Miracle-dz/UniFAR-FTUs huggingface dataset:
Modeling and Optimization of Next-Generation Wireless Access Networks

THE ultimate goal of the next generation access networks is to provide all network users, whether they are fixed or mobile, indoor or outdoor, with high data rate connectivity, while ensuring a high quality of service. In order to realize this ambitious goal, delay, jitter, error rate and packet loss should be minimized: a goal that can only be achieved through integrating different technologies, including passive optical networks, 4th generation wireless networks, and femtocells, among others. This thesis focuses on medium access control and physical layers of future networks. In this regard, the first part of this thesis discusses techniques to improve the end-to-end quality of service in hybrid optical-wireless networks. In these hybrid networks, users are connected to a wireless base station that relays their data to the core network through an optical connection. Hence, by integrating wireless and optical parts of these networks, a smart scheduler can predict the incoming traffic to the optical network. The prediction data generated herein is then used to propose a traffic-aware dynamic bandwidth assignment algorithm for reducing the end-to-end delay. The second part of this thesis addresses the challenging problem of interference management in a two-tier macrocell/femtocell network. A high quality, high speed connection for indoor users is ensured only if the network has a high signal to noise ratio. A requirement that can be fulfilled with using femtocells in cellular networks. However, since femtocells generate harmful interference to macrocell users in proximity of them, careful analysis and realistic models should be developed to manage the introduced interference. Thus, a realistic model for femtocell interference outside suburban houses is proposed and several performance measures, e.g., signal to interference and noise ratio and outage probability are derived mathematically for further analysis. The quality of service of cellular networks can be degraded by several factors. For example, in industrial environments, simultaneous fading and strong impulsive ii noise significantly deteriorate the error rate performance. In the third part of this thesis, a technique to improve the bit error rate of orthogonal frequency division multiplexing systems in industrial environments is presented. This system is the most widely used technology in next-generation networks, and is very susceptible to impulsive noise, especially in fading channels. Mathematical analysis proves that the proposed method can effectively mitigate the degradation caused by impulsive noise and significantly improve signal to interference and noise ratio and bit error rate, even in frequency-selective fading channels.
A Convergent Parallel Study on Knowledge, Perceptions, and Attitudes of Mainstream Workers during COVID-19

Background: This study explores and assesses the knowledge, perceptions, and attitudes of mainstream workers during the COVID-19 pandemic in the Ha'il Region, Kingdom of Saudi Arabia. Methods: Using convergent parallel mixed-methods design, 502 frontline workers were enlisted via snowball and purposive sampling. Descriptive statistics and thematic analysis were used to analyze the quantitative and qualitative data, respectively. Results: There is a well-prepared response to COVID-19, namely, a commendable knowledge, attitude, and practices (KAP) gap documented in reliable information concerning the virus, specifically, awareness that COVID-19 can be a potentially fatal disease (100%);that droplets from infected people (29.8%) can spread the disease;and taking actions to prevent the spread of COVID-19 in the community can save their lives. Four themes and three subthemes yielded: (1) actual, tangible knowledge with subtheme pieces of information;(2) the extent of danger with subtheme uncertainties;(3) precautionary measures;and (4) a yearning to know more, with the subtheme of novel information. Conclusions: Communication among health authorities and at-risk individuals in response to COVID-19 must be facilitated. This is to support those in the healthcare industry in shaping an intervention strategy that emphasizes both preparation and protection.
Feasibility of Internally Reinforced Thin-Walled Beams for Industrial Applications

In this work, several types of reinforcement geometries of hollow-box beams for industrial applications are compared. A novel type of sandwich beams under bending and torsion uncoupled loadings is proposed as the best solution of all those that were studied. For the comparative analysis of the solutions, the models are modelled by the Finite Element Method (FEM) using the commercial software ANSYS Mechanical APDL. The feasibility of the novel beams was assessed by comparing the stiffness behavior of the beams with simple hollow-box beams in terms of deflection. An efficiency parameter was defined in order to determine the relative difference in terms of deflection. It is found that the novel geometries represent a great improvement under bending loadings, better than under torsion loadings. Nevertheless, for bending and torsion combined loadings, if bending stresses are predominant, the beams can still be interesting for some applications, mainly those with mobile parts.
Characterizing the role of impulsivity in costly, reactive aggression using a novel paradigm

A lack of self-control has long been theorized to predict an individual’s likelihood to engage in antisocial behaviors. However, existing definitions of self-control encompass multiple psychological constructs and lab-based measures of aggression have not allowed for the examination of aggression upon provocation where self-control is needed most. We introduce two versions of a novel paradigm, the Retaliate or Carry-on: Reactive AGgression Experiment (RC-RAGE) to fill this methodological gap. Using large online samples of US adults ( N = 354 and N = 366), we evaluate to what extent dispositional impulsivity, self-control, aggression, and state anger contribute to aggression upon provocation when there is a financial cost involved. Results showed that costly retaliation on this task was related to trait aggression and being in an angry emotional state, but not related to social desirability. Importantly, we show that the tendency to act impulsively is a better predictor of costly retaliation than other forms of self-control, such as the ability to delay gratification, resist temptation, or plan ahead. As a browser-based task, the RC-RAGE provides a tool for the future investigation of reactive aggression in a variety of experimental settings.
Electrical Impedance: Principles, Measurement, and Applications

Basics Two-terminal circuit elements Resistors, capacitors, inductors Phasors Impedance and admittance Power and RMS value Beyond two-terminal networks Impedance and linear response theory Impedance as an electromagnetic quantity The graphical representation of electrical impedance Density quantities Frequency ranges Impedance definitions n-terminal definitions n-terminal-pair definitions Change of definition Cable effects Devices and appliances of interest in impedance measurement Generators Voltage and current measurement Voltage and current ratio devices Cables and connectors Shielding Common practice methods I-V method Two-voltage methods Three-voltage method Bridges Transformer bridges Beyond 2T definition of impedance standards The LCR meter Calibration Resonance methods Mutual inductance measured as self-inductance Network analysis Going digital Sampling Direct digital synthesis Digital signal analysis Digital impedance bridges Sampling impedance meters Some applications of impedance measurement Measurement of electromagnetic properties of materials Sensor reading Semiconductor device characterization Biological measurements Metrology: traceability and uncertainty Traceability Uncertainty Metrology: standards Impedance standards Inductance standards Capacitance standards Synthesized impedance standards Cryogenic standards Standards of phase angle, time constant, etc Open and short standards High-frequency and microwave standards Metrology: realization and reproduction The International System of Units Realization of impedance units Reproduction of the ohm Counting electrons The future of SI Appendices SI Harmonic electromagnetic fields CODATA recommended values Reactance Chart Nomenclature Bibliography Index
Numerical simulation of core-annular flow in curved pipe

A numerical study, using the volume-of-fluid method (VOF), has been made of core-annular flow in a curved pipe. We investigated two cases: core-annular flow in a 90 bend and in a 180 return bend. Special attention was given to the influence of secondary flows perpendicular to the pipe axis. These secondary flows play an important role in the behaviour of core-annular flow in a curved pipe.
The 'yes moments': understanding students' sense of achievement during on-the-job training program

: Addressing the lack of empirical studies on the student’s experiences during the on-the-job training (OJT) program, this study explored situations that triggered student’s sense of achievement. Data were collected using semi-structured interviews from 56 students and were analysed using a qualitative approach. The findings suggest four critical ‘yes moments’ that lead to a sense of achievement: 1) being trusted; 2) the ability to accomplish a task; 3) being given a compliment; 4) the ability to solve a problem. The significance of the study lies in its contribution to the existing body of knowledge in tourism and hospitality education in terms of understanding students learning behavior. Also, the study is substantial for its insightful contributions to potentially improve the employability of students and in the long run, meet the supply and demand of labor in the hotel industry. The interpretations of the findings, implications, and directions for future are discussed.
Design and development of an external cavity diode laser for laser cooling and spectroscopy applications

External cavity diode lasers are used increasingly as sources of light in applications ranging from industrial photonic systems to basic laboratory research on the interaction of light and atoms. External cavity diode lasers offer more stable output frequency and narrow spectral bandwidth than the typical free-running diode lasers. These characteristics are achieved by exploiting the sensitivity of diode lasers to external optical feedback. In this study the design and development of an external cavity diode laser system for future applications in spectroscopy and laser cooling of rubidium atoms is presented. The external cavity diode laser including mechanical components and control electronics of the system is developed from basic components. The system uses frequency selective optical feedback from a diffraction grating in a Littrow configuration to provide collimated, narrow-band, frequency tunable light near 780 nm. The external cavity diode laser is designed to increase the mode-hop-free frequency tuning range, and allow accurate frequency tuning and stabilisation. A low-noise current source and a temperature controller for thermal stability were developed as part of the system since the output frequency changes with temperature and current. The temperature controller is optimised experimentally for the thermal characteristics of the external cavity. An electronic sidelock servo circuit for frequency locking of the external cavity diode laser to an external reference for long term frequency stabilisation is proposed and discussed. The servo circuit electrically controls the grating tilt and the current through the diode laser in order to lock the frequency of the diode laser. The external cavity diode laser is optimised and characterised near 780 nm. Results obtained in this study indicate that the external cavity diode laser is suitable for future applications in spectroscopy and laser cooling of neutral rubidium atoms.
The magnitude, direction, and tempo of forest change in Greater Yellowstone in a warmer world with more fire

Yellowstone world Abstract. As temperatures continue rising, the direction, magnitude, and tempo of change in disturbance-prone forests remain unresolved. Even forests long resilient to stand-replacing fire face uncertain futures, and efforts to project changes in forest structure and composition are sorely needed to anticipate future forest trajectories. We simulated fire (incorporating fuels feedbacks) and forest dynamics on five landscapes spanning the Greater Yellowstone Ecosys- tem (GYE) to ask the following questions: (1) How and where are forest landscapes likely to change with 21st-century warming and fire activity? (2) Are future forest changes gradual or abrupt, and do forest attributes change synchronously or sequentially? (3) Can forest declines be averted by mid-21st-century stabilization of atmospheric greenhouse gas (GHG) concentra- tions? We used the spatially explicit individual-based forest model iLand to track multiple attributes (forest extent, stand age, tree density, basal area, aboveground carbon stocks, domi- nant forest types, species occupancy) through 2100 for six climate scenarios. Hot-dry climate scenarios led to more fire, but stand-replacing fire peaked in mid-century and then declined even as annual area burned continued to rise. Where forest cover persisted, previously dense forests were converted to sparse young woodlands. Increased aridity and fire drove a ratchet of successive abrupt declines (i.e., multiple annual landscape-level changes ≥ 20%) in tree density, basal area, and extent of older ( > 150 yr) forests, whereas declines in carbon stocks and mean stand age were always gradual. Forest changes were asynchronous across landscapes, but decli- nes in stand structure always preceded reductions in forest extent and carbon stocks. Forest decline was most likely in less topographically complex landscapes dominated by fire-sensitive tree species ( Picea engelmannii , Abies lasiocarpa , Pinus contorta var. latifolia ) and where fire resisters ( Pseudotsuga menziesii var. glauca ) were not already prevalent. If current GHG emis- sions continue unabated (RCP 8.5) and aridity increases, a suite of forest changes would transform the GYE, with cascading effects on biodiversity and myriad ecosystem services. However, stabilizing GHG concentrations by mid-century (RCP 4.5) would slow the ratchet, moderating fire activity and dampening the magnitude and rate of forest change. Monitoring changes in forest structure may serve as an operational early warning indicator of impending forest decline.
Experimental Idler Design and Development of Hull Concepts for Noise Reduction in Tracked Vehicles

Abstract : The first phase of this study rank ordered the major noise sources of the M113A1 Armored Personnel Carrier and developed a preliminary mathematical model of the track and suspension system. Vibration-to-noise transfer functions were experimentally derived for inclusion in the model. The present study was designed to capitalize upon those achievements by designing a high compliance idler, and by refining the computer model so that additional precision could be gained and a greater number of parameters varied. A power flow analysis of the hull was conducted along with structural modifications and damping treatment of a number of promising areas. Computer runs were made to verify the model and to study the effect upon interior noise of several theoretical changes to the suspension system. Test of the experimental compliant idler indicate that heat buildup and durability will not present problems. A cursory examination of its noise level indicated that this idler may provide significant noise reduction. analysis of the acoustic and vibratory power flow was consistent, in that computed power radiated into the crew area agreed well with computed acoustic dissipation. However, due to the limited extent of the hull changes accomplished, the structural modifications provided no noise reduction and the damping treatment provided only slight noise reduction.
Posttreatment aeration to reduce THMs

Posttreatment aeration inside water tanks or in chlorine contact basins to strip trihalomethanes (THMs) after formation is an underused and cost‐effective treatment option to reduce disinfection by‐products. In this study, diffused aeration achieved removal rates of 9 to > 99.5%, depending on air‐to‐water ratio, water temperature, and THM species. Spray aeration–a more efficient process–achieved THM reductions of 20 to > 99.5%, depending on droplet diameter, droplet travel distance, water temperature, and THM species. Droplet diameter is an important design variable and is controlled by operating pressure and nozzle characteristics. Droplet travel distance, however, exerted a greater influence on THM removals. The average droplet diameter and travel distance variables can be developed into a unit air‐to‐water volumetric ratio that can be used to reasonably predict total THM removals. Free chlorine does not appear to be reduced by aeration because only a small fraction of it will be amenable to removal in a closedsystem environment.
A vulnerability and resilience framework for small states

This chapter presents a revised vulnerability/resilience framework, building on the work of Briguglio et al. (2009). 1 The chapter also revises and updates the economic vulnerability and economic resilience indices, the former associated with exposure to external shocks and the latter with policies that can enable a country to minimise or withstand the negative effects of such shocks. A number of policy implications are derived from the study presented in this chapter.
The Indelible Challenges of Student Retention in Higher Education: Imperatives for a Closer Scrutiny

Student attrition remains a serious challenge for universities across the globe despite the extended attention it continues to attract. Given the meagre research available in the Global South and particularly in Africa, this study was conducted to assess the status of student attrition in 15 Ethiopian public universities. The study examined the scope, nature and causes of student attrition at the level of institutions, programs and gender wise. The findings revealed that the attrition rate at Ethiopian public universities manifests a high level of waste that goes against the national ambition of expanding higher education through wider participation and student success. Universities were also found deficient in terms of tracking the progress of their students, hampering their potential for follow up and early interventions. It is argued that closer scrutiny and robust responses are needed both at policy and institutional levels in order to bring about the improvements sought.
Heterogeneous Sediment Input at the Nankai Trough Subduction Zone: Implications for Shallow Slow Earthquake Localization

Subducted sediment plays a key role in modulating pore pressure and seismic behavior at subduction zones. We investigated the seismic character of incoming sediments to test how sediment and basement variations relate to the along‐strike changes within the accretionary prism and plate boundary conditions at the Nankai Trough. High‐resolution seismic data reveal for the first time the presence of countourite mounded drifts in the Shikoku Basin. These features have probably introduced permeability heterogeneities into an otherwise homogenous mud‐dominant unit. Additionally, we found that normal faults in this unit are more extensive than previously documented, which probably enhances along‐strike fluid transport. The wedge taper is more correlative with the thickness of the mud‐dominant facies than the turbidite thickness. This may be due to the permeability heterogeneities associated with contourite deposits and normal faults, or due to the absence of thick turbidite deposits. Turbidite deposits can either aid the drainage of the margin where they are not confined by basement topography, or contribute to high pore fluid pressures where they are confined by less permeable mudstone or basement topography. When confined turbidite deposits and contourite mounded drifts are subducted, they may contribute to localized compartments of excess pore pressure which provide the necessary conditions for slow slip behavior. We determined that along‐strike variations in seismic behavior are likely related to the subducting basement topographic and sediment characteristics, which vary on a local (<10 km) scale.
Advanced Technologies in Manufacturing, Engineering and Materials

This is a collection of selected, peer reviewed papers from the 2013 International Forum on Mechanical and Material Engineering (IFMME 2013), June 13-14, Guangzhou, China. The 406 papers are grouped as follows: Chapter 1: Dynamic Systems, Vibration and Noise, Applied Mechanics; Chapter 2: Design and Modelling in Manufacture, Dynamic Simulation, Machinery and Equipments; Chapter 3: Fluid, Flow Engineering and Control Technology, Aerodynamics, Wind and Heat Engineering; Chapter 4: Vehicle Engineering; Chapter 5: Material Science and Technology; Chapter 6: Material Processing Technology, Forming, Welding and Joint Technologies, Surface and Coating Engineering; Chapter 7: Material Design and Experiment Researches Analysis, Testing and Evaluation; Chapter 8: Advanced Manufacturing Technology and Mechatronics; and, Chapter 9: Control Technology and Automation Systems. It also includes: Chapter 10: Sensors, Measurement, Detection and Intelligent Information and Data Processing, Fault Diagnosis; Chapter 11: Communication and Signal Engineering; Chapter 12: Computer and Information Technologies Applications in Industry and Engineering, Electric and Power Engineering Applications; Chapter 13: The Internet of Things Technologies; and, Chapter 14: Industrial, Management and Education Engineering.
Review Paper (SE—Structures and Environment): Radiometric and Thermal Properties of, and Testing Methods for, Greenhouse Covering Materials

Abstract In this paper, the most critical physical properties for the greenhouse covering materials are reviewed. The physical properties considered include the radiometric properties (transmissivity, reflectivity and absorptivity) over several radiation bands and also the K -value (the overall heat transfer coefficient). Only a few standard methods for testing these physical properties of covering materials for greenhouses exist. Usually, some of the testing methods used for plastics in general, are also applied to greenhouse covers despite important functional differences. These testing methods are reviewed with regard to their suitability for application to greenhouse covering materials. Also, reported values of the most important physical properties of greenhouse covering materials are presented and reviewed. The values presented are found to vary considerably among the materials considered. These variations are attributed mainly to the testing method employed and also to the type of the material. Existing testing methods are used arbitrarily and technical information is presented in a rather confusing way. Modification of existing testing methods is required because, in most cases, they are insufficient for greenhouse covering materials. Also new testing methods should be elaborated, and specially designed for greenhouse covering materials.