the possible gains of utilizing the mmWave band where the severe penetration losses of mmWave can be exploited to mitigate the significant ICI in UDNs. Also, the vast bandwidth available in the mmWave band helps to allocate more Resource Blocks (RBs) per SCs which corresponds to supporting more MTCDs

An Interpretive Analysis of how Audit Quality is Perceived in Economies in Transition

With the movement of many internationalaccounting firms into Egypt, and the growth of local auditfirms, it is particularly interesting, and relevant forgovernmental legislators, to study how the providers of theaudit service perceive the quality of what they do. In thissense, the purpose of this paper is to report the perceptions ofprofessional auditors in Egypt concerning how they perceivethe quality of the service they provide. The paper also analyzesdifferences between perceptions of the Big 4 audit firms andother local audit firms. Based on 28 semi-structuredinterviews, it was revealed that the interviewees generallybelieved that the audit quality is preserved high in thepresence of four factors: (1) high ethical standards to guideand regulate the profession; (2) a well planned and conductedaudit; (3) a more knowledgeable audit team; and (4) having agood relationship with the client management

The Usefulness of Different Accounting Earnings Measures: The Case of Egypt

The objective of this paper is to investigate whichmeasure of accounting income (comprehensive income,operating income, or net income) is more useful to equityinvestors in explaining future earnings, future cash flows, andstock returns. This study proposes that different measures ofincome are more useful for different uses. The research isundertaken within the Egyptian environment that allowsconsiderable asset revaluations and holds the reporting ofextraordinary items. Therefore, such environment provides arich ground for testing the expected effects of reportingcomprehensive income and its components on the Egyptianinvestors. The results do not support the superiority ofcomprehensive income measures in explaining the followingperiod’s net income compared to net income. None of the fourtested measures of earnings is able to explain the followingperiod’s cash flows. Operating income is superior to the otherthree measures of income in explaining stock return

Macro and Micro Earnings Manipulation: The Role of Accounting Standard Setting Process

Preparers of financial statements are in aposition to influence the view of economic reality presented inthose statements to interested parties. The term 'macromanipulation'is used to describe the lobbying of preparersagainst regulators (accounting standards setters) to persuadethem to produce regulation that is more favorable to theinterests of preparers. The aime of this paper is to introduce asuggested tool that could be used to ascertain why somefinancial accounting standards turn out to the benefit of one ofthe stakeholders involved in the process of accountingstandards setting. This paper utilizes the construct of power toreveal the influences from parties involved in the process ofaccounting standards setting. The comprehensive incomereporting standard is used in this paper as an example of thesetypes of standard that may involve 'macro-manipulation'

Distribution and temporal behaviour of O3 and NO2 near selected schools in Seberang Perai, Pulau Pinang and Parit Buntar, Perak, Malaysia

Air quality has deteriorated in urban areas as a result of increased anthropogenic activities. Quantitative information on the influence of meteorological conditions on several pollutants in a tropical climate is still lacking. Real-time ozone (O3) and nitrogen dioxide (NO2) levels were measured nearby selected schools in Malaysia to examine the impact of meteorological factors on monitoring pollutants. The results showed the overall 10 min average concentrations of the main parameters during school holiday were 24 ppb (O3) and 33 ppb (NO2) while during school day the overall 10 min average concentrations were 26 ppb (O3) and 51 ppb (NO2). Although there are no minimum requirements for short-term exposure by MAAQG, if compared to 1 h average requirements, all concentrations were still below the suggested values. Regarding spatial distribution, a different trend in pollutant concentration among the schools was observed because of the influence of temperature (AT) and wind speed (WS). The results were verified by Pearson correlation, where signifi cant correlations (p<0.01) were determined between air pollutants and meteorological factors, which were temperature, wind speed and relative humidity. Meanwhile, the distribution of O3 was moderately correlated with NO2. However, the results of multivariate analysis indicate that temperature and relative humidity had the most significant influence on the formation of O3. In summary, the results of this study showed that all precursors and meteorological parameters contribute to the production of O3. Hence, reducing O3 precursors, which are emitted by vehicles, is essential to lessening the exposure to O3

Characterization of Chemical Composition in Fine Particles (PM2.5) from Industrial Site in Malaysia

This research aims to investigate variations of fine Particulate Matter (PM2.5) and chemical composition in an industrialized area. Concentration levels of fine Particulate Matter (PM2.5) were continuously monitored at three sampling site S1, S2 and S3. The variations of PM2.5 concentration were analysed using descriptive statistics, time series plot, diurnal plot and correlation. Source apportionment and factor analysis were carried out using the chemical composition data from ICP-OES. Meteorological effects on PM2.5 concentration were used to investigate the effects on PM2.5 concentration. The results showed that, the average PM2.5 concentration was 19.75 ± 12, 46.68 ± 27, and 20.55 ± 9 ?g m-3 at sites in a S1, S2 and S3, respectively. The highest PM2.5 concentration was recorded in S2 (115 ?g m-3). The PM2.5 concentration in the diurnal plot exhibited an inversed unimodal pattern during morning (7:00 to 9:00) and evening (16:00 to 18:00). PM2.5 concentration in S2 on weekends was 36% lower than that on weekdays. PM2.5 was found to exhibit an inversed relation with wind speed and temperature. Although wind speed had a negative association with PM2.5 in S1 and S2, a positive correlation was observed at S3. Source apportionment from factor analysis distinguished three groups of possible sources; crustal materials (Al, K, Sr, Ti and Na), vehicles emission (Cr, Fe, Mn, Zn and Ni) and industrial activities (Ca, Mg and Pb)

Knowledge, Attitudes, and Practice towards Occupational Health and Safety among Nursing Students in Gaza Strip, Palestine

Health and safety in the workplace are critical components in healthcare institutions. Unsafe working conditions are among the causes of poor&nbsp; quality of care and burnout. This study aims to assess the knowledge, attitudes, and practice of occupational health and safety among nursing&nbsp; students at Al-Israa University. Methods: In this cross-sectional study, a structured online questionnaire was distributed from March to May 2021. Of the 350 eligible students, 219&nbsp; students answered the questionnaire (Response rate=62.6). Data were analyzed using the statistical software IBM-SPSS version 22. Descriptive&nbsp; statistic, Independent- samples T-Test, and ANOVA tests were used. Results: The majority of participants were female (81.7%) and studying in a diploma program. 21% of nursing students have experienced a needle&nbsp; stick injury. The mean scores for knowledge, attitudes, and practice were (M±SD:78.2% ±12.9, M±SD:80.6% ±7.1, and M±SD:81.2% ±7.6) respectively.&nbsp; In terms of knowledge, attitudes, and practice the mean scores were statistically significant between nursing students who attended a safety&nbsp; precautions course and those who didn not (P-value &lt;.05). In terms of attitudes, the mean scores were statistically significant between diploma and&nbsp; bachelor students (P-value =.026).In terms of practice, the means scores were statistically significant between males and females (P-value =.017),&nbsp; nursing students who had experience with needle sticks and those who didn’t (P-value =.015). Conclusion: The authors recommend that clinical&nbsp; training departments and universities continue to offer occupational health and safety courses and training for health science students. Since the&nbsp; training had a positive impact on the students' practices.&nbsp

The effect of seasonal variation on indoor and outdoor carbon monoxide concentrations in Eastern Mediterranean climate

AbstractMonitoring of carbon monoxide (CO) concentration in school microenvironments is extremely important due to its impact on children’s health. CO concentration levels were monitored inside and outside 36 natural ventilated classrooms of 12 schools located in Gaza Strip, Palestine. Measurements were carried out by using electrochemical analyzer during fall, winter, and spring from October 2011 to May 2012. The average concentration of indoor and outdoor CO was 0.79±0.75 and 0.96±0.91ppm, respectively. The reported concentration levels showed that the indoor CO concentration was lower than the outdoor CO concentration. The mean daily indoor–outdoor ratio ranged between 0.30 and 1.90 in the three seasons. The measured indoor and outdoor CO concentrations showed seasonal variation. During winter, the mean indoor CO was 3.0 and 1.50 times higher than that during fall and spring, respectively. Meanwhile, the outdoor CO concentration in winter was 2.80 and 1.4 times higher than in fall and spring, respectively. Although these levels were below World Health Organization guidelines, these concentrations pose a risk to students’ health and affect their academic performance